A method for comprehensive recovery of indium, gallium and phosphorus from oily cutting mixed waste

Abstract

The application relates to the field of metal recovery, and particularly discloses a method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste, which comprises the following steps: oxidizing and calcining the oily cutting mixed waste to obtain mixed oxides; grinding and pulping the mixed oxides with dilute sulfuric acid to obtain a pulping mixed solution; performing mineral slurry diaphragm electrolysis leaching on the pulping mixed solution, obtaining a sulfuric acid electrolysis leaching solution containing In2(SO4)3, Ga2(SO4)3 and H3PO4 in a cathode area, obtaining an electrodeposited indium on the cathode, and obtaining anode mud deposits containing silicon dioxide and di-aluminum trioxide in an anode area and on an anode; extracting indium from the sulfuric acid electrolysis leaching solution, neutralizing and then hydrolyzing and precipitating gallium in the indium extraction residual liquid, and then continuously neutralizing and precipitating calcium phosphate or superphosphate by using lime water or calcium oxide; and the application has the characteristics of efficiently, low-cost and pollution-free comprehensive recovery of indium, gallium and phosphorus from waste containing silicon dioxide, di-aluminum trioxide, oil and grease, indium phosphide and gallium phosphide.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal recovery, more particularly, it relates to a method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste. BACKGROUND

[0002] With the development of modern industry, especially the rapid rise of high-tech and new energy industries, the demand for rare metals is increasing, and indium and gallium, as rare metals, have wide applications in many high-tech fields such as medicine and health, national defense and military, aerospace, electronic information industry, etc. For example, indium is mainly used to manufacture ITO thin film materials, low melting point alloys and solders, semiconductor compound materials and indium alloys; and gallium plays an important role in the fields of solar cells, LEDs, integrated circuits, etc. due to its unique physical and chemical properties.

[0003] However, indium and gallium are rare and dispersed metals without independent ore deposits, and their content in nature is extremely limited, mainly associated with lead-zinc ore, bauxite and copper ore, with small geological reserves and wide applications, which is difficult to meet the increasing demand of the industry for the above-mentioned rare metals. Therefore, it is particularly important to recover and process the above-mentioned metal raw materials.

[0004] Indium phosphide and gallium phosphide crystals with silica or alumina as substrate are mainly used for photovoltaic power generation and LED energy-saving lamps. Although the above-mentioned crystals have low hardness, they are brittle and need to be cut or ground with lubricating oil, which will produce a certain amount of oily cutting and grinding waste. Therefore, the obtained waste contains oil, and at the same time, silica and alumina are introduced as substrate materials in the production process of indium phosphide and gallium phosphide, so that the waste also contains a certain amount of silica and alumina, obtaining oily cutting mixed waste of silica, alumina, indium phosphide and gallium phosphide. At the same time, the quartz boat used for pulling single crystal of indium phosphide or gallium phosphide will also produce a certain amount of waste containing indium phosphide or gallium phosphide when cleaned. The above-mentioned mixed waste contains silica, alumina, indium phosphide and gallium phosphide at the same time, which causes difficulties in the comprehensive recovery of indium, gallium and phosphorus components.

[0005] At present, there are some researches and literatures on the recovery of rare metal elements such as indium and gallium. A vacuum heating decomposition method is used to decompose InP at 800-1200℃, condense metal indium and phosphorus vapor at 400-500℃, and then reduce the temperature to 250-300℃ to recover red phosphorus and cast ingot metal indium ingot. For example, InP is melted in a MClxNCly binary crystal salt melt at 450-700℃ under the condition of inert gas protection to decompose to obtain metal indium liquid and phosphorus vapor, and the crystal salt melt and metal indium are condensed at 50-100℃, and the phosphorus vapor is discharged with inert gas and condensed to recover elemental phosphorus. At present, there are also researches on the sulfuric acid roasting method, which roasts indium phosphide, dissolves with water to obtain In2(SO4)3 and H3PO4 solution, and then electrolyzes fine indium, and the generated phosphorus vapor is oxidized to P2O5 with air for recovery. Some technologies use normal pressure hydrochloric acid or sulfuric acid oxidation leaching, and then use metal zinc or aluminum to replace sponge indium, and use ammonia to neutralize the liquid after replacement to precipitate zinc or aluminum phosphate and ammonium phosphate.

[0006] However, the above-mentioned methods use materials containing 79% indium and 21% phosphorus, which are single pure indium phosphide waste, and the mixed waste containing silicon, aluminum, indium, gallium, phosphorus and lubricating oil in the present application not only has great difference in composition, but also has great difference in the content of indium phosphide and gallium phosphide in the waste. When vacuum high temperature decomposition is used, the obtained metal indium will be mixed with silicon dioxide and aluminum trioxide, and the indium and gallium alloy also needs to be separated again; if the crystal salt melt method is used, a large amount of high melting point silicon dioxide and aluminum trioxide in the mixed waste cannot be melted, which makes the decomposition efficiency of indium phosphide and gallium phosphide low; and when the sulfuric acid roasting method is used, the sulfuric acid indium and sulfuric acid gallium solution dissolved with water also contains a considerable amount of silicon dioxide colloid, which affects the solid-liquid separation; and the use of hydrochloric acid or sulfuric acid oxidation leaching method cannot exclude the influence of silicon colloid or aluminum colloid on the extraction of indium and gallium.

[0007] A new recovery method needs to be researched for the waste containing silicon dioxide, aluminum trioxide, oil and grease, and indium phosphide and gallium phosphide to recover indium, gallium and phosphorus therefrom. SUMMARY

[0008] In order to comprehensively recover indium, gallium and phosphorus from waste containing silicon dioxide, aluminum trioxide, oil and grease, and indium phosphide and gallium phosphide, the present application provides a method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste.

[0009] The present application provides a method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste, which adopts the following technical scheme:

[0010] A method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste, comprising the following steps:

[0011] S1, oxidizing and calcining the oily cutting mixed waste to obtain non-oily mixed oxides containing silicon, aluminum, indium, gallium and phosphorus;

[0012] S2, grinding and pulping the mixed oxides in step S1 with dilute sulfuric acid to obtain a pulping mixed solution;

[0013] S3, performing mineral slurry diaphragm electrolysis leaching on the pulping mixed solution in step S2 to obtain a sulfuric acid electrolytic leaching solution containing In2(SO4)3, Ga2(SO4)3 and H3PO4 in the cathode area, and to obtain an electrodeposited indium on the cathode, and to obtain a silica and di-aluminum trioxide containing anode mud deposit in the anode area and on the anode;

[0014] S4, extracting indium from the sulfuric acid electrolytic leaching solution obtained in the cathode area in step S3, and neutralizing and hydrolyzing the obtained indium extraction residue to precipitate gallium, and filtering to obtain a gallium hydroxide precipitate and a phosphorus containing filtrate, and adding lime water or calcium oxide base to the filtrate to precipitate calcium phosphate or superphosphate.

[0015] By adopting the technical scheme, the mixed waste is first oxidized and calcined in the application, and the indium phosphide and gallium phosphide are converted into indium oxide, gallium oxide and di-phosphorus pentoxide, which is beneficial to subsequent sulfuric acid mineral slurry electrolytic leaching, and the oil in the mixed waste is burned as much as possible, and even if there is residual carbon black, only a small amount of carbon black is left, and then dilute sulfuric acid is used for pulping, so that indium and gallium and phosphorus form corresponding sulfates, and then diaphragm electrolysis leaching treatment is performed in step S3, and a sulfuric acid electrolytic leaching solution containing In2(SO4)3, Ga2(SO4)3 and H3PO4 is obtained in the cathode area, and part of the indium is electrodeposited on the cathode, and most of the silicon dioxide and aluminum oxide are deposited in the anode area, and then the indium is extracted from the sulfuric acid electrolytic leaching solution, and the gallium is precipitated in the residue, and the phosphorus is subsequently precipitated, and finally the comprehensive recovery of indium, gallium and phosphorus in the waste containing silicon and aluminum is realized.

[0016] Moreover, part of the indium is obtained by electrodeposition on the cathode in the diaphragm electrolysis by adopting the method in the application, and the indium is obtained by extraction in the subsequent sulfuric acid electrolytic leaching solution, and the gallium is precipitated, and most of the silicon dioxide and di-aluminum trioxide exist in the anode area, realizing the comprehensive recovery of the above-mentioned substances, and the recovery efficiency is high.

[0017] Optionally, step S1 is specifically operated as follows: the oily cutting mixed waste is oxidized and calcined, the calcination temperature is 400±50℃, and the calcination time is extended by 30-40min after the oil in the oily cutting mixed waste is no longer burned, and the mixed oxides are obtained.

[0018] Optionally, the calcination in step S1 is performed under the conditions of normal pressure air, or oxygen-enriched air, or mixed with hydrogen peroxide, and the hydrogen peroxide is added in an amount of 5-10% of the oily cutting mixed waste;

[0019] More preferably, the oxidation calcination is carried out under the condition of oxygen-enriched air with an oxygen volume content of 32-36% or under the condition of mixing with hydrogen peroxide.

[0020] By using the above technical scheme, through high-temperature oxidation calcination, not only the oil in the mixed waste can be completely burned out, but also the indium phosphide and gallium phosphide can be converted into indium oxide, gallium oxide and diaphosphorus pentoxide, thereby being beneficial to subsequent sulfuric acid ore pulp electrolytic leaching. Especially under the condition of oxygen-enriched air or adding hydrogen peroxide, the phosphorus vapor generated by the decomposition of indium phosphide and gallium phosphide can be rapidly oxidized into diaphosphorus pentoxide, avoiding the generation of phosphorus vapor and H3P gas, reducing environmental pollution and being more environmentally friendly.

[0021] Optionally, in step S2, the solid-liquid ratio of dilute sulfuric acid to mixed oxide is 1: (2-3), and the pH of the prepared slurried mixed solution is 1-2.

[0022] Optionally, in step S3, when the ore pulp diaphragm electrolytic leaching treatment is carried out, the electrolytic leaching temperature is 30±10℃, the anode current density is 300-400 A / m 2 , and the cathode current density is 100-200 A / m 2 .

[0023] By using the above technical scheme, compared with the commonly used sulfuric acid or hydrochloric acid leaching, the content of colloidal silicon or colloidal aluminum in the leaching solution is relatively high, causing the leaching solution to be difficult to filter, and affecting the extraction and separation of indium. In the present application, the diaphragm electrolytic leaching method is adopted, so that the silicon gel and aluminum gel negative ions (Si03) 2- , (AlO2) - ) in the electrolytic leaching solution are discharged and neutralized on the anode and oxidized and neutralized with the generated oxygen, and are deposited in the form of anode sludge at the bottom of the anode area, while In 3+ , Ga 3+ , etc. pass through the diaphragm into the cathode area. Under the condition of low current density electrolysis of indium, part of In 3+ is electrolytically deposited on the cathode as metallic indium, while gallium cannot or is not easy to be electrolytically deposited and remains in the cathode area electrolytic leaching solution and is separated from indium. The sulfuric acid and phosphoric acid in the electrolytic leaching solution exist in the anode and cathode areas.

[0024] Optionally, in step S3, the ore pulp diaphragm electrolytic leaching method is realized by a diaphragm electrolysis device, the cathode of the diaphragm electrolysis device is a stainless steel plate, an overflow port of electrolyte is arranged at the upper part of the cathode area, the anode is a graphite or titanium alloy plate, a stirring device is arranged in the anode area, and a bottom flow discharge port controlled by a valve is arranged at the bottom;

[0025] The slurry mixed solution obtained is continuously added above the anode area for stirring electrolytic leaching, and the sediment is discharged through the underflow discharge outlet at the bottom of the anode area and returned to the step S2 operation for grinding and slurry preparation until the indium and gallium contents in the discharged underflow sediment are both less than 0.03wt%, the valve at the underflow discharge outlet of the anode area is closed to stop the backflow, and the underflow sediment of the anode area is filtered, and the filtrate is returned for grinding and slurry preparation in the step S2.

[0026] The sulfuric acid electrolytic leaching solution continuously overflows from the cathode area and is returned to the step S2 for grinding and slurry preparation until the indium content in the overflowed sulfuric acid electrolytic leaching solution is ≥500mg / L, the returning is stopped, and the step S3 operation is performed.

[0027] By adopting the above technical scheme, the mixed waste in the slurry mixed solution can be fully and repeatedly electrolytic leached through the above-mentioned continuous return and grinding and slurry preparation, the leaching rate of indium gallium phosphorus is improved, indium gallium phosphorus and other components can be continuously enriched, and the subsequent recovery process is facilitated. Finally, the amount of the electrodeposits of the anode area to be filtered is small, easy to filter, and more importantly, the valuable component content is low, the total electrolytic leaching rate is high, part of the metallic indium can be directly obtained on the cathode, the overflowed electrolyte contains less silicon and aluminum, and the extraction recovery of indium and the hydrolysis precipitation of gallium and the filtration of superphosphoric acid calcium are easy.

[0028] Optionally, in the step S4, the obtained sulfuric acid electrolytic leaching solution is filtered and then extracted with P204 kerosene extractant to extract indium, and then hydrochloric acid is used for back extraction to obtain an indium-containing hydrochloric acid back extraction solution, which is returned for back extraction until the indium content in the indium-containing hydrochloric acid back extraction solution is ≥10g / L, and then the indium-containing hydrochloric acid back extraction solution is removed and replaced with a metal replacement agent to obtain metallic indium.

[0029] By adopting the above technical scheme, the obtained sulfuric acid electrolytic leaching solution is first extracted with P204 kerosene extractant to extract indium, and the indium ions in the leaching solution are transferred from the aqueous phase to the organic phase, so as to realize the separation and recovery of indium and other elements such as gallium.

[0030] Optionally, in the step S4, the indium extraction residual liquid is first adjusted to a pH of 5.2-5.4 to hydrolyze and precipitate gallium as gallium hydroxide, and then filtered, and lime water or calcium oxide is added to the filtrate to continue neutralization to a pH of 6-7 to precipitate calcium phosphate or superphosphoric acid calcium.

[0031] Optionally, in the step S4, sodium hydroxide, sodium carbonate or sodium bicarbonate is added to the indium extraction residual liquid to adjust the pH to 5.2-5.4.

[0032] By adopting the technical scheme, the indium extraction residual liquid is first neutralized by sodium alkali to precipitate gallium hydroxide, the residual phosphoric acid is in the form of sodium phosphate salt and remains in the solution to separate from gallium, then lime water or calcium oxide is used for neutralization to obtain calcium phosphate precipitate, so that gallium and calcium phosphate are separately precipitated and recovered. The gallium hydroxide and calcium superphosphate are not precipitated at the same time when the indium extraction residual liquid is directly neutralized by lime water or calcium oxide, and effective separation and recovery is not realized.

[0033] Optionally, the gallium hydroxide precipitate in step S4 is dissolved by hydrochloric acid, and when the gallium content after dissolution is less than 1 g / L, the gallium is enriched by extraction with phosphoric acid tributyl coal oil extractant, back extraction with ammonium sulfate solution, and then replaced by a metal replacement agent to obtain metallic gallium.

[0034] When the gallium content of the gallium hydroxide precipitate after dissolution by hydrochloric acid in step S4 is greater than or equal to 1 g / L, the gallium is directly replaced by a metal replacement agent to obtain metallic gallium.

[0035] Optionally, the metal replacement agent is zinc or aluminum.

[0036] Optionally, in step S4, SiO2 in the sulfuric acid electrolytic leaching solution is less than or equal to 300 mg / L, and Al2O3 is less than or equal to 300 mg / L.

[0037] In summary, the present application has the following beneficial effects:

[0038] In the present application, the mixed waste material after oxidation and calcination is in the form of oxides, which is easy to be electrochemically leached by sulfuric acid, and then subjected to diaphragm electrolytic leaching. In addition to part of the metallic indium obtained on the cathode, the electrolytic overflow liquid containing indium, gallium and phosphorus is first extracted by P204 coal oil extractant to recover indium, the residual liquid is then neutralized by sodium alkali to hydrolyze and precipitate gallium, and the filtrate is neutralized by lime water or calcium oxide to precipitate superphosphoric acid. Due to the electrochemical oxidation in the anode area and above the anode, silicon and aluminum are in the form of silicon dioxide and aluminum trioxide anode mud, which is discharged as the underflow, so that indium, gallium and phosphorus can be comprehensively recovered from the mixed waste material at low cost, low pollution and high efficiency. DETAILED DESCRIPTION

[0039] The present application is further described in detail below in conjunction with examples. It is particularly pointed out that: in the following examples, the specific conditions are not specified, and the conventional conditions or the conditions recommended by the manufacturer are used. In the following examples, the raw materials used can be obtained from ordinary commercial sources unless otherwise specified.

[0040] Example 1

[0041] The oil cutting mixed waste is produced after lubricating cutting processing and then fine grinding of the device in the processing and manufacturing of indium phosphide, gallium phosphide semiconductor electronic devices. The mixed waste contains 10wt% lubricating oil, 44.5wt% silicon dioxide, 8.2wt% aluminum trioxide, 4.5wt% indium, 0.8wt% gallium and 6.2wt% phosphorus.

[0042] A method for comprehensive recovery of indium, gallium and phosphorus from oil cutting mixed waste, comprising the following steps:

[0043] S1, the above-mentioned oil cutting mixed waste is placed in a calcining furnace and subjected to oxidation calcination under air condition, the calcination temperature is 400℃, after the observation of no combustion of lubricating oil in the calcination process, the oxidation calcination time is extended for 30min, the total calcination time is 2.5h, to ensure complete decomposition of all oils and fats, and after cooling to room temperature, it is taken out and ground to 60 mesh or more, to obtain non-oily mixed oxides containing silicon, aluminum, indium, gallium and phosphorus, the tail gas generated in the calcination process is monitored, the oxidation calcination tail gas contains mainly carbon dioxide and 1.1% volume ratio of phosphorus vapor and H3P gas;

[0044] S2, the mixed oxides in step S1 are ground and slurried with dilute sulfuric acid, the solid-liquid ratio of the mixed oxides to dilute sulfuric acid is 1:2, to obtain a slurry mixture with pH of 1;

[0045] S3, the slurry mixture in step S2 is added to the anode area of a 1L diaphragm electrolytic cell, the diaphragm of the diaphragm electrolytic cell is a double-layer plastic screen with a pore size of Φ0.1mm, the anode of the anode area is a graphite electrode, the cathode of the cathode area is a stainless steel electrode, the volume ratio of the anode area to the cathode area is 3:2, and the area ratio of the anode-graphite electrode to the cathode-stainless steel electrode is 1:3, and the anode current density is controlled at 300A / m 2 , the cathode current density is 100A / m 2 , the electrolytic cell pressure is 1V, the upper part of the cathode area of the diaphragm electrolytic cell is provided with an electrolyte overflow port, the anode area is provided with a stirring device, and the bottom of the anode area is provided with a valve-controlled bottom flow discharge port.

[0046] The stirring device in the anode area is started, the stirring speed is 200r / min, the electrolytic leaching temperature is 30℃, after electrolytic leaching for 1h, the slurry mixture is continuously added to the anode area at a rate of 5-10mL / min for electrolytic leaching, and the sulfuric acid electrolytic leaching liquid continuously overflowed from the cathode area is overflow liquid, which is returned to the grinding and slurry preparation process in step S2, at the same time, the deposits discharged from the bottom of the anode area are returned to the grinding and slurry preparation process in step S2;

[0047] The valve at the outlet of the anode zone is closed to stop the backflow when the content of indium and gallium in the bottom flow sediment discharged from the bottom of the anode zone is less than 0.03wt%, the bottom flow sediment of the anode zone is filtered, and the filtrate is returned to the grinding and slurry preparation in step S2, and the filter residue is sent back to the rotary kiln for treatment; simultaneously, the backflow of the cathode zone is stopped when the content of indium in the overflow liquid is greater than or equal to 500 mg / L, and the step S3 operation is performed;

[0048] In the electrolytic leaching process, the overflow liquid from the cathode zone is taken for analysis after electrolytic leaching for 2 hours, which contains 70.5 g / L of sulfuric acid, 265.4 mg / L of In, 85.6 mg / L of Ga, 30.3 mg / L of (SiO2), and 9.5 mg / L of (Al2O3);

[0049] The overflow liquid from the cathode zone is taken for analysis after electrolytic leaching for 4 hours, which contains 85.2 g / L of sulfuric acid, 385.5 mg / L of In, 186.3 mg / L of Ga, 38.5 mg / L of (SiO2), and 13.2 mg / L of (Al2O3);

[0050] The overflow liquid from the cathode zone is taken for analysis after electrolytic leaching for 8 hours, which contains 105 g / L of sulfuric acid, 528.6 mg / L of In, 250.3 mg / L of Ga, 50.8 mg / L of (SiO2), and 24.7 mg / L of (Al2O3);

[0051] The bottom flow sediment discharged from the anode zone is analyzed to contain (SiO2) of 47.8%, (Al2O3) of 10.6%, In of 0.035%, Ga of 0.023%, and P of 0.83%, and it is found that the cathode plate has been electroplated with metallic indium, the electrolytic leaching rate of indium is 99.2%, and the electrolytic leaching rate of gallium is 97.1%.

[0052] S4, the sulfuric acid electrolytic leaching liquid obtained from the overflow of the cathode zone in step S3 is extracted with P204 kerosene extractant, and In is extracted for three times in succession to obtain an In-containing extract liquid and a residual liquid, the residual liquid contains In of 6.8 mg / L and Ga of 248.7 mg / L, the three-stage extraction rate of indium is 98.7%, the In-containing extract liquid is first back-extracted with hydrochloric acid, and then the back-extracted liquid is returned for back-extraction until the indium content in the back-extracted liquid reaches 32.5 g / L, and then the back-extracted liquid is removed, and then aluminum is used as a metal displacement agent to displace metallic indium;

[0053] Then, sodium hydroxide is added to the residual extract liquid to neutralize to pH 5.2, and hydrolysis and precipitation are performed to form gallium hydroxide, and gallium hydroxide precipitate and filtrate are obtained by filtration, the Ga content in the filtrate is 2.3 mg / L, the hydrolysis and precipitation rate is 99.1%, and then the gallium hydroxide precipitate is dissolved with hydrochloric acid (the amount of hydrochloric acid added is enough to completely dissolve the gallium hydroxide, and the gallium content after dissolution is greater than or equal to 1 g / L), and then aluminum foil is used as a metal displacement agent to displace gallium to obtain metallic gallium.

[0054] The filtrate obtained after filtering the hydrolysis precipitate was neutralized to pH 7 with lime water to form calcium phosphate or superphosphate precipitate, and the filtrate was analyzed to contain 0.015 g / L of phosphorus after filtration, and the precipitation rate of the superphosphate or calcium phosphate precipitate was 97.2%.

[0055] Example 2

[0056] An oily cutting mixed waste material formed by cleaning a quartz boat used for pulling single crystals of indium phosphide and gallium phosphide in a semiconductor production process and cutting and grinding an electronic device of indium phosphide and gallium phosphide containing oily silica, aluminum oxide, indium phosphide, and gallium phosphide was used as a treatment object. The mixed waste material contained 5.6 wt% of lubricating oil, 62.3 wt% of silica, 10.1 wt% of aluminum oxide, 2.7 wt% of indium, 2.1 wt% of gallium, and 4.4 wt% of phosphorus.

[0057] A method for comprehensively recovering indium, gallium, and phosphorus from an oily cutting mixed waste material was performed according to the method in Example 1, except that:

[0058] Hydrogen peroxide was mixed during the oxidative calcination in step S1, and the amount of the hydrogen peroxide added was 10 wt% of the oily cutting mixed waste material to be treated. The calcination was performed at 450°C under normal pressure for 3 h, and the mixture was ground to 60 mesh after cooling to room temperature. The tail gas generated during the calcination was monitored, and the tail gas contained mainly carbon dioxide and less than 0.05% of phosphorus vapor and H3P gas.

[0059] The solid-liquid ratio of the mixed oxide to dilute sulfuric acid was 1:3 in step S2, so that the pH of the slurried mixture was 2.

[0060] Step S3 was performed according to the method in Example 1 in a diaphragm electrolytic cell, and the anode current density was 400 A / m 2 , the cathode current density was 150 A / m 2 , the electrolytic cell voltage was 1.2 V, and the area ratio of the anode to the cathode was 3:8.

[0061] The overflow liquid in the cathode zone was analyzed after 8 h of the cyclic electrolytic leaching, and it contained 121.0 g / L of sulfuric acid, 585.3 mg / L of In, 785.6 mg / L of Ga, 80.5 mg / L of (SiO2), and 51.2 mg / L of (Al2O3).

[0062] The bottom flow sediment in the anode zone was analyzed to contain (SiO2) of 82.5%, (Al2O3) of 16.2%, In of 0.08%, Ga of 0.12%, and P of 0.45%, and the indium electrolytic leaching rate was 95.3%, and the gallium electrolytic leaching rate was 94.2%.

[0063] It can be seen that, when mixed waste material is oxidized and calcined with hydrogen peroxide, calcination at 450℃ in air is better, and the electrochemical leaching rate of indium, gallium and phosphorus is improved by increasing the current density and cell voltage. The tail gas after oxidation and calcination contains little phosphorus vapor and H3P gas.

[0064] The overflow liquid in the cathode zone was operated according to the method in Example 1. The third extraction rate of indium was 99.3%, the hydrolysis precipitation rate of gallium was 92.5%, and the precipitation rate of calcium superphosphate or calcium phosphate precipitate was 97.5%.

[0065] Example 3

[0066] A method for comprehensive recovery of indium, gallium and phosphorus from oily cutting mixed waste material, the same batch of mixed waste material as in Example 2 was taken as the treatment object, and the method in Example 2 was followed. The difference was that the calcination temperature in step S1 was 350℃, and the calcination was carried out under the condition of oxygen enrichment with an oxygen volume content of 36%. After the oil in the oily cutting mixed waste material was observed to no longer burn, the oxidation calcination time was extended by 40min, and a mixed oxide was obtained. The tail gas generated during calcination was monitored. The oxidation calcination tail gas contained mainly carbon dioxide and 0.1% volume ratio of phosphorus vapor and H3P gas.

[0067] The electrolytic leaching temperature in step S3 was 25℃.

[0068] The electrolytic leaching rate of indium in step S3 was 94.8%, and the electrolytic leaching rate of gallium was 93.5%, which was lower than that of indium and gallium in Example 2. The overflow liquid in the cathode zone was operated according to the method in Example 2. The third extraction rate of indium was 99.2%, the hydrolysis precipitation rate of gallium was 96.5%, and the precipitation rate of calcium superphosphate or calcium phosphate precipitate was 97.1%.

[0069] Example 4

[0070] A method for comprehensive recovery of indium, gallium and phosphorus from oily cutting mixed waste material, the same batch of mixed waste material as in Example 2 was taken as the treatment object, and the method in Example 2 was followed. The difference was that the calcination time in step S1 was until the oil in the oily cutting mixed waste material no longer burned, and the oxidation calcination time was not extended. After cooling, the material was ground. The tail gas generated during calcination was monitored. The oxidation calcination tail gas contained mainly carbon dioxide and 0.6% volume ratio of phosphorus vapor and H3P gas.

[0071] Comparative Example 1

[0072] A method for comprehensively recovering indium, gallium and phosphorus from oily cutting mixed waste, the same batch of mixed waste as in Example 2 is taken as the processing object, and the method in Example 2 is followed, except that in step S3, no diaphragm electrolysis leaching operation is performed, but a bone glue flocculating agent is added to the slurry mixed solution obtained in step S2, the bone glue flocculating agent is added in an amount of 0.05wt% of the slurry mixed solution, then filtered, and the obtained filtrate is subjected to step S4 operation.

[0073] Performance detection

[0074] The recovery rates of indium and gallium in the methods of the examples and comparative examples of the present application are counted, and the statistical results are shown in Table 1.

[0075] Table 1:

[0076]

[0077] Referring to the statistical results in Table 1 above, the method provided in the present application achieves a high recovery rate and efficient recovery effect for indium and gallium, and in combination with the detection results in Example 1 and Comparative Example 1, for mixed waste containing silicon dioxide, aluminum trioxide, indium phosphide and gallium phosphide, when the indium phosphide and gallium phosphide are converted to sulfates by adding sulfuric acid, the addition of the flocculating agent will remove the silicon dioxide and aluminum trioxide, which will also wrap the target metals indium and gallium, resulting in loss and low yield, and part of the silicon dioxide and aluminum trioxide will also enter the slurry, affecting the subsequent extraction separation effect, and ultimately the yield is significantly reduced.

[0078] The specific embodiments are merely an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for comprehensive recovery of indium, gallium, and phosphorus from oily cutting mixed waste material, characterized by, The method comprises the following steps: S1, oxidizing and calcining oily cutting mixed waste containing silicon dioxide, aluminum trioxide, oil, indium phosphide and gallium phosphide to obtain non-oily mixed oxides containing silicon, aluminum, indium, gallium and phosphorus; S2, grinding and pulping the mixed oxides in step S1 with dilute sulfuric acid to obtain a pulping mixed solution; S3, performing mineral slurry diaphragm electrolytic leaching on the pulping mixed solution in step S2 to obtain sulfuric acid electrolytic leaching solution containing In2(SO4)3, Ga2(SO4)3 and H3PO4 in the cathode area, and to obtain electrodeposited indium on the cathode, and to obtain anode sludge deposits containing silicon dioxide and aluminum trioxide in the anode area and on the anode; S4, extracting indium from the sulfuric acid electrolytic leaching solution obtained in step S3, and then neutralizing and hydrolyzing the obtained indium extraction residue to precipitate gallium, and filtering to obtain gallium hydroxide precipitate and phosphorus-containing filtrate, and adding lime water or calcium oxide to the filtrate to precipitate calcium phosphate or superphosphate; The mineral slurry diaphragm electrolytic leaching in step S3 is realized by a diaphragm electrolysis device, the cathode of the diaphragm electrolysis device is a stainless steel plate, an electrolyte overflow port is arranged at the upper part of the cathode area, the anode is a graphite or titanium alloy plate, a stirring device is arranged in the anode area, and a bottom flow discharge outlet controlled by a valve is arranged at the bottom part; During the mineral slurry diaphragm electrolytic leaching, the obtained pulping mixed solution is continuously added above the anode area for stirring and electrolytic leaching, the deposits are discharged from the bottom flow discharge outlet at the bottom part of the anode area and returned to step S2 for grinding and pulping until the contents of indium and gallium in the discharged bottom flow deposits are both less than 0.03wt%, the valve at the bottom flow discharge outlet of the anode area is closed to stop the backflow, the bottom flow deposits in the anode area are filtered, and the filtrate is returned to be used for grinding and pulping in step S2; the sulfuric acid electrolytic leaching solution continuously overflows from the cathode area and is returned to step S2 for grinding and pulping until the indium content in the overflowed sulfuric acid electrolytic leaching solution is ≥500mg / L, the returning is stopped, and step S3 is performed; In step S4, the SiO2 content in the sulfuric acid electrolytic leaching solution is ≤300mg / L, and the Al2O3 content is ≤300mg / L. In step S1, the oily cutting mixed waste is calcined, the calcination temperature is 400±50℃, and the calcination time is prolonged by 30-40min after the oil in the oily cutting mixed waste stops burning to obtain the mixed oxides.

2. The method according to claim 1, characterized in that: In step S1, the calcination is performed under the conditions of normal pressure air, or oxygen-enriched air, or mixed hydrogen peroxide, and the hydrogen peroxide is added in an amount of 5-10% of the oily cutting mixed waste.

3. The method according to claim 2, characterized in that: In step S2, the pH of the pulping mixed solution is 1-2, and the solid-liquid ratio of dilute sulfuric acid to mixed oxides is 1:(2-3).

4. The method according to claim 1, characterized in that: In step S4, the obtained sulfuric acid electrolytic leaching solution is filtered, then P204 kerosene extractant is used for indium extraction, then hydrochloric acid is used for back extraction to obtain an indium-containing hydrochloric acid back extraction solution, the indium-containing hydrochloric acid back extraction solution is returned to be used for back extraction until the indium content in the indium-containing hydrochloric acid back extraction solution is ≥10g / L, then the indium-containing hydrochloric acid back extraction solution is removed, and a metal displacement agent is used for displacement to obtain metallic indium.

5. The method according to claim 1, characterized in that: In the step S3, the temperature of the electrolytic leaching is 30±10℃, the anode current density is 300-400 A / m 2 , and the cathode current density is 100-200 A / m 2 .

6. The method according to claim 1, characterized in that: ​ 7. The method according to claim 1, characterized in that: The residue of the indium extraction in step S4 is first adjusted to pH 5.2-5.4 to hydrolyze and precipitate gallium hydroxide, then filtered, and then lime water or calcium oxide is added to the filtrate to continue neutralization to pH 6-7 to precipitate calcium phosphate or superphosphate.

8. The method according to claim 1, characterized in that: The gallium hydroxide precipitate in step S4 is dissolved with hydrochloric acid, and when the gallium content after dissolution is less than 1 g / L, the gallium is enriched by extraction with phosphoric acid tributyl coal oil extractant, back extraction with ammonium sulfate solution, and then replaced with a metal displacer to produce metallic gallium; when the gallium content after the gallium hydroxide precipitate in step S4 is dissolved with hydrochloric acid is ≥1 g / L, the gallium is directly replaced with a metal displacer to produce metallic gallium.

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