A physicochemical method for simultaneously treating acidic etching waste liquid and potassium ferricyanide waste liquid

Abstract

The present application relates to wastewater treatment technical field, provide a kind of physicochemical method for treating acid etching waste liquid and potassium ferricyanide waste liquid simultaneously, comprising the following steps: S1.diluted after adding water in part etching waste liquid, add iron oxide, react for a period of time;Then add iron powder, after a period of time, add hydrochloric acid, after filtration separation, obtain metal copper and filtrate;S2.mixture of remaining etching waste liquid and biomass material is treated after using equal volume impregnation method, at 300-500 DEG C, under mixed protective atmosphere, calcine for a period of time;Then again at 600-1100 DEG C, under nitrogen atmosphere, calcine for a period of time;Iron-based carbon material is prepared;S3.iron-based carbon material, filtrate is directly mixed with potassium ferricyanide wastewater, react for a period of time, after filtration, evaporation, crystallization treatment can enter biochemical treatment system;It can realize the efficient recovery of metal copper, while the removal efficiency of ferricyanate in potassium ferricyanide wastewater is high, realizes waste treatment with waste, and the degree of resource utilization is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, in particular to a physicochemical method for simultaneously treating acid etching waste liquid and potassium ferricyanide waste liquid. BACKGROUND

[0002] The copper chloride acid etching liquid has the characteristics of safety and stability, fast etching rate, etc., and is a kind of etching liquid widely used in printed circuit board etching, so the etching waste liquid is produced in large quantities. If it is directly discharged without treatment, it will not only cause serious environmental pollution, but also cause great waste of resources. The acid copper chloride etching waste liquid is composed of hydrochloric acid, copper chloride and iron chloride, etc., which is a potential resource, and its resource utilization has economic value and environmental protection significance. At present, the treatment methods mainly include two categories: one is to regenerate the etching waste liquid; the other is to synthesize copper compounds by using the etching waste liquid as raw material.

[0003] In addition, the enterprise production process will involve cleaning process, and the detergent used is usually a mixed solution prepared by potassium ferricyanide, which causes a certain amount of wastewater containing potassium ferricyanide in the production process of the enterprise. The main pollutants of this kind of wastewater are potassium ferricyanide, and the wastewater is alkaline and has poor biodegradability. Although this kind of production wastewater has few pollutants and small water quantity, the pollutant concentration is high, and it has high toxicity, so it is difficult to meet the discharge standard by using traditional methods.

[0004] Therefore, it is urgent to develop a method for simultaneously treating acid etching waste liquid and potassium ferricyanide wastewater and recycling other products. SUMMARY

[0005] After a lot of research, we found that after the acid etching waste liquid is treated and mixed with the potassium ferricyanide wastewater, the metal copper can be efficiently recovered, the removal efficiency of ferricyanate in the potassium ferricyanide wastewater is high, the effect of waste treatment by waste is achieved, and the degree of resource utilization is high. Therefore, the purpose of the present application is to provide a physicochemical method for simultaneously treating acid etching waste liquid and potassium ferricyanide waste liquid, comprising the following steps:

[0006] S1. After diluting part of the etching waste liquid with water, adding iron oxide, and reacting for a period of time, then adding iron powder, and reacting for a period of time, adding hydrochloric acid, and filtering and separating, metal copper and filtrate are obtained;

[0007] S2. The remaining etching waste liquid is mixed with biochar material, treated by equal volume impregnation method, and then calcined at 300-500℃ under mixed protective atmosphere for 1-3h; and then calcined at 600-1100℃ under nitrogen atmosphere for 2-5h; to obtain iron-based carbon material;

[0008] S3. The iron-based carbon material and filtrate are directly mixed with potassium ferricyanide wastewater, and after a period of reaction, the wastewater is treated by filtration, evaporation and crystallization, and then enters the biochemical treatment system.

[0009] The technical scheme of the embodiment of the application has at least the following advantages and beneficial effects:

[0010] 1. In the treatment method, before the treated filtrate is mixed with the potassium ferricyanide wastewater, the iron-based carbon material is added to remove the cyanate ions and Cu 2+ in the wastewater more quickly and stably.

[0011] 2. The existing etching waste liquid is innovatively used as an iron source, and a biomass material is used as a carbon source to prepare the iron-based carbon material, which is beneficial to the full dispersion of iron atoms in the carrier carbon, realizes uniform distribution, effectively reduces the agglomeration of active substances, induces the ferrous ions and cyanate ions in the filtrate to form a precipitate quickly and stably, and then efficiently removes cyanide; more importantly, Cu 2+ in the solution can be simultaneously induced to be reduced to Cu + , which promotes the combination of Cu + and cyanate ions in the wastewater to generate a precipitate, and exhibits great reactivity and stability, so that the cyanate ions in the wastewater can be more completely removed.

[0012] 3. The treatment method can realize the harmless treatment and resource utilization of the acidic etching waste liquid, and realize the non-toxic and harmless treatment of the potassium ferricyanide wastewater, so that the wastewater can be finally discharged in accordance with the standard, that is, the purpose of "waste treatment by waste" is achieved. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the application more clear, the technical scheme in the embodiments of the application will be clearly and completely described below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0014] The physicochemical method for simultaneously treating the acidic etching waste liquid and the potassium ferricyanide wastewater provided by the embodiments of the application will be specifically described below.

[0015] A physicochemical method for simultaneously treating the acidic etching waste liquid and the potassium ferricyanide wastewater, comprising the following steps:

[0016] S1. After diluting the partial etching waste liquid with water (the ratio of the volume of water added to the volume of etching waste liquid is 2-5:1), iron oxide is added, the amount of iron oxide added is 10-30 g / L based on the solid-liquid ratio of the diluted etching waste liquid, and the reaction is carried out for a period of time, so that the acid is removed in advance by using iron oxide, so that the content of hydrochloric acid in the etching waste liquid is reduced to meet the safety requirements, to prevent the generation of hydrogen gas in the subsequent displacement process, and to reduce the safety risk in the subsequent production; then a small amount of iron powder is added several times, the number of moles of Fe atoms in the iron powder is 1-1.2 times the number of moles of Cu 2+ ions in the etching waste liquid, and the number of moles of Fe 3+ ions in the etching waste liquid is 0.3-0.8 times the number of moles of Cu 2+ ions, so that Cu 3+ is reduced to elemental copper for recovery, and Fe 2+ ions are converted to Fe 2+ ions; the iron powder is oxidized to ferrous chloride; after a period of reaction, hydrochloric acid is added, and the ratio of the volume of hydrochloric acid added to the volume of the solution is 0.4-0.5:1, so that the iron in the copper-coated iron precipitate generated during the reaction process can be quickly dissolved and converted to ferrous chloride, and pure elemental copper is recovered, and after filtration and separation, metallic copper and a filtrate are obtained;

[0017] Since the etching waste liquid contains not only ferric chloride and copper chloride, but also a large amount of hydrochloric acid, if iron powder is directly used for displacement, a large amount of hydrogen gas will be generated, which has a high risk coefficient, therefore, before treatment, the present application uses iron oxide to remove acid, so that the content of hydrochloric acid is reduced to meet the safety requirements, to prevent the generation of hydrogen gas in the subsequent displacement process, and to reduce the safety risk in the subsequent production; then iron powder is used for displacement to recover copper; in addition, copper-coated iron precipitate will be generated during the treatment process, therefore, by adding hydrochloric acid to dissolve the iron, elemental copper is recovered, and ferrous chloride is generated, i.e. the main components in the obtained filtrate are converted to ferrous chloride, and part of the divalent copper that is not completely recovered is also contained;

[0018] S2. Then the remaining etching waste liquid is mixed with biochar material, and after treatment by the equal-volume impregnation method, it is calcined at 300-500 DEG C under a mixed protective atmosphere for 1-3 h; then it is calcined at 600-1100 DEG C under a nitrogen atmosphere for 2-5 h to obtain an iron-based carbon material;

[0019] In the present application, the inventors use existing etching waste liquid as an iron source and biomass material as a carbon source to prepare an iron-based carbon material, which is beneficial to the full dispersion of iron atoms in the carrier carbon, realizes uniform distribution, effectively reduces the agglomeration of active substances, induces the rapid and stable formation of precipitate of ferrous ions and cyanide ions in the filtrate to remove cyanide; more importantly, Cu 2+ is reduced to Cu + , and Cu +The cyanate ions in the wastewater are combined with the cyanide ions to form a precipitate, which exhibits great reactivity and stability, so that the cyanate ions in the wastewater can be removed more thoroughly.

[0020] More specifically, the mixed protective gas is helium and nitrogen, or nitrogen and argon; when the mixed protective gas is introduced, the flow rate of the mixed protective gas is controlled as follows: within 30 minutes before calcination, the flow rate of nitrogen is controlled at 50-100 ml / min, and the flow rate of helium or argon is controlled at 10-20 ml / min; then, the flow rate is gradually increased at a rate of 5-10 ml / min.

[0021] In the pre-calcination stage, the biochar material is efficiently decomposed at 300-500 DEG C, in the decomposition process, the nitrogen-containing mixed gas is introduced, and the flow rate of nitrogen in the mixed gas is higher than that of helium or argon, so that the biochar material is safely and stably in a nitrogen-rich atmosphere for in-situ nitrogen doping, the nitrogen is left in the carbon skeleton, the nitrogen element is more uniformly distributed, and the active sites for iron atom embedding are provided; then, by increasing the calcination temperature to above 600 DEG C and continuously doping nitrogen, the specific surface area and internal porosity of the material are further improved, and in this process, a large number of pores are left due to gas generation, which is beneficial to the full dispersion of iron atoms in the carrier carbon, realizes uniform distribution, effectively reduces the agglomeration of active substances, and better induces Cu 2+ to Cu + , promotes Cu + to rapidly combine with cyanate ions in the wastewater to form a precipitate, improves the treatment effect of potassium ferricyanide wastewater.

[0022] S3. The iron-based carbon material and the filtrate are directly mixed with the potassium ferricyanide wastewater, and this step mainly uses the iron-based carbon material to induce the ferrous ions in the filtrate to rapidly and stably form a precipitate with cyanate ions to remove cyanide; more importantly, Cu 2+ is reduced to Cu + , and Cu + is promoted to rapidly combine with cyanate ions in the wastewater to form a precipitate, which exhibits great reactivity and stability, so that the cyanate ions in the wastewater can be removed more thoroughly; after a period of reaction, the precipitate is subjected to solid-liquid separation, and the clear liquid after treatment is evaporated, concentrated, crystallized and desalted by using a triple-effect evaporator, which not only achieves the purpose of concentration and desalination, but also further removes toxic ingredients, ferricyanate, in the wastewater, providing a strong guarantee for non-toxicity and harmlessness; then, it can enter the biochemical treatment system, such as a biochemical tank, and be discharged after reaching the standard.

[0023] Example 1

[0024] A physicochemical method for simultaneously treating acid etching waste liquid and potassium ferricyanide waste liquid, comprising the following steps:

[0025] S1. Add 4000 mL distilled water to 1000 mL etching waste liquid for dilution, then add 100 g iron oxide, react for 0.5 h; then add iron powder in small amounts for several times, stir until the reaction is complete, the number of moles of Fe atoms in the iron powder is 1.2 times the number of moles of Cu ions in the etching waste liquid, and the number of moles of Fe ions in the etching waste liquid is 0.5 times the number of moles of Cu ions in the etching waste liquid; then add hydrochloric acid after reacting for 1 h, the ratio of the volume of hydrochloric acid added to the volume of the solution is 0.4:1, and after separation by filtration, metallic copper and a filtrate are obtained; 2+ 1.2 times the number of moles of Fe ions in the etching waste liquid and 0.5 times the number of moles of Cu ions in the etching waste liquid, react for 1 h, then add hydrochloric acid, the ratio of the volume of hydrochloric acid added to the volume of the solution is 0.4:1, and after separation by filtration, metallic copper and a filtrate are obtained; 3+ 1.2 times the number of moles of Fe ions in the etching waste liquid and 0.5 times the number of moles of Cu ions in the etching waste liquid, react for 1 h, then add hydrochloric acid, the ratio of the volume of hydrochloric acid added to the volume of the solution is 0.4:1, and after separation by filtration, metallic copper and a filtrate are obtained;

[0026] S2. After the biomass raw material straw is crushed and dried, it is calcined at 200℃ for 0.5 h under nitrogen protection; then it is immersed in the remaining 500 mL etching waste liquid mixture, treated by equal-volume immersion method, and then calcined at 400℃ under a mixed gas atmosphere of nitrogen and argon for 2 h; when the mixed gas of nitrogen and argon is introduced, the flow rate of the mixed gas is controlled as follows: within 30 min before calcination, the flow rate of nitrogen is controlled at 60 ml / min, and the flow rate of argon is controlled at 15 ml / min; thereafter, both are gradually increased at a rate of 5 ml / min; then it is calcined at 800℃ under a nitrogen atmosphere for 3 h to obtain an iron-based carbon material;

[0027] S3. The iron-based carbon material obtained in S2 and the filtrate obtained in S1 are directly mixed with potassium ferricyanide wastewater, reacted for 2 h, filtered, and then the clear liquid after filtration is evaporated, concentrated, crystallized, and desalted by a triple-effect evaporator, and then enters the biochemical pool.

[0028] The clear liquid after filtration is detected: ferricyanide ions and Cu 2+ are not detected, and the content of Fe is 10 ppm.

[0029] Example 2

[0030] The difference between this example and Example 1 is that in S1, the ratio of the volume of water added to the volume of etching waste liquid is 5:1.

[0031] The clear liquid after filtration is detected: ferricyanide ions and Cu 2+ are not detected, and the content of Fe is 12 ppm.

[0032] Example 3

[0033] The difference between this example and Example 1 is that in S1, the ratio of the amount of iron oxide added to the solid-liquid ratio of the diluted etching waste liquid is 10 g / L.

[0034] The clear liquid after filtration is detected: ferricyanide ions and Cu 2+ are not detected, and the content of Fe is 14 ppm.

[0035] Example 4

[0036] The difference between this example and Example 1 is that in S1, the ratio of the volume of hydrochloric acid added to the volume of solution is 0.5:1.

[0037] The filtrate after filtration was detected: ferricyanide ion and Cu 2+ were not detected, and the Fe content was 11 ppm.

[0038] Example 5

[0039] The difference between this example and Example 1 is that in S2, the mixed protective atmosphere is burned at 350°C for 1.5 hours, and then burned at 900°C in a nitrogen atmosphere for 3.5 hours.

[0040] The filtrate after filtration was detected: ferricyanide ion and Cu 2+ were not detected, and the Fe content was 13 ppm.

[0041] Example 6

[0042] The difference between this example and Example 1 is that in S2, the mixed protective gas is helium and nitrogen; when the mixed gas is introduced, the flow rate of the mixed gas is controlled as follows: within 30 minutes before calcination, the flow rate of nitrogen is controlled at 70 ml / min, and the flow rate of helium is controlled at 10 ml / min; thereafter, the flow rate is gradually increased at a rate of 10 ml / min.

[0043] The filtrate after filtration was detected: ferricyanide ion and Cu 2+ were not detected, and the Fe content was 15 ppm.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 1 is that it does not contain the treatment step S2; that is, the filtrate obtained in S1 is directly mixed with potassium ferricyanide wastewater for treatment.

[0046] The filtrate after filtration was detected: ferricyanide ion content: 1.69 mg / L, Cu 2+ content: 0.93 mg / L, and Fe content: 6845 ppm.

[0047] Comparative Example 2

[0048] The difference between this comparative example and Example 1 is that in S2, the flow rate of the mixed gas is introduced at a constant rate of 10 ml / min during the reaction process.

[0049] The filtrate after filtration was detected: ferricyanide ion content: 6.36 mg / L, Cu 2+The content of 0.84 mg / L, the content of Fe 2566 ppm.

[0050] Comparative Example 3

[0051] The difference between the present comparative example and Example 1 is that in S2, only argon is passed during the reaction.

[0052] The filtrate after filtration treatment is detected: the content of ferricyanide ion is 7.25 mg / L, the content of Cu 2+ The content of 0.71 mg / L, the content of Fe 4218 ppm.

[0053] As can be seen from the above, before mixing the treated filtrate with potassium ferricyanide wastewater, the iron-based carbon material is added to more quickly and stably promote the formation of ferrous ions and cyanide ions in the solution to form a precipitate, and Cu 2+ is reduced to Cu + is combined with cyanide ions in the wastewater to form a precipitate, so that the cyanide ions in the wastewater can be more completely removed, and there is no excess iron salt left in the filtrate, reducing the subsequent evaporation cost.

[0054] As can be seen from Comparative Example 1, without the iron-based carbon material, directly mixing the treated filtrate with excess ferrous ion solution and potassium ferricyanide wastewater to precipitate ferricyanide ions will cause excess iron salt to remain in the filtrate, increasing the amount of salt mud at the end and the subsequent evaporation cost, and the ferricyanide ions in the wastewater are not completely removed, and the divalent copper ions in the etching waste liquid that have not been completely treated cannot be reprocessed or utilized, so that the final treated water discharged cannot meet the discharge standard. In addition, as can be seen from Comparative Examples 2-3, during the preparation of the iron-based carbon material, the gas flow rate is not controlled, or the mixed gas or single gas is not selected, so that the prepared iron-based carbon material has poor mixing treatment effect on the filtrate and potassium ferricyanide wastewater, and the content of ferricyanide ions and Cu 2+ content in the wastewater still exist, which cannot meet the discharge standard, which is mainly due to the uneven dispersion of iron atoms in the carrier carbon in the iron-based carbon material, reducing its induction effect, so that the combination ability of cyanide ions is poor, and the cyanide ions and Cu 2+ in the wastewater cannot be completely removed.

[0055] The above is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent, characterized by, The method comprises the following steps: S1. After diluting the part of etching waste liquid with water, add iron oxide and react for a period of time; Then add iron powder and react for a period of time, separate the precipitate, add hydrochloric acid, separate by filtration, and obtain metal copper and filtrate; S2. Mix the remaining etching waste liquid with biochar material, treat by using equal volume impregnation method, calcine at 300-500 DEG C under mixed protective atmosphere for 1-3h, then calcine at 600-1100 DEG C under nitrogen atmosphere for 2-5h; The mixed protective gas is nitrogen and helium, or nitrogen and argon; When the mixed protective gas is introduced, the flow rate of the mixed protective gas is controlled as follows: within 30min before calcination, the flow rate of nitrogen is controlled at 50-100ml / min, and the flow rate of helium or argon is controlled at 10-20ml / min; After that, gradually increase the rate to 5-10ml / min; S3. Mix the iron-based carbon material prepared in S2 and the filtrate prepared in S1 directly with potassium ferricyanide wastewater, react for a period of time, and then filter and treat by three-effect evaporation to enter the biochemical treatment system.

2. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, In S1, the ratio of the volume of water added to the volume of etching waste liquid is 2-5:

1.

3. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, In S1, the amount of iron oxide added is 10-30g / L of the solid-liquid ratio of the diluted etching waste liquid.

4. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, In S1, the number of moles of Fe atoms in the iron powder is 1 to 1.2 times the number of moles of Cu in the etching waste liquid 2+ 1 to 1.2 times the number of moles of Fe in the etching waste liquid 3 + 0.3 to 0.8 times the number of moles of Fe in the etching waste liquid 5. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, In S1, the ratio of the volume of hydrochloric acid added to the volume of solution is 0.4-0.5:

1.

6. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, The mass ratio of etching waste liquid in S1 and S2 is 2-3:

1.

7. The physico-chemical process for simultaneous treatment of acid etching effluent and potassium ferricyanide effluent as claimed in claim 1 wherein, In S3, the filtrate treated by filtration is evaporated, concentrated, crystallized and desalted by using a three-effect evaporator.