A method for improving the filtration performance of pre-neutralization solution and acid leaching solution of leached indium germanium slag

Abstract

The invention relates to a method for improving the filtration performance of a pre-neutralized solution and an acid leaching solution for leaching indium germanium slag. The method comprises the following steps: pre-neutralizing a zinc sulfate acid solution containing silicon, trivalent iron, indium and germanium to a pH value of 4-4.5 with zinc oxide ore powder at 70-80°C, filtering to obtain indium germanium-rich slag, and then using electrolytic zinc residual liquid or germanium indium extraction residual liquid or sulfuric acid liquid to leach indium germanium precipitated slag under the conditions of liquid / solid=1.5-2 and 80±5°C to obtain an acid leaching solution for extracting germanium with N235 and extracting indium with P204. In order to improve the filtering performance of the pre-neutralization solution and the acid leaching solution of leached indium germanium slag, the present invention adopts the method of adding zinc oxide ore powder and adding zinc sulfate acid solution containing silicon, trivalent iron, indium and germanium at one time for pre-neutralization, and finely adjusting the pH value to 4-4.5 by using zinc oxide ore powder to precipitate indium germanium, which can improve the filtering performance of the pre-neutralization solution, and firstly slurrying the pre-neutralization precipitated indium germanium slag and then slowly leaching for 2-4 hours by using acid solution, which can improve the filtering performance of the acid leaching solution, improve the indium germanium extraction production capacity and reduce the production cost.

Description

Technical Field

[0001] The invention belongs to the field of hydrometallurgy, in particular to a method for improving the filtering performance of pre-neutralization liquid and acid leaching liquid for leaching indium germanium slag. Background Art

[0002] After the low-indium-germanium zinc oxide raw material is neutrally leached to separate zinc sulfate, the acid leaching solution obtained by acid leaching of the intermediate leaching residue still contains low indium-germanium, which is not conducive to the subsequent extraction of indium-germanium by extraction. It is necessary to enrich the indium-germanium in the acid leaching solution and then acid-leach it to increase the indium-germanium content in the acid leaching solution to reduce the amount of extraction solution and reduce the extraction cost. The method used in production is to pre-neutralize the acid leaching solution. The so-called pre-neutralization is a commonly used term in the hydrometallurgical industry, that is, to neutralize the acidic liquid to about pH = 4 to 4.5, which is lower than the pH of neutral leaching = 5 to 5.4 and higher than the pH of acid leaching 0.5 to 3. At pH = 4 to 4.5, indium-germanium is hydrolyzed and precipitated to obtain enrichment, and a higher content of acid leaching solution is obtained during acid leaching, which can improve the efficiency of extracting indium-germanium and reduce production costs. Since the intermediate leaching residue of zinc oxide ore powder contains impurities such as silicon and iron in addition to zinc, indium and germanium, SiO2 and trivalent iron will also be leached during acid leaching of the intermediate leaching residue. When zinc oxide ore powder is used for pre-neutralization, some of the silicon and trivalent iron therein are also leached into the solution, which increases the silicon-iron content in the pre-neutralized solution. At pH = 4-4.5, SiO2 colloid and Fe(0H)3 colloid are easily formed, which makes filtration difficult, and in severe cases, it is impossible to filter at all. In order to improve the filtration performance of the pre-neutralized solution, pure lime water (milk) is used for pre-neutralization. Although the filtration is improved, due to the large amount of CaS04 generated, the amount of pre-neutralized slag is large, and indium and germanium are not enriched. Using Na2C03 or Na0H for pre-neutralization reduces the amount of slag, but brings in a large amount of Na + , when the neutralized solution is returned to the electro-zinc production, Na + It harms the electrolysis of zinc. Using lime or alkali for pre-neutralization also consumes a large amount of acid in the acid solution, which is not cost-effective. Adding animal glue or polyacrylamide or polyether to improve the filtration performance, animal glue or polyacrylamide does not improve much, and due to the coagulation of silica gel, Fe(0H)3 colloid wraps in indium germanium, which reduces the leaching rate during subsequent acid leaching. When the indium germanium-rich slag is acid-leached, part of the silicon and iron in the slag are leached into the solution, which makes filtration difficult. In addition, the animal glue in the leachate will affect the extraction phase separation. In severe cases, the extraction cannot be carried out. Although polyether is used as a flocculant, it does not affect the extraction, but it is used twice (used during pre-neutralization and used during acid leaching of the pre-neutralized slag), and the dosage is large. The price of polyether is about 24,000 yuan / t, which greatly increases the cost of indium germanium extraction. Summary of the invention

[0003] In view of the above problems, the present invention provides a method for improving the filtration performance of the pre-neutralization solution and the acid leaching solution of the leached indium germanium residue, which can improve the indium germanium extraction production capacity and reduce the production cost.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: a method for improving the filtration performance of the pre-neutralization solution and the acid leaching solution of the leached indium germanium slag, and the specific implementation steps are as follows:

[0005] Step 1, weigh a certain amount of zinc oxide ore powder, add it into a pre-neutralization container at one time, and slurry it with clean water or without slurrying;

[0006] Step 2, adding the acidic zinc sulfate solution containing silicon, trivalent iron, indium and germanium at a liquid / solid ratio of 10 to 30 into the pre-neutralization container containing zinc oxide ore powder in step 1 to carry out a neutralization reaction;

[0007] Step 3, heating the pre-neutralization reaction in step 2 and mechanically stirring to pre-neutralize and enrich the precipitated indium germanium, while stirring, fine-tuning the pH to 4-4.5 with zinc oxide ore powder or lime water, heating to 70-80° C., stirring at a speed of 200-500 r / min, and pre-neutralizing for 0.5-1 hour;

[0008] Step 4: After the pre-neutralization in step 3 is completed, the mixture is allowed to stand for 10 to 30 minutes and filtered to obtain indium germanium-containing precipitate residue and ZnS04 filtrate, and then rinsed once with 40 to 50°C clean water;

[0009] Step 5, using electrolytic zinc residual liquid or indium germanium extraction residual liquid or sulfuric acid liquid to leach the indium germanium precipitate residue of step 4, the leaching conditions are liquid / solid=1.5-2, temperature 80±5°C, stirring speed 50-200r / min, slowly adding acid solution, leaching time 2-4 hours, leaching final acid pH=1.5-2;

[0010] Step 6, the acid leaching solution obtained in step 5 is allowed to stand for a period of time and then filtered to obtain an indium germanium-containing acidic solution and a filter residue, the indium germanium-containing acidic solution is sent to the indium germanium extraction section, and the filter residue is sent to the electro-zinc intermediate leaching or acid leaching section.

[0011] Preferably, the acidic zinc sulfate solution containing silicon, trivalent iron, indium and germanium in step 2 is an acidic solution obtained by first neutrally leaching ZnS04 from the zinc-containing raw material and then acidically leaching indium and germanium from the leaching residue, and its chemical composition is In 1000-1800 mg / L, Ge 20-40 mg / L, SiO2 500-800 mg / L, Fe 3+ 1~1.5g / L, Zn 120~140g / L, H + 20~100g / L.

[0012] Preferably, the amount of zinc oxide ore powder in step 1 is weighed according to the acidic liquid / solid ratio of 10 to 30 described in step 2; and lime water is used as a pre-neutralizing agent when the pH value is fine-tuned in step 3.

[0013] Preferably, the pH value of the final leaching acid in step 5 is adjusted using lime water or zinc oxide ore powder.

[0014] Preferably, in step 6, the indium-germanium-containing acidic solution is subjected to N235 extraction of germanium, and P204 extraction of indium.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In the present invention, during pre-neutralization, the zinc oxide ore powder neutralizer is first directly added into the pre-neutralization container as required, and then a low-content indium germanium acid solution is added at one time, and the pre-neutralization is performed quickly at high temperature, and the pH value is finely adjusted with zinc oxide ore powder or lime water, and the filter is filtered for a certain period of time to improve the filtration performance of the pre-neutralized solution. Secondly, the pre-neutralized precipitated indium germanium slag is first slurried, and then slowly leached with an acidic solution for 2 to 4 hours at a certain temperature, and the filter is filtered after the leaching is completed. The filtration performance of the acid leaching solution can be improved;

[0017] 2. The present invention improves the filtration performance of the pre-neutralization solution and the acid leaching solution of the precipitated indium germanium slag without using lime or alkali for pre-neutralization and without adding a precipitation aid, thereby increasing the indium germanium extraction production capacity and reducing the production cost. DETAILED DESCRIPTION

[0018] The following will be combined with the exemplary embodiments and descriptions of the present invention to explain the present invention, but not to limit the present invention.

[0019] A method for improving the filtration performance of pre-neutralization solution and acid leaching solution of leached indium germanium slag, the specific implementation steps are as follows:

[0020] Step 1, weigh a certain amount of zinc oxide ore powder, add it into a pre-neutralization container at one time, and slurry it with clean water or without slurrying;

[0021] Step 2, adding the acidic zinc sulfate solution containing silicon, trivalent iron, indium and germanium at a liquid / solid ratio of 10 to 30 into the pre-neutralization container containing zinc oxide ore powder in step 1 to carry out a neutralization reaction;

[0022] The acidic zinc sulfate solution containing silicon, trivalent iron, indium and germanium is obtained by neutral leaching of ZnS04 from zinc-containing raw materials and acid leaching of indium and germanium from the leaching residue. Its chemical composition is In 1000-1800mg / L, Ge 20-40mg / L, SiO2 500-800mg / L, Fe 3+ 1~1.5g / L, Zn120~140g / L, H + 20~100g / L;

[0023] Step 3, heating the pre-neutralization reaction of step 2 and mechanically stirring to pre-neutralize and enrich the precipitated indium germanium, while stirring, using zinc oxide ore powder or lime water to fine-tune the pH to 4-4.5, heating to 70-80°C, stirring at a speed of 200-500r / min, and pre-neutralizing for 0.5-1 hour; wherein the pre-neutralized enriched precipitated indium germanium is a low indium germanium acid leaching solution obtained by acid leaching the intermediate leaching residue of the zinc raw material; the amount of zinc oxide ore powder neutralizer added at one time is calculated according to the amount of acidic liquid to be neutralized to reach the pH value of 4-4.5; the fine-tuning in this step is to continue to neutralize the acidic liquid with zinc oxide ore powder to reach the pH value requirement when the added neutralizer is insufficient;

[0024] Step 4: After the pre-neutralization in step 3 is completed, the mixture is allowed to stand for 10 to 30 minutes and filtered to obtain indium germanium-containing precipitate residue and ZnS04 filtrate, and then rinsed once with 40 to 50°C clean water;

[0025] Step 5, leaching the indium germanium precipitate residue of step 4 with electrolytic zinc residual liquid or indium germanium extraction residual liquid or sulfuric acid liquid, the leaching conditions are liquid / solid=1.5-2, temperature 80±5°C, stirring speed 50-200r / min, slowly adding acid solution, leaching time 2-4 hours, leaching final acid pH=1.5-2; wherein the pH value of the leaching final acid is adjusted by lime water or zinc oxide ore powder;

[0026] Step 6, the acid leaching solution obtained in step 5 is allowed to stand for a period of time and then filtered to obtain an indium-germanium-containing acidic solution and a filter residue, the indium-germanium-containing acidic solution is sent to an indium-germanium extraction section, specifically, the indium-germanium acidic solution is extracted with germanium by N235, and indium is extracted with P204, and the filter residue is sent to an electro-zinc intermediate leaching or acid leaching section.

[0027] Specifically, the amount of zinc oxide ore powder in step 1 is weighed at an acidic liquid / solid ratio of 10 to 30 in step 2; and lime water is used as a pre-neutralizing agent when the pH value in step 3 is fine-tuned.

[0028] During the implementation process, when the zinc oxide raw material containing silicon, iron, indium and germanium is neutrally leached, most of the silicon, indium and germanium are not leached. Although iron is leached, it is hydrolyzed into the intermediate leaching residue at pH = 5-5.4. When the intermediate leaching residue is acid-leached at high temperature, most of the indium, germanium and iron are leached, and a considerable part of silicon is also leached, and exists as SiO2 colloid. When the acid leaching solution is pre-neutralized, the SiO2 molecules in the solution will gradually polymerize from small molecular groups to large molecular groups as the pH value increases to form silica gel. When the acid solution is slowly neutralized for a long time with zinc oxide ore powder, the SiO2 component and high iron component in the ore powder will have sufficient time to be leached, increasing the SiO2 component and Fe(0H)3 component in the solution. The coagulation process of silica gel and Fe(0H)3 colloid is an N-type curve. On both sides of the highest and lowest points of the coagulation equivalence point (or isoelectric point), the colloidal molecular clusters are of medium size. As the pH value moves toward the high end, it can aggregate into large molecular clusters and settle, which does not affect the filtration speed. If the pH value continues to increase, that is, it moves toward the alkaline direction (to the right of the lowest equivalence point), the large molecular clusters will dissolve into small molecular clusters. On the left side of the lowest equivalence point, that is, it moves toward the acidic direction, the colloidal molecular clusters will not aggregate and settle, which will affect the filtration. When the highest equivalence point is reached, the colloidal molecular clusters are the smallest. If the acidity continues to increase, the molecular clusters will gradually decompose into single molecules, which will not affect the filtration. The pH value of the pre-neutralization falls exactly between the lowest and highest points, and the colloidal molecular clusters are not small, which easily causes filtration difficulties. In order to avoid this phenomenon, the present invention adds the neutralizing agent zinc oxide ore powder at one time so that the acid leaching solution can be quickly neutralized, which not only makes the silicon, iron, etc. in the ore powder leach as little as possible, reduces the colloid molecular weight in the solution, but also makes the SiO2 colloid and Fe(0H)3 colloid in the solution move closer to the lowest point of the gelation curve, thereby achieving the purpose of improving the filtration performance of the pre-neutralized solution. The acid leaching of the pre-neutralized slag is operated in the opposite direction, that is, after the pre-neutralized slag is added, the acid leaching agent is slowly added at a small liquid-solid ratio of liquid / solid = 1.5-2, and the leaching temperature and stirring speed are reduced, so that the micelles precipitated in the slag cannot be leached in large quantities, thereby reducing the colloidal molecular clusters in the solution, and allowing the colloidal molecular clusters in the solution to polymerize into large molecular clusters and settle time, thereby improving the filtration performance of the acid leaching solution. This is why the present invention can have good filtration performance without using colloidal precipitating agents such as animal glue, polyacrylamide, polyether, etc.

[0029] Example 1

[0030] The acid leaching solution of the leaching residue in the electrolytic zinc workshop of a certain enterprise contains In 1311mg / L, Ge 30mg / L, SiO2 580mg / L, Fe 3+ 1.42g / L, Zn 124g / L, H +25.8g / L. Take 5 liters of acid leaching solution, weigh 250g of neutralizing agent zinc oxide ore powder according to liquid / solid = 20, add the dry powder into the pre-neutralization container at one time, then add 5 liters of acid leaching solution at one time, control the stirring speed to 300r / min, and quickly heat up to 80℃ for pre-neutralization. Use zinc oxide ore powder to fine-tune the solution pH to 4.5, pre-neutralize for 40min, let stand for 20min and filter. Use a vacuum pump with a suction capacity of 10 liters / min and filter for 1 hour. The filtrate contains In4mg / L and Ge 4.5mg / L. The filter residue contains In 1.22%, Ge 0.032%, SiO22%, and Fe 3.5%.

[0031] Example 2

[0032] The acid leaching solution of Example 1 was added according to the liquid-to-solid ratio of Example 1, and the temperature was raised to 80°C. Then the neutralizer was slowly added, and the pre-neutralization was performed for 2 hours to reach pH = 4.5 for filtration. The filtration time was as long as 6 hours. According to the same operation, the zinc oxide ore powder was first used to neutralize to pH = 3.8, and then lime was used to neutralize to pH = 4.5. The filtration speed did not improve significantly, and it still took 6 hours to filter. Lime was used as the pre-neutralizing agent, and the filtration speed was increased to 2 hours after neutralization to pH = 4. However, the pre-neutralization slag was 2.5 times that of Example 1, and indium germanium was not enriched.

[0033] Example 3

[0034] The pre-neutralized slag of Example 1 was acid leached, liquid / solid = 2, temperature 80°C, final acid 81g / L, time 2 hours, and filtered with the vacuum pump of Example 1, and the filtration time was more than 4 hours. The same pre-neutralized slag was acid leached, and the leaching agent was slowly added. The leaching time was 4 hours and 6 hours respectively, and the other conditions remained unchanged. The filtration rate for 4 hours of leaching was 2.5 hours, and the filtration rate for 6 hours of leaching was 1 hour. After 4 hours of leaching, animal glue was added to assist precipitation, and the filtration time was 1 hour. After 6 hours of leaching, animal glue was added to assist precipitation, and the filtration time was 0.5 hours. The fastest filtration time was 8 minutes. Leaching for 2 hours, filtering for 7 hours, the slag contained In0.21%, Ge was trace; leaching for 4 hours, filtering for 2.5 hours, the slag contained In 0.11%, Ge 0.012%; leaching for 6 hours, filtering for 1 hour, the slag contained In 0.22%, Ge 0.012%. The leaching time has little effect on the leaching rate of indium germanium, but has a great impact on the filtration performance of the solution.

[0035] The invention uses a method of adding zinc oxide ore powder and a zinc sulfate acid solution containing silicon, trivalent iron, indium and germanium at one time for pre-neutralization, and finely adjusting the pH value to 4-4.5 by using zinc oxide ore powder to precipitate indium germanium, which can improve the filtering performance of the pre-neutralized solution. The pre-neutralized indium germanium slag is first pulped and then slowly leached with an acidic solution for 2-4 hours, which can improve the filtering performance of the acid leaching solution, increase the indium germanium extraction production capacity, and reduce the production cost.

[0036] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for improving the filtration performance of pre-neutralization solution and acid leaching solution of leached indium germanium slag, characterized in that: The specific implementation steps are as follows: Step 1, weigh a certain amount of zinc oxide ore powder, add it into a pre-neutralization container at one time, and slurry it with clean water or without slurrying; Step 2, adding the zinc sulfate acid solution containing silicon, trivalent iron, indium and germanium at a liquid / solid ratio of 10 to 30 into the pre-neutralization container containing zinc oxide ore powder in step 1 to carry out a neutralization reaction; Step 3, heating the neutralization reaction in step 2 and mechanically stirring to pre-neutralize and enrich the precipitated indium germanium, while stirring, fine-tuning the pH to 4-4.5 with zinc oxide ore powder or lime water, heating to 70-80° C., stirring at a speed of 200-500 r / min, and pre-neutralizing for 0.5-1 hour; Step 4: After the pre-neutralization in step 3 is completed, the mixture is allowed to stand for 10 to 30 minutes and filtered to obtain indium germanium-containing precipitate and ZnS04 filtrate, and then rinsed once with 40 to 50°C clean water; Step 5, using electrolytic zinc residual liquid or indium germanium extraction residual liquid or sulfuric acid liquid to leach the indium germanium precipitate residue of step 4, the leaching conditions are liquid / solid = 1.5-2, temperature 80±5°C, stirring speed 50-200r / min, slowly adding acid solution, leaching time 2-4 hours, leaching final acid pH = 1.5-2; Step 6, the acid leaching solution obtained in step 5 is allowed to stand for a period of time and then filtered to obtain an indium germanium-containing acidic solution and a filter residue, the indium germanium-containing acidic solution is sent to the indium germanium extraction section, and the filter residue is sent to the electro-zinc intermediate leaching or acid leaching section.

2. The method for improving the filtration performance of the pre-neutralization solution and the acid leaching solution of the leached indium germanium slag according to claim 1, characterized in that: The zinc sulfate acid solution containing silicon, trivalent iron, indium and germanium in step 2 is an acid solution obtained by first neutrally leaching ZnS04 from the zinc-containing raw material and then acidically leaching indium and germanium from the leaching residue. The chemical composition of the acid solution is In 1000-1800 mg / L, Ge 20-40 mg / L, SiO2 500-800 mg / L, Fe 3+ 1~1.5g / L, Zn 120~140g / L, H + 20~100g / L.

3. The method for improving the filtration performance of the pre-neutralization solution and the acid leaching solution of the leached indium germanium slag according to claim 1, characterized in that: The pH value of the final leaching acid in step 5 is adjusted by using lime water or zinc oxide ore powder.

4. The method for improving the filtration performance of the pre-neutralization solution and the acid leaching solution of the leached indium germanium slag according to claim 1, characterized in that: In step 6, the indium-germanium-containing acidic solution is subjected to N235 to extract germanium, and P204 to extract indium.