Process for recovering zinc from zinc-containing smelting smoke dust

Abstract

The invention discloses a process for recovering zinc from zinc-containing smelting smoke dust, which comprises the following steps: carrying out primary acid leaching on the zinc-containing smelting smoke dust to obtain primary acid leaching liquid and primary acid leaching residues; tannin is added into the primary acid leaching liquid for germanium removal, and germanium-removed liquid and germanium residues are obtained; an oxidizing agent is added into the germanium-removed liquid for iron removal, and iron-removed liquid and iron slag are obtained; a reducing agent is added into the iron-removed liquid to remove copper and cadmium, and copper-cadmium-removed liquid and copper-cadmium slag are obtained; a cobalt and nickel purifying agent is added into the copper and cadmium removed liquid for cobalt and nickel removal, and cobalt and nickel removed liquid and cobalt and nickel slag are obtained; and electrolyzing the cobalt and nickel removed solution to obtain a zinc elementary substance and a waste electrolyte. According to the method, impurities except zinc in the smoke dust are removed through a four-stage purification process, and finally the zinc elementary substance with the Zn content of 99.99% and the recovery rate of about 90% is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a process for recovering zinc from zinc-containing smelting dust. Background Art

[0002] In recent years, with the rapid development of the national economy, the utilization of metal ore resources has increased year by year. In order to alleviate the current shortage of primary ore resources, the research and development of secondary resources has attracted more and more attention from the country. Zinc-containing smelting dust is an important secondary resource. Its main source is the dust from steel smelting and lead-zinc smelting processes. Its main component is zinc oxide. It also contains a large amount of valuable metals such as lead, copper, and germanium. It has a high recycling value, but it faces many problems such as low comprehensive utilization rate and recycling difficulties. Therefore, it is very important to use a reasonable and simple process to achieve the comprehensive recovery of valuable metals in zinc-containing dust to reduce environmental pollution and improve the level of resource utilization in my country. Summary of the invention

[0003] In order to overcome the above-mentioned defects of the prior art, the purpose of the present invention is to provide a process for recovering zinc from zinc-containing smelting dust, so as to solve the problem of low recovery rate of zinc and other valuable metals in the existing zinc-containing smelting dust.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions: The present invention provides a process for recovering zinc from zinc-containing smelting dust, comprising the following steps: (1) Acid leaching is performed on zinc-containing smelting dust to obtain an acid leaching solution and an acid leaching residue; (2) adding tannin to the primary acid leaching solution to remove germanium, thereby obtaining a germanium-removed solution and germanium slag; (3) adding an oxidant to the degerminated liquid to remove iron, thereby obtaining deironized liquid and iron slag; (4) adding a reducing agent to the iron-removed liquid to remove copper and cadmium, thereby obtaining a copper- and cadmium-removed liquid and copper-cadmium slag; (5) adding a cobalt-nickel purifier to the copper-cadmium-removed liquid to remove cobalt and nickel, thereby obtaining a cobalt-nickel-removed liquid and a cobalt-nickel slag; (6) The solution after the removal of cobalt and nickel is electrolyzed to obtain zinc element and waste electrolyte.

[0005] Preferably, in the single acid leaching process of step (1), the endpoint pH of the single acid leaching reaction is controlled to be 5.0-5.5.

[0006] Preferably, in the primary acid leaching process of step (1), the acid used is one or more of the waste electrolyte generated after electrolytic removal of cobalt and nickel, and the secondary acid leaching solution, and the liquid-to-solid ratio is (2-3):1; the primary acid leaching temperature is 60-70°C, and the primary acid leaching time is 1-2h.

[0007] Preferably, in step (2), the mass ratio of tannin to primary acid extraction liquid is 5-6 kg / t.

[0008] Preferably, in step (3), the oxidant is hydrogen peroxide, and the mass ratio of the oxidant to the germanium-removed liquid is 4-5 kg / t.

[0009] Preferably, in step (4), the reducing agent is zinc powder, and the mass ratio of the reducing agent to the iron-removed liquid is 15-20 kg / t.

[0010] Preferably, in step (5), the cobalt-nickel purifier is one or more of zinc powder, zinc flakes, and Sb2O3, and the mass ratio of the cobalt-nickel purifier to the copper-cadmium-removed liquid is 8-10 kg / t.

[0011] Preferably, in step (6), the electrolysis voltage is 3.1-3.6 V, the cathode is a pure aluminum plate, and the anode is a lead-silver alloy plate.

[0012] Preferably, the above process further comprises the following steps: subjecting the primary acid leaching residue obtained in step (1) to secondary acid leaching to obtain secondary acid leaching liquid and lead slag.

[0013] Preferably, in the secondary acid leaching, the endpoint pH of the secondary acid leaching reaction is controlled to be 1.5-2.5; the acid used is sulfuric acid, and the liquid-to-solid ratio is (2-3):1; the secondary acid leaching temperature is 80-90°C, and the secondary acid leaching time is 1-2h.

[0014] The beneficial effects of the present invention are: 1. The zinc leachate is purified. The leaching of smelting dust produces a large amount of harmful ions, which affect the purity of the zinc leachate. The present invention removes impurities other than zinc through a four-stage purification process. The main component of the final leachate is zinc sulfate, which can be directly electrolyzed to obtain zinc element.

[0015] 2. Comprehensive recovery of valuable metals in smoke dust is achieved. The present invention comprehensively recovers a variety of valuable metals, including lead slag, germanium slag, iron slag, copper-cadmium slag, and cobalt-nickel slag, which can be further smelted or directly sold.

[0016] 3. Realize the recycling of waste liquid. The secondary acid leaching liquid and electrolytic waste liquid are used for primary acid leaching. The pH of the primary acid leaching can directly meet the impurity removal requirements without the need for additional neutralization, thus realizing the economic recycling of waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0018] Figure 1 The present invention is a schematic diagram of a process for recovering zinc from zinc-containing smelting dust. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1 The embodiment of the present invention provides a process for recovering zinc from zinc-containing smelting dust, comprising the following steps: (1) Mix the zinc-containing smelting dust with the waste electrolyte generated by the electrolytic removal of cobalt and nickel and one or more of the secondary acid leaching liquid for primary acid leaching, and control the endpoint pH of the primary acid leaching reaction to be 5.0-5.5 to obtain a primary acid leaching liquid and a primary acid leaching residue; wherein the liquid-to-solid ratio is (2-3):1; the primary acid leaching temperature is 60-70°C, and the primary acid leaching time is 1-2h. The liquid-to-solid ratio is the ratio of the liquid volume L to the solid mass kg.

[0021] (2) Add tannin to the primary acid leaching solution to remove germanium. The mass ratio of tannin to the primary acid leaching solution is 5-6 kg / t, and a germanium-removed liquid and germanium slag are obtained.

[0022] (3) adding an oxidant to the degermanium liquid to remove iron, wherein the mass ratio of the oxidant to the degermanium liquid is 4-5 kg / t, to obtain deironized liquid and iron slag; wherein the oxidant is preferably hydrogen peroxide.

[0023] (4) Adding a reducing agent to the de-ironized liquid to remove copper and cadmium, the mass ratio of the reducing agent to the de-ironized liquid being 15-20 kg / t, to obtain a de-ironized liquid and copper-cadmium slag; the reducing agent is preferably zinc powder.

[0024] (5) Adding a cobalt-nickel purifier to the copper-cadmium removal liquid to remove cobalt and nickel, the mass ratio of the cobalt-nickel purifier to the copper-cadmium removal liquid is 8-10 kg / t, to obtain a cobalt-nickel removal liquid and cobalt-nickel slag; the cobalt-nickel purifier is preferably one or more of zinc powder, zinc flakes, and Sb2O3.

[0025] (6) The solution after the removal of cobalt and nickel is electrolyzed at a voltage of 3.1 to 3.6 V, with a cathode of pure aluminum and an anode of lead-silver alloy to obtain zinc and waste electrolyte.

[0026] In some preferred embodiments, the process further comprises mixing the primary acid leaching residue obtained in step (1) with a sulfuric acid solution for secondary acid leaching, controlling the endpoint pH of the secondary acid leaching reaction to be 1.5-2.5, and obtaining secondary acid leaching liquid and lead slag. The sulfuric acid concentration is preferably 20-30wt%, and the liquid-to-solid ratio is (2-3):1; the secondary acid leaching temperature is 80-90°C, and the secondary acid leaching time is 1-2h.

[0027] In some preferred embodiments, the process further comprises calcining the germanium slag obtained in step (2) to obtain germanium concentrate, and the calcination temperature is preferably 700-800° C. and the calcination time is 30-60 min.

[0028] In some preferred embodiments, the zinc-containing smelting dust contains 60-70% Zn, 2-4% Pb, and a small amount of valuable metals such as Cu, Cd, Co, Ni, and Ge.

[0029] To make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. In the following examples, all the drugs used are commercially available products.

[0030] Example 1 A process for recovering zinc from zinc-containing smelting dust comprises the following steps: (1) Primary acid leaching: The zinc smelting dust (containing 65.32% Zn, 3.15% Pb, and the rest being valuable metals such as Cu, Cd, Co, Ni, and Ge) is mixed with the waste electrolyte produced after electrolytic removal of cobalt and nickel and the secondary acid leaching liquid for primary acid leaching. The liquid-to-solid ratio is 2:1 (L:kg), the leaching temperature is 70°C, the leaching time is 2h, the leaching endpoint pH is 5.2, and the primary acid leaching liquid and primary acid leaching residue are obtained by filter pressing.

[0031] (2) Secondary acid leaching: The primary acid leaching residue was mixed with 20 wt% sulfuric acid solution for secondary acid leaching, with a liquid-to-solid ratio of 2:1, a leaching temperature of 90 °C, a leaching time of 2 h, a leaching endpoint pH of 2, and filter press to obtain the secondary acid leaching solution and lead slag.

[0032] (3) Removal of germanium: Add tannin to the primary acid leaching solution obtained in step (1) to remove germanium. The mass ratio of tannin to the primary acid leaching solution is 5 kg / t. The reaction time is 30 min. Filter press to obtain a germanium-removed liquid and germanium slag.

[0033] (4) Iron removal: hydrogen peroxide is added to the degerminated germanium liquid to remove iron. The mass ratio of hydrogen peroxide to degerminated germanium liquid is 5 kg / t. The reaction time is 20 min. The degerminated liquid and iron slag are obtained by filtration.

[0034] (5) Removal of copper and cadmium: zinc powder is added to the de-ironified liquid to carry out a replacement reaction to remove copper and cadmium. The mass ratio of zinc powder to de-ironified liquid is 15 kg / t. The reaction time is 30 min. The de-ironified liquid and copper-cadmium slag are obtained by filter pressing.

[0035] (6) Removal of cobalt and nickel: Add cobalt-nickel purifier and zinc powder to the copper-cadmium removal liquid to remove cobalt and nickel. The mass ratio of cobalt-nickel purifier to copper-cadmium removal liquid is 10 kg / t. The reaction time is 20 min. The cobalt-nickel removal liquid and cobalt-nickel slag are obtained by filtration.

[0036] (7) Electrolysis: The solution after the removal of cobalt and nickel is electrolyzed, with the cathode being a pure aluminum plate and the anode being a lead-silver alloy plate. The electrolysis voltage is 3.6 V, and zinc element and waste electrolyte are obtained.

[0037] Example 2 A process for recovering zinc from zinc-containing smelting dust comprises the following steps: (1) Primary acid leaching: The zinc smelting dust (containing 68.75% Zn, 2.06% Pb, and the rest being valuable metals such as Cu, Cd, Co, Ni, and Ge) is mixed with the waste electrolyte produced after electrolytic removal of cobalt and nickel and the secondary acid leaching liquid for primary acid leaching. The liquid-to-solid ratio is 2:1 (L:kg), the leaching temperature is 60°C, the leaching time is 1h, the leaching endpoint pH is 5.0, and the primary acid leaching liquid and primary acid leaching residue are obtained by filter pressing.

[0038] (2) Secondary acid leaching: The primary acid leaching residue was mixed with 20 wt% sulfuric acid solution for secondary acid leaching, with a liquid-to-solid ratio of 2:1, a leaching temperature of 80 °C, a leaching time of 1 h, a leaching endpoint pH of 1.5, and filter press to obtain the secondary acid leaching solution and lead slag.

[0039] (3) Removing germanium: adding tannin to the primary acid leaching solution obtained in step (1) to remove germanium, the mass ratio of tannin to the primary acid leaching solution being 6 kg / t, the reaction time being 20 min, and filtering to obtain a germanium-removed liquid and germanium slag.

[0040] (4) Iron removal: hydrogen peroxide is added to the degerminated germanium liquid to remove iron. The mass ratio of hydrogen peroxide to degerminated germanium liquid is 4 kg / t. The reaction time is 20 min. The degerminated liquid and iron slag are obtained by filtration.

[0041] (5) Removal of copper and cadmium: zinc powder is added to the de-ironified liquid to carry out a replacement reaction to remove copper and cadmium. The mass ratio of zinc powder to de-ironified liquid is 18 kg / t. The reaction time is 20 min. The de-ironified liquid and copper-cadmium slag are obtained by filter pressing.

[0042] (6) Removal of cobalt and nickel: Add cobalt-nickel purifier and zinc flakes to the copper-cadmium removal liquid to remove cobalt and nickel. The mass ratio of cobalt-nickel purifier to copper-cadmium removal liquid is 8.8 kg / t. The reaction time is 30 min. The cobalt-nickel removal liquid and cobalt-nickel slag are obtained by filtration.

[0043] (7) Electrolysis: The solution after the removal of cobalt and nickel is electrolyzed, with the cathode being a pure aluminum plate and the anode being a lead-silver alloy plate. The electrolysis voltage is 3.1 V, and zinc element and waste electrolyte are obtained.

[0044] Example 3 A process for recovering zinc from zinc-containing smelting dust comprises the following steps: (1) Primary acid leaching: The zinc smelting dust (containing 62.64% Zn, 2.87% Pb, and the rest being valuable metals such as Cu, Cd, Co, Ni, and Ge) is mixed with the waste electrolyte produced after electrolytic removal of cobalt and nickel and the secondary acid leaching liquid for primary acid leaching. The liquid-to-solid ratio is 2:1 (L:kg), the leaching temperature is 65°C, the leaching time is 1.5h, the leaching endpoint pH is 5.5, and the primary acid leaching liquid and primary acid leaching residue are obtained by filter pressing.

[0045] (2) Secondary acid leaching: The primary acid leaching residue was mixed with 20 wt% sulfuric acid solution for secondary acid leaching, with a liquid-to-solid ratio of 2:1, a leaching temperature of 85 °C, a leaching time of 1.5 h, a leaching endpoint pH of 2.5, and filter press to obtain the secondary acid leaching solution and lead slag.

[0046] (3) Removing germanium: adding tannin to the primary acid leaching solution obtained in step (1) to remove germanium, the mass ratio of tannin to the primary acid leaching solution being 4.5 kg / t, the reaction time being 25 min, and filtering to obtain a germanium-removed liquid and germanium slag.

[0047] (4) Iron removal: hydrogen peroxide is added to the degerminated germanium liquid to remove iron. The mass ratio of hydrogen peroxide to degerminated germanium liquid is 4 kg / t. The reaction time is 30 min. The degerminated liquid and iron slag are obtained by filtration.

[0048] (5) Removal of copper and cadmium: zinc powder is added to the de-ironified liquid to carry out a replacement reaction to remove copper and cadmium. The mass ratio of zinc powder to de-ironified liquid is 20 kg / t. The reaction time is 25 min. The de-ironified liquid and copper-cadmium slag are obtained by filter pressing.

[0049] (6) Removal of cobalt and nickel: Add zinc powder and Sb2O3~~~, a cobalt-nickel purifier, to the copper-cadmium removal liquid to remove cobalt and nickel. The mass ratio of the cobalt-nickel purifier to the copper-cadmium removal liquid is 8 kg / t. The reaction time is 30 min. The cobalt-nickel removal liquid and cobalt-nickel slag are obtained by filter pressing.

[0050] (7) Electrolysis: The solution after the removal of cobalt and nickel is electrolyzed, with the cathode being a pure aluminum plate and the anode being a lead-silver alloy plate. The electrolysis voltage is 3.5 V, and zinc element and waste electrolyte are obtained.

[0051] The purity of elemental zinc and the content of lead in lead slag in Examples 1 to 3 were tested respectively, and the recovery rate of zinc and the recovery rate of lead were calculated. The results are shown in Table 1.

[0052] Table 1

[0053] It can be seen from the above table that the process proposed in the present invention can obtain metallic zinc containing 99.99% Zn and a recovery rate of about 90% from smelting smoke containing 60-70% Zn and 2-4% Pb, thereby realizing resource utilization of zinc. At the same time, lead-containing slag with a recovery rate of about 50% can be obtained, which can be further smelted or directly sold.

[0054] It should be noted that the above embodiments all belong to the same inventive concept, and the description of each embodiment has its own focus. For matters that are not described in detail in some embodiments, reference may be made to the description in other embodiments.

[0055] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A process for recovering zinc from zinc-containing smelting dust, characterized in that: The following steps are involved: (1) Acid leaching is performed on zinc-containing smelting dust to obtain an acid leaching solution and an acid leaching residue; (2) adding tannin to the primary acid leaching solution to remove germanium, thereby obtaining a germanium-removed solution and germanium slag; (3) adding an oxidant to the degermanium liquid to remove iron, thereby obtaining a deironized liquid and iron slag; (4) adding a reducing agent to the iron-removed liquid to remove copper and cadmium, thereby obtaining a copper- and cadmium-removed liquid and copper-cadmium slag; (5) adding a cobalt-nickel purifier to the copper-cadmium-removed liquid to remove cobalt and nickel, thereby obtaining a cobalt-nickel-removed liquid and a cobalt-nickel slag; (6) electrolyzing the solution after the removal of cobalt and nickel to obtain zinc element and waste electrolyte.

2. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In the single acid leaching process of step (1), the endpoint pH of the single acid leaching reaction is controlled to be 5.0-5.

5.

3. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In the primary acid leaching process of step (1), the acid used is one or more of the waste electrolyte generated after electrolytic removal of cobalt and nickel, and the secondary acid leaching solution, and the liquid-to-solid ratio is (2-3):1; the primary acid leaching temperature is 60-70°C, and the primary acid leaching time is 1-2h.

4. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In step (2), the mass ratio of the tannin to the primary acid extract is 5-6 kg / t.

5. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In step (3), the oxidant is hydrogen peroxide, and the mass ratio of the oxidant to the germanium-removed liquid is 4-5 kg / t.

6. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In step (4), the reducing agent is zinc powder, and the mass ratio of the reducing agent to the iron-removed liquid is 15-20 kg / t.

7. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In step (5), the cobalt-nickel purifier is one or more of zinc powder, zinc flakes, and Sb2O3, and the mass ratio of the cobalt-nickel purifier to the copper-cadmium-removed liquid is 8-10 kg / t.

8. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: In step (6), the electrolysis voltage is 3.1-3.6 V, the cathode is a pure aluminum plate, and the anode is a lead-silver alloy plate.

9. The process for recovering zinc from zinc-containing smelting dust according to claim 1, characterized in that: The following steps are also included: The primary acid leaching residue obtained in step (1) is subjected to secondary acid leaching to obtain secondary acid leaching liquid and lead slag.

10. The process for recovering zinc from zinc-containing smelting dust according to claim 9, characterized in that: In the secondary acid leaching, the endpoint pH of the secondary acid leaching reaction is controlled to be 1.5-2.5; the acid used is sulfuric acid, and the liquid-to-solid ratio is (2-3):1; the secondary acid leaching temperature is 80-90°C, and the secondary acid leaching time is 1-2h.

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