Additive and process for removing cobalt from zinc sulfate solution

Abstract

The invention discloses an additive and a process for removing cobalt from a zinc sulfate solution. The additive is composed of all inorganic substances and mainly comprises the following chemical components in percentage by weight: 8%-16% of Cu, 1.5%-4.0% of Sb, 1.5%-4.0% of Pb, 2.0%-3.5% of Mn, 1.5%-2.5% of K, 14%-23% of Si, 5.0%-10.0% of Al and the balance of O, S and ash. The main technological process for removing cobalt from the zinc sulfate solution comprises the following steps: heating the to-be-purified cobalt-containing zinc sulfate solution to a specified temperature, then adding acid to adjust the pH value, and adding zinc powder and an additive to carry out a cobalt removal reaction. The novel additive is mainly used for replacing antimony salt and arsenic salt in a traditional zinc powder replacement cobalt removal process, and compared with a traditional antimony salt and arsenic salt cobalt removal process, the novel additive has the advantages that the cobalt removal reaction temperature can be reduced by 5-10 DEG C, and the zinc powder consumption can be reduced by at least 30%. The method is a great improvement on the zinc powder replacement cobalt removal process of the zinc sulfate solution, and the purification and cobalt removal cost of the zinc sulfate solution can be greatly reduced.

Description

Technical Field

[0001] The invention belongs to the field of hydrometallurgy, and in particular relates to an additive and a process for removing cobalt from a zinc sulfate solution. Background Art

[0002] In the process of hydrometallurgy, the purification and impurity removal of zinc sulfate solution is a very important link, and its effect directly determines whether the subsequent zinc electrowinning can proceed smoothly. In zinc sulfate solution, cobalt is an impurity element that is difficult to remove. At present, there are two main purification and cobalt removal processes commonly used by domestic zinc smelting enterprises. One is the zinc powder replacement method, in which the antimony salt purification process is the main one; the other is the organic reagent cobalt removal method, including xanthate cobalt removal, β-naphthol cobalt removal and some other organic reagent cobalt removal methods. The main disadvantage of the antimony salt purification process is that the zinc powder consumption is large, especially when the cobalt content of the zinc sulfate solution is high, not only the zinc powder consumption is large, but also the degree of cobalt removal is not high. The biggest disadvantage of the organic reagent cobalt removal method is that organic matter is introduced into the electrolyte, which will have an adverse effect on the subsequent zinc electrowinning process and may cause the occurrence of the electrowinning "burning plate" phenomenon. This is also the main reason why the organic reagent cobalt removal method is less used by domestic manufacturers. Domestic manufacturers mainly use the zinc powder replacement method.

[0003] There are three main reasons why cobalt is difficult to remove from zinc sulfate solution: first, cobalt belongs to the iron group and is highly inert. It has a higher overvoltage when it precipitates from the solution at a lower temperature. Second, the outer electron configuration of cobalt is 3d 7 4s 2 , the sub-outer d orbital is not filled with electrons, and it is easy to combine with the s electrons of hydrogen atoms to form a bond to form a hydride. This strong combination of hydrogen and cobalt makes the overvoltage of hydrogen precipitation on cobalt very small, so any factor that causes the hydrogen overvoltage to decrease may lead to the precipitation of hydrogen. At this time, the replacement process often does not occur between zinc and cobalt, but between zinc and hydrogen. In this way, once cobalt is replaced and precipitated by zinc, a large amount of hydrogen will be precipitated on it, which actually stops the reduction and precipitation of Co ions. Third, zinc ions have a strong inhibitory effect on the replacement of cobalt. When cobalt is precipitated, it is accompanied by hydrogen reduction, which leads to an increase in pH near the electrode surface, and Zn in the solution 2+Basic zinc sulfate or zinc hydroxide can be generated and adsorbed on the surface of zinc powder, which hinders the reduction and deposition of cobalt. Therefore, removing cobalt from zinc sulfate solution by replacement method has always been a topic of concern and research for metallurgical researchers. The additive of the present invention is composed of pure inorganic substances, wherein the added Pb, Sb, and Cu can greatly increase the precipitation overvoltage of hydrogen, combine with the precipitated cobalt, reduce the precipitation speed of hydrogen on cobalt, and promote the reaction of zinc powder replacing cobalt. The added strong oxidant potassium permanganate can oxidize divalent Co ions into trivalent cobalt hydrolysis precipitation, further reducing the Co ion content in the solution, thereby improving the zinc powder replacement and cobalt removal effect, and reducing the zinc powder consumption. Summary of the invention

[0004] The invention discloses an additive and a process for removing cobalt from a zinc sulfate solution, so as to solve any of the above and other potential problems in the prior art.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is: an additive for removing cobalt from zinc sulfate solution, wherein the mass percentages of the components of the additive are: Cu 8-16wt%, Sb 1.5-4.0wt%, Pb 1.5-4.0wt%, Mn 2.0-3.5wt%, K1.5-2.5%, Si 14-23%, Al 5.0-10.0%, and the rest are O, S and unavoidable impurities.

[0006] Another object of the present invention is to provide a process for removing cobalt from zinc sulfate solution using the above-mentioned additive, the process specifically comprising the following steps:

[0007] S1) preparing an additive;

[0008] S2) pre-treating the zinc sulfate solution to be purified for standby use;

[0009] S3) adding the additive prepared in S1) to the zinc sulfate solution treated in S2) and stirring the mixture to obtain a mixed solution;

[0010] S4) adding a certain amount of zinc powder to the mixed solution obtained in S3), stirring evenly, terminating the reaction, and performing solid-liquid separation, thereby completing the removal of cobalt from the zinc sulfate solution.

[0011] Furthermore, the industrial raw materials used for the additive in S1) are copper sulfate, potassium permanganate, antimony white, lead carbonate, diatomaceous earth, bentonite and kaolin.

[0012] Furthermore, the copper sulfate 20% to 40%, potassium permanganate 6% to 10%, antimony white 2% to 5%, lead carbonate 2% to 5%, diatomaceous earth, bentonite and kaolin or a mixture of several of them accounts for 40% to 70%.

[0013] Furthermore, the pretreatment process of S2) is specifically as follows: heating the zinc sulfate solution to be purified to 70° C. to 90° C., and adding acid to adjust the pH value of the solution to 3.0 to 5.0.

[0014] Furthermore, the Co ion content in the zinc sulfate solution to be purified is less than 20 mg / L, and the acid used to adjust the pH value of the solution is sulfuric acid or zinc electrolytic waste electrolyte.

[0015] Furthermore, the additive in S3) is 10-50 mg / L and stirred for 10-30 minutes.

[0016] Furthermore, the amount of zinc powder added in S4) is 100 to 500 times the Co ion content in the zinc sulfate solution, and the stirring reaction time is 1.0 to 3.0 hours.

[0017] Furthermore, the process can reduce the reaction temperature by 5 to 10° C. and the zinc powder consumption by at least 30% compared with the traditional antimony salt purification process.

[0018] Compared with the traditional zinc sulfate cobalt removal process, the present invention has the following advantages:

[0019] (1) Compared with the traditional zinc powder replacement cobalt removal process using antimony salt or arsenic salt as additives, the reaction temperature can be reduced by 5-10°C, and the zinc powder consumption can be reduced by at least 30%, greatly saving production costs;

[0020] (2) Compared with the organic reagent cobalt removal method, the additive components are all inorganic substances, and the added amount is very small, which will not have an adverse effect on the subsequent zinc electrowinning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flowchart of a process for removing cobalt from a zinc sulfate solution. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below by way of examples, but the scope of the present invention is not limited to these examples.

[0023] The invention discloses an additive for removing cobalt from a zinc sulfate solution. The mass percentages of the components of the additive are as follows: 8-16wt% of Cu, 1.5-4.0wt% of Sb, 1.5-4.0wt% of Pb, 2.0-3.5wt% of Mn, 1.5-2.5% of K, 14-23% of Si, 5.0-10.0% of Al, and the remainder is O, S and inevitable impurities.

[0024] like Figure 1 As shown, the present invention uses the above-mentioned additive to remove cobalt from zinc sulfate solution, and the process specifically comprises the following steps:

[0025] S1) preparing an additive;

[0026] S2) pre-treating the zinc sulfate solution to be purified for standby use;

[0027] S3) adding the additive prepared in S1) to the zinc sulfate solution treated in S2) and stirring the mixture to obtain a mixed solution;

[0028] S4) adding a certain amount of zinc powder to the mixed solution obtained in S3), stirring evenly, terminating the reaction, and performing solid-liquid separation, thereby completing the removal of cobalt from the zinc sulfate solution.

[0029] The industrial raw materials used for the additive in S1) are copper sulfate, potassium permanganate, antimony white, lead carbonate, diatomaceous earth, bentonite and kaolin.

[0030] The copper sulfate 20% to 40%, potassium permanganate 6% to 10%, antimony white 2% to 5%, lead carbonate 2% to 5%, diatomaceous earth, bentonite and kaolin or a mixture of several thereof accounts for 40% to 70%.

[0031] The pretreatment process of S2) is specifically as follows: heating the zinc sulfate solution to be purified to 70° C. to 90° C., and adding acid to adjust the pH value of the solution to 3.0 to 5.0.

[0032] The Co ion content in the zinc sulfate solution to be purified is less than 20 mg / L, and the acid used to adjust the pH value of the solution is sulfuric acid or zinc electrolytic waste electrolyte.

[0033] The additive in S3) is 10-50 mg / L and stirred for 10-30 minutes.

[0034] The amount of zinc powder added in S4) is 100 to 500 times the Co ion content in the zinc sulfate solution, and the stirring reaction time is 1.0 to 2.0 hours.

[0035] The process reduces the reaction temperature by 5-10°C and reduces the zinc powder consumption by at least 30%.

[0036] Example 1

[0037] 1. The raw material is a purified liquid from a zinc smelting production plant, the composition of which is: Cu 2.96 mg / L, Cd 94.82 mg / L, Co 4.18 mg / L, Ni 0.28 mg / L, pH = 5.02;

[0038] 2. Use two beakers to take 1000 ml of the above-mentioned purified liquid for testing. 1# uses antimony salt purification process to remove cobalt, and 2# uses the new additive and process of the present invention to remove cobalt. The test conditions of 1# are: reaction temperature 85°C, zinc powder addition amount 3.0 g / L, antimony salt addition amount 3.0 mg / L, reaction time 2.0 h; the test conditions of 2# are reaction temperature 75°C, zinc electrodeposition waste liquid is used to adjust the pH to 4.0, zinc powder addition amount 2.0 g / L, new additive addition amount 15 mg / L, reaction time 1.5 h.

[0039] 3. After the reaction is completed, liquid-solid separation is carried out and the purified liquid is sent for analysis. The analysis results are shown in Table 1.

[0040] Table 1 Experimental results of Example 1

[0041]

[0042]

[0043] From Table 1, it can be seen that the cobalt removal effect of the new additive is significantly better than that of the antimony salt process, and the reaction temperature is reduced by 10°C, and the zinc powder consumption is reduced by 33.3%.

[0044] Example 2

[0045] 1. The raw material is a purified liquid from a zinc smelting production plant, the composition of which is: Cu 1.45 mg / L, Cd 124.1 mg / L, Co 8.45 mg / L, Ni 0.21 mg / L, pH = 5.10;

[0046] 2. Use two beakers to take 1000 ml of the above-mentioned purified liquid for testing. 1# uses antimony salt purification process to remove cobalt, and 2# uses the new additive and process of the present invention to remove cobalt. The test conditions of 1# are: reaction temperature 85°C, zinc powder addition amount 6.5g / L, antimony salt addition amount 4.0mg / L, reaction time 2.0h; the test conditions of 2# are reaction temperature 80°C, zinc electrodeposition waste liquid is used to adjust the pH to 3.5, zinc powder addition amount 4.5g / L, new additive addition amount 25mg / L, reaction time 1.5h.

[0047] 3. After the reaction is completed, liquid-solid separation is carried out and the purified liquid is sent for analysis. The analysis results are shown in Table 2.

[0048] Table 2 Experimental results of Example 2

[0049]

[0050] From Table 2, it can be seen that the cobalt removal effect of the new additive is equivalent to that of the antimony salt process, the reaction temperature is reduced by 5°C, and the zinc powder consumption is reduced by 30.7%.

[0051] Example 3

[0052] 1. The raw material is a purified liquid from a zinc smelting production plant, the composition of which is: Cu 0.5 mg / L, Cd 54.2 mg / L, Co 10.23 mg / L, Ni 0.35 mg / L, pH = 5.05;

[0053] 2. Use two beakers to take 1000 ml of the above-mentioned purified liquid for testing. 1# uses antimony salt purification process to remove cobalt, and 2# uses the new additive and process of the present invention to remove cobalt. The test conditions of 1# are: reaction temperature 90°C, zinc powder addition amount 8.0 g / L, antimony salt addition amount 5.0 mg / L, reaction time 2.0 h; the test conditions of 2# are reaction temperature 80°C, zinc electrodeposition waste liquid is used to adjust the pH to 3.0, zinc powder addition amount 5.5 g / L, new additive addition amount 30 mg / L, reaction time 1.5 h.

[0054] 3. After the reaction is completed, liquid-solid separation is carried out and the purified liquid is sent for analysis. The analysis results are shown in Table 3.

[0055] Table 3 Experimental results of Example 3

[0056]

[0057] From Table 3, it can be seen that the cobalt removal effect of the new additive is equivalent to that of the antimony salt process, the reaction temperature is reduced by 10°C, and the zinc powder consumption is reduced by 31.25%.

[0058] The above is a detailed introduction to an additive and process for removing cobalt from zinc sulfate solution provided in the embodiments of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application; at the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0059] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. As mentioned throughout the specification and claims, "including" and "comprising" are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problem within a certain error range and basically achieve the technical effect. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0060] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0061] The above description shows and describes several preferred embodiments of the present application, but as mentioned above, it should be understood that the present application is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the application concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present application, and should be within the scope of protection of the claims attached to the present application.

Claims

1. An additive for removing cobalt from zinc sulfate solution, characterized in that: The mass percentage of each component of the additive is: Cu 8-16wt%, Sb 1.5-4.0wt%, Pb1.5-4.0wt%, Mn 2.0-3.5wt%, K 1.5-2.5wt%, Si 14-23wt%, Al 5.0-10.0wt%, and the rest is O, S and inevitable impurities.

2. A process for removing cobalt from zinc sulfate solution using the additive as claimed in claim 1, characterized in that: The process specifically comprises the following steps: S1) preparing an additive; S2) pre-treating the zinc sulfate solution to be purified for standby use; S3) adding the additive prepared in S1) to the zinc sulfate solution treated in S2) and stirring the mixture to obtain a mixed solution; S4) adding a certain amount of zinc powder to the mixed solution obtained in S3), stirring evenly, terminating the reaction, and performing solid-liquid separation, thereby completing the removal of cobalt from the zinc sulfate solution.

3. The process according to claim 2, characterized in that The industrial raw materials used for the additive in S1) are copper sulfate, potassium permanganate, antimony white, lead carbonate, diatomaceous earth, bentonite and kaolin.

4. The process according to claim 3, characterized in that The copper sulfate 20% to 40%, potassium permanganate 6% to 10%, antimony white 2% to 5%, lead carbonate 2% to 5%, diatomaceous earth, bentonite and kaolin or a mixture of several thereof accounts for 40% to 70%.

5. The process according to claim 2, characterized in that The pretreatment process of S2) is specifically as follows: heating the zinc sulfate solution to be purified to 70° C. to 90° C., and adding acid to adjust the pH value of the solution to 3.0 to 5.

0.

6. The process according to claim 5, characterized in that The Co ion content in the zinc sulfate solution to be purified is less than 20 mg / L, and the acid used to adjust the pH value of the solution is sulfuric acid or zinc electrolytic waste electrolyte.

7. The process according to claim 2, characterized in that The additive in S3) is 10-50 mg / L and stirred for 10-30 minutes.

8. The process according to claim 2, characterized in that The amount of zinc powder added in S4) is 100 to 500 times the Co ion content in the zinc sulfate solution, and the stirring reaction time is 1.0 to 3.0 hours.

9. The process according to claim 2, characterized in that The process can reduce the reaction temperature by 5-10° C. compared with the traditional antimony salt purification and cobalt removal process, and reduce the zinc powder consumption by at least 30%.

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