Method and device for extracting metallic zinc from zinc-containing slag

Abstract

The present invention discloses a method and device for extracting metallic zinc from zinc-containing slag, comprising: obtaining zinc liquid molten slag containing metallic zinc; flowing the zinc liquid molten slag into and storing it in a slag bag; and performing air quenching on the zinc liquid molten slag in the slag bag to obtain dust containing metallic zinc. The invention adopts a dust removal device to collect volatiles in the air quenching process, and the main component of the volatiles is zinc oxide (ZnO). This is a method for extracting low-zinc slag that is technologically feasible and has the lowest production cost. The low-zinc slag just out of the furnace has a high temperature. After being temperature-controlled in the slag bag and sent to the air quenching station, it is easy to realize the recovery of zinc elements in the liquid slag state. Compared with the volatilization process of a fuming furnace or a rotary kiln, this process not only utilizes the heat of the slag itself, but also saves the energy consumption required for heating the slag from room temperature to a semi-molten state.

Description

Technical Field

[0001] The present invention relates to the technical field of extracting metals from tailings, and in particular to a method and device for extracting metallic zinc from zinc-containing slag. Background Art

[0002] Generally speaking, for the slag that still contains a certain amount of zinc and sulfur in the tailings (referred to as low-zinc slag) after the target metal is extracted by pyrometallurgical smelting, the zinc content in the slag is too low to be directly extracted by an independent smelting process. Most of the slag is processed by fuming or rotary kiln volatilization to recover metallic zinc.

[0003] This low-zinc slag is usually a solid slag formed by water quenching after being discharged from a pyrometallurgical furnace, and is mostly stored in piles. The valuable metal zinc in the low-zinc slag cannot be used in a timely and effective manner. The main reason is that the zinc content in the low-zinc slag is low, and it is economically uneconomical to extract zinc alone. Only when the low-zinc slag accumulates to a certain amount, whether for environmental reasons or other reasons, will the company consider starting to treat the stockpiled solid smelting slag, that is, heating the low-zinc slag to a semi-molten state and treating it by fuming or volatilization. This method is also very high in terms of energy consumption alone. Therefore, how to extract metallic zinc from low-zinc slag at a low production cost has become a problem that needs to be solved urgently. Summary of the invention

[0004] The object of the present invention is to provide a method and device for extracting metallic zinc from zinc-containing slag, so as to solve the above-mentioned technical problems.

[0005] To achieve the above object, the present invention provides a method for extracting metallic zinc from zinc-containing slag, comprising:

[0006] Obtaining zinc liquid molten slag containing metallic zinc;

[0007] The zinc liquid molten slag flows into and is stored in a slag ladle;

[0008] The zinc liquid molten slag in the slag bag is subjected to wind quenching treatment to obtain dust containing metallic zinc.

[0009] Optionally, the method further includes: judging the weight of the zinc liquid molten slag flowing into the slag ladle, and stopping the flow of the zinc liquid molten slag into the slag ladle when the weight of the zinc liquid molten slag flowing into the slag ladle meets a threshold value.

[0010] Optionally, the method further comprises: measuring the temperature of the liquid zinc molten slag in the slag ladle.

[0011] Optionally, the liquid zinc molten slag in the slag ladle is subjected to wind quenching treatment, comprising:

[0012] Moving the slag bag to the air quenching operation station;

[0013] Open the air quenching operating valve and stabilize the air quenching working pressure;

[0014] The sliding water inlet of the slag bag is opened to carry out air quenching treatment.

[0015] Optionally, the air quenching working pressure ranges from 0.4 to 0.6 MPa.

[0016] Optionally, the method further includes: when the wind quenching treatment is completed, closing the sliding water gate and the wind quenching operation valve in sequence.

[0017] Optionally, the method further comprises: obtaining solid slag produced after wind quenching, wherein the solid slag can be used as a building material or waste slag for landfill.

[0018] Optionally, the particle size of the solid slag is about 50 mesh.

[0019] Optionally, the dust containing metallic zinc is dust containing zinc oxide.

[0020] The present invention also provides a device for extracting metallic zinc from zinc-containing slag, comprising:

[0021] An obtaining unit, used for obtaining liquid zinc molten slag containing metallic zinc;

[0022] A storage unit, used for flowing the zinc liquid molten slag into and storing it in a slag ladle;

[0023] The air quenching unit performs air quenching on the zinc liquid molten slag in the slag bag to obtain dust containing metallic zinc.

[0024] Technical effects and advantages of the present invention:

[0025] The present invention provides a method for extracting metallic zinc from zinc-containing slag, comprising: obtaining zinc liquid molten slag containing metallic zinc; flowing the zinc liquid molten slag into and storing it in a slag bag; and performing wind quenching on the zinc liquid molten slag in the slag bag to obtain dust containing metallic zinc.

[0026] The invention has the following effects:

[0027] 1. The liquid low-zinc slag in the original smelting process is treated by slag bag temperature control + air quenching, and the volatiles in the air quenching process are collected by a dust removal device. The main component of the volatiles is zinc oxide (ZnO). This is a technologically feasible and lowest-cost extraction method for low-zinc slag.

[0028] 2. The temperature of the low-zinc slag just out of the furnace is relatively high. After being temperature-controlled in the slag bag and sent to the wind quenching station, it is easy to realize the recovery of zinc elements in the liquid slag state.

[0029] 3. Compared with the fuming furnace or rotary kiln volatilization process, this process not only utilizes the heat of the slag itself but also saves the energy consumption required to heat the slag from room temperature to a semi-molten state.

[0030] 4. After the liquid low-zinc slag is treated with air quenching, the zinc-containing substances in the slag undergo a full oxidation reaction, the recovery rate of metallic zinc is very high, and the zinc content in the treated tailings is very low, so it can be treated as waste slag.

[0031] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Process flow chart for extracting metallic zinc from low-zinc liquid slag;

[0033] Figure 2 This is a schematic diagram of a device for extracting metallic zinc from zinc-containing slag. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in 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.

[0035] In order to better illustrate the scheme, the overall concept of the present invention is roughly described below:

[0036] For low-zinc slag, the liquid high-temperature slag is usually quenched with water to form solid slag for storage. If conditions permit, the solid slag is heated to a liquid or semi-molten state for the recovery of valuable metal zinc. This operation alone wastes a lot of energy, even exceeding the value of the recovered metal zinc. However, with the rise in the price of non-ferrous metal zinc, the recovery of metal zinc in low-zinc slag has a greater profit margin. On the other hand, according to the requirements of relevant national policies, solid waste slag containing a certain amount of zinc element must first be extracted from valuable metals to reduce its zinc content to a reasonable level to achieve resource utilization. Overall, it is of great practical value to develop a new recycling process.

[0037] Therefore, in order to effectively utilize the heat of liquid slag itself, give full play to the smelting advantages of liquid slag, and extract valuable metal zinc from low-zinc slag at the lowest production cost, the present invention discloses a method for extracting metal zinc from zinc-containing slag. The method comprises: obtaining zinc liquid molten slag containing metal zinc; flowing the zinc liquid molten slag into and storing it in a slag bag; and performing wind quenching on the zinc liquid molten slag in the slag bag to obtain dust containing metal zinc.

[0038] To better understand the scheme, the following Figure 1 The method for extracting metallic zinc from zinc-containing slag is introduced in detail.

[0039] After the completion of high-temperature pyrometallurgy, the low-zinc liquid molten slag (i.e., zinc liquid molten slag containing metallic zinc) discharged regularly flows into the slag ladle through the slag chute. When the slag reaches the predetermined weight, the slag flow is stopped. After standing for 1 minute, the temperature is measured. If the slag temperature meets the requirements, the slag ladle is moved to the air quenching operation station and the air quenching operation valve is opened. The air quenching working pressure is maintained at 0.4-0.6Mpa. When the wind pressure is stable, the sliding water inlet of the slag ladle is opened, and the wind pressure is kept stable during the entire air quenching process; when the air quenching process is over, the sliding water inlet is closed first and then the air is stopped; during the air quenching process, the particle size of the solid slag can be kept at about 50 mesh.

[0040] After the wind quenching is completed, the dust collection system is cleaned and the dust is released. Most of the dust is zinc oxide (and contains a small amount of impurities), which is also the finished product of this patent. The dust can be used as a raw material for reducing metallic zinc in the next step. The solid slag produced after wind quenching can be used as a building material raw material or waste slag.

[0041] The present invention also provides an example to illustrate the feasibility of the method for extracting metallic zinc from zinc-containing slag.

[0042] Air quenching treatment stage: In this example, smelting liquid slag containing about 10% zinc is selected. First, the liquid molten zinc-containing slag regularly discharged after high-temperature smelting is completed is flowed into the slag ladle through the slag chute, and the slag flow is stopped when the slag volume reaches the set weight; after the slag ladle is allowed to stand for 1 minute, the slag temperature is measured. When the temperature reaches 1350℃±, the slag ladle is moved to the air quenching operation station and the air quenching operation valve is opened, and the air quenching working pressure is maintained at 0.4-0.6Mpa; when the wind pressure is stable, the slag ladle sliding gate is opened, and the wind pressure is kept stable during the entire air quenching process; at the end of the air quenching process, the sliding gate is closed first and then the air is stopped; during the air quenching process, the solid slag particle size can be maintained at about 50 mesh.

[0043] Dust collection stage: After the wind quenching operation is completed, the dust in the dust bag is collected. This dust is a mixture containing zinc oxide and a small amount of impurities, which is also the finished product of this patent. The mixture can be used as a raw material for reducing metallic zinc in the next step. The solid slag produced after wind quenching can be used as a building material raw material or waste slag.

[0044] The present invention aims to solve the problem of how to extract valuable metal zinc from low-zinc liquid slag produced by high-temperature smelting by pyrometallurgy, and proposes an independent disposal process and device that is simple, feasible, and has a high extraction efficiency. The prior art is to store the liquid slag after solidification or to remelt (or melt) it in a solid state for treatment. The present invention extends the production process of low-zinc slag, and transforms the terminal tailings from solid waste into raw materials for building materials (or waste slag for landfill), which not only increases the economic benefits of the enterprise but also improves the industrial chain. The tailings formed by the prior art are all solid waste slag, which needs to be further processed before they can be used as waste slag. The hot air generated during the wind quenching operation in the present invention can be used in the drying process of raw and auxiliary materials, saving energy and production costs for the enterprise.

[0045] The present invention also provides a device for extracting metallic zinc from zinc-containing slag, such as Figure 2 The device comprises: an obtaining unit for obtaining zinc liquid molten slag containing metallic zinc; a storage unit for flowing the zinc liquid molten slag into and storing it in a slag bag; and an air quenching unit for air quenching the zinc liquid molten slag in the slag bag to obtain dust containing metallic zinc.

[0046] Since the content protected by this device is similar to that protected by the above method, it will not be introduced in detail here. Please refer to the description of the above method for details.

[0047] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for extracting metallic zinc from zinc-containing slag, characterized in that: include: Obtaining zinc liquid molten slag containing metallic zinc; The zinc liquid molten slag flows into and is stored in a slag ladle; Measuring the temperature of the zinc liquid molten slag in the slag ladle; When the temperature of the zinc liquid molten slag reaches about 1350°C, the slag bag is subjected to wind quenching to obtain dust containing zinc oxide; Wherein, the working pressure range of the air quenching in the air quenching treatment is 0.4-0.6Mpa.

2. The method for extracting metallic zinc from zinc-containing slag according to claim 1, characterized in that: The method further includes: determining the weight of the zinc liquid molten slag flowing into the slag ladle, and stopping the flow of the zinc liquid molten slag into the slag ladle when the weight of the zinc liquid molten slag flowing into the slag ladle meets a threshold.

3. The method for extracting metallic zinc from zinc-containing slag according to claim 1, characterized in that: The slag bag is subjected to wind quenching treatment, including: Moving the slag bag to the air quenching operation station; Open the air quenching operating valve and stabilize the air quenching working pressure; The sliding water inlet of the slag bag is opened to carry out air quenching treatment.

4. The method for extracting metallic zinc from zinc-containing slag according to claim 3, characterized in that: The method further comprises: when the wind quenching treatment is finished, closing the sliding gate and the wind quenching operation valve in sequence.

5. The method for extracting metallic zinc from zinc-containing slag according to claim 1, characterized in that: The method further comprises: obtaining solid slag produced after wind quenching, and using the solid slag as building raw material or waste slag for landfill.

6. The method for extracting metallic zinc from zinc-containing slag according to claim 5, characterized in that: The particle size of the solid slag is about 50 meshes.

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