A method for separating zinc and iron

Abstract

The present invention relates to the field of metallurgical technology, and in particular to a method for separating zinc and iron. The method for separating zinc and iron of the present invention comprises the following steps: mixing zinc smelting slag with SO2 at 100-110°C and in the presence of a solvent to obtain a reducing solution and a reducing slag; mixing the reducing solution with H2S at 50-60°C to obtain sulfided slag and a post-sulfided liquid; and subjecting the post-sulfided liquid to high-temperature crystallization. The present invention uses SO2 to reduce zinc smelting slag, which not only improves the leaching effect of zinc and iron metals, but also reduces the high-valent iron in the zinc smelting slag to low-valent iron, reduces the reduction cost, and improves the sedimentation and filtration performance of the ore pulp; the present invention directly uses ferrous sulfate to prepare ferrous sulfate, which provides a reference method for the separation of zinc and iron in the zinc smelting process and the resource utilization of iron.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for separating zinc and iron. Background Art

[0002] Since iron and zinc have similar ionic radii, they often exist in zinc concentrate in the form of zinc ferrite. In the roasting-leaching-electrowinning (RLE) commonly used in zinc smelting, the leached sulfide is converted into soluble metal oxides during the roasting process. In this process, zinc and iron that coexist in the partial mosaic inevitably generate zinc ferrite, which is difficult to be leached in the neutral leaching and low-acid leaching processes. In order to improve the recovery rate of zinc, the intermediate leaching residue and low-acid leaching residue need to be further treated.

[0003] The treatment of medium leaching slag and low leaching slag can be divided into pyrometallurgical process and wet process. The pyrometallurgical process includes rotary kiln, fuming furnace and other processes. Zinc volatilizes in the form of steam and is collected in the form of zinc oxide after oxidation in the flue, while iron and associated metals such as copper remain in the smelting slag. This process has problems such as high energy consumption and low metal recovery rate; the wet process includes hot acid leaching process and reduction leaching process. The hot acid leaching process can effectively destroy zinc ferrite and has a higher metal leaching rate, but the Fe3+ concentration in the slurry affects the liquid-solid separation. At present, it can be separated by jarosite method, goethite method and hematite method. The iron slag obtained by jarosite method and goethite method has low iron content and large slag volume, and is a hazardous waste that needs further treatment. The hematite slag obtained by the hematite method can be used as a raw material for ironmaking, realizing the resource utilization of wet zinc and iron smelting, but its economic added value is currently low.

[0004] Ferrous sulfate is mainly obtained as a by-product in the production of titanium dioxide and is widely used in agriculture, animal husbandry, water treatment, batteries and other fields. Nonferrous metallurgy contains a large amount of iron-containing waste slag, which is an ideal raw material for preparing ferrous sulfate. 2+ Ferrous sulfate crystals are obtained by separation, but in practice, due to the high zinc content of the solution, a large amount of zinc is mixed in the ferrous sulfate crystals, resulting in a reduction in the direct yield of zinc, and the resulting ferrous sulfate is not pure and difficult to use. At present, there is no report on directly recovering and preparing industrial ferrous sulfate with a high yield from the hydrometallurgical zinc smelting process.

[0005] Therefore, it is urgent to develop a method for separating zinc and iron. Summary of the invention

[0006] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a method for separating zinc and iron, so as to realize the recycling of valuable metallic iron in the zinc smelting industry.

[0007] To this end, the first aspect of the present invention provides a method for separating zinc and iron, comprising the following steps:

[0008] Mixing zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a reduction solution and a reduction slag;

[0009] Mixing the reducing liquid with H2S at 50-60°C to obtain sulfided slag and post-sulfided liquid;

[0010] The vulcanized liquid is subjected to high temperature crystallization.

[0011] The present invention uses SO2 to reduce zinc smelting slag, which not only improves the leaching effect of zinc and iron metals, but also reduces the high-valent iron in the zinc smelting slag to low-valent iron, reduces the reduction cost, and improves the sedimentation and filtration performance of the slurry; the present invention directly uses ferrous sulfate to prepare ferrous sulfate, which provides a reference method for the separation of zinc and iron in the zinc smelting process and the resource utilization of iron.

[0012] In some embodiments of the present invention, the partial pressure of SO2 is 0.1-0.2 MPa. In other preferred embodiments of the present invention, the partial pressure of SO2 is 0.1, 0.15 or 0.2 MPa.

[0013] In some embodiments of the present invention, the zinc-smelting slag is mixed with SO2 for 3 to 4 hours; in other preferred embodiments of the present invention, the zinc-smelting slag is mixed with SO2 for 3, 3.5 or 4 hours.

[0014] In some embodiments of the present invention, the mixing of the zinc smelting slag and SO2 includes a first-stage reduction leaching and a second-stage reduction leaching performed in sequence; the first-stage reduction leaching includes: mixing the zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a first-stage reduction liquid and a first-stage reduction slag; the second-stage reduction leaching includes: mixing the first-stage reduction slag with SO2 at 100-110°C in the presence of a solvent to obtain a second-stage reduction liquid and a second-stage reduction slag; mixing the second-stage reduction liquid with the zinc smelting slag and SO2 to perform a first-stage reduction leaching. The first-stage reduction liquid is mixed with H2S for subsequent treatment.

[0015] In some embodiments of the present invention, the reduction leaching period lasts for 1.5 to 2 hours.

[0016] In some embodiments of the present invention, the second stage reduction leaching time is 1.5 to 2 hours.

[0017] In some embodiments of the present invention, the reducing solution and H2S are mixed for 4 to 5 hours; in other preferred embodiments of the present invention, the reducing solution and H2S are mixed for 4, 4.5 or 5 hours.

[0018] In some embodiments of the present invention, the concentrated solution is subjected to high temperature crystallization, and the temperature of the high temperature crystallization is 130-180° C., and the time is 1-3 hours. High temperature crystallization can promote the movement of solute molecules in a high energy state, reduce crystal defects, and thus obtain higher quality crystals with better purity and uniformity, which is conducive to crystallization at a higher concentration, so that the formation of crystals is more complete.

[0019] In some embodiments of the present invention, before the sulfided liquid is subjected to high temperature crystallization, the sulfided liquid is analyzed at 80-90°C for 0.5-3h, and then concentrated at 80-90°C for 2-3h. Analysis can return the H2S dissolved in the solution for use, increase the utilization rate of H2S, reduce the amount of H2S prepared externally, reduce costs and eliminate safety and environmental risks; concentration can increase the iron concentration in the solution and improve the crystallization efficiency.

[0020] In some embodiments of the present invention, the method for separating zinc from iron further comprises the following steps: subjecting the sulfided slag to an acid treatment. The sulfided slag reacts with the acid to generate salt and H2S, which can be collected and used as a raw material. The reuse of H2S reduces the amount of H2S prepared externally, further reducing the cost of H2S.

[0021] In some embodiments of the present invention, the acid treatment is carried out at a temperature of 90 to 100° C. for a time of 4 to 5 hours.

[0022] In some embodiments of the present invention, the acid used in the acid treatment comprises sulfuric acid.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0025] Figure 1 A process flow diagram of one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0027] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0028] The first aspect of the present invention provides a method for separating zinc and iron, comprising the following steps:

[0029] Mixing zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a reduction solution and a reduction slag;

[0030] Mixing the reducing liquid with H2S at 50-60°C to obtain sulfided slag and post-sulfided liquid;

[0031] The vulcanized liquid is subjected to high temperature crystallization.

[0032] The present invention uses SO2 to reduce zinc smelting slag, which not only improves the leaching effect of zinc and iron metals, but also reduces the high-valent iron in the zinc smelting slag to low-valent iron, reduces the reduction cost, and improves the sedimentation and filtration performance of the slurry; the present invention directly uses ferrous sulfate to prepare ferrous sulfate, which provides a reference method for the separation of zinc and iron in the zinc smelting process and the resource utilization of iron.

[0033] In some embodiments of the present invention, the zinc smelting slag includes low-leaching slag, which is a product of low-acid leaching or weak-acid leaching process of hydrometallurgical zinc smelting, and contains 15-25% zinc and 16-25% iron.

[0034] The reaction equation of zinc smelting slag (mainly zinc ferrite ZnFe2O4) mixed with SO2 is as follows:

[0035] ZnFe2O4+2H2SO4+SO2→ZnSO4+2FeSO4+2H2O

[0036] In some embodiments of the present invention, the partial pressure of SO2 is 0.1-0.2 MPa; in other preferred embodiments of the present invention, the partial pressure of SO2 is 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or 0.2 MPa.

[0037] In some embodiments of the present invention, the molar ratio of Zn to SO2 in the zinc-smelting slag is 1:(1-2). As an example, the molar ratio of Zn to SO2 in the zinc-smelting slag may be 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0038] As an example, the mixing of the zinc smelting slag and SO2 is carried out in the presence of 100, 101, 102, 103, 104, 105, 106, 107, 108, 109 or 110°C.

[0039] In some embodiments of the present invention, the zinc-smelting slag is mixed with SO2 for 3 to 4 hours; in other preferred embodiments of the present invention, the zinc-smelting slag is mixed with SO2 for 3, 3.5 or 4 hours.

[0040] In some embodiments of the present invention, the solvent includes a zinc-containing solution produced by a leaching process such as electrolytic waste liquid in hydrometallurgy and high-acid leaching liquid.

[0041] In some embodiments of the present invention, the mixing of the zinc-smelting slag and SO2 comprises a first-stage reduction leaching and a second-stage reduction leaching performed sequentially.

[0042] In some embodiments of the present invention, the first stage reduction leaching comprises: mixing zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a first stage reduction solution and a first stage reduction slag. The first stage reduction solution is mixed with H2S for subsequent treatment.

[0043] In some embodiments of the present invention, the two-stage reduction leaching includes: mixing the first-stage reduction slag with SO2 at 100-110°C and in the presence of a solvent to obtain a second-stage reduction liquid and a second-stage reduction slag; mixing the second-stage reduction liquid with zinc smelting slag and SO2 to perform reduction leaching.

[0044] In some embodiments of the present invention, the raw material for the second-stage reduction leaching further includes electrolytic waste liquid in the hydrometallurgical zinc smelting process.

[0045] In some embodiments of the present invention, the time of the reduction leaching is 1.5 to 2 hours; the H2SO4 concentration at the end of the reduction leaching reaction is 10 to 15 g / L, and the Fe 3+ <0.5g / L, total iron content (TFe) is 50~65g / L.

[0046] In some embodiments of the present invention, the time of the second stage reduction leaching is 1.5 to 2 hours; the H2SO4 concentration at the reaction end point of the second stage reduction leaching is 50 to 70 g / L, and Fe 3+ The mineral content of raw materials is 0.2~1.2g / L, and the total iron content (TFe) is 40~55g / L.

[0047] In some preferred embodiments of the present invention, the ratio of the amount of Zn to H2S in the reducing solution is (1-2). As an example, the ratio of the amount of Zn to H2S in the reducing solution can be 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0048] In some preferred embodiments of the present invention, the reducing solution and H2S are mixed at 50, 51, 52, 53, 54, or 55°C.

[0049] In some embodiments of the present invention, the reducing solution and H2S are mixed for 4 to 5 hours; in other preferred embodiments of the present invention, the reducing solution and H2S are mixed for 4, 4.5 or 5 hours.

[0050] In some embodiments of the present invention, the reducing liquid and H2S are mixed in a closed environment. Reacting in a closed environment can prevent the occurrence of safety and environmental accidents caused by the escape of H2S.

[0051] The reaction equation for the mixture of reducing liquid and H2S is as follows:

[0052] ZnSO4+H2S→ZnS+H2SO4↓

[0053] In some embodiments of the present invention, the Zn concentration in the sulfided liquid is <3 g / L.

[0054] In some embodiments of the present invention, the temperature of the high temperature crystallization is 130-180°C and the time is 1-3 hours. As an example, the temperature of the high temperature crystallization can be 130, 135, 140, 145, 150, 155, 160, 165, 170, 175 or 180°C. High temperature crystallization can promote the movement of solute molecules in a high energy state and reduce crystal defects, thereby obtaining higher quality crystals with better purity and uniformity; in addition, at high temperatures, the solubility of many substances increases, which helps to crystallize at a higher concentration, making the formation of crystals more complete.

[0055] In some embodiments of the present invention, before the sulfided liquid is subjected to high-temperature crystallization, the sulfided liquid is analyzed at 80 to 90°C for 0.5 to 3 hours, and then concentrated at 80 to 90°C for 2 to 3 hours. Analysis can return the H2S dissolved in the solution for use, increase the utilization rate of H2S, reduce the amount of external preparation of H2S, reduce costs and eliminate safety and environmental risks; concentration can increase the iron concentration in the solution and improve the crystallization efficiency. Concentration can increase the iron concentration in the solution to improve the subsequent crystallization efficiency. In addition, concentration can produce H2S, which can be used as a raw material. The reuse of H2S reduces the amount of external preparation of H2S and reduces the cost of H2S.

[0056] In some embodiments of the present invention, a method for separating zinc and iron further comprises the following step: subjecting the sulfided slag to acid treatment.

[0057] In some embodiments of the present invention, the acid treatment specifically includes: mixing the sulfide slag with an acid; the present invention has no limitation on the acid, and the sulfide slag can be treated with an acid commonly used in the art. The sulfide slag reacts with the acid to generate salt and H2S, which can be collected and used as a raw material. The reuse of H2S reduces the amount of H2S prepared externally, further reducing the cost of H2S.

[0058] In some embodiments of the present invention, the acid treatment is carried out at a temperature of 90 to 100° C. for a time of 4 to 5 hours.

[0059] In some embodiments of the present invention, the acid used in the acid treatment comprises sulfuric acid.

[0060] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. Where specific techniques or conditions are not indicated in the examples, the techniques or conditions described in the literature in this area or the product instructions are used. Where the manufacturers of reagents or instruments are not indicated, they are all conventional products that can be obtained commercially.

[0061] Example 1

[0062] The method for separating zinc and iron in this embodiment has a process flow as follows: Figure 1 As shown, the following steps are included:

[0063] (1) Single-stage reduction leaching: The low-level leaching slag produced by a hydrometallurgical zinc smelting plant was taken, which contained 20.21% zinc and 26.7% iron. The low-level leaching slag was subjected to single-stage reduction leaching at 100°C and a SO2 partial pressure of 0.1 MPa for 2 h to obtain a single-stage reduction solution and a single-stage reduction slag. The molar ratio of Zn to SO2 in the low-level leaching slag was 1:1.2.

[0064] (2) Two-stage reduction leaching: The first-stage reduction slag, the electrolytic waste liquid in the hydrometallurgical zinc smelting process and SO2 are subjected to two-stage reduction leaching at 100°C and a SO2 partial pressure of 0.1 MPa for 2 hours to obtain the second-stage reduction slag and the second-stage reduction liquid. The second-stage reduction liquid and the low-leaching slag are further subjected to the first-stage reduction leaching; wherein the molar ratio of Zn and SO2 in the low-leaching slag is 1:1.2.

[0065] (3) Zinc sulfide precipitation: The reducing solution obtained in steps (1) and (2) has the following components: Zn 85 g / L, Fe 56 g / L, Fe 3+0.5g / L, H2SO4 18g / L; the reducing leaching solution is added into a closed container, H2S is introduced and reacted at 50°C for 4h, and the obtained slag is separated by sedimentation to obtain zinc sulfide slag and post-sulfurization liquid; wherein the molar ratio of Zn and H2S in the reducing leaching solution is 1:1.5.

[0066] (4) High acid leaching: sulfuric acid is added to the sulfide slag, and high acid leaching is carried out at 90°C for 4 hours. During the process, acid is added to maintain the acid concentration not less than 250 g / L. After high acid leaching, H2S and filtrate are obtained. H2S is used as the raw material of step (2), and the filtrate is returned to step (1) for further leaching.

[0067] (5) Analysis and concentration: The zinc concentration in the sulfided liquid is 2.1 g / L. The sulfided liquid is analyzed at 90° C. for 0.5 hour to obtain a analyzed liquid and analyzed tail gas. The analyzed tail gas is returned to step (3) to carry out sulfidation zinc precipitation. The analyzed liquid is concentrated at 90° C. for 2.5 hours. The concentrated liquid is introduced into an autoclave for high-temperature crystallization. The reaction is carried out at 160° C. for 1.5 hours. After the reaction is completed, the liquid is allowed to stand for 10 minutes. The supernatant solution (the liquid containing iron crystals) in the autoclave is then discharged, cooled and depressurized. After the temperature reaches 85° C., the ferrous sulfate crystals in the autoclave are taken out. The grade of the ferrous sulfate is 96.8%. The liquid containing iron crystals can be used in a wet process system for hematite precipitation to produce a hematite product containing more than 60% iron.

[0068] Example 2

[0069] The method for separating zinc and iron in this embodiment has a process flow as follows: Figure 1 As shown, the following steps are included:

[0070] (1) One-stage reduction leaching: Take the low-leaching slag produced by a hydrometallurgical zinc smelting plant, which contains 18.9% zinc and 19.5% iron. The low-leaching slag is subjected to one-stage reduction leaching at 110°C and a SO2 partial pressure of 0.15MPa for 2 hours to obtain a one-stage reduction solution and a one-stage reduction slag; wherein the molar ratio of Zn to SO2 in the low-leaching slag is 1:1.5.

[0071] (2) Two-stage reduction leaching: The first-stage reduction slag, electrolytic waste liquid in the hydrometallurgical zinc smelting process and SO2 are subjected to two-stage reduction leaching at 110°C and a SO2 partial pressure of 0.15 MPa for 2 hours to obtain second-stage reduction slag and second-stage reduction liquid. The second-stage reduction liquid and low-leaching slag are further subjected to one-stage reduction leaching.

[0072] (3) Sulfide precipitation of zinc: The composition of the reduction leaching solution obtained in steps (1) and (2) is as follows: Zn 75g / L, Fe 53.5g / L, Fe 3+0.8g / L, H2SO4 16g / L, add the reduction leaching solution into a closed container, introduce H2S to react at 50°C for 4 hours, and obtain zinc sulfide slag and post-sulfurization liquid after sedimentation and separation; wherein the amount ratio of Zn and H2S in the reduction leaching solution is 1:1.5.

[0073] (4) High acid leaching: sulfuric acid is added to the sulfide slag, and the sulfide slag is subjected to high acid leaching at 92°C for 4 hours, during which the acid concentration is maintained at not less than 250 g / L; after high acid leaching, H2S and filtrate are obtained, and the H2S is used as the raw material of step (2), and the filtrate is returned to step (1) for further leaching.

[0074] (5) Analysis and concentration: The sulfided liquid is analyzed at 90° C. for 1 hour to obtain a analyzed liquid and analyzed tail gas. The analyzed liquid is concentrated at 90° C. for 2.5 hours. The analyzed tail gas is returned to step (3) for sulfided zinc precipitation. The concentrated liquid is passed into an autoclave for high-temperature crystallization. The reaction is carried out at 160° C. for 1.5 hours. After the reaction is completed, the concentrated liquid is passed into a high-temperature and high-pressure static container. The supernatant (iron-containing crystallized liquid) is regularly discharged from the upper port. The iron-containing crystallized liquid can be used in a wet process system for hematite precipitation to produce a hematite product containing more than 60% iron. The crystallization bottom flow is discharged from the lower part. The crystallization bottom flow is filtered to obtain ferrous sulfate. The crystallized liquid contains 8.6 g / L iron and the grade of ferrous sulfate is 96.1%.

[0075] Example 3

[0076] The method for separating zinc and iron in this embodiment has a process flow as follows: Figure 1 As shown, the following steps are included:

[0077] (1) One-stage reduction leaching: Take the low-leaching slag produced by a hydrometallurgical zinc smelting plant, which contains 18.9% zinc and 19.5% iron. The low-leaching slag is subjected to one-stage reduction leaching at 100°C and a SO2 partial pressure of 0.18MPa for 1.5 hours to obtain a one-stage reduction solution and a one-stage reduction slag; wherein the molar ratio of Zn to SO2 in the low-leaching slag is 1:1.7.

[0078] (2) Two-stage reduction leaching: The first-stage reduction slag, the electrolytic waste liquid in the hydrometallurgical zinc smelting process and SO2 are subjected to two-stage reduction leaching at 100°C and a SO2 partial pressure of 0.18 MPa for 1.5 hours to obtain second-stage reduction slag and second-stage reduction liquid. The second-stage reduction liquid and low-leaching slag are further subjected to one-stage reduction leaching; wherein the molar ratio of Zn to SO2 in the low-leaching slag is 1:1.7.

[0079] (3) Sulfidation and zinc precipitation: the reduction leaching solution obtained in steps (1) and (2) is added to a continuous reaction system. In the continuous system, the actual sulfidation temperature is 60°C. The reduction leaching solution is added to a closed container, H2S is introduced and reacted for 5 hours, and zinc sulfide slag and post-sulfidation liquid are obtained after sedimentation and separation; wherein the molar ratio of Zn to H2S in the reduction leaching solution is 1:1.4.

[0080] (4) High acid leaching: sulfuric acid is added to the sulfide slag, and high acid leaching is carried out at 92°C for 4 hours, during which the acid concentration is maintained at not less than 250 g / L; after high acid leaching, H2S and filtrate are obtained, and H2S is used as the raw material of step (2), and the filtrate is returned to step (1) for further leaching.

[0081] (5) Analysis and concentration: The sulfided liquid is analyzed at 90° C. for 0.5 hours to obtain a analyzed liquid and analyzed tail gas. The analyzed tail gas is returned to step (3) to carry out sulfidation zinc precipitation. The analyzed liquid is concentrated at 90° C. for 2.5 hours. The obtained concentrated liquid is passed into an autoclave for high-temperature crystallization. The reaction is carried out at 130° C. for 3 hours. After the reaction is completed, the concentrated liquid is passed into a high-temperature and high-pressure static container. The supernatant (iron-containing crystallized liquid) is regularly discharged from the upper port. The iron-containing crystallized liquid can be used in a wet process system for hematite precipitation to produce a hematite product containing more than 60% iron. The crystallization bottom flow is discharged from the lower part. The crystallization bottom flow is filtered to obtain ferrous sulfate. The crystallized liquid contains 25 g / L iron and the grade of ferrous sulfate is 95.9%.

[0082] Comparative Example 1

[0083] The zinc-iron separation method of this comparative example is different from that of Example 1 in that, in step (2), H2S is introduced and reacted at 30°C for 7 hours, and the remaining conditions are carried out with reference to those of Example 1. The grade of ferrous sulfate obtained in this comparative example is 82.4%.

[0084] Comparative Example 2

[0085] The zinc-iron separation method of this comparative example is different from that of Example 1 in that, in step (2), H2S is introduced and reacted at 70°C for 7 hours, and the remaining conditions are carried out with reference to those of Example 1. The grade of ferrous sulfate obtained in this comparative example is 75.1%.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "some implementation schemes" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for separating zinc and iron, characterized in that: The following steps are involved: Mixing zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a reduction solution and a reduction slag; Mixing the reducing liquid with H2S at 50-60°C to obtain sulfided slag and post-sulfided liquid; The vulcanized liquid is subjected to high temperature crystallization.

2. The method for separating zinc and iron according to claim 1, characterized in that: The partial pressure of SO2 is 0.1-0.2 MPa.

3. The method for separating zinc and iron according to claim 1, characterized in that: The mixing of the zinc smelting slag and SO2 includes a first stage reduction leaching and a second stage reduction leaching performed sequentially.

4. The method for separating zinc and iron according to claim 3, characterized in that: The one-stage reduction leaching comprises: mixing zinc smelting slag with SO2 at 100-110°C in the presence of a solvent to obtain a one-stage reduction solution and a one-stage reduction slag; and / or, The two-stage reduction leaching comprises: mixing the first-stage reduction slag with SO2 at 100-110°C in the presence of a solvent to obtain a second-stage reduction liquid and a second-stage reduction slag.

5. The method for separating zinc and iron according to claim 3, characterized in that: The reduction leaching time is 1.5 to 2 hours; and / or, The time of the second stage reduction leaching is 1.5 to 2 hours.

6. The method for separating zinc and iron according to claim 1, characterized in that: The reducing solution and H2S are mixed for 4 to 5 hours.

7. The method for separating zinc and iron according to claim 1, characterized in that: The temperature of the high temperature crystallization is 130-180° C., and the time is 1-3 hours.

8. The method for separating zinc and iron according to claim 1, characterized in that: Before high-temperature crystallization of the sulfided liquid, the sulfided liquid is analyzed at 80 to 90° C. for 0.5 to 3 hours, and then concentrated at 80 to 90° C. for 2 to 3 hours.

9. The method for separating zinc and iron according to claim 1, characterized in that: The following steps are also included: The sulfided slag is treated with acid.

10. The method for separating zinc and iron according to claim 9, characterized in that: The temperature of the acid treatment is 90-100° C. and the time is 4-5 hours.

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