Circuit board copper chloride etching waste liquid precipitation treatment and recycling method and device thereof

Abstract

The invention discloses a circuit board copper chloride etching waste liquid precipitation treatment and recycling method and a device thereof, and the method comprises the following steps: mixing circuit board copper chloride etching waste liquid with a pH value regulator to react, so that copper salt precipitation is precipitated in the solution; at least one of the circuit board copper chloride etching waste liquid and the pH value regulator contains the circuit board copper chloride etching waste liquid containing ammonium and / or ammonia; then, carrying out solid-liquid separation on a solid-liquid mixture obtained after the reaction in the previous step to obtain filtrate A and filter residues C; then, the filter residues C are subjected to deamination treatment, and a recycled copper product is generated; and finally, directly using all or part of the filtrate A or using the filtrate A as an etching regeneration sub-solution and / or an etching oxidant solution after blending to be reused in a circuit board copper chloride etching system. The equipment investment cost is low, the maintenance cost is low, the environmental pollution in the treatment process is little, and the liquid medicine obtained after copper is taken can be recycled to improve the production income.

Description

Method and device for precipitation treatment and reuse of circuit board copper chloride etching waste liquid Technical Field

[0001] The invention belongs to the technical field of recycling and reusing circuit board etching waste liquid, and particularly relates to a precipitation treatment and reusing method for circuit board copper chloride etching waste liquid and a device thereof. Background Art

[0002] Etching is a crucial step in the current printed circuit board (PCB) production process. Commonly used etching solutions include acidic copper chloride and alkaline ammonia copper chloride. This process is collectively referred to in the industry as copper chloride etching, distinguishing it from other etching processes, such as sulfuric acid / hydrogen peroxide etching, organic acid etching, persulfate etching, and chromic acid / sulfuric acid etching.

[0003] The main components of the acidic copper chloride etching solution are hydrochloric acid and copper chloride. Some process formulas also contain ammonium chloride and / or sodium chloride and / or ferric chloride.

[0004] The main components of the alkaline cupric chloride ammonia etching solution are copper salt of cupric chloride ammonia complex, ammonium chloride, and ammonia water, wherein ammonium bicarbonate and / or ammonium carbonate and / or organic acid amine can be selected as additives.

[0005] In actual etching production, the proportions of various components in the etching solution constantly change as the etching solution in the etching tank reacts with the copper metal. To ensure stable etching performance, new etching solution must be added to the etching solution in the etching line. This new etching solution is called etching solution in the industry, while the solution that overflows from the etching line is called etching waste liquid.

[0006] Currently, the methods for recycling alkaline copper chloride ammonia etching waste liquid in the industry include acidification, extraction and electrolysis.

[0007] (1) The acidification method is to directly add sulfuric acid to the alkaline copper chloride ammonium etching waste liquid to produce copper sulfate, and then use electrolysis to recover metallic copper through electrochemical reduction. However, the remaining salt solution cannot be recycled and reused in the etching process because it contains a large amount of ammonium sulfate that does not exist in the alkaline copper chloride ammonium etching.

[0008] (2) The extraction method uses a strong organic chelating agent to extract copper ions from the etching waste liquid. The remaining liquid is used to prepare a regenerated etching liquid. Then, sulfuric acid is used to extract the organic extractant that chelates the copper ions to obtain copper sulfate, which is then recovered by electrolysis to obtain copper metal. Although the extraction process has a high recycling rate of production raw materials, a large amount of free ammonia is generated during the recovery process due to the destruction of the copper-ammonia complex. The vigorous stirring required for the extraction process causes ammonia to easily escape. In addition, the chelating agent remains in the remaining liquid of the etching waste liquid after extraction, which will cause the regenerated etching liquid to contain organic impurities of the chelating agent, affecting the efficiency and quality of etching production.

[0009] (3) The electrolysis method is to directly use alkaline copper chloride ammonia etching waste liquid as the electrolyte for electrolysis to extract copper. During the electrolysis process, the copper ammonia complex is destroyed and free ammonia is released. The heat generated during the electrolysis process greatly reduces the solubility of ammonia, resulting in a large amount of ammonia volatilization. In addition, since the electrolyte contains a large amount of ammonium ions and chloride ions at the same time, there is a possibility of producing explosive and dangerous nitrogen trichloride during the electrolysis process. In addition, chlorine is produced during the electrolysis process, which reacts with the ammonia in the electrolyte to convert into nitrogen, resulting in a waste of ammonia, resulting in poor economic benefits of this copper recovery method.

[0010] There are two methods for recycling and treating acidic copper chloride etching waste liquid: alkalization method and electrolysis method.

[0011] (1) The alkalization method is to use one or more of sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, and sodium bicarbonate for a neutralization reaction to generate copper hydroxide and / or copper carbonate precipitates and then perform solid-liquid separation to recover the copper element. However, for acidic etching solutions containing ammonium chloride, or when ammonium hydroxide is used in the alkalization recovery treatment of acidic copper chloride etching waste liquid, the resulting copper-containing precipitate contains ammonium salt impurities and is difficult to remove using existing environmental protection treatment processes and technologies, affecting the subsequent recovery and utilization of the copper compound product.

[0012] (2) When using the electrolytic method, each etching production line requires several large electrolytic equipment worth millions of yuan. Electrolytic equipment is expensive because it is equipped with multiple metal electrodes and diaphragms. In addition, it consumes a lot of electricity to convert copper ions into metallic copper during use, resulting in large investment in electrolytic equipment, high energy consumption, and heavy maintenance costs.

[0013] Therefore, the existing recycling and treatment processes for acidic and alkaline copper chloride etching waste liquids for circuit boards have many imperfect process problems. Therefore, the industry is looking forward to the introduction of a new recycling process that is safer and simpler, requires less equipment investment, has a higher reuse rate, and can even achieve 100% recycling.

[0014] Summary of the Invention

[0015] A first object of the present invention is to provide a method for precipitating and treating waste copper chloride etching liquid containing ammonium and / or ammonia for recycling circuit boards, which has low equipment investment cost, low maintenance cost, less environmental pollution during the treatment process, and the liquid after copper extraction can be recycled to improve production benefits.

[0016] The second object of the present invention is to provide a device for the above-mentioned circuit board copper chloride etching waste liquid precipitation treatment and reuse method.

[0017] The first object of the present invention is achieved through the following technical measures:

[0018] A method for precipitating and recycling circuit board copper chloride etching waste liquid containing ammonium and / or ammonia, wherein the process steps are as follows:

[0019] (1) mixing a circuit board copper chloride etching waste liquid with a pH adjuster to react, so that copper salt precipitates in the solution, and at least one of the circuit board copper chloride etching waste liquid and the pH adjuster comprises the circuit board copper chloride etching waste liquid containing ammonium and / or ammonia;

[0020] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain a filtrate A and a filter residue C;

[0021] (3) deammoniating the filter residue C to generate a recovered copper product;

[0022] (4) Reusing all or part of the filtrate A directly or after being prepared as an etching regeneration sub-liquid and / or etching oxidant solution in the circuit board copper chloride etching system.

[0023] The working principle of the present invention is to neutralize the etching waste liquid containing ammonium and / or ammonia to obtain a copper compound precipitate or a mixture of the copper compound and an iron compound - a filter residue (the specific reaction formula is detailed below). The filter residue is then treated to remove ammonia and nitrogen to recover the copper product and the filtrate is directly or re-prepared into an etching sub-liquid and / or an etching oxidant solution.

[0024] Wherein, at least one of the circuit board copper chloride etching waste liquid and the pH adjuster described in step (1) of the present invention contains ammonium and / or ammonia. The circuit board copper chloride etching waste liquid is circuit board acidic copper chloride etching waste liquid and / or circuit board alkaline copper chloride ammonia etching waste liquid, which can be a single circuit board copper chloride etching waste liquid or a mixture of more than one circuit board copper chloride etching waste liquid.

[0025] The filtrate A described in step (3) of the present invention can be reused in whole or in part as an acidic etching regeneration sub-liquid and / or an acidic etching oxidant solution directly or after being prepared in the circuit board acidic copper chloride etching system; or it can be reused in whole or in part as an alkaline etching regeneration sub-liquid directly or after being prepared in the circuit board alkaline copper chloride ammonia etching system.

[0026] The main component of the recovered copper product described in step (3) of the present invention is at least one of copper hydroxide, copper carbonate, basic copper carbonate, copper oxide, and percuprate.

[0027] The pH adjuster in step (1) of the present invention includes two types: acidic pH adjuster and alkaline pH adjuster. The acidic pH adjuster is at least one selected from acidic copper chloride etching waste liquid of circuit boards, hydrochloric acid, organic acid, and carbon dioxide. The alkaline pH adjuster is at least one selected from alkaline copper chloride ammonia etching waste liquid of circuit boards, sodium hydroxide, potassium hydroxide, ammonia and / or ammonium hydroxide, sodium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate, and ammonium bicarbonate.

[0028] Preferably, the organic acid in the acidic pH adjuster is formic acid. When the acidic pH adjuster contains formic acid, the resulting filtrate A also contains formate. The acidic regeneration etching liquid prepared using filtrate A contains formic acid. When reused in acid etching production, the oxidant added during the acid etching process can promptly oxidize and consume the reducing formic acid, without negatively impacting the acid etching process. Furthermore, the alkaline regeneration etching liquid prepared using filtrate A contains ammonium formate. When reused in alkaline etching production, the ammonium formate also has no negative impact on the chemical reaction of the alkaline etching.

[0029] Preferably, when the acidic pH adjuster includes carbon dioxide, the carbon dioxide is first used to adjust the pH of the alkaline circuit board copper chloride etching waste liquid downward until copper salt precipitates and the resulting pH is greater than 7. The pH is then further adjusted downward using an acidic pH adjuster selected from the group consisting of the acidic circuit board copper chloride etching waste liquid, hydrochloric acid, and an organic acid. More preferably, when the pH is further adjusted downward using the acidic pH adjuster selected from the group consisting of the acidic circuit board copper chloride etching waste liquid, hydrochloric acid, and an organic acid, the resulting pH is no less than 7, so as to maximize the formation of copper salt precipitation and avoid the wasteful release of large amounts of carbon dioxide.

[0030] Preferably, the alkaline pH adjuster is at least one of circuit board alkaline copper chloride ammonia etching waste liquid, ammonia water, ammonium carbonate, and ammonium bicarbonate. Because when the alkaline pH adjuster contains at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate, the resulting filtrate A will contain excessive potassium ions and / or sodium ions, most of which need to be discharged and cannot be reused in etching production. Therefore, the preferred embodiment of the alkaline pH adjuster can reduce the use of inorganic base raw materials containing potassium or sodium as alkaline pH adjusters, overcome the problem of difficulty in achieving environmentally friendly recycling, and thus improve the recycling rate.

[0031] More preferably, the alkaline pH adjuster is solid ammonium carbonate, so as to minimize the volume increase of the reaction solution during the pH adjustment process. The ammonium ions added to the reaction solution due to the addition of solid ammonium carbonate can be removed in step (3), and the components in the solution can be easily balanced when the solution is subsequently prepared into an etching regeneration sub-solvent for reuse.

[0032] Whether the circuit board copper chloride etching waste liquid described in step (1) is a mixture of circuit board acidic copper chloride etching waste liquid and circuit board alkaline copper chloride ammonia etching waste liquid, or circuit board acidic copper chloride etching waste liquid and / or circuit board alkaline copper chloride ammonia etching waste liquid are used as pH adjusters, the following reactions will occur during the mixing process: CuCl2+4NH4OH→Cu(NH3)4Cl2↓+4H2O; 2CuCl2+3NH4OH→Cu2(OH)3Cl↓+3NH4Cl; CuCl2+2NH4OH→Cu(OH)2↓+2NH4Cl; 4Cu(NH3)2Cl+6H + +4H2O+O2→2Cu2(OH)3Cl↓+2NH4Cl+6NH4 + ; 2Cu(NH3)4Cl2+5H + +3H2O→Cu2(OH)3Cl↓+3NH4Cl+5NH4 + ; FeCl3+3NH4OH→Fe(OH)3↓+3NH4Cl (when the acidic copper chloride etching waste liquid of the circuit board contains iron ions); FeCl2+2NH4OH→Fe(OH)2↓+2NH4Cl (when the acidic copper chloride etching waste liquid of the circuit board contains iron ions).

[0033] When the copper chloride etching waste liquid of the circuit board described in step (1) is alkaline and is neutralized with the acidic pH adjuster, the chemical reaction that occurs is as follows. The hydrogen ions in the following reaction equation come from the acidic pH adjuster. 4Cu(NH3)2Cl+6H + +4H2O+O2→2Cu2(OH)3Cl↓+2NH4Cl+6NH4 + ; 2Cu(NH3)4Cl2+5H + +3H2O→Cu2(OH)3Cl↓+3NH4Cl+5NH4 + .

[0034] When the copper chloride etching waste liquid of the circuit board described in step (1) is acidic and undergoes a neutralization reaction with the sodium hydroxide and / or potassium hydroxide and / or ammonia and / or ammonium hydroxide in the alkaline pH adjuster, the chemical reaction that occurs is as follows. + +0H - →H2O;CuCl2+20H -→Cu(OH)2↓+2Cl - ; 2CuCl2+3OH - →Cu2(OH)3Cl+3Cl - ; FeCl3+30H - →Fe(OH)3↓+3Cl - (When the copper chloride etching waste liquid of the circuit board contains iron ions); FeCl2+20H - →Fe(OH)2↓+2Cl - (When the copper chloride etching waste liquid of the circuit board contains iron ions); CuCl2+4NH4OH→Cu(NH3)4Cl2↓+4H2O (When the pH adjuster contains ammonia and / or ammonium hydroxide).

[0035] When the circuit board copper chloride etching waste liquid described in step (1) is acidic and undergoes a neutralization reaction with the carbonate and / or bicarbonate in the alkaline pH adjuster, the chemical reaction that occurs is as follows.

[0036] (i) Carbonate 2H + +CO3 2- →H2O+CO2↑; CuCl2+2CO3 2- +2H + →Cu(OH)2↓+2Cl - +2CO2↑; FeCl3+3CO3 2- +3H + →Fe(OH)3↓+3Cl - +3CO2↑(when the copper chloride etching waste liquid of the circuit board contains iron ions); FeCl2+2CO3 2- +2H + →Fe(OH)2↓+2Cl - +2CO2↑(when the copper chloride etching waste liquid of the circuit board contains iron ions). (ii) Bicarbonate H + +HCO3 - →H2O+CO2↑; CuCl2+2HCO3 - →Cu(OH)2↓+2Cl - +2CO2↑; FeCl3+3HCO3 - →Fe(OH)3↓+3Cl - +3CO2↑(when the copper chloride etching waste liquid of the circuit board contains iron ions); FeCl2+2HCO3 - →Fe(OH)2↓+2Cl - +2CO2↑(when the copper chloride etching waste liquid of the circuit board contains iron ions).

[0037] When the copper chloride etching waste liquid of the circuit board described in step (1) is acidic and is mixed with the alkaline pH adjuster to neutral or alkaline, the carbonate and / or bicarbonate in the alkaline pH adjuster is continuously added to the solution to produce copper carbonate and / or basic copper carbonate precipitate. 2- →CuCO3↓+2Cl - ; CuCl2+2HCO3 - →CuCO3↓+2Cl - +H2O+CO2↑; 2CuCl2+4HCO3 - →Cu2(OH)2CO3+H2O+4Cl - +3CO2↑.

[0038] Since at least one of the circuit board copper chloride etching waste liquid and the pH adjuster contains ammonium and / or ammonia, the filtrate A obtained in step (2) mainly contains ammonium salts and chloride salts, and may also contain inorganic acids or ammonium hydroxide, other components originally in the circuit board copper chloride etching waste liquid, and copper ammonia complexes and / or soluble copper salts. The main components of the filter residue C obtained in step (2) include at least one of copper ammonia chloride, basic copper chloride, copper hydroxide, copper carbonate, and basic copper carbonate, and are also mixed with ammonium salts and / or ammonium hydroxide and / or copper ammonia complexes. When the circuit board copper chloride etching waste liquid and / or the pH adjuster contain circuit board acidic copper chloride etching waste liquid with iron ions, the filtrate A may also contain iron salts, and the filter residue C may also contain iron hydroxides and / or iron salts. The inventors have found that although new ammonium salts and / or chloride salts are generated in step (1), a considerable portion of the soluble salts in the solution are wrapped and carried away by the solid precipitate during the solid-liquid separation in step (2). Therefore, the chloride salts and ammonium salts in the filtrate A do not need to be discarded in large quantities due to excessive amounts.

[0039] The deamination treatment in step (3) is performed by at least one of the following methods: (i) mixing the filter residue C with a deamination oxidizing agent to perform a deamination oxidation reaction treatment; (ii) directly heating and oxidizing the filter residue C to remove ammonia.

[0040] (i) Deamination and oxidation reaction treatment

[0041] The deamination oxidant is hypochlorite and / or chlorine gas, and the oxidizing properties of hypochlorite and / or chlorine gas are utilized to remove the ammonium salt and / or ammonia in the filter residue C, with nitrogen being generated during the reaction. The hypochlorite is specifically potassium hypochlorite and / or sodium hypochlorite.

[0042] The mixture after the deamination and oxidation reaction is subjected to solid-liquid separation to obtain filtrate B and filter residue D. Filtrate B contains chloride salts and / or hypochlorites and / or inorganic bases, and the main components of filter residue D are copper hydroxide and / or copper carbonate and / or copper oxide and / or percuprate. When filter residue C contains iron hydroxides and / or iron salts, the iron-containing components therein will also be present in filter residue D in the form of iron hydroxides and / or iron oxides, and / or in filtrate B in the form of iron salts and / or percuprates. The types and proportions of the various components in the resulting filter residue D can be controlled by the pH value of the reaction solution during the chemical reaction, the operating temperature, the redox potential parameter value, the reaction time, and the ammonia and / or ammonium concentration in the reaction solution at the end of the reaction. If the resulting filtrate B contains excess deamination and oxidation agents, hypochlorite and inorganic base, it can be used for oxidation treatment in other processes.

[0043] During the deamination oxidation process, at least one of the following chemical reactions occurs:

[0044] (1) When the deamination oxidant contains hypochlorite, Cu(NH3)4Cl2+6ClO - →2HCl+6Cl - +CuO↓+2N2↑+5H2O; 2Cu2(OH)3Cl+3ClO - +2NH4Cl→4HCl+3Cl - +4CuO↓+N2↑+5H2O;

[0045] (2) When the deamination oxidant contains chlorine, Cu(NH3)4Cl2+6Cl2+H2O→14HCl+CuO↓+2N2↑; Cu2(OH)3Cl+2NH4Cl+3Cl2→9HCl+2CuO↓+N2↑+H2O;

[0046] Chlorine dissolves in water to form hypochlorite and chloride ions, so when the deamination oxidant contains chlorine, the same reaction as when the deamination oxidant contains hypochlorite may also occur. When the reaction mixture is alkaline and the deamination oxidant contains chlorine, the reaction between chlorine and the alkaline substance may also produce chlorate.

[0047] When the filter residue C contains ferrous salts and / or ferrous hydroxide, at least one of the following reactions will occur during the deamination oxidation reaction. 2+ +3ClO - +3H2O→2Fe(OH)3+4Fe 3+ +3Cl - ; 2Fe 2+ +Cl2→2Fe 3+ +2Cl - ; 6Fe(OH)2+3ClO -+3H2O→6Fe(OH)3+3Cl - ; 6Fe(OH)2+3Cl2→2Fe 3+ +4Fe(OH)3+6Cl - .

[0048] The inventors have discovered that maintaining a pH of 6.8 or higher during the deamination and oxidation reaction can prevent the formation of nitrogen trichloride, a dangerous and explosive substance, during the recovery process. Furthermore, the presence of hydroxide in the reaction mixture can effectively promote the removal of ammonia and / or ammonium.

[0049] Therefore, as a preferred embodiment of the present invention: when a deamination oxidation reaction is used in step (3), an inorganic base is added to the reaction mixture during the deamination treatment to maintain the pH of the reaction solution at ≥6.8. More preferably, the pH of the reaction solution is maintained at ≥7. The inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, preferably sodium hydroxide.

[0050] During the deamination oxidation reaction, when an inorganic base is added to the reaction mixture or the pH value of the reaction mixture itself is ≥7, at least one of the following reactions occurs. - +2OH - →5Cl - +N2↑+5H2O; 2NH3+3ClO - →3Cl - +N2↑+3H2O; 2NH4Cl+3Cl2+8OH - →8Cl - +N2↑+8H2O; 2NH3+3Cl2+6OH - →6Cl - +N2↑+6H2O.

[0051] In the deamination oxidation reaction process, the addition of an alkaline pH value adjuster other than the circuit board alkaline copper chloride ammonia etching waste liquid can convert the basic copper chloride, copper carbonate, and basic copper carbonate in the filter residue C into copper hydroxide. - →Cl - +2Cu(OH)2↓; CuCO3+2OH - →Cu(OH)2↓+CO3 2- ; Cu2(OH)2CO3+2OH - →2Cu(OH)2↓+CO3 2- .

[0052] After many experiments, the inventors found that when the alkalinity of the reaction mixture is high, the deamination oxidation process is more likely to further oxidize divalent copper into cuprate and oxidize ferric hydroxide into ferrate. - +ClO - →2CuO2 - +Cl - +3H2O; 2CuO+2OH - +ClO - →2CuO2 - +Cl - +H2O; 2Fe(OH)3+OH - +3ClO - →2FeO4 2- +3HCl+2H2O (when the reaction mixture contains iron hydroxide).

[0053] Since cuprate is a water-insoluble solid, while ferrate is soluble in water, the ferric oxide and / or ferric hydroxide in the reaction mixture can be oxidized with a deamination oxidant under conditions of high alkalinity to form soluble ferrate, which can then be separated from the resulting sodium cuprate solid.

[0054] Preferably, when the filter residue C contains iron hydroxide, the deamination oxidation reaction is carried out at a relatively high reaction solution alkalinity, reaction solution ORP value, and reaction temperature. More preferably, during the deamination treatment, the pH value of the reaction mixture is controlled at ≥9, and the reaction solution is heated and its redox potential is controlled at a relatively high value to promote the formation of percuprate and / or ferrate.

[0055] (ii) Heating and oxidizing ammonia removal treatment

[0056] During the heating reaction to remove ammonia, copper oxide solids are generated, along with hydrogen chloride gas, / or ammonia gas, / or carbon dioxide gas, and / or water. If the filter residue C contains ammonium chloride, sublimation of ammonium chloride will also occur due to the increase in temperature, so the tail gas needs to be absorbed.

[0057] During the direct heating oxidation ammonia removal process, at least one of the following chemical reactions occurs:

[0058] When the filter residue C contains iron salts and / or iron hydroxides, at least one of the following reactions will occur during the heating and oxidation process to remove ammonia, generating iron oxide.

[0059] Therefore, in step (3), the filter residue C is subjected to a heating oxidation treatment to remove ammonia, thereby obtaining a solid whose main component is copper oxide, which may also contain iron oxide and / or other metal oxide impurities in small amounts.

[0060] The iron oxide crystal structure powder particles generated at high temperatures by the thermal oxidation ammonia removal treatment differ from the iron oxide crystal structure generated at room temperature, and the former is poorly soluble in sulfuric acid at room temperature. By utilizing the chemical peculiarity of the high-temperature iron oxide crystal structure, which is slightly soluble in sulfuric acid, the mixture of copper oxide and iron oxide obtained by the thermal oxidation ammonia removal treatment in step (3) can be separated by dissolving the copper oxide powder in sulfuric acid. Therefore, when the filter residue C contains iron compounds, thermal oxidation ammonia removal treatment is preferably used in step (3).

[0061] In step (4), there are several specific implementation methods:

[0062] (1) When it is only needed to be reused in the alkaline etching process, the filtrate A is prepared according to the process requirements with at least one of ammonia water, liquid ammonia, ammonium chloride, and other additives to obtain an alkaline etching regeneration sub-liquid, and the sub-liquid is reused in the alkaline etching production line.

[0063] (2) When it is only needed to be reused in the acid etching process, filtrate A is taken to prepare acid etching regeneration sub-liquid and / or acid etching oxidant respectively and reused in the acid etching production line. At this time, the reuse amount of filtrate A as acid regeneration etching sub-liquid and acid etching oxidant solution is allocated according to the process conditions. During the preparation process, filtrate A is prepared according to the process requirements and reused as regeneration etching sub-liquid in the acid etching system. If filtrate A is acidic, it is directly or after preparation and reused as acid regeneration etching sub-liquid in the acid etching system; when filtrate A is used to prepare acid etching oxidant and reused in the acid etching system, if filtrate A is acidic, filtrate A is adjusted to neutral or alkaline and then sodium chlorate and / or potassium chlorate is added to prepare a chemically stable mixed solution as acid etching oxidant.

[0064] (3) When it needs to be reused in the acid etching production line and the alkaline etching production line, the filtrate A is distributed according to the preparation requirements of the alkaline regeneration etching sub-liquid, the acid regeneration etching sub-liquid and / or the acid etching oxidant according to the process requirements, and then reused in the etching process directly or after being adjusted according to the process requirements as in the above embodiments (1) and (2).

[0065] This process improves upon the existing neutralization reaction precipitation recovery process for acidic and alkaline copper chloride etching wastewater by adding the two aforementioned ammonia nitrogen removal processes. This process can remove the ammonium salts in the copper sludge precipitate generated by the neutralization reaction in the existing process. Compared to the existing technology, this process has the following four advantages:

[0066] First, it is suitable for circuit board etching production enterprises that use both acidic etching and alkaline etching processes containing ammonium chloride components at the same time, and take the appropriate amount of acid and alkaline etching waste liquid for on-site online treatment to achieve 100% recycling and reuse. In the copper hydroxide and / or copper carbonate and / or basic copper carbonate and / or copper oxide and / or sodium percopperate obtained after the deamination treatment in step (3), sodium percopperate can be subjected to a reduction reaction to obtain copper oxide. Copper hydroxide, copper carbonate, basic copper carbonate, and copper oxide can all be converted into copper salt products through simple chemical reactions, and even further become electrolytic copper, or the obtained copper oxide can be directly used as a copper supplement source in the acid copper electroplating process, so that circuit board production enterprises can convert waste copper liquid treatment into copper source materials for recycling in production, thereby improving cost-effectiveness indicators and environmental governance indicators.

[0067] Secondly, with the industry's advancements in alkaline etching processes for circuit boards, new weakly alkaline copper-ammonium chloride etching processes have emerged, with the pH of the etching solution controlled close to the neutral pH of 7. This process improves etching quality by six times compared to existing processes. This weakly alkaline copper-ammonium chloride etching wastewater is particularly well-suited for the present invention's precipitation treatment and reuse method with the addition of an acidic pH adjuster. This eliminates the risk of new pollution sources, such as the continuous increase in the volume of the reaction solution during wastewater treatment, which prevents 100% recycling.

[0068] Third, the new type of copper chloride and ferric chloride mixed acidic etching solution, or ammonium chloride is added on this basis, its etching performance is much better than the acidic copper chloride etching process performance of the prior art, its production efficiency can be increased by 1.6 times, and the etching quality is improved by 30%, which is becoming more and more popular in the industry. After the iron-containing acidic etching waste liquid is mixed with the alkaline etching waste liquid, the filter residue C produced contains iron compounds. The method of the present invention can effectively separate the copper and iron compounds to facilitate their respective recovery. It should be pointed out that since most iron sources on the market contain heavy metal impurities such as manganese, the acidic etching waste liquid containing iron elements also often contains trace amounts of manganese ions and other heavy metal ions. If the iron-containing acidic etching waste liquid is used in step (1), the filter residue C obtained in step (2) will also be mixed with heavy metal impurities other than copper and iron. At this time, if the method (i) in step (3) is adopted, further impurity removal treatment is required to remove impurities such as manganese in the iron compound from the copper and iron compounds. By adopting method (ii) of step (3), metallic impurities such as iron and manganese contained in the precipitated copper mud can be converted into copper oxide, iron oxide, and manganese dioxide after high-temperature treatment. Since copper oxide is easily soluble in sulfuric acid, iron oxide and manganese dioxide after high-temperature treatment are not easily soluble in sulfuric acid. Utilizing the above-mentioned material properties, the filter residue C after high-temperature heating and oxidation treatment is mixed with a solution containing sulfuric acid, and after solid-liquid separation, a copper sulfate solution can be obtained. The iron oxide and manganese dioxide that are insoluble in sulfuric acid are further separated and treated to obtain high-purity iron oxide for reuse. Method (ii) does not require additional impurity removal processes and equipment, thereby reducing production and recycling costs.

[0069] The present invention can be improved as follows: when the copper chloride etching waste liquid of the circuit board in step (1) contains alkaline etching waste liquid, the alkaline etching waste liquid is first heated to remove ammonia and then treated as part or all of the copper chloride etching waste liquid of the circuit board according to the method of the present invention. This improvement can reduce the concentration of ammonia and / or ammonium in the alkaline etching waste liquid, and subsequently reduce the amount of acidic pH value adjuster, thereby avoiding the generation of excessive ammonium chloride and excessive filtrate A during the reaction process of step (1) and the inability to recycle and reuse, resulting in accumulation waste and environmental pollution, and can also be beneficial to the preparation of etching regeneration liquid. Ammonia, water vapor and / or carbon dioxide gas escape during the heating and ammonia removal process, and ammonia water and / or water can be used for absorption to obtain a solution containing ammonium carbonate and / or ammonium bicarbonate and / or ammonia water for reuse in the preparation of alkaline etching sub-liquid, or the prepared liquid can be directly used for absorption when preparing the alkaline regeneration etching sub-liquid.

[0070] Preferably, when the circuit board copper chloride etching waste liquid described in step (1) contains circuit board alkaline copper chloride ammonia etching waste liquid, the circuit board alkaline copper chloride ammonia etching waste liquid is first heated to ≥55° C. for ammonia drive treatment.

[0071] Preferably, the ammonia-containing tail gas released during the heating and ammonia removal process of the alkaline etching waste liquid is led to the alkaline etching regeneration sub-liquid for absorption treatment.

[0072] The present invention can also be improved as follows: before performing step (1), the acidic etching waste liquid and / or the alkaline etching waste liquid are subjected to water-oil separation and / or solid-liquid separation treatment, so that the ink, film residue and solid impurities in the acidic etching waste liquid are cleaned, and / or the ink, film residue, stannous hydroxide precipitate and other solid impurities in the alkaline etching waste liquid are cleaned.

[0073] The present invention can also be improved as follows: in step (2) of the present invention, the filter residue C is subjected to a separation treatment to remove chlorine salts and / or metal impurities other than copper.

[0074] The present invention can also be improved as follows: when step (3) of the present invention adopts method (i), the amount of the deamination oxidant added is controlled according to the redox potential parameter of the reaction solution to adjust the deamination reaction rate, the amount of the inorganic base added is controlled according to the pH parameter value of the reaction solution, and the temperature and time of the reaction solution are controlled so that the ammonia or ammonium salt content concentration of the reaction solution meets the process requirements after treatment.

[0075] The present invention can also be improved as follows: when the present invention adopts method (i) in step (3), the deamination oxidant used is chlorine produced by a chlorine generator in an electrolytic process instead of hypochlorite solution and commercial chlorine purchased from the market. This can not only optimize the control of the deamination oxidation process and facilitate recycling and reuse without introducing new impurities to reduce production costs, but also reduce the introduction of water, thereby reducing the discharge of waste liquid of filtrate B.

[0076] The present invention can also be improved as follows: when the step (3) adopts the method (i), the filter residue D obtained is subjected to a reduction reaction with hydrogen peroxide and / or sodium sulfite solution and / or sodium bisulfite and sodium percolate to obtain copper oxide, which is then washed with clean water to remove chloride salts and sodium and potassium ions therein to obtain copper oxide of higher purity for recycling.

[0077] The chemical reaction principle of the reduction reaction of sodium percopperate to produce copper oxide is as follows: 2NaCuO2+Na2SO3+H2O→2CuO+Na2SO4+2NaOH; 2NaCuO2+NaHSO3+H2O→2CuO+NaHSO4+2NaOH; 2NaCuO2+H2O2→2CuO+2NaOH+O2↑.

[0078] The present invention can also be improved by using filtrate B containing an oxidant solution and / or hydrogen peroxide to chemically treat the hydrogen electrolyzed in a chlorine generator using an electrolysis process, thereby reducing or even eliminating the harmfulness of the hydrogen.

[0079] The present invention may also be improved as follows: when step (3) of the present invention adopts method (ii), the temperature of directly heating the filter residue C is not less than 100° C., thereby obtaining a good yield of copper oxide. When iron ions and manganese ions are present in the filter residue C, the filter residue C is heated at a higher temperature and oxygen or air is introduced to the filter residue C for heating reaction, which helps to convert the iron ions and manganese ions therein into iron oxide and manganese dioxide.

[0080] The present invention can be improved as follows: when step (3) adopts method (ii), the filter residue C is mechanically crushed at high temperature during the direct heating and oxidation process, and / or the filter residue C is oxidized using a process of intermittent heating oxidation → cooling and crushing → reheating and oxidation. This improves the situation in which the iron and manganese compounds are encapsulated in the solid copper slag, making it difficult for them to undergo oxidation. The improved process can further increase the reaction rate of high-temperature iron oxide and manganese dioxide.

[0081] Preferably, in step (3), the filter residue C is subjected to intermittent heating oxidation and cooling pulverization, and is then washed with water after mechanical pulverization to remove impurities such as ammonium salts and / or soluble salts such as sodium and potassium salts contained in the original filter residue C. Further heating oxidation after washing can obtain purer copper and iron compounds.

[0082] The present invention can also be improved as follows: when step (3) of the present invention adopts method (ii), the recovered iron oxide is made into an iron source material and reused in the acid etching process.

[0083] The present invention can be improved as follows: when the filtrate A contains iron salts, the newly prepared alkaline etching regeneration sub-liquid is subjected to precision filtration treatment in step (4) before use to remove the iron hydroxide solids therein.

[0084] The present invention can also be improved as follows: the reaction temperature of the reactants is controlled during the reaction process of step (1) and / or step (3), and / or the filtrate A is cooled before step (4). The latter can allow the filtrate A to precipitate more solid salts by cooling, making the filtrate A more in line with the process requirements for preparing a recycled etching solution.

[0085] The present invention can also be improved as follows: the filtrate A is heated and evaporated and concentrated using an evaporator before performing step (4), so that the filtrate A can be 100% recycled while reducing the solution volume, and there is no excessive waste liquid that cannot be recycled and generates a new pollution source.

[0086] The second object of the present invention is to provide a device for the precipitation treatment and reuse of copper chloride etching waste liquid from circuit boards, which is assembled from the following equipment components. It mainly includes:

[0087] At least one reaction tank or at least one solid heating device, at least one solid-liquid separator, and at least one temporary storage tank. At least two of the reaction tank, solid-liquid separator, and temporary storage tank are connected via a pipeline or a pipeline equipped with a pump and / or valve;

[0088] The reaction tank is used to mix the copper chloride etching waste liquid of the circuit board with the pH adjuster to react so that the reaction liquid precipitates copper mud, and / or the precipitated copper mud and the deamination oxidant to carry out the deamination oxidation reaction using method (i) in step (3).

[0089] The solid heating device is used in step (3) to directly perform high-temperature heating, oxidation and ammonia removal treatment on the copper mud or copper slag separated from the solid-liquid separator in mode (ii).

[0090] The solid-liquid separator is used for solid-liquid separation of a solid-liquid mixture.

[0091] The temporary storage tank is used for storing the solution and / or preparing the etching sub-liquid.

[0092] The solid heating device can be an electric heating device or an oxidation combustion reaction heating device.

[0093] Preferably, the solid-liquid separator can be a filter, a rotary centrifuge, or a filter press.

[0094] Preferably, detection devices are installed in the reaction tank, solid-liquid separator, temporary storage tank, connected pipelines, and the production workshop space. The detection devices include any one or any combination of a hydrometer, a colorimeter, a pH meter, an acidity meter, a redox potentiometer, a thermometer, a liquid level meter, a flow meter, a chlorine detector, and a hydrogen detector, which can be used according to process control requirements.

[0095] Preferably, a stirring device is installed in the reaction tank and / or temporary storage tank. The stirring device can be any stirring device among liquid reflux stirring device, rotary impeller stirring device, pneumatic stirring device, or any combination thereof that can perform stirring according to process requirements.

[0096] Preferably, a hot / cold temperature exchanger is installed in the reaction tank and / or temporary storage tank to cool or release heat from the solution in the reaction tank and / or temporary storage tank. Simultaneously, process control is performed to cool the reaction solution to remove solid salts, making the reaction solution more suitable for preparing a recycled etching solution after filtration.

[0097] Preferably, a feeding port, a discharging port, an overflow port and an exhaust port are provided in the reaction tank and / or temporary storage tank so that the equipment structure meets various technical requirements of the process and the gas produced during the production process can be easily collected and processed.

[0098] The present invention can be improved as follows: a heating reaction kettle is added to heat the alkaline etching waste liquid to drive out ammonia.

[0099] The present invention can also be improved as follows: an aqueous solution heating and concentrating evaporator is added to heat, concentrate and evaporate the filtrate A to reduce the volume of the filtrate A.

[0100] The present invention can be improved as follows: a crushing device is added to crush and / or grind the copper mud that has been subjected to high-temperature heating treatment.

[0101] The present invention can be improved as follows: a water-oil separator and / or a filtering device is added to remove impurities from the etching waste liquid or pH value adjustment liquid or recycled solution.

[0102] The present invention can also be improved by adding an exhaust gas treatment device, which can adopt either a vacuum jet gas-liquid mixing device or a spray tower gas-liquid mixing device, or a combination of the two, to provide treatment according to process requirements. The exhaust gas treatment device can also perform classification treatment based on the temperature and chemical properties of the exhaust gas.

[0103] The present invention can also be improved as follows: a cleaning tank device with a stirrer is added to wash and purify the copper mud produced in the recovery process or the copper slag after heat treatment.

[0104] The present invention can also be improved as follows: using an electrolytic process chlorine generator to produce chlorine as a deamination oxidant to optimize safety control in the deamination oxidation process and reduce production costs while reducing wastewater discharge.

[0105] The electrolytic process chlorine generator is an electrolytic cell with electrolytic anode and cathode cell areas as separations. Chlorine is produced by electrolytic reaction of chloride salt solution or acidic copper chloride etching waste liquid, and the chlorine is used for deamination oxidation reaction.

[0106] Preferably, when the electrolytic process chlorine generator is used to prepare the deamination oxidant, the reaction tank for the deamination oxidation reaction is installed with a vacuum jet gas-liquid mixing treatment device and / or a spray tower gas-liquid mixing device to better drain the chlorine separated by electrolysis from the electrolytic process chlorine generator to the reaction tank to participate in the deamination oxidation reaction.

[0107] The present invention can also be improved by adding an automatic detection and feeding controller. Field data measured by various detection devices is sent to the automatic detection and feeding controller for processing, thereby controlling the addition of materials during the reaction process. Furthermore, the output current of the electrolytic power supply in the electrolytic chlorine generator can be adjusted according to the deamination and oxidation reaction conditions to control the amount of chlorine released, thereby implementing a safety interlock for electrolytic chlorination. Furthermore, temperature-controlled process control can be implemented for the solid heating device to safely treat the exhaust gas from the solid heating device. This allows for automated and safe control of the production process flow of the entire equipment.

[0108] The present invention can also be improved as follows: an overflow buffer tank is added, and the overflow buffer tank is connected to at least one of the reaction tank, solid-liquid separator, temporary storage tank, and electrolytic process chlorine generator through a pipeline, or is placed below the overflow port of at least one of the reaction tank, solid-liquid separator, temporary storage tank, and electrolytic process chlorine generator, so as to solve the problem of high and low liquid levels between the containers in the process equipment of the present invention and ensure that the solution flows according to the process requirements.

[0109] The present invention can also be improved as follows: a sealed tank cover at normal pressure is added to cover and seal the required tanks to reduce material loss and environmental pollution.

[0110] The present invention can also be improved as follows: a hydrogen eliminator is added to eliminate hydrogen electrolyzed by a chlorine generator using a partial electrolysis process, so as to eliminate the source of danger generated during production.

[0111] Compared with the prior art, the present invention has the following beneficial effects:

[0112] 1. The recycling and treatment method of the present invention is safe, simple and reliable. It can process acidic copper chloride etching waste liquid or alkaline copper chloride ammonia etching waste liquid on site in real time, and can also simultaneously mix acidic copper chloride etching waste liquid and alkaline copper chloride ammonia etching waste liquid for on-site recycling and reuse.

[0113] 2. The recycling process of the present invention requires only simple mixing equipment, solid-liquid separation equipment, reaction tanks, and / or heating tanks to achieve the objectives of the present invention. These equipment are simple in structure, easy to repair and maintain, and their cost is much lower than that of expensive electrolysis equipment. Therefore, the equipment investment scale is small, the daily maintenance cost is low, and the economic benefits are high.

[0114] 3. During the recovery and treatment process of the present invention, the copper ammonia complex in the waste liquid is destroyed to generate ammonium salt, without the generation of a large amount of free ammonia, thus effectively avoiding the volatilization of a large amount of ammonia and reducing environmental pollution;

[0115] 4. The recycling process of the present invention has low energy consumption and no new pollution sources. The solution after copper extraction can be recycled without affecting the efficiency and quality of etching production, thereby effectively improving production benefits and even achieving 100% recycling, which complies with current environmental protection regulations and emission reduction policy requirements;

[0116] 5. For acidic copper chloride etching waste liquid containing ammonium chloride, the recovery and treatment process of the present invention not only avoids the presence of ammonium salt impurities in the copper-containing precipitate obtained by the alkalization method, but also avoids the safety problem of generating nitrogen trichloride by the electrolysis method;

[0117] 6. When the etching waste liquid contains iron components, the recovery process of the present invention can separate and collect the copper compounds and iron compounds in the waste liquid.

[0118] 7. The copper hydroxide and / or copper oxide products recovered in the process of the present invention can be reused in the acid copper electroplating process in the production of circuit boards instead of phosphorus copper, enabling manufacturers to turn waste copper-containing etching waste liquid into valuable resources while solving the three major pollution sources of heavy metals, ammonia nitrogen and phosphorus, which has positive significance for environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0119] FIG1 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to a basic embodiment of the present invention;

[0120] FIG2 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 2 of the present invention;

[0121] Figure 2.1 is an enlarged schematic diagram of 2-A in Figure 2;

[0122] Figure 2.2 is an enlarged schematic diagram of 2-B in Figure 2;

[0123] Figure 2.3 is an enlarged schematic diagram of 2-C in Figure 2;

[0124] Figure 2.4 is an enlarged schematic diagram of 2-D in Figure 2;

[0125] Figure 2.5 is an enlarged schematic diagram of 2-E in Figure 2;

[0126] FIG3 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 3 of the present invention;

[0127] Figure 3.1 is an enlarged schematic diagram of 3-A in Figure 3;

[0128] Figure 3.2 is an enlarged schematic diagram of 3-B in Figure 3;

[0129] Figure 3.3 is an enlarged schematic diagram of 3-C in Figure 3;

[0130] Figure 3.4 is an enlarged schematic diagram of 3-D in Figure 3;

[0131] Figure 3.5 is an enlarged schematic diagram of 3-E in Figure 3;

[0132] Figure 3.6 is an enlarged schematic diagram of 3-F in Figure 3;

[0133] FIG4 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 4 of the present invention;

[0134] Figure 4.1 is an enlarged schematic diagram of 4-A in Figure 4;

[0135] Figure 4.2 is an enlarged schematic diagram of 4-B in Figure 4;

[0136] Figure 4.3 is an enlarged schematic diagram of 4-C in Figure 4;

[0137] FIG5 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 5 of the present invention;

[0138] Figure 5.1 is an enlarged schematic diagram of 5-A in Figure 5;

[0139] Figure 5.2 is an enlarged schematic diagram of 5-B in Figure 5;

[0140] FIG6 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 6 of the present invention;

[0141] Figure 6.1 is an enlarged schematic diagram of 6-A in Figure 6;

[0142] Figure 6.2 is an enlarged schematic diagram of 6-B in Figure 6;

[0143] Figure 6.3 is an enlarged schematic diagram of 6-C in Figure 6;

[0144] Figure 6.4 is an enlarged schematic diagram of 6-D in Figure 6;

[0145] Figure 6.5 is an enlarged schematic diagram of 6-E in Figure 6;

[0146] Figure 6.6 is an enlarged schematic diagram of 6-F in Figure 6;

[0147] FIG7 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 7 of the present invention;

[0148] Figure 7.1 is an enlarged schematic diagram of 7-A in Figure 7;

[0149] Figure 7.2 is an enlarged schematic diagram of 7-B in Figure 7;

[0150] Figure 7.3 is an enlarged schematic diagram of 7-C in Figure 7;

[0151] FIG8 is a schematic diagram of a method and apparatus for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to Example 8 of the present invention;

[0152] Figure 8.1 is an enlarged schematic diagram of 8-A in Figure 8;

[0153] Figure 8.2 is an enlarged schematic diagram of 8-B in Figure 8;

[0154] Figure 8.3 is an enlarged schematic diagram of 8-C in Figure 8;

[0155] Figure 8.4 is an enlarged schematic diagram of 8-D in Figure 8;

[0156] Figure 8.5 is an enlarged schematic diagram of 8-E in Figure 8.

[0157] Figure numerals: 1 (if more than one, mark them as 1-1 and 1-2) - reaction tank, 2 (if more than one, mark them as 2-1 and 2-2) - solid heating device, 3 (if more than one, mark them as 3-1 to 3-5) - solid-liquid separator, 8 to 18 - temporary storage tank, 19 to 20 - water-oil separator, 21 to 23 - vacuum jet gas-liquid mixing device, 24 to 26 - spray tower gas-liquid mixing device, 27 to 28 - impeller stirring device, 29 - liquid reflux stirring device, 30 - pneumatic stirrer, 31 to 32 - hot and cold temperature exchanger, 33 - electrolysis process chlorine generator, 34 - electrolysis anode tank area, 35 - electrolysis cathode tank area, 36 - electrolysis power supply, 37 - electrolysis tank area partition Items, 38-Automatic Detection and Feeding Controller, 39-55-Detection Device, 56-84-Valves, 85-Sodium Hydroxide, 86-Sodium Hydroxide Solution, 87-Potassium Hydroxide, 88-Potassium Hydroxide Solution, 89-Potassium Carbonate, 90-Sodium Carbonate, 91-Sodium Bicarbonate, 92-Potassium Bicarbonate, 93-Sodium Hypochlorite Solution, 94-Potassium Hypochlorite Solution, 95-Chlorine, 96-Copper Hydroxide, 97-Filtrate A, 98-Filtrate B, 99-Filter Residue C, 100-Filter Residue D, 101-Ammonium Chloride, 102-Ammonia Water, 103-Additives, 104-Clean Water, 105-Acid Etching Regeneration Sub-Liquid, 106-Alkaline Etching Regeneration Sub-Liquid, 107-Acid Etching Production Line , 108-alkaline etching production line, 109~110-copper mud and copper slag cleaning tank with impeller stirring, 111-hydrochloric acid, 112-acidic copper chloride etching waste liquid, 113-alkaline copper chloride ammonia etching waste liquid, 114~117-sealed tank cover, 118-sodium chloride solution, 119-potassium chloride solution, 120~126-overflow buffer tank with pump valve, 127~130-solid feeder, 131-conveyor belt, 132-liquid ammonia, 133-sulphuric acid solution, 136~139-filtration device, 140~141-mechanical crushing device, 142-formic acid, 143-air, 144-sodium chlorate, 145-potassium chlorate, 146-acidic etching oxidant solution, 1 47-Combustible gas, 148-150-Copper slag after heat treatment, 151-Copper sulfate solution, 152-Iron oxide powder, 153-Sodium chloride solid, 154-Ammonium carbonate, 155-Ammonium bicarbonate, 156-Chemical reactor, 157-Hydrogen peroxide, 158-Sodium sulfite solution, 159-Sodium bisulfite, 160-Hydrogen eliminator, 161-Copper oxide, 162-163-Tail gas treatment device, 164-Alkaline etching waste liquid ammonia drive heating reactor, 165-Aqueous solution heating and concentration evaporator, 166-Electroplating copper brightener, 167-169-Liquid reflux stirring device, 170-200-Pump, 201-Carbon dioxide source, 202-Carbon dioxide. DETAILED DESCRIPTION

[0158] The present invention will be further described below through specific embodiments.

[0159] The 1-cubic-meter reaction tank, temporary storage tank, stirring device, vacuum jet gas-liquid mixing device, spray tower gas-liquid mixing device, ammonia displacement heating reactor, aqueous solution heating and concentrating evaporator, and electrolytic chlorine generator used in the embodiments of the present invention are all products of Foshan Yegao Environmental Protection Equipment Manufacturing Co., Ltd. in Guangdong Province. The detection sensors, solid-state heating devices, pumps, valves, and PLC controllers are commercially available. The chemical raw materials used are all commercially available chemical raw materials. In addition to those listed above, those skilled in the art may also select other products with similar performance to those listed above based on routine selection, and any of these products can achieve the objectives of the present invention.

[0160] Example 1

[0161] As shown in FIG1 , a basic embodiment of a method and apparatus for precipitation treatment and recovery of copper chloride etching waste liquid for a circuit board according to the present invention is shown, which includes: a reaction tank 1 , a solid-liquid separator 3 , temporary storage tanks 8 to 13 , and a hot and cold temperature exchanger 31 .

[0162] The reaction tank 1 is equipped with an impeller stirrer 27, a hot and cold temperature exchanger 31, and detection devices 39 and 40 respectively equipped with a pH meter and an oxidation-reduction potentiometer, which are connected to the solid-liquid separator 3 through a pipeline provided with a valve 71 and a pump 56;

[0163] The solid-liquid separator 3 adopts an ordinary filter press;

[0164] The temporary storage tank 8 is used to store acidic copper chloride etching waste liquid 112, the temporary storage tank 9 is used to store a mixture of sodium hypochlorite solution 93 and potassium hypochlorite solution 94 as a deammonification oxidant, the temporary storage tank 10 is used to store sodium hydroxide solution 86, the temporary storage tank 11 is used to store the filtrate A97 from the solid-liquid separator 3, the temporary storage tank 12 is used to load the filter residue C99 separated from the solid-liquid separator 3, and the temporary storage tank 13 is used to store the filtrate D98 from the solid-liquid separator 3.

[0165] In addition, a solid feeder 128 is used, which is equipped with a solid mixture of sodium hydroxide 85, potassium hydroxide 87, potassium carbonate 89, sodium carbonate 90, ammonium carbonate 154, and ammonium bicarbonate 155.

[0166] The clean water 104 pipeline is installed above the reaction tank 1.

[0167] The etching waste liquid to be treated is the acidic copper chloride etching waste liquid 112, which has an acidity of 2M and is mainly composed of hydrochloric acid, copper chloride, and an aqueous solution containing ammonium chloride and sodium chloride additives. Method (i) is used in step (3).

[0168] The treatment process is to first start the pump 170 to pump the acidic copper chloride etching waste liquid in the temporary tank 8 into the reaction tank 1, and start the impeller stirrer 27 and the hot and cold temperature exchanger 31. The pH of the reaction liquid in the reaction tank 1 is controlled by the pH meter of the detection device 39 during the process. The process setting value of the pH meter in step (1) is pH 5.5. That is, the pH meter controls the solid feeder 128 to add alkaline pH adjusters sodium hydroxide 85, potassium hydroxide 87, potassium carbonate 89, sodium carbonate 90, ammonium carbonate 154, and ammonium bicarbonate 155 to the reaction tank 1, so that the pH value of the reaction liquid reaches pH 5.5 and precipitates. After the reaction liquid reaches the process index, the impeller stirrer 27 is turned off and the neutralized reaction liquid is subjected to cold precipitation treatment through the hot and cold temperature exchanger 31. Upon completion, valve 59 and pump 173 are opened to pump the solid-liquid mixture in reaction tank 1 into filter press 3 for solid-liquid separation. Filtrate A is then directed to temporary storage tank 11. Once the mixture in reaction tank 1 is completely extracted, valve 59 and pump 173 are closed. Filter press 3 is opened and collected in temporary storage tank 12. Filter residue C, primarily composed of copper hydroxide and basic copper chloride, is collected by impurities such as soluble chloride salts and copper chloride ammonia complexes. After collecting the solid residue C, filter press 3 is reclosed and ready for the next operation.

[0169] The filter residue C copper hydroxide and basic copper chloride solids in the temporary storage tank 12 are put back into the reaction tank 1, and the valve 60 is opened to introduce clean water 104 into the reaction tank 1. The impeller stirrer 27 is turned on, and the pH meter of the detection device 39 and the redox potential meter of the detection device 40 work simultaneously. The ORP meter of the detection device 40 controls the pump 171 to put the deammoniation oxidant solution in the temporary storage tank 9 into the reaction tank 1. The process control setting value of the ORP meter is above 450mv. Before adding the deammoniation oxidant solution, the NH4 content of the reaction liquid in the reaction tank 1 is detected. + The content is 5 g / L. Open valves 57 and 58, pumps 171 and 172 to feed the sodium hydroxide solution 86 and deamination oxidant in tank 10 into the reaction tank 1. The amount of sodium hydroxide solution 86 is controlled according to the pH meter of the detection device 39 in step (3) at the process setting value of pH 6.8. The deamination oxidant is added to maintain the ORP value of the reaction at 450 mv. The temperature of the reaction liquid is controlled at 30°C by a hot and cold temperature exchanger. When the reaction liquid reaches the above three control indicators and maintains the reaction time for 14 hours according to the process, NH4 + When the ion concentration reaches 80 mg / L, the deamination and oxidation reaction is considered complete. Valve 59 and pump 173 are reopened to pump the solid-liquid mixture in reaction tank 1 to filter press 3 for solid-liquid separation. Filtrate B 98 is drained into temporary storage tank 13, and filter residue D 100 is retained in filter press 3. The deamination and oxidation reaction removes most of the sodium chloride, ammonium chloride, and copper chloride ammonia complex impurities in filter residue C from filter residue D, yielding higher-purity copper hydroxide.

[0170] A portion of the filtrate A97 is taken, the pH value is adjusted, and sodium chlorate and potassium chlorate solids are added to prepare an acid etching oxidant, which is then reused in the acid etching production line. The remaining filtrate A97 is directly reused as an acid etching regeneration liquid in the acid etching production line.

[0171] After testing, filtrate B was found to contain 80 mg / L of residual ammonia nitrogen for subsequent treatment.

[0172] Open the solid-liquid separator 3 and take out the filter residue D copper hydroxide for recycling.

[0173] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0174] (1) reacting a 2M copper chloride etching waste liquid of a circuit board to be treated with a solid mixture of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate and ammonium bicarbonate as an alkaline pH adjuster until the pH of the reaction solution reaches pH 5.5 and copper mud is precipitated;

[0175] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C;

[0176] (3) The filter residue C is mixed with potassium hypochlorite and sodium hypochlorite solutions using the method described in method (i) to undergo a deamination oxidation reaction. During this process, sodium hydroxide solution 86 is added to the reaction tank via a feed pump to maintain the pH value of the reaction solution at pH = 6.8. The oxidant is added until the redox potential of the reaction solution reaches and is maintained above 450 mV. The reaction is completed by controlling the temperature at 30°C for 14 hours. After the reaction is completed, the solid-liquid mixture in the reaction tank 1 is subjected to a further solid-liquid separation to obtain filtrate B and filter residue D, the main component of which is copper hydroxide.

[0177] (4) A portion of the filtrate A is taken to adjust the pH value and then added with sodium chlorate and potassium chlorate to prepare an acidic etching oxidant solution for reuse in the acid etching production line. The remaining filtrate A is reused in the acid etching production line as an acid etching regeneration sub-liquid.

[0178] This example illustrates the use of the present invention to treat acidic copper chloride etching wastewater during the recovery process by adding alkaline pH adjusters such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, and ammonium bicarbonate to produce a neutralization chemical reaction to produce copper sludge precipitation. The precipitated copper sludge is recovered using the deamination and oxidation treatment method (i) in step (3). Filtrate A is used to prepare regenerated etching liquid and acidic etching oxidant, achieving 100% recycling.

[0179] Example 2

[0180] As shown in Figure 2, this is Example 2 of a method and device for precipitation treatment and reuse of copper chloride etching waste liquid from a circuit board according to the present invention, which mainly includes 2 reaction tanks, 5 solid-liquid separators, 8 temporary storage tanks, 2 hot and cold temperature exchangers, 2 water-oil separators, 1 solid feeder, 1 set of electrolytic process chlorine generator, 1 copper mud and copper slag cleaning tank with impeller stirring, 14 sensors and 1 automatic detection and feeding controller, 1 hydrogen eliminator, 1 chemical reactor 156, and 1 aqueous solution heating and concentration evaporator 165.

[0181] The reaction tank 1-1 is equipped with an impeller stirrer 27, a sealed tank cover 114, a hot and cold temperature exchanger 31, a pH detection device 39, a specific gravity detection device 40, a temperature detection device 41, and a liquid level detection device 42. The reaction tank 1-2 is equipped with a sealed tank cover 115, a liquid reflux stirrer 29, a hot and cold temperature exchanger 32, a vacuum jet gas-liquid mixing device 21, a spray tower gas-liquid mixing device 24, a pH detection device 43, an oxidation-reduction potential (ORP) detection device 44, a temperature detection device 45, and a liquid level detection device 46.

[0182] The solid-liquid separators 3-1 and 3-2 are filters with common filter media structures, while the solid-liquid separators 3-3 to 3-5 are common plate and frame filter presses.

[0183] The temporary storage tank is used to temporarily store different solutions as shown in Figure 2. The temporary storage tank 10 is equipped with an impeller stirrer 28 and a liquid level gauge of a sensor 50.

[0184] The water-oil separators 19 and 20 and the solid-liquid separators 3-1 and 3-2 remove impurities from the acidic pH value adjuster and the alkaline copper chloride ammonium etching waste liquid to be treated. After the impurities are removed, the waste liquid is drained to the temporary storage tanks 8 and 9 for storage.

[0185] The acidic pH adjuster is a mixture of hydrochloric acid 111 and formic acid 142. The alkaline copper chloride ammonium etching waste liquid 113 to be treated has a pH of pH 8.3, and its main components are a mixture of ammonia water, ammonium chloride and copper chloride ammonium.

[0186] The aqueous solution heating and concentrating evaporator 165 is used to evaporate and concentrate the filtrate A in the temporary storage tank 11.

[0187] The solid feeder 128 is loaded with sodium hydroxide 85, which is added to the reaction tank 1-2 to adjust the pH value of the deamination oxidation reaction solution.

[0188] The electrolytic cell separator 37 in the electrolytic chlorine generator is a cation exchange membrane. A mixture of sodium chloride and potassium chloride is electrolyzed to produce a mixture of chlorine 95, hydrogen, sodium hydroxide solution 86, and potassium hydroxide solution 88. The electrolyzed hydrogen is directed through a vacuum jet gas-liquid mixing device 22 to a hydrogen eliminator 160 for reaction with an oxidant for safe disposal. Chlorine 95 is then directed to reaction tank 1-2 to participate in the chemical reaction.

[0189] The automatic detection and feeding controller 38 obtains field data through multiple detection devices for automatic control of the production process of the entire equipment.

[0190] The copper mud and copper slag cleaning tank 110 with impeller stirring is specially used for washing filter residue D with water, and a pH value detection device 47 and a photoelectric colorimetric detection device 51 are installed in the tank to detect the pH and copper salt concentration in the washing liquid and remove impurities from the copper hydroxide therein.

[0191] The process flow of this method adopts the process method of mode (i) in step (3), wherein the steps are as follows: the acidic pH value adjusting agent is pumped into the water-oil separator 19, the alkaline copper chloride ammonia etching waste liquid 113 to be treated is pumped into the water-oil separator 20, and after being subjected to impurity removal treatment by the respective filters 3 and 4, the acidic pH value adjusting agent is pumped into the temporary storage tank 8 and the alkaline copper chloride ammonia etching waste liquid to be treated is pumped into the temporary storage tank 9. The pump 173 is turned on to pump the alkaline etching waste liquid into the reaction tank 1-1 at a constant volume. The agitator 27 and the hot and cold temperature exchanger 31 are turned on. The temperature of the reaction liquid is measured by the temperature detection device 41, the copper ion concentration of the reaction liquid is measured by the specific gravity detection device 40, the pH meter of the detection device 39 and the level meter of the detection device 42 are all sampled and tested for the temperature, copper ion concentration, pH value and liquid level of the reaction liquid, and the on-site detection data are transmitted to the automatic detection and feeding controller 38 for processing and program execution. According to the process sequence, control pump 171 is activated to inject an acidic pH adjuster into the solution in reaction tank 1-1. The pH is adjusted to and maintained at pH 7.9 during the reaction. During this process, the hot / cold temperature exchanger 31 maintains the temperature of the reaction solution at room temperature. When the hydrometer on detection device 40 reaches the set value, the precipitation reaction is complete. Valve 60 is opened and pump 174 is activated to pump the solid-liquid mixture in reaction tank 1-1 to filter press 5 for solid-liquid separation. Once the solution in reaction tank 1-1 is evacuated, valve 60 is closed and pump 174 is shut down. Filtrate A97 is drained to temporary storage tank 11 for storage, while filter residue C is retained in filter press 5. After the treatment of reaction tank 1-1 is completed, the filter press 5 plates and frames are opened, and filter residue C is removed and placed in temporary storage tank 10. The main component of filter residue C is copper chloride ammonia complex. The filter press 5 plates and frames are then reclosed to prepare for the next process step. The mixture of sodium hydroxide solution 86 and potassium hydroxide 88 in the temporary storage tank 12 is added to the temporary storage tank 10 according to the control of the liquid level detection device 50, and the impeller stirrer 28 is turned on to dissolve the precipitate into a suspension solution. The suspension in the tank 10 is tested for ammonia nitrogen. +The ion concentration is 15 g / L. The suspension in the temporary storage tank 10 is completely added to the reaction tank 1-2 by opening valve 61 and pump 175. After the solution in the temporary storage tank 10 is evacuated, valve 61 and pump 175 are closed, pumps 183 and 184 and the liquid reflux agitator 29 are opened, and the jet pump 189 in the hydrogen eliminator 160 is opened to generate a vacuum pressure in the ejector 22 to prepare for the absorption of the electrolyzed hydrogen. The electrolytic process chlorine generator, solid feeder 128, and hot and cold temperature exchanger 32 are opened to allow the deamination oxidation reaction to proceed normally. During the process, the on-site detection data of the pH detection device 43, the ORP detection device 44, the temperature detection device 45, the liquid level detection device 46 and the ORP detection device 47 in the hydrogen eliminator 160 are transmitted to the automatic detection and feeding control machine 38 for processing. The controller 38 adjusts the output current of the electrolysis power supply according to the on-site deamination oxidation reaction conditions and the ORP value and pH value of the solution to control the electrolytic precipitation amount of chlorine and perform feeding control on the solid feeder 128. At the same time, the pump 188 is used to add oxidant to the hydrogen eliminator 160 based on the data of the detection device 47. When the process reaction tank 1-2 is operated, its ORP value is controlled to be above 850mv and the pH value is controlled to be pH7.5. The temperature of the reaction liquid is controlled at room temperature and maintained for 36 hours. After the NH4 + The reaction is complete when the ion concentration reaches 70 mg / L. The chlorine generator, pumps 183 and 184, agitator 29, and hot / cold temperature exchanger 32 of the electrolysis process are shut down. Valve 72 and pump 185 are opened to pump the solid-liquid mixture in reaction tank 1-2 into filter press 6 for solid-liquid separation. Filtrate B is drained into temporary storage tank 14, and filter residue D, whose main component is copper hydroxide, is retained in filter press 6. Once the mixed liquid in reaction tank 1-2 has been completely extracted, valve 72 and pump 185 are closed. The filter press 6 is opened, and the filter residue D100 is removed and placed in a copper sludge and copper slag cleaning tank 110 equipped with an impeller agitator. Clean water 104 is added to the cleaning tank 110, and the impeller agitator is turned on for cleaning. The pH value of the washing solution and the copper salt concentration in the solution are determined using the pH detection device 47 and the photoelectric colorimeter detection device 51. Once the cleaning requirements are met, valve 73 and pump 186 are opened to pump the solid-liquid mixture in tank 110 into the filter press 7 for solid-liquid separation. The filtrate is then drained back to the temporary storage tank 16 for further processing, while the filter residue copper hydroxide 96 is retained in the filter press 7. Once the solid-liquid mixture in tank 110 has been extracted, valve 73 is closed and pump 186 is turned off. The filter press 7 is opened, and the filter residue copper hydroxide 96 is removed and placed in the temporary storage tank 15 for recycling. The frame is then closed again to prepare for the next step.

[0192] The filtrate A extracted from the temporary storage tank 11 is pumped to the aqueous solution heating and concentrating evaporator 165 for concentration, and the distilled water can be collected and reused. According to the process requirements, the concentrated solution of filtrate A is pumped to the temporary storage tank 18 through pump 177 for temporary storage. The solution in tank 18 is added to the chemical reactor 156 to prepare the alkaline etching regeneration sub-liquid. Solid ammonium chloride is added to the concentrated solution of filtrate A in the chemical reactor 156 to supplement the chloride ion concentration. The ammonia content of the regeneration etching sub-liquid 106 is adjusted by adding liquid ammonia 132 and / or ammonia water 102. The prepared alkaline etching regeneration sub-liquid is reused in the alkaline etching production line 108.

[0193] The ammonia nitrogen impurity content of the filtrate B was still 70 mg / L after testing. The solution in the temporary storage tank 14 was to be processed later.

[0194] During the operation, the detection data of the workshop site is transmitted to the automatic detection and feeding controller 38 through the hydrogen detection device 48 and the chlorine detection device 49 for processing and safety interlocking of the production system.

[0195] A method for treating waste liquid from alkaline etching of circuit boards by acidification and precipitation, wherein the process steps are as follows:

[0196] (1) The alkaline copper chloride ammonia etching waste liquid of the circuit board with a pH of 8.3 that has been pre-treated for impurities removal is mixed with an acidic pH value adjuster that has been pre-treated for impurities removal to acidify until the pH value of the reaction solution reaches pH 7.9 and precipitated copper mud is precipitated.

[0197] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C.

[0198] (3) The filter residue C is mixed with an inorganic alkaline solution and then subjected to a deamination oxidation reaction with chlorine gas. During this period, sodium hydroxide is added through a solid feeder to maintain the pH value of the reaction solution at pH 7.5. The oxidant chlorine gas is added until the redox potential of the reaction solution reaches and is maintained in a numerical range of 850 mV or above. The temperature of the reaction solution is kept at room temperature and the reaction is carried out for 36 hours. After the reaction, the obtained solid-liquid mixture is subjected to solid-liquid separation to obtain a filtrate B and a filter residue D whose main component is copper hydroxide;

[0199] (4) washing the filter residue D obtained in step (3) with clean water to obtain a purified copper hydroxide recovery.

[0200] (5) The concentrated solution of filtrate A is prepared as alkaline etching regeneration liquid and reused in the alkaline etching production line.

[0201] This embodiment illustrates the recovery and processing of copper sludge by neutralizing the alkaline copper chloride ammonia etching waste liquid to be treated using an acidic pH adjuster to precipitate the copper sludge. A chlorine oxidant is then used to deammoniate and oxidize the precipitated copper sludge under alkaline conditions to produce copper hydroxide from the oxidation reaction of the copper chloride ammonia complex. During the electrolytic chlorine production process, hydrogen electrolyzed at the electrolytic cathode is directed to a hydrogen eliminator for safe disposal. Another feature of this embodiment is that the filtrate A produced during the neutralization and precipitated copper sludge reaction is heated, evaporated, and concentrated, and then prepared according to process requirements to produce a regenerated etching liquid for reuse in the alkaline etching production line.

[0202] Example 3

[0203] As shown in Figure 3, this is Example 3 of a method and device for precipitation treatment and reuse of copper chloride etching waste liquid from a circuit board according to the present invention, which mainly includes 2 reaction tanks, 3 solid-liquid separators, 12 temporary storage tanks, 4 solid feeders, 14 detection devices, a conveyor belt, two sets of electrolytic process chlorine generators (wherein the partitions 37 of the two electrolytic cells are both anion exchange membranes), two tail gas treatment tanks, two etching production lines, 1 automatic detection and feeding controller, and 1 solid heating device.

[0204] The reaction tank 1-1 is equipped with an impeller agitator 27, a sealed tank cover 114, a pH detection device 39, and a photoelectric colorimeter detection device 40. A flow meter 43 is installed on the connecting pipe between the reaction tank 1-1 and the solid-liquid separator 3. The reaction tank 1-2 is equipped with a sealed tank cover 117, a vacuum jet gas-liquid mixer 21, a hot and cold temperature exchanger 32, a pH detection device 45, an ORP detection device 46, a temperature detection device 47, and a liquid level detection device 48. A flow meter 49 is installed on the connecting pipe between the reaction tank 1-2 and the solid-liquid separator 4.

[0205] The solid-liquid separator 3-1 is a common filter press, the solid-liquid separator 3-2 is a titanium metal scraper rotary centrifuge, and the solid-liquid separator 3-3 is a common filter.

[0206] As shown in Figure 3, the multiple temporary storage tanks are used to temporarily store different solutions. Temporary storage tank 11 is used to prepare the acidic etching solution and is therefore equipped with a liquid reflux stirrer 29. Temporary storage tank 13 is used to prepare the alkaline etching solution and is therefore equipped with an impeller stirrer 28 and a hot and cold temperature exchanger 31 for heating. Temporary storage tank 12 stores hydrochloric acid, and temporary storage tank 18 stores sodium chlorate oxidant solution 146. Temporary storage tank 15 is used to mix the anolyte from the two electrolytic cells with the etching working solution on the etching line.

[0207] The solid feeder 128 is loaded with the filter residue C99 transported from the conveyor belt 131 and feeds it into the reaction tank 1-2 during operation.

[0208] The reaction tank 1-2 is provided with a solid feeder 129, which is loaded with solid sodium hydroxide 85 and sodium carbonate 90.

[0209] The acidic copper chloride etching solution to be treated mainly comprises copper chloride, ferric chloride, sodium chloride and hydrochloric acid, and has an acidity of 1 M. The pH value alkaline adjuster is an alkaline copper chloride ammonia etching solution, mainly comprising copper chloride ammonia, ammonia water, ammonium chloride and additives, and has a pH value of pH 7.5.

[0210] The anolyte in both chlorine generators A and B in the two electrolytic processes described above is an acidic etching working solution, while acidic copper chloride etching waste liquid also serves as the catholyte for A and B. A detection device 44, a hydrometer, is installed in the cathode compartment of electrolytic cell A. Its data is sent to an automatic detection and feeding controller 38 for processing, which controls a pump 178 to feed acidic etching waste liquid into the cathode compartment of electrolytic cell A, causing it to continuously electrolyze copper. This causes electrolytic cell A's anode to electrolyze chlorine and its cathode to electrolyze copper. The cathode compartment of electrolytic cell B is equipped with a detection device 50, a pH meter, and a redox potentiometer 51. Acidity meter 50 controls the hydrochloric acid in temporary storage tank 12 to be pumped to the cathode of electrolytic cell B via pump 185, ensuring an acidic cathode electrolyte. ORP meter 51 controls the oxidant in temporary storage tank 18 to be pumped to the cathode of electrolytic cell B via pump 186, ensuring neither copper nor hydrogen is electrolytically deposited at the cathode. This allows electrolytic cell B's anode to produce chlorine 95, which reacts with the oxidant at the cathode in an electrochemical reaction. During the process, the anolyte from both electrolytic cells is used to oxidize and regenerate the etching solution on the acid etching line via exchange tank 15, eliminating the need for the addition of external oxidant during the acid etching process. Furthermore, some chlorine 95 escaping from the anode is diverted to reaction tank 1-2 to participate in the chemical reaction. The amount of chlorine introduced is used by the ORP meter in detection device 46 in reaction tank 1-2 to control the output power of one or both of the electrolytic power supplies, as well as their on / off control, to achieve control over the amount of deammonification oxidant added.

[0211] During the reaction process, the solution in the reaction tank 1-2 is controlled by a pH meter of the detection device 45 to add a mixture of sodium hydroxide and sodium carbonate to adjust the pH value of the reaction solution.

[0212] The tail gas treatment tank is divided into an acidic tail gas treatment tank and an ammonia-alkaline tail gas treatment tank. The reaction liquid in the acidic tail gas treatment tank 162 is a sodium hydroxide solution 86, and the reaction liquid in the ammonia-alkaline tail gas treatment tank 163 is a sulfuric acid solution 133. According to the process design, the tail gas treatment tank can be installed with any one or two combinations of gas-liquid mixers. As shown in Figure 3, the acidic tail gas from each tank is introduced into the S inlet of tank 162 for treatment, and the ammonia-alkaline tail gas from each tank and the tail gas discharged by the solid heating device are introduced into the J inlet of tank 163 for treatment. The tail gas treatment tank is respectively equipped with a pH detection device 52 or 53, which prompts the need to replace the tail gas treatment reaction liquid according to the process requirements during operation. The device 163 is also equipped with a pneumatic agitator 30 to inject air into the tail gas treatment reaction liquid to help accelerate the reaction of ammonia with sulfuric acid.

[0213] The etching production line is provided with an acid etching production line 107 and an alkaline etching production line 108, so that the prepared acid etching regeneration sub-liquid 105 is reused in the acid etching line for etching. The alkaline etching sub-liquid 106 is put into the alkaline production line 108 for etching recycling.

[0214] The automatic detection and feeding controller 38 obtains sampling data from multiple detection devices and automatically controls the production process of the entire equipment.

[0215] Sodium sulfite solution 158 and sodium bisulfite solution 159 are prepared to wash the filter residue D, so that part of the sodium ferrate and sodium percuprate in the filter residue D100 is reduced to copper oxide and iron oxide.

[0216] The solid heating device 2 is used to perform high-temperature heat treatment and oxidation processing on the copper oxide and iron oxide after the reduction reaction of the filter residue D, so as to restructure the iron oxide and copper oxide and evaporate water.

[0217] This method treats the acidic copper chloride etching waste liquid, using alkaline copper chloride ammonia etching waste liquid as the alkaline pH adjuster. The process involves operating two tail gas treatment devices to treat the tail gas. Then, the acidic etching waste liquid 112 in the temporary storage tank 8 is added to the reaction tank 1-1 via pump 170. The impeller agitator 27 is activated, and various on-site data of the reaction liquid are transmitted to the automatic detection and feeding controller 38 via the pH detection device 39 and the temperature detection device 40 for processing. During the process, the pH meter controls pump 171 to add the alkaline etching waste liquid 113 from the temporary storage tank 9 to the reaction tank 1-1 for neutralization and precipitation. The pH value of the reaction liquid is controlled to pH 4.8, and copper sludge is precipitated after the neutralization reaction. The precipitated tail gas from the reaction tank 1-1 is then directed to the S inlet of the tail gas treatment tank 162 for treatment. According to the process, after the solution in reaction tank 1-1 has completed its reaction, valve 58 is opened and pump 172 is started to pump the solid-liquid mixture in reaction tank 1-1 into filter press 3 for solid-liquid separation. During this process, the pipeline flowmeter detection device 43 displays a reading indicating that liquid is flowing in the pipeline. When the reading of detection device 43 returns to zero, the material in reaction tank 1-1 has been completely extracted. Valve 58 is closed and pump 172 is shut down. Filtrate A97 from filter press 3 is pumped into temporary storage tank 10 through overflow buffer tank 120 and filtration device 5. The plates and frames of filter press 3 are opened, and the filter residue C99 is dropped onto conveyor belt 131 and transported to solid feeder 128. After the filter press is completed, the plates and frames of filter press 3 are reclosed to prepare for the next process. Filtrate A97 in temporary storage tank 10 is quantitatively distributed according to process requirements and pumped into temporary storage tank 11 and 13 via pump 175 and pumped into temporary storage tank 13 via pump 174. According to the process requirements, ammonium chloride 101, hydrochloric acid 111, and additive 103 are added to the temporary storage tank 11, and the liquid reflux stirrer 29 is started to prepare the acidic etching regeneration sub-liquid; according to the requirements, ammonium chloride 101, ammonia water 102, additive 103, and liquid ammonia 132 are added to the temporary storage tank 13, and the impeller stirrer 28 and the hot and cold temperature exchanger 31 are started to prepare the alkaline etching regeneration sub-liquid. The hot and cold temperature exchanger 31 is used to adjust the temperature so that the alkaline etching regeneration sub-liquid reduces the escape of ammonia gas and can smoothly dissolve the ammonium chloride in the preparation process. The acidic etching regeneration sub-liquid 105 in the temporary storage tank 11 is added to the acidic etching production line 107 for etching recycling; the alkaline regeneration etching sub-liquid 106 prepared in the temporary storage tank 13 is added to the alkaline etching production line 108 for etching recycling.

[0218] The level of clean water 104 is controlled by the liquid level detection device 48 in the reaction tank 1-2. At the same time, the solid feeder 128 is turned on to quantitatively add filter residue C99 to the reaction tank 1-2. The pump 62 is turned on to operate the jet gas-liquid mixer 21. The hot and cold temperature exchanger 32 is turned on to adjust the temperature of the reaction liquid according to the process. The exhaust gas is directed to the S inlet of the exhaust gas treatment tank 162 for treatment. The solution in the reaction tank 1-2 is sampled for ammonia nitrogen concentration testing to obtain NH4 +The ion concentration is 28 g / L. The two electrolytic process chlorine generators are turned on, and a solid feeder 129 is controlled by a pH detection device 45 to add a mixture of sodium hydroxide 85 and sodium carbonate 90 to the reaction tank 1-2. The anolyte of both electrolytic cells is acidic copper chloride etching waste liquid. During the electrolysis process, two electrolytic anode tanks, overflow buffer tanks 124 and 126, and a temporary storage tank 15 are used to cause the anolyte to precipitate chlorine gas through a pump and pipeline and be introduced into the reaction tank 1-2 to participate in the reaction. The remaining chlorine gas undergoes an oxidation reaction with the cuprous and ferrous ions in the etching working solution. The copper ion concentration of the cathode electrolyte of electrolytic cell A is controlled by a pump 178 according to the set value of the specific gravity detection device 44 to add acidic copper chloride etching waste liquid 112 to the cathode region of electrolytic cell A, and copper metal is electrolytically deposited at the cathode. After the cathode electrolyte in electrolytic cell A is filled, any excess cathode electrolyte is pumped through overflow buffer tank 123 to temporary storage in temporary storage tank 14 or pumped to temporary storage tank 8. During the process, pH detection device 45, ORP detection device 46, temperature detection device 47, and liquid level detection device 48 transmit on-site sampling data to automatic detection and feeding controller 38 for processing and control. The pH value of the reaction liquid in reaction tank 1-2 is controlled to 14, the ORP value is controlled to be above 10 mV, and the temperature of the reaction liquid is controlled to 55°C. When the ammonia nitrogen concentration of the solution in reaction tank 1-2 is 40 mg / L after 18 hours of reaction according to process requirements, the process is considered complete and the electrolyzer, solid feeders 128 and 129, and pump 191 are shut down. Valve 79 is opened, pump 192 is started, and rotary centrifuge 4 is used to separate the solid-liquid mixture in reaction tank 1-2. During the process, flow meter detection device 49 displays the reading. Filtrate B is pumped through overflow buffer tank 125 into temporary storage tank 17 for further processing. Its components are primarily chloride and sodium ferrate solution, and ammonia nitrogen impurities are measured at 40 mg / L. Filter residue D is scraped off by the scraper on rotary centrifuge 4 and falls into temporary storage tank 16. When the flowmeter detection device 49 returns to zero, the solid-liquid mixture in reaction tank 1-2 has been completely extracted. Valve 79, pump 192, and rotary centrifuge 4 are then closed. Filter residue D100 is a solid mixture primarily composed of sodium percolate and impurities such as chloride. Sodium bisulfite 159 and sodium sulfite solution 158 are added to temporary storage tank 16 to react with the solid mixture, reducing the sodium percolate to copper oxide and a small amount of sodium ferrate to iron oxide. The solid-liquid mixture is then separated in solid-liquid separator 3-2 to produce solid residue copper oxide and iron oxide.

[0219] The copper oxide and iron oxide in the reduced solid slag are then fed into a solid heating device 2 for high-temperature heating. The solid heating device utilizes a combustion-exothermic reaction between combustible gas 147 and air 143. The heating process is performed at 650°C for one hour, and the copper oxide and iron oxide products produced at high temperature are recycled.

[0220] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0221] (1) Acidic etching waste liquid containing 1M / L hydrochloric acid to be treated is mixed with an alkaline pH adjuster, which is a circuit board alkaline etching waste liquid with a pH of 7.5, and reacted until the pH of the reaction solution reaches pH 4.8 and precipitated copper mud is precipitated.

[0222] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain a filtrate A and a filter residue C; wherein the filtrate A is divided into two portions with fixed volumes according to the process requirements to respectively prepare an acidic etching regeneration sub-liquid and an alkaline etching regeneration sub-liquid, wherein the acidic etching regeneration sub-liquid is returned to the acidic etching production line for etching recycling, and the alkaline etching regeneration sub-liquid is returned to the alkaline etching production line for etching recycling.

[0223] (3) The filter residue C is put into water and mixed with an inorganic base to form a suspension, and then subjected to a deamination oxidation reaction with chlorine. During the process, the pH value of the reaction liquid is controlled to pH 14, its redox potential is controlled to be above 10mv, the temperature of the reaction liquid is 55°C, and the reaction time is up to 18 hours. After the reaction, the resulting mixture is subjected to solid-liquid separation to obtain filtrate B and filter residue D whose main component is sodium percopperate.

[0224] (4) The solid slag after the reduction reaction is placed in a solid heating device for high-temperature oxidation treatment, so that the solid slag undergoes high-temperature reaction to become a new powder mixture of copper oxide and iron oxide for product recycling.

[0225] The characteristic of this embodiment is that a solution mixed with acidic and alkaline copper chloride etching waste liquid is used for neutralization and precipitation reaction. The obtained filtrate A is divided into two parts according to the process and reused as etching solution. The filter residue C is subjected to two impurity removal treatment methods, namely the deamination oxidation reaction of method (i) in step (3) and the heating oxidation reaction combined with method (ii). This makes the mixture of copper oxide and iron oxide easy to separate during use, and realizes 100% recovery and recycling of the acidic and alkaline copper chloride etching waste liquids when they are treated simultaneously in the production plant.

[0226] Example 4

[0227] As shown in FIG4 , a fourth embodiment of a method and apparatus for precipitation treatment and reuse of copper chloride etching waste liquid from a circuit board according to the present invention is shown, which includes: a reaction tank 1, five solid-liquid separators 3-1 to 3-5, 12 temporary storage tanks 8 to 19, five detection devices, two solid heating devices 2-1 and 2-2, a mechanical crushing device 140, a copper sludge and copper slag cleaning tank 110 with an impeller agitator, a pump, and a valve.

[0228] The reaction tank 1 is equipped with an impeller stirrer 27 and a pH meter detection device 39, which is connected to the solid-liquid separator 3-1 through a pipeline provided with a valve 58 and a pump 172;

[0229] The solid-liquid separators 3-1 to 3-3 are all ordinary filter presses, and the solid-liquid separator 3-4 is an ordinary wire-wound precision filter element filter.

[0230] The temporary storage tank 8 is used to store acidic etching waste liquid, the temporary storage tank 9 is used to store alkaline etching waste liquid, the temporary storage tank 10 is used to store the filter residue C99 from the solid-liquid separator 3-1, the temporary storage tank 11 is used to store the filtrate A97, the temporary storage tank 12 is used to prepare the acidic etching sub-liquid, the temporary storage tank 13 is used to prepare the acidic etching oxidant solution, the temporary storage tank 14 is used to prepare the alkaline etching regeneration sub-liquid, the temporary storage tank 15 is used to load the mixture 148 of copper oxide powder and iron oxide powder after mechanical crushing and water washing and filter pressing separation, and the temporary storage tank 16 is used to temporarily store the waste liquid of the water-washed copper oxide and iron oxide powder mixture 148.

[0231] The mechanical crusher 140 is used to mechanically process and crush the copper slag 148 after being processed by the solid heating device 2-1.

[0232] The solid heating device 2-1 is used to perform heating, oxidation and deamination reaction treatment on the filter residue C99 of the precipitated copper mud.

[0233] The solid heating device 2-2 is used to perform high-temperature oxidation treatment on the copper slag 148 that has been heated, crushed and washed.

[0234] The copper sludge and copper slag cleaning tank 110 with an impeller agitator is used to dissolve copper oxide using sulfuric acid to separate the copper oxide from the mixture 149 of iron oxide and manganese dioxide.

[0235] The alkaline copper chloride ammonia etching waste liquid to be treated is an aqueous solution with a pH of 8.8 containing ammonia water, ammonium chloride, copper chloride ammonia, and additives. The acidic pH value adjuster is an acidic copper chloride etching waste liquid, the main components of which are an acidic solution of hydrochloric acid, copper chloride, ferric chloride, and ammonium chloride, with an acidity of 3.5M / L.

[0236] The process flow of this method is to start pump 171 to pump the alkaline etching waste liquid from the temporary storage tank 9 into a certain volume of solution 113 into the reaction tank 1, and then start the impeller stirrer 27. Based on the pH meter of the detection device 39, pump 170 is controlled to add the acidic pH adjuster from the temporary storage tank 8 into the reaction tank 1 to react with the alkaline etching waste liquid 113. During this process, when the pH meter reaches the set value of pH 3.2, pump 53 is shut down, and a precipitate precipitates in the reaction solution. Valve 58 and pump 172 are opened to pump the solid-liquid mixture from the reaction tank 1 into the filter press 3 for solid-liquid separation. The resulting filtrate A is then directed to the temporary storage tank 11, and the filter residue C is retained in the filter press 3. After the solid-liquid mixture in the reaction tank 1 is completely extracted, valve 58 and pump 172 are shut down. The filter press 3 is opened, the filter residue C is removed, and placed in the temporary storage tank 10. The filter plate frame is then closed and prepared for the next process step. Valves 60 and 61 and pumps 174 and 175 are opened to pump a portion of filtrate A97 from temporary tank 11 into temporary tanks 12 and 13, respectively, to prepare the acidic etching regeneration solution and acidic etching oxidant solution. Simultaneously, the remaining portion of filtrate A is pumped via pump 173 into temporary tank 14 to prepare the alkaline etching regeneration solution. The prepared alkaline etching regeneration solution 106 is passed through filter 7 to remove insoluble matter.

[0237] The solid filter residue C99 is removed from the temporary storage tank 10 and placed in the solid heating device 2-1. This device uses an electric heater. The solid heating device 2-1 is turned on to heat the filter residue C directly at 120°C for 3 hours. After the thermal oxidation and ammonia removal reaction is complete as required by the process, the electric heating device 134 is turned off, and the copper slag 148 product is removed and transferred to the mechanical crushing device 140 for crushing. After crushing, the copper slag 148 is placed in the cleaning tank 109 and washed with water to remove soluble salt impurities in the copper slag 148. After the water washing is complete, the pump 179 is turned on to pump the solid-liquid mixture in the cleaning tank 109 to the solid-liquid separator 3-2 for solid-liquid separation. The waste water from the washing is drained to the temporary storage tank 16 for further treatment. The filter residue 148 separated from the solid-liquid separator 3-2 is placed in the temporary storage tank 15 for temporary storage.

[0238] The copper slag 148 in the tank 15 is placed in the electric solid heating device 2-2 and subjected to a high-temperature oxidation treatment at 850° C. During the process, the copper slag is stirred and tumbled for oxidation reaction for two hours, and then taken out and cooled.

[0239] Copper slag 149 and sulfuric acid solution 133 are added to cleaning tank 110 to prepare a copper sulfate solution. After the reaction is complete, pump 180 is activated to separate the solid-liquid mixture in tank 110 through solid-liquid separator 3-3. The resulting crude acidic copper sulfate solution is stored in temporary tank 18 and then finely filtered through a precision filter serving as solid-liquid separator 3-4 to yield a relatively pure acidic copper sulfate solution 151. The sulfuric acid-insoluble iron oxide and manganese dioxide are retained by solid-liquid separators 3-3 and 3-4, respectively. Solid-liquid separator 3-3 is then opened to remove iron oxide 152, which is then stored in temporary tank 17. After separating the manganese dioxide from iron oxide 152, the iron oxide is reused to prepare the acidic etching regeneration solution.

[0240] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0241] (1) mixing the circuit board alkaline etching waste liquid with a pH of 8.8 to be treated with an acidic pH adjuster to react until the pH of the reaction solution reaches pH 3.2 and precipitated copper mud is precipitated;

[0242] (2) performing solid-liquid separation on the mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C;

[0243] (3) The filter residue C is subjected to a first electric heating at 120° C. oxidation to remove ammonia, during which copper oxide and iron oxide are generated.

[0244] (4) Filtrate A is taken to prepare acidic etching regeneration liquid and acidic etching oxidant solution for reuse in the acid etching production line, and alkaline etching regeneration liquid is prepared for reuse in the alkaline etching production line.

[0245] (5) After the first electric heating oxidation treatment, the filter residue C is subjected to mechanical crushing and water washing for desalination, and the treated copper slag is subjected to electric heating at a high temperature of 850°C again for deammonification and / or dechlorination and / or decoppering of other metal impurities, thereby obtaining copper oxide powder, iron oxide powder and a trace amount of manganese dioxide impurity products.

[0246] (6) The copper oxide powder and the iron oxide powder are reacted with the sulfuric acid solution, and after fine filtration, an acidic copper sulfate solution and iron oxide powder are obtained. The iron oxide powder is reused in the preparation of the acidic etching regeneration liquid after separating the manganese dioxide impurities.

[0247] The characteristic of this embodiment is that acid and alkaline copper chloride etching waste liquids are mixed and neutralized and precipitated in the factory area of ​​a circuit board production enterprise. The process adopts method (ii) in step (3), which can reduce the process and equipment used for deamination oxidizing agents, is safe and simple to operate, and saves a large amount of equipment investment funds. Without adding new pollution sources, the mixed treatment of acid and alkaline copper chloride etching waste liquids can be easily achieved while achieving the ideal effect of 100% recycling and reuse.

[0248] Example 5

[0249] As shown in Figure 5, an embodiment of a method for precipitation treatment and recovery of copper chloride etching waste liquid of a circuit board of the present invention and its device is shown, which includes: reaction tanks 1-1 and 1-2, solid-liquid separators 3-1 and 3-2, temporary storage tanks 8~14, a spray tower gas-liquid mixing device 24, a hot and cold temperature exchanger 31, and a chemical reactor 156.

[0250] The reaction tank 1-1 is equipped with an impeller stirrer 27, a hot and cold temperature exchanger 31, and detection devices 41 and 42, each equipped with a pH meter and a redox potentiometer. Reaction tank 1-1 is connected to the solid-liquid separator 3-1 via a pipeline equipped with a valve 71 and a pump 56. Reaction tank 1-2 is equipped with an impeller stirrer 28, a pH meter as detection device 43, and a redox potentiometer as detection device 44. Reaction tank 1-2 is connected to the solid-liquid separator 3-2 via a pipeline equipped with a valve 75 and a pump 59.

[0251] The solid-liquid separators 3-1 and 3-2 are both ordinary filter presses;

[0252] The chemical reactor 156 is an electric heating reactor, in which an impeller stirrer is installed. The detection devices 39 and 40 of the pH meter and the thermometer are used to control the process of heating and removing ammonia from the alkaline etching waste liquid.

[0253] The temporary storage tank 8 is used to store alkaline copper chloride etching waste liquid 113, the temporary storage tank 9 is used to store a mixed solution of hydrochloric acid 111 and formic acid 142 as a pH adjuster, the temporary storage tank 10 is used to store the filter residue C99 squeezed out by the filter press 3, the temporary storage tank 11 is used to store the filtrate A97 from the solid-liquid separator 3-1, the temporary storage tank 12 is used to load the filter residue D100 separated from the solid-liquid separator 3-2, the temporary storage tank 13 is used to store the filtrate D98 from the solid-liquid separator 3-2, and the temporary storage tank 14 is used to store the sodium hypochlorite solution 93.

[0254] In addition, a solid feeder 128 is installed on the top of the reaction tank 1-2, which is filled with sodium hydroxide 85.

[0255] The alkaline copper chloride etching waste liquid 113 to be treated has a pH of 7.3 and is primarily composed of an aqueous solution of ammonium chloride, ammonium carbonate, ammonium bicarbonate, ammonia water, and cupric ammonium chloride. Its copper ion concentration is 90 g / L. The pH-adjusting agent is hydrochloric acid.

[0256] The recycling and regeneration process begins by activating pump 170 to pump the alkaline copper chloride etching waste liquid 113 from temporary storage tank 8 into chemical reactor 156. The impeller agitator and heater in the reactor are activated to heat the alkaline etching waste liquid 113 to remove ammonia. This ammonia removal process is controlled by the pH meter in detection device 39 and the thermometer in detection device 40. During this process, the operating temperature within the reactor is controlled at 95°C, and the pH of the heated reaction liquid in the reactor is controlled at pH 6.8. Ammonia-containing tail gas escaping from the reactor is directed to the spray tower gas-liquid mixing device 24 to prepare the regenerated etching sub-liquid for absorption and utilization. When the values ​​of detection devices 39 and 40 reach the process setpoints, the heater in the chemical reactor is shut off and the solution in the reactor is cooled. After the solution in the reactor cools, the concentrated slurry is pumped via pump 171 to the reaction tank 1-1 for the next step of the neutralization and copper salt precipitation chemical reaction. The reaction liquid in the reaction tank 1-1 is controlled by the pH meter of the detection device 41 to add the hydrochloric acid solution to the tank 9 by the pump 172. The process setting value of the pH meter in step (1) is pH 5.0. When the pump 172 adds the acidic adjuster hydrochloric acid, the pH value of the reaction liquid in the reaction tank 1-1 reaches pH 5.0 and a precipitate is precipitated. The reaction liquid is cooled by the hot-cold temperature exchanger 31 during the neutralization exothermic reaction. When the precipitate reaction is completed, the valve 59 and the pump 173 are opened to pump the solid-liquid mixture in the reaction tank 1-1 to the filter press 3 for solid-liquid separation, and the filtrate A is directed to the temporary storage tank 11. After the mixture in the reaction tank 1-1 is completely extracted, the valve 59 and the pump 173 are closed. The filter residue C is collected by opening the pressure plate of the filter press 3 and temporarily placed in the temporary storage tank 10. When the filter press 3 completes collecting the filter residue C solid, the plate frame is reclosed and waits for the next operation.

[0257] Filtrate A97 is pumped by pump 174 into the spray tower gas-liquid mixer 24 to prepare the alkaline etching regeneration liquid. This process involves absorbing ammonia-containing tail gas and adding ammonium carbonate, ammonium chloride, and ammonia water as raw materials. After testing by a laboratory technician to meet the regeneration liquid preparation standards, it is returned to the alkaline etching production line.

[0258] The solid residue C in the temporary storage tank 10 was added to the reaction tank 1-2. Valve 64 and pump 177 were opened to introduce sodium hypochlorite solution 93 into the reaction tank 1-2. A sample was taken for analysis and the ammonia nitrogen concentration was 11 g / L. The impeller agitator 28 was turned on. The pH meter in the detection device 43 and the redox potential meter in the detection device 44 were activated simultaneously. The detection device 44 controlled pump 177 to add the deammonification oxidant solution in the temporary storage tank 14 to the reaction tank 1-2. The ORP meter process setting value was 420 mV. While adding the deamination oxidant solution, the solid feeder 128 is turned on to feed sodium hydroxide 85 into the reaction tank 1-2. The amount of sodium hydroxide 85 added is controlled according to the pH meter of the detection device 43, which is the process setting value of pH 8.8 in step (3). The temperature of the reaction liquid is room temperature. When the ammonia nitrogen concentration is 140 mg / L after 34 hours of reaction, the deamination oxidation reaction is determined to be complete. The valve 63 and the pump 176 are turned on to pump the solid-liquid mixture in the reaction tank 1-2 into the filter press 4 for solid-liquid separation. The filtrate B98 is drained into the temporary storage tank 13, and the filter residue D100 is retained in the filter press 4. The filter press 4 is then turned on to collect the filter residue D retained in the filter press and temporarily placed in the temporary storage tank 12. The filter residue D is mainly composed of copper hydroxide after the deamination oxidation reaction.

[0259] The sodium hydroxide in the filter residue D is recycled. After the filtrate B in the temporary storage tank 13 is tested at that time, the ammonia nitrogen impurity still remains at 140 mg / L.

[0260] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0261] (1) removing ammonia from alkaline circuit board copper chloride etching waste liquid with a pH value of 7.3 by high temperature in a chemical reactor and then mixing with an acidic substance to react until the pH value of the reaction solution reaches pH 5.0 and copper mud is precipitated;

[0262] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C;

[0263] (3) The filter residue C is mixed with sodium hypochlorite to carry out a deamination oxidation reaction. During this period, sodium hydroxide 85 is added to the reaction tank through a solid feeder to maintain the pH value parameter of the reaction solution at pH = 8.8. The oxidant is added until the redox potential of the reaction solution reaches and is maintained above 520 mV for 34 hours, which is considered to be the completion of the reaction. After the reaction is completed, the solid-liquid mixture in the reaction tank 1-2 is subjected to solid-liquid separation to obtain filtrate B and filter residue D whose main component is copper hydroxide.

[0264] (4) Filtrate A is used to absorb the ammonia-containing tail gas discharged from the chemical reactor and is added with ammonium carbonate, ammonium chloride and ammonia water to prepare alkaline etching regeneration liquid, which is then reused in the alkaline etching production line.

[0265] The method is characterized in that the alkaline etching waste liquid is first subjected to a heating and ammonia removal reaction before the neutralization precipitation reaction to reduce the pH value of the original alkaline copper chloride etching waste liquid, thereby reducing the amount of the acidic pH value adjuster input, and the volume of the filtrate A97 obtained after the neutralization precipitation reaction will not be greater than the volume of the waste liquid to be treated.

[0266] This embodiment illustrates the use of the process of the present invention to treat alkaline copper chloride etching waste liquid for a separate recovery process, in which hydrochloric acid is added as an acidic pH adjuster for a neutralization precipitation reaction. After heating and removing ammonia, an acidic pH adjuster is added to generate ammonium chloride in the reaction solution to lower the pH value of the solution so that a copper salt precipitate is precipitated in the solution. Subsequently, the precipitated copper mud is subjected to a deamination and oxidation treatment using method (i) in step (3) to recover copper hydroxide. In the process, the alkaline etching waste liquid is subjected to a heating and ammonia removal treatment using a reactor, so that there is no excess filtrate A97 that cannot be reused after the waste liquid treatment, so that the entire recovery system does not generate a new source of pollution.

[0267] Example 6

[0268] As shown in Figure 6, this is Example 6 of a method and device for precipitation treatment and reuse of copper chloride etching waste liquid from a circuit board according to the present invention, which mainly includes 2 reaction tanks, 3 solid-liquid separators, 10 temporary storage tanks, 2 solid feeders, 14 detection devices, a conveyor belt, two sets of electrolytic process chlorine generators 33A and 33B (wherein the partition 37A of the electrolytic cell 33A is a cation exchange membrane, and the partition 37B of the electrolytic cell 33B is a filter cloth), two tail gas treatment tanks, two etching production lines, and 1 automatic detection and feeding controller.

[0269] The reaction tank 1-1 is equipped with an impeller agitator 27, a sealed tank cover 114, a pH detection device 39, and a photoelectric colorimeter detection device 40. A flow meter 43 is installed on the connecting pipe between the reaction tank 1-1 and the solid-liquid separator 3-1. The reaction tank 1-2 is equipped with a sealed tank cover 116, a vacuum jet gas-liquid mixer 21, a hot and cold temperature exchanger 32, a pH detection device 45, an ORP detection device 46, a temperature detection device 47, and a liquid level detection device 48. A flow meter 49 is installed on the connecting pipe between the reaction tank 1-2 and the solid-liquid separator 3-2.

[0270] The solid-liquid separator 3-1 is a common filter press, the solid-liquid separator 3-2 is a titanium metal scraper rotary centrifuge, and the solid-liquid separator 3-3 is a common filter.

[0271] As shown in FIG6 , the multiple temporary storage tanks are used to temporarily store different solutions. Temporary storage tank 11 is used to prepare the acidic etching solution, and is therefore equipped with a liquid reflux stirrer 29; temporary storage tank 14 is used to prepare the acidic etching oxidant solution; and temporary storage tank 13 is used to prepare the alkaline etching solution, and is therefore equipped with an impeller stirrer 28 and a hot and cold temperature exchanger 31 for heating.

[0272] The solid feeder 128 is loaded with the filter residue C99 transported from the conveyor belt 131 and feeds it into the reaction tank 1-2 during operation.

[0273] The reaction tank 1-2 is provided with a solid feeder 129, which is loaded with solid sodium hydroxide 85 and sodium carbonate 90.

[0274] The acidic copper chloride etching solution to be treated mainly comprises copper chloride, ammonium chloride and hydrochloric acid, and has an acidity of 1.8 M. The alkaline pH value adjuster is an alkaline copper chloride ammonia etching solution, mainly comprising copper chloride ammonia, ammonia water, ammonium chloride and additives, and has a pH value of pH 8.3.

[0275] In the treatment process step (3), method (i) is used for deamination and oxidation treatment.

[0276] Both electrolytic chlorine generators use acidic copper chloride etching wastewater as the anolyte and catholyte. Electrolytic cell 33A uses a cation exchange membrane as the separator, while electrolytic cell 33B uses filter cloth as the separator. During electrolysis, two anodes react to produce chlorine 95, while the cathode reacts to deposit copper. During the electrolysis process, acidic etching wastewater is continuously added to the anode compartments of the two electrolytic cells. This addition is controlled by a hydrometer 44 installed in the anode compartments and by a pump 182 controlled by a hydrometer 52. During the electrolysis process, chlorine 95 escaping from the two anode compartments and from the buffer tank 124 is directed by an ejector 21 to the reaction tank 1-2 to participate in the chemical reaction. The amount of chlorine gas introduced is controlled by the ORP meter of the detection device 46 in the reaction tank 1-2 to control the output power of the two electrolytic power supplies 36A and 36B and to turn them on and off to achieve the control of the amount of oxidant added for the deamination reaction.

[0277] During the reaction process, the solution in the reaction tank 1-2 is controlled by a pH meter of the detection device 45 to add a mixture of sodium hydroxide and sodium carbonate to adjust the pH value of the reaction solution.

[0278] The tail gas treatment tank is divided into an acidic tail gas treatment tank and an ammonia-alkaline tail gas treatment tank. The reaction liquid of the acidic tail gas treatment tank is a sodium hydroxide solution 86, and the reaction liquid of the ammonia-alkaline tail gas treatment tank is a sulfuric acid solution 133. According to the process design, the tail gas treatment tank can be installed with any one or two combinations of gas-liquid mixers. As shown in Figure 6, the acidic tail gas of each tank is introduced into the S inlet of tank 162 for treatment, and the ammonia-alkaline tail gas of each tank is introduced into the J inlet of tank 163 for treatment. pH detection devices 50 and 51 are respectively installed in the tail gas treatment tank, and during operation, it is prompted that the tail gas treatment reaction liquid needs to be replaced according to the process requirements. Tank 163 is also equipped with a pneumatic agitator 30 to inject air into the tail gas treatment reaction liquid to help ammonia accelerate the reaction with sulfuric acid.

[0279] The etching production line comprises an acid etching line 107 and an alkaline etching line 108. The prepared acid etching regeneration sub-liquid 105 and acid etching oxidant 146 are respectively fed back into the acid etching line via pumps 178 and 184 to react with the circuit copper plates. The alkaline etching sub-liquid 106 is then fed into the alkaline line 108 via pump 180 for recycling and etching with the circuit copper plates.

[0280] The automatic detection and feeding controller 38 obtains on-site sampling data from multiple detection devices and automatically controls the production process of the entire equipment.

[0281] This method treats the acidic copper chloride etching waste liquid, using an alkaline copper chloride ammonia etching waste liquid as the alkaline pH adjuster. The process involves activating two tail gas treatment devices, adding the acidic etching waste liquid 112 from the temporary storage tank 8 to the reaction tank 1-1 via pump 170, activating the impeller agitator 27, and transmitting various on-site data of the reaction liquid via a pH detector 39 and a temperature detector 40 to an automatic detection and feeding controller 38 for processing. During the process, the pH meter 39 controls the pump 171 to add the alkaline etching waste liquid 113 from the temporary storage tank 9 to the reaction tank 1-1 for neutralization and precipitation. The pH value of the reaction liquid is controlled to pH 5.2, causing copper sludge to precipitate. The precipitated tail gas from the reaction tank 1-1 is then directed to the S inlet of the tail gas treatment tank 162 for treatment. According to the process, when the solution in reaction tank 1-1 has completed its reaction, valve 58 is opened and pump 172 is started to pump the solid-liquid mixture in reaction tank 1-1 into filter press 3 for solid-liquid separation. During this process, the pipeline flow meter detection device 43 displays a reading indicating that liquid is flowing in the pipeline. When the reading of detection device 43 returns to zero, indicating that the material in reaction tank 1-1 has been completely extracted, valve 58 is closed and pump 172 is shut down. Filtrate A97 flowing from filter press 3 is pumped into temporary storage tank 10 through overflow buffer tank 120 and filter device 5. The plates and frames of filter press 3 are opened, and the filter residue C99 is removed and dropped onto conveyor belt 131, where it is transported to solid feeder 128. After the filter press 3 has completed unloading, the plates and frames of filter press 3 are reclosed and prepared for the next process. Filtrate A97 from temporary storage tank 10 is quantitatively distributed according to process requirements and pumped into temporary storage tanks 11, 13, and 14, respectively, via pumps 176, 175, and 174. Ammonium chloride 101, hydrochloric acid 111, and additive 103 are added to temporary storage tank 11 according to process requirements, and liquid reflux agitator 29 is activated to prepare an acidic etching regeneration solution. Ammonium chloride 101, ammonia water 102, and additive 103 are added to temporary storage tank 13 according to requirements, and impeller agitator 28 and hot / cold temperature exchanger 32 are activated to prepare an alkaline etching regeneration solution. The hot / cold temperature exchanger 31 is used to regulate the temperature of the alkaline etching regeneration solution, minimizing ammonia gas emission while ensuring the endothermic dissolution of ammonium chloride during the preparation process. Sodium hydroxide 85 is added to temporary storage tank 14 to adjust the pH to neutral, and then sodium chlorate 144 is added to prepare an acidic etching oxidant solution 146.

[0282] The liquid level of clean water 104 is controlled by the liquid level detection device 48 in reaction tank 1-2. Simultaneously, the solid feeder 128 is activated to quantitatively add filter residue C99 to reaction tank 1-2. Pump 62 is activated to operate the jet gas-liquid mixer 21. The hot and cold temperature exchanger 32 is activated to adjust the reaction liquid temperature according to the process. The exhaust gas is directed to the S inlet of the exhaust gas treatment tank 162 for treatment. The solution in reaction tank 1-2 is sampled and tested for ammonia nitrogen concentration, which is 126 g / L. The two electrolytic chlorine generators are activated, and the solid feeder 129 is controlled by the pH detection device 45 to add a mixture of sodium hydroxide 85 and sodium carbonate 90 to reaction tank 1-2. The anolyte in each of the two electrolytic chlorine generators is acidic copper chloride etching wastewater. The chlorine produced by the anode during operation deammonifies and oxidizes the material in reaction tank 1-2, while the cathode electrodeposit copper. The copper ion concentration in the anolyte of each electrolyzer is controlled by controlling pumps 182 and 183 to add acidic copper chloride etching waste liquid 112 to the anode compartments of the two electrolytic cells, respectively, based on the set values ​​of specific gravity detection devices 44 and 52. The catholyte is a mixture of acidic copper chloride etching waste liquid 112 and electroplating copper brightener 166. Because electrolytic cell 33A is separated by a cation exchange membrane and electrolytic cell 33B by a filter cloth, copper ions in the two anode compartments migrate to the cathode compartment under the action of the electric field, where they are electrolytically deposited as metallic copper. During this process, pH detection device 45, ORP detection device 46, temperature detection device 47, and liquid level detection device 48 installed on reaction tank 1-2 transmit on-site sampling data to automatic detection and feeding controller 38 for processing and control. The pH of the reaction liquid in reaction tank 1-2 was controlled at pH 11, the ORP value was controlled to be above 1 mV, and the temperature of the reaction liquid was maintained at 5°C. After 52 hours of reaction, a sample was taken to test the ammonia nitrogen concentration in the reaction liquid, which was 80 mg / L. Once completed, the electrolyzer, solid feeders 128 and 129, and pumps 182, 183, and 187 were shut down. Valve 73 was opened, and pump 188 and rotary centrifuge 4 were activated to separate the solid-liquid mixture in reaction tank 1-2. During this process, flowmeter detection device 49 provided the reading. Filtrate B was pumped through overflow buffer tank 125 into temporary storage tank 17 for further processing. Testing at that time revealed that filtrate B still contained 80 mg / L of ammonia nitrogen. Filter residue D was scraped off by the scraper on rotary centrifuge 4 and dropped into temporary storage tank 16. When the flowmeter detection device 49 returns to zero, the solid-liquid mixture in the reaction tank 1-2 has been completely extracted. Valve 73, pump 188, and rotary centrifuge 4 are then closed. The resulting residue D100 primarily consists of a solid mixture of copper hydroxide and copper carbonate. Clean water 104 is added to the temporary storage tank 16 to wash the solid copper compounds and remove any soluble salts.

[0283] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0284] (1) mixing a 1.8 M / L acidic etching waste liquid containing hydrochloric acid to be treated with an alkaline pH adjuster, which is a circuit board alkaline etching waste liquid with a pH of 8.3, to react until the pH of the reaction solution reaches pH 5.2 and precipitated copper mud is precipitated;

[0285] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C; and distributing the filtrate A into three portions of fixed volume according to the process requirements, and using them to re-prepare the acid etching regeneration sub-liquid, the acid etching oxidant solution and the alkaline etching regeneration sub-liquid, respectively; the acid etching regeneration sub-liquid and the acid etching oxidant solution are returned to the acid etching production line for etching recycling, and the alkaline etching regeneration sub-liquid is returned to the alkaline etching production line for etching recycling.

[0286] (3) The filter residue C is put into water and mixed with an inorganic base to form a suspension, and then subjected to a deamination oxidation reaction with chlorine. During the process, the pH value of the reaction liquid is controlled to pH 11, its redox potential is controlled to be above 1 mV, and the temperature of the reaction liquid is controlled to be 5°C. After the reaction is carried out for 52 hours, the resulting mixture is subjected to solid-liquid separation to obtain a filtrate B and a filter residue D whose main components are a solid mixture of copper hydroxide and copper carbonate.

[0287] (4) Wash the solid copper compound with water to remove soluble salts.

[0288] This embodiment is characterized by utilizing acidic and alkaline copper chloride etching waste liquids to undergo a neutralization precipitation reaction. The resulting filtrate A is divided into three portions according to the process for reuse as etching solution. The filter residue C is subjected to a deamination oxidation reaction in method (i) of step (3), and the filter residue D is then washed with water to obtain a solid copper compound. The acidic and alkaline copper chloride etching waste liquids are thereby treated in an environmentally friendly manner within the production plant, achieving 100% recycling of the waste liquids.

[0289] Example 7

[0290] As shown in FIG7 , the embodiment 7 of the method and apparatus for precipitation treatment and reuse of copper chloride etching waste liquid of a circuit board according to the present invention comprises: a reaction tank 1, two solid-liquid separators 3-1 and 3-2, 10 temporary storage tanks 8 to 17, 12 detection devices, a solid heating device 2, a mechanical crushing device 140, a copper mud and copper slag cleaning tank 110 with an impeller agitator, an exhaust gas processor 162 of a spray tower gas-liquid mixing device, a pump, and a valve.

[0291] The reaction tank 1 is equipped with an impeller stirrer 27, a detection device 39, a pH meter, and a liquid level meter 40, which are connected to the solid-liquid separator 3-1 through a pipeline provided with a valve 57 and a pump 171;

[0292] The solid-liquid separators 3-1 and 3-2 are both ordinary filter presses.

[0293] The temporary storage tank 8 is used to store acidic etching waste liquid, the temporary storage tank 9 is used to store filter residue C99, the temporary storage tank 10 is used to store filtrate A97 from the solid-liquid separator 3-1, the temporary storage tank 11 is used to store the acidic etching regeneration sub-liquid, the temporary storage tank 12 is used to prepare the acidic etching oxidant solution, the temporary storage tank 13 is used to store the acidic etching oxidant solution 146, the temporary storage tank 14 stores the acidic etching regeneration sub-liquid 105, the temporary storage tank 15 is used to load the washed copper oxide powder discharged from the filter press 4, and the temporary tank 16 is used to store the waste liquid of the washed copper oxide flowing out of the filter press 4.

[0294] The solid heating device 2 is used to perform heating, oxidation and deamination reaction treatment on the filter residue C99 of the precipitated copper mud.

[0295] The mechanical crusher 140 is used to mechanically process and crush the copper slag 148 after being processed by the solid heating device 2.

[0296] The copper sludge and copper slag cleaning tank 110 with an impeller agitator is used to wash the copper slag 148 with water to remove soluble impurities.

[0297] The detection device 39 is a pH meter, 40 is a liquid level meter, 41 is a liquid level meter, 42 is an acidity meter, 43 is a pH meter, 44 is a hydrometer, 45 is an acidity meter, 46 is a hydrometer, 47 is a redox potentiometer, 48 is a liquid level meter, 49 is a hydrometer, and 50 is a thermometer.

[0298] The acidic copper chloride etching waste liquid to be treated has an acidity of 1.2M / L, a copper ion concentration of 140 g / L, and an ammonium chloride concentration of 7 g / L. The alkaline pH adjuster is ammonium carbonate, ammonium bicarbonate, ammonia water, or liquid ammonia.

[0299] The process flow of this method is to start pump 170 to pump the acidic etching waste liquid from the temporary storage tank 8 into a certain volume of solution 112 into the reaction tank 1, and start the impeller stirrer 27. The addition of an external alkaline pH adjuster is controlled by the pH meter of the detection device 39. During the process, all external alkaline pH adjusters are shut off when the pH meter reaches the set value of pH 4.5. A precipitate of alkaline copper chloride and copper ammonia complex precipitates in the reaction solution. Valve 57 and pump 171 are opened to pump the solid-liquid mixture from the reaction tank 1 into the filter press 3 for solid-liquid separation. The resulting filtrate A is directed to the temporary storage tank 10, and the filter residue C is retained in the filter press 3. After the solid-liquid mixture in the reaction tank 1 is completely extracted, valve 57 and pump 171 are closed. The filter press 3 is opened, the filter residue C99 is removed, and placed in the temporary storage tank 9. The filter press plate frame is then closed to prepare for the next process step. Open valves 58 and 59 and pumps 172 and 173 to pump the filtrate A97 in temporary storage tank 10 to temporary storage tanks 11 and 12 respectively to prepare acid etching regeneration solution and acid etching oxidant solution. Pump the prepared solutions into temporary storage tanks 13 and 14 respectively for temporary storage.

[0300] The solid filter residue C99 is removed from the temporary storage tank 9 and placed in the solid heating device 2. This device uses an electric heater. The solid heating device 2 is turned on to heat the filter residue C directly at 400°C for 3 hours. After the thermal oxidation reaction to remove ammonia is completed as required by the process, the electric heating device 134 is turned off, and the copper slag 148 product is removed and transferred to the mechanical crushing device 140 for crushing. After crushing, the copper slag 148 is placed in the cleaning tank 109 and washed with water to remove soluble salt impurities in the copper slag 148. After the water washing is completed, the pump 180 is turned on to pump the solid-liquid mixture in the cleaning tank 109 to the solid-liquid separator 3-2 for solid-liquid separation. The waste water from the washing is drained to the temporary storage tank 16 for further treatment. The copper oxide in the filter residue 161 separated from the solid-liquid separator 3-2 is temporarily stored in the temporary storage tank 15.

[0301] During the heating and ammonia removal process, the acidic tail gas containing ammonium chloride escapes from the solid heating device 2 and is directed to the spray tower 24 for absorption treatment. The waste liquid from the tail gas treatment device 162 is retained for further treatment. The device 162 is equipped with a liquid level meter 48 and a hydrometer 49 to control the replacement of the tail gas absorption liquid.

[0302] A method for precipitating and treating waste copper chloride etching liquid for circuit board and reusing it, wherein the process steps are as follows:

[0303] (1) mixing the circuit board acidic etching waste liquid to be treated with an alkaline pH adjuster to react until the pH value of the reaction solution reaches pH 4.5 and precipitated copper mud is precipitated;

[0304] (2) performing solid-liquid separation on the mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C;

[0305] (3) The filter residue C is subjected to an oxidative treatment to remove ammonia by electric heating at 400°C, during which copper oxide is generated.

[0306] (4) Filtrate A is taken to prepare acid etching regeneration liquid and acid etching oxidant solution respectively and reused in the acid etching production line.

[0307] (5) The copper slag after the heating and oxidation treatment is subjected to mechanical crushing and water washing and desalting treatment, and a copper oxide powder product is obtained after solid-liquid separation.

[0308] The characteristic of this embodiment is that the acidic copper chloride etching waste liquid is subjected to a mixing, neutralization, and precipitation reaction in the factory area of ​​a circuit board production enterprise. The method (ii) in step (3) is adopted in the process. This method can reduce the process and equipment used for deamination oxidants, is safe and simple to operate, and saves a large amount of equipment investment funds. After further environmental protection treatment of the ammonia nitrogen-containing wastewater generated in the process, the acidic copper chloride etching waste liquid can achieve the ideal effect of 100% recycling and reuse without using the electrolytic copper extraction method.

[0309] Example 8

[0310] As shown in Figure 8, this is Example 8 of a method and device for precipitation treatment and reuse of copper chloride etching waste liquid from a circuit board according to the present invention, which mainly includes 2 reaction tanks, 4 solid-liquid separators, 8 temporary storage tanks, 2 hot and cold temperature exchangers, 1 water-oil separator, 1 solid feeder, 1 electrolytic process chlorine generator, 1 copper mud and copper slag cleaning tank with impeller stirring, 14 sensors, 1 automatic detection and feeding controller, 1 hydrogen eliminator, 1 chemical reactor 156, and 1 carbon dioxide source.

[0311] The reaction tank 1-1 is equipped with an impeller stirrer 27, a sealed tank cover 114, a hot and cold temperature exchanger 31, a pH detection device 39, a specific gravity detection device 40, a temperature detection device 41, and a liquid level detection device 42. The reaction tank 1-2 is equipped with a sealed tank cover 115, a liquid reflux stirrer 29, a hot and cold temperature exchanger 32, a spray tower gas-liquid mixing device 24, a pH detection device 43, an oxidation-reduction potential (ORP) detection device 44, a temperature detection device 45, and a liquid level detection device 46.

[0312] The solid-liquid separator 3-1 is a filter with a common filter medium structure, while the solid-liquid separators 3-2 to 3-4 are common plate and frame filter presses.

[0313] The temporary storage tank is used to temporarily store different solutions as shown in Figure 2. The temporary storage tank 10 is equipped with an impeller stirrer 28 and a liquid level gauge of a sensor 50.

[0314] The water-oil separator 20 and the solid-liquid separator 3-1 remove impurities from the alkaline copper chloride ammonia etching waste liquid that needs to be treated. After the impurities are removed, the waste liquid is respectively drained to the temporary storage tank 9 for storage.

[0315] The acidic pH adjuster comprises carbon dioxide gas 202 and hydrochloric acid 111. The alkaline copper ammonia chloride etching waste liquid 113 to be treated has a pH of 8.3, and its main components are a mixture of ammonia water, ammonium chloride and copper ammonia chloride.

[0316] The solid feeder 128 is loaded with sodium hydroxide 85, which is added to the reaction tank 1-2 to adjust the pH value of the deamination oxidation reaction solution.

[0317] The electrolytic cell separator 37 in the electrolytic chlorine generator is a cation exchange membrane. Sodium chloride solution is electrolyzed to produce chlorine 95, hydrogen, and sodium hydroxide solution 86. The electrolyzed hydrogen is directed through a vacuum jet gas-liquid mixing device 22 to a hydrogen eliminator 160 for reaction with an oxidant for safe disposal. Chlorine 95 is then directed through a spray tower 24 to reaction tank 1-2 to participate in the chemical reaction.

[0318] The automatic detection and feeding controller 38 obtains field data through multiple detection devices for automatic control of the production process of the entire equipment.

[0319] The copper mud and copper slag cleaning tank 110 with impeller stirring is specially used for washing filter residue D with water, and a pH value detection device 47 and a photoelectric colorimetric detection device 51 are installed in the tank to detect the pH and copper salt concentration in the washing liquid and remove impurities from the copper hydroxide therein.

[0320] The process flow of this method adopts the process method of mode (i) in step (3), and the alkaline copper chloride ammonium etching waste liquid 113 to be treated is pumped into the water-oil separator 20, and is pumped into the temporary storage tank 9 after being subjected to impurity removal treatment by the filter 4. The pump 172 is turned on to pump the alkaline etching waste liquid into the reaction tank 1-1 at a constant volume. The agitator 27 and the hot and cold temperature exchanger 31 are turned on. The reaction liquid is sampled and tested for temperature, copper ion concentration, pH value and liquid level by the thermometer of the detection device 41, the hydrometer of the detection device 40, the pH meter of the detection device 39 and the liquid level meter of the detection device 42, and the on-site detection data is transmitted to the automatic detection and feeding controller 38 for processing and program execution. According to the process procedure, the solution in reaction tank 1-1 is treated by opening valve 63 to introduce carbon dioxide gas 202 into the solution in tank 1 via vacuum ejector 21 for a gas-liquid mixing reaction, lowering the pH of the reaction solution to pH 7.2 and causing solid precipitation. Subsequently, control pump 170 is activated to inject an acidic pH adjuster into the solution in reaction tank 1-1, adjusting the pH to pH 7.0 and causing a large amount of precipitate to form in the reaction solution. During this process, a hot / cold temperature exchanger 31 maintains the temperature of the reaction solution at room temperature. When the hydrometer in detection device 40 reaches the set value, the precipitation reaction is complete. Valve 60 is opened and pump 174 is activated to pump the solid-liquid mixture in reaction tank 1-1 to filter press 5 for solid-liquid separation. Once the solution in reaction tank 1-1 is evacuated, valve 60 is closed and pump 174 is shut down. Filtrate A97 is drained to temporary storage tank 11 for future use, while residue C is retained in filter press 5. After completing the treatment work in the reaction tank 1, open the filter press 5 plate frame, remove the filter residue C and place it in the temporary storage tank 10. The main component of the filter residue C is copper chloride ammonia complex salt. Close the filter press 5 plate frame again to prepare for the next process. The sodium hydroxide solution 86 in the temporary storage tank 12 is added to the temporary storage tank 10 according to the control of the liquid level detection device 50, and the impeller stirrer 28 is turned on to dissolve the precipitate into a suspension solution. The suspension in the tank 10 is tested for ammonia nitrogen by the operator. The NH4 +The ion concentration is 21 g / L. The suspension in the temporary storage tank 10 is completely added to the reaction tank 1-2 by opening valve 61 and pump 175. After the solution in the temporary storage tank 10 is evacuated, valve 61 and pump 175 are closed, pump 184 and liquid reflux agitator 29 are opened, and the jet pump 189 in the hydrogen eliminator 160 is opened to generate a vacuum pressure in the ejector 22 to prepare for the absorption of the electrolyzed hydrogen. The electrolytic process chlorine generator, solid feeder 128, and hot and cold temperature exchanger 32 are opened to allow the deamination oxidation reaction to proceed normally. During the process, the on-site detection data of the pH detection device 43, the ORP detection device 44, the temperature detection device 45, the liquid level detection device 46 and the ORP detection device 47 in the hydrogen eliminator 160 are transmitted to the automatic detection and feeding control machine 38 for processing. The controller 38 adjusts the output current of the electrolysis power supply according to the on-site deamination oxidation reaction conditions and the ORP value and pH value of the solution to control the electrolytic precipitation amount of chlorine and perform feeding control on the solid feeder 128. At the same time, the pump 188 is used to add oxidant to the hydrogen eliminator 160 based on the data of the detection device 47. When the process reaction tank 1-2 is operated, its ORP value is controlled to be above 950mv, the pH value is controlled to be pH7.5, the temperature of the reaction liquid is controlled at room temperature and maintained for 36 hours, and the NH4 + The reaction is complete when the ion concentration reaches 50 mg / L. The chlorine generator, pumps 183 and 184, agitator 29, and hot / cold temperature exchanger 32 of the electrolysis process are shut down. Valve 72 and pump 185 are opened to pump the solid-liquid mixture in reaction tank 1-2 into filter press 6 for solid-liquid separation. Filtrate B is drained into temporary storage tank 14, and filter residue D, whose main component is copper hydroxide, is retained in filter press 6. Once the mixed liquid in reaction tank 1-2 has been completely extracted, valve 72 and pump 185 are closed. The filter press 6 is opened, and the filter residue D100 is removed and placed in a copper sludge and copper slag cleaning tank 110 equipped with an impeller agitator. Clean water 104 is added to the cleaning tank 110, and the impeller agitator is turned on for cleaning. The pH value of the washing solution and the copper salt concentration in the solution are determined using the pH detection device 47 and the photoelectric colorimeter detection device 51. Once the cleaning requirements are met, valve 73 and pump 186 are opened to pump the solid-liquid mixture in tank 110 into the filter press 7 for solid-liquid separation. The filtrate is then drained back to the temporary storage tank 16 for further processing, while the filter residue copper hydroxide 96 is retained in the filter press 7. Once the solid-liquid mixture in tank 110 has been extracted, valve 73 is closed and pump 186 is turned off. The filter press 7 is opened, and the filter residue copper hydroxide 96 is removed and placed in the temporary storage tank 15 for recycling. The frame is then closed again to prepare for the next step.

[0321] The filtrate A is concentrated according to the process requirements. The solution in the tank 11 is pumped to the chemical reactor 156 to prepare the alkaline etching regeneration sub-liquid. Solid ammonium chloride is added to the concentrated solution of the filtrate A in the chemical reactor 156 to replenish the chloride ion concentration. The ammonia content of the regeneration etching sub-liquid 106 is adjusted by adding liquid ammonia 132 and / or ammonia water 102. The prepared alkaline etching regeneration sub-liquid is reused in the alkaline etching production line 108.

[0322] The filtrate B was tested and the ammonia nitrogen impurity content still remained at 50 mg / L. The filtrate B was then drained into the temporary storage tank 14 to be used as an oxidant in the subsequent treatment.

[0323] During the operation, the detection data of the workshop site is transmitted to the automatic detection and feeding controller 38 through the hydrogen detection device 48 and the chlorine detection device 49 for processing and safety interlocking with the production system.

[0324] A method for treating waste liquid from alkaline etching of circuit boards by acidification and precipitation, wherein the process steps are as follows:

[0325] (1) The alkaline copper chloride ammonia etching waste liquid of the circuit board with a pH of 8.3 that has been pre-treated for impurity removal is mixed with carbon dioxide gas, which is an acidic pH value adjuster, to react with the gas and liquid to acidify the reaction solution, so that the pH value of the reaction solution is reduced to pH 7.2. Subsequently, hydrochloric acid is continuously added until the pH value of the reaction solution reaches pH 7.0 and copper mud is precipitated.

[0326] (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain filtrate A and filter residue C.

[0327] (3) The filter residue C is mixed with an inorganic alkaline solution and then subjected to a deamination oxidation reaction with chlorine gas. During this period, sodium hydroxide is added through a solid feeder to maintain the pH value of the reaction solution at pH 7.5. The oxidant chlorine gas is added until the redox potential of the reaction solution reaches and is maintained in a numerical range above 950 mV. The temperature of the reaction solution is kept at room temperature and the reaction is carried out for 36 hours. After the reaction, the obtained solid-liquid mixture is subjected to solid-liquid separation to obtain a filtrate B and a filter residue D whose main component is copper hydroxide;

[0328] (4) washing the filter residue D obtained in step (3) with clean water to obtain a purified copper hydroxide recovery.

[0329] (5) The concentrated solution of filtrate A is prepared as alkaline etching regeneration liquid and reused in the alkaline etching production line.

[0330] This example illustrates the recovery and processing of copper sludge by neutralizing alkaline copper chloride ammonia etching wastewater in need of treatment using carbon dioxide gas and hydrochloric acid as acidic pH adjusters to precipitate copper sludge. Carbon dioxide is first used to react with free ammonia in the wastewater to produce ammonium bicarbonate, thereby lowering its pH. This prevents a significant increase in the volume of the neutralization reaction solution, preventing the volume of filtrate A97 from increasing and potentially causing waste liquid discharge that cannot be reused. Chlorine gas is then used as an oxidant to deammoniate and oxidize the precipitated copper sludge under alkaline conditions. During the deammoniate and oxidization process, sodium percolate is difficult to form even at high redox potentials due to the low pH and alkalinity of the reaction solution. Consequently, copper hydroxide is produced by the oxidation of the copper chloride ammonia complex. During the electrolytic chlorine production process, hydrogen generated by electrolysis at the cathode is directed to a hydrogen eliminator, where it is safely treated using filtrate D98 as an oxidant to react with the hydrogen. In this example, filtrate A produced during the neutralization reaction of the precipitated copper sludge is prepared according to process requirements to produce a regenerated etching sub-liquid for reuse in the alkaline etching production line.

Claims

1. A method for precipitating and treating waste copper chloride etching liquid containing ammonium and / or ammonia for recycling circuit boards, characterized in that: The process steps are as follows: (1) mixing a circuit board copper chloride etching waste liquid with a pH adjuster to react, so that copper salt precipitates in the solution, and at least one of the circuit board copper chloride etching waste liquid and the pH adjuster comprises the circuit board copper chloride etching waste liquid containing ammonium and / or ammonia; (2) performing solid-liquid separation on the solid-liquid mixture obtained after the reaction in step (1) to obtain a filtrate A and a filter residue C; (3) deammoniating the filter residue C to generate a recovered copper product; (4) Reusing all or part of the filtrate A directly or after being prepared as an etching regeneration sub-liquid and / or etching oxidant solution in the circuit board copper chloride etching system.

2. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 1, wherein: The main component of the copper product recovered in step (3) is at least one of copper hydroxide, copper carbonate, basic copper carbonate, copper oxide, and cuprate.

3. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 1, wherein: The pH adjuster in step (1) includes two types of pH adjusters: an acidic pH adjuster and an alkaline pH adjuster. The acidic pH adjuster is at least one of circuit board acidic copper chloride etching waste liquid, hydrochloric acid, an organic acid, and carbon dioxide; the alkaline pH adjuster is at least one selected from circuit board alkaline copper chloride ammonia etching waste liquid, sodium hydroxide, potassium hydroxide, ammonia and / or ammonium hydroxide, sodium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate, and ammonium bicarbonate; the organic acid in the acidic pH adjuster is formic acid.

4. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 3, wherein: When the acidic pH adjuster contains carbon dioxide, the pH of the alkaline copper chloride etching waste liquid of the circuit board is first adjusted downward by using the carbon dioxide until copper salt precipitates and the resulting pH is greater than 7. Then, the pH is further adjusted downward by using at least one of the acidic copper chloride etching waste liquid of the circuit board, hydrochloric acid, and an organic acid. When the pH is further adjusted downward by using the acidic pH adjuster of at least one of the acidic copper chloride etching waste liquid of the circuit board, hydrochloric acid, and an organic acid, the resulting pH is not less than 7, so as to generate as much copper salt precipitate as possible and avoid the release of a large amount of carbon dioxide.

5. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 1, wherein: The deamination treatment in step (3) is carried out by at least one of the following methods: (i) mixing the filter residue C with a deamination oxidizing agent to carry out a deamination oxidation reaction treatment; (ii) directly heating and oxidizing the filter residue C to remove ammonia.

6. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 5, wherein: The deamination oxidant is hypochlorite and / or chlorine, and the ammonium salt and / or ammonia in the filter residue C are removed by utilizing the oxidizing property of hypochlorite and / or chlorine. Nitrogen is generated during the reaction process. The hypochlorite is specifically potassium hypochlorite and / or sodium hypochlorite. When the deamination oxidation reaction is used in the step (3), an inorganic base is added to the reaction mixture during the deamination treatment process to maintain the pH value of the reaction solution at ≥6.

8.

7. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 6, wherein: When the filter residue C contains iron hydroxide, deamination oxidation reaction treatment is carried out at a higher reaction solution alkalinity, reaction solution ORP value and reaction temperature.

8. The method for reusing the circuit board copper chloride etching waste liquid by precipitation treatment according to claim 1, wherein: In step (4), there are several implementation methods as follows: When it is only needed to be reused in the alkaline etching process, take the filtrate A and mix it with ammonia water, liquid ammonia, ammonium chloride, and other additives according to the process requirements. At least one of the agents is prepared to obtain an alkaline etching regeneration liquid, and the alkaline etching regeneration liquid is recycled to the alkaline etching production line; When it only needs to be reused in the acid etching process, filtrate A is taken to prepare acid etching regeneration sub-liquid and / or acid etching oxidant respectively and reused in the acid etching production line. At this time, the reuse amount of filtrate A is allocated according to the process conditions to be the acid regeneration etching sub-liquid and the acid etching oxidant solution. During the preparation process, filtrate A is prepared according to the process requirements and reused as the regeneration etching sub-liquid in the acid etching system. If filtrate A is acidic, it is directly or after preparation and reused as the acid regeneration etching sub-liquid in the acid etching system; When filtrate A is used to prepare an acidic etching oxidant and then reused in the acidic etching system, if filtrate A is acidic, filtrate A is adjusted to neutral or alkaline and then sodium chlorate and / or potassium chlorate is added to prepare a chemically stable mixed solution as the acidic etching oxidant; When it needs to be reused in the acid etching production line and the alkaline etching production line, the filtrate A is distributed according to the preparation requirements of the alkaline regeneration etching sub-liquid, the acid regeneration etching sub-liquid and / or the acid etching oxidant according to the process requirements, and then reused in the etching process directly or after being adjusted according to the process requirements as in the above embodiments (1) and (2).

9. The method for precipitating and treating waste copper chloride etching liquid for circuit board according to claim 1, wherein: When the circuit board copper chloride etching waste liquid in step (1) contains alkaline etching waste liquid, the alkaline etching waste liquid is first heated to remove ammonia; or when the circuit board copper chloride etching waste liquid described in step (1) contains circuit board alkaline copper chloride ammonia etching waste liquid, the circuit board alkaline copper chloride ammonia etching waste liquid is first heated to ≥55° C. for ammonia removal; or before performing step (1), the acidic etching waste liquid and / or the alkaline etching waste liquid are first subjected to water-oil separation and / or solid-liquid separation treatment, so that the ink, film residue and solid debris in the acidic etching waste liquid are cleaned, and / or the ink, film residue, stannous hydroxide precipitate and other solid impurities in the alkaline etching waste liquid are cleaned.

10. A device for the method for precipitation treatment and reuse of circuit board copper chloride etching waste liquid according to any one of claims 1 to 9, characterized in that: Mainly include: At least one reaction tank (1) or the reaction tank and at least one solid heating device (2), at least one solid-liquid separator (3), and at least one temporary storage tank (8-18), wherein at least two of the reaction tank (1), the solid-liquid separator (3), and the temporary storage tank (8-18) are connected via a pipeline or a pipeline provided with a pump and / or a valve; The reaction tank (1) is used for mixing the copper chloride etching waste liquid of the circuit board with the pH adjuster to react so that the reaction liquid precipitates copper mud, and / or for the precipitated copper mud and the deamination oxidant to carry out the deamination oxidation reaction of step (3).

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