A method for resource utilization of copper-containing waste magnesia bricks

Abstract

The invention relates to the technical field of step-by-step recovery of valuable elements in non-ferrous metallurgical solid waste, and discloses a method for resource utilization of copper-containing waste magnesia bricks. The method comprises the following steps: S1, crushing and preparing materials; S2, vacuum reduction, in which blocky or spherical copper-containing waste magnesia bricks are reduced under vacuum conditions to obtain metallic magnesium and reduction slag; and S3, returning the reduction slag to a pyrometallurgical smelting process to recover copper. The invention processes the copper-containing waste magnesia bricks by first crushing and preparing materials, then performing vacuum reduction to extract magnesium, and returning the reduction slag to a pyrometallurgical smelting process to recover copper, thereby realizing resource recovery of copper and magnesium in the copper-containing waste magnesia bricks. The method has a short process flow and high recovery efficiency, thereby solving the problem of traditional pyrometallurgical processes affecting furnace conditions and avoiding the shortcomings of existing wet processes with high costs and large wastewater volumes. The whole-process magnesium recovery rate is greater than 95%, and the copper recovery rate is greater than 99%, thereby realizing efficient resource recovery of copper and magnesium in the copper-containing waste magnesia bricks.

Description

Technical Field

[0001] The invention relates to the technical field of step-by-step recovery of valuable elements in non-ferrous metallurgical solid waste, in particular to a method for resource utilization of copper-containing waste magnesia bricks. Background Art

[0002] Most large copper smelters worldwide use a pyrometallurgical process based on "matte smelting - matte converting - pyrometallurgical refining" to extract metallic copper from copper concentrate. This pyrometallurgical copper smelting process requires the use of large quantities of magnesia refractory bricks in the metallurgical furnaces. During the production process, these bricks come into contact with and are continuously eroded by the copper-containing melt. During production and maintenance, these eroded bricks are replaced and removed, resulting in large quantities of copper-containing scrap magnesia bricks. These scrap magnesia bricks must be recycled because they contain a large amount of copper-containing material and small amounts of gold, silver, arsenic, and chromium.

[0003] There are two main processes for processing copper-containing waste magnesia bricks. The first utilizes a "mineral processing and enrichment - smelting copper extraction" process, where the waste magnesia bricks are first crushed and ground, then enriched into a high-magnesium copper concentrate using mineral processing. The high-magnesium copper concentrate is then fed to a copper smelter for copper recovery. The second utilizes a "wet leaching - displacement enrichment - smelting copper extraction" process, where magnesium is first leached with sulfuric acid, then copper is enriched by displacement with iron powder. The magnesium-containing leachate is used to produce a magnesium salt product, and the leached slag and copper displacement slag are then returned to smelting for copper recovery. While the first option effectively recovers copper, gold, and silver from waste magnesia bricks, separating copper from magnesium using mineral processing technology is difficult. The resulting high-magnesium copper concentrate contains more than 20% magnesium, which exists as high-melting-point magnesium oxide. Feeding this into a copper smelter can easily generate high-melting-point MgO•SiO2 slag, which increases slag viscosity and copper content, and is prone to forming furnace nodules, shortening the service life of the metallurgical furnace. Although Option 2 achieves efficient removal and resource recovery of magnesium, it produces a large amount of wastewater and the replacement process cost is high, resulting in the overall process benefit being not obvious.

[0004] Therefore, in view of the problems existing in the resource utilization of copper-containing waste magnesia bricks in the copper smelting industry, it is meaningful to develop a method for resource utilization of copper-containing waste magnesia bricks with short process, low cost and high efficiency. Therefore, we need to propose a method for resource utilization of copper-containing waste magnesia bricks. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for resource utilization of copper-containing waste magnesia bricks. The method comprises the following steps: first crushing and preparing the materials, then vacuum reducing and extracting magnesium, and returning the reduced slag to a pyrometallurgical smelting process to recover copper to treat the copper-containing waste magnesia bricks. The method realizes resource recovery of copper and magnesium in the copper-containing waste magnesia bricks. The process flow is short and the recovery efficiency is high. The method solves the problem of the traditional pyrometallurgical process affecting the furnace condition and avoids the shortcomings of the existing wet process with high cost and large amount of wastewater. The magnesium recovery rate of the whole process is greater than 95%, and the copper recovery rate is greater than 99%. The method realizes efficient resource recovery of copper and magnesium in the copper-containing waste magnesia bricks, thereby solving the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for resource utilization of copper-containing waste magnesia bricks, comprising the following steps:

[0007] S1. Crushing and preparing materials: crushing the copper-containing waste magnesia bricks and mixing them with the reducing agent and catalyst in proportion, and then pressing the powder of the copper-containing waste magnesia bricks into blocks or balls;

[0008] S2. Vacuum reduction: Under vacuum conditions, the block or spherical copper-containing waste magnesium bricks are reduced to obtain metallic magnesium and reduction slag;

[0009] S3. Returning the reducing slag to the pyrometallurgical smelting process to recover copper.

[0010] Preferably, in step S1, crushing and preparing materials includes the following steps:

[0011] S11. Use a crusher or grinder to crush the copper-containing waste magnesium bricks into particles or powder that meet the particle size requirements;

[0012] S12, adding a reducing agent and a catalyst mixed in proportion to the crushed copper-containing waste magnesia bricks, wherein the reducing agent is used to promote the reduction of copper oxide in the copper-containing waste magnesia bricks into metallic copper, and the catalyst is used to increase the reaction rate;

[0013] S13. Uniform mixing: Use a stirring device to fully mix the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst to ensure that the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst are evenly distributed and that the powdered copper-containing waste magnesia bricks are in full contact with the reducing agent and the catalyst;

[0014] S14, compression molding: The mixed materials are pressed into blocks or balls by applying pressure using a press or an extruder.

[0015] Preferably, in step S1, the maximum particle size of the copper-containing waste magnesia bricks after crushing is less than 100 mesh, the property requirement of the reducing agent is a powder with a maximum particle size less than 100 mesh, and when pressing the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst, the block or ball making pressure is greater than 2.0 MPa.

[0016] Preferably, the reducing agent is silicon-calcium alloy or calcium carbide, the catalyst is fluoride salt, and the fluoride salt is calcium fluoride or sodium fluoride;

[0017] The mass ratio of the amount of reducing agent added to the copper-containing waste magnesium bricks is 10-25:100, and the mass ratio of the amount of catalyst added to the copper-containing waste magnesium bricks is 1-3:100.

[0018] Preferably, in step S2, the process of vacuum reduction of magnesium metal is as follows:

[0019] S21, placing the lump or spherical copper-containing waste magnesium bricks mixed with a reducing agent and a catalyst in a vacuum furnace;

[0020] S22, heating the prepared materials in the vacuum furnace to trigger a reduction reaction, wherein the reducing agent reduces the metal oxides in the copper-containing waste magnesium bricks to metallic magnesium. At the same time, the catalyst promotes the reduction reaction to improve the reduction efficiency;

[0021] S23. Metallic magnesium is extracted from the copper-containing waste magnesium bricks and forms a reduction slag with the substances that did not participate in the reaction. After the reaction is completed, the metallic magnesium is separated from the reduction slag by cooling and separation, and the metallic magnesium is refined and purified.

[0022] Preferably, in step S2, the vacuum degree in the vacuum furnace is less than 50 Pa, the heating temperature of the reduction reaction in the vacuum furnace is controlled at 1000° C.-1250° C., and the duration of the reduction reaction is 2-4 hours.

[0023] Preferably, in step S3, the process of recovering copper from the reducing slag through a pyrometallurgical smelting process comprises the following steps:

[0024] S31, crushing the reduced slag into an appropriate particle size, and mixing it with the flux and flux in proportion, and adjusting the composition and melting point of the reduced slag;

[0025] S32, adding the mixed reducing slag to a converter, and blowing air or other oxidants into the converter to cause a reduction reaction of the metal oxides in the reducing slag, and starting smelting under high temperature conditions, so that the metallic copper element is gradually separated from the slag to form a metal phase and a slag phase;

[0026] S33. Separate the metallic copper from the slag by gravity separation, electromagnetic separation or flotation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention treats copper-containing waste magnesia bricks by first crushing and preparing materials, then vacuum reducing and extracting magnesium, and returning the reduced slag to pyrometallurgical smelting to recover copper, thereby realizing resource recovery of copper and magnesium in copper-containing waste magnesia bricks. The process flow is short and the recovery efficiency is high, which not only solves the problem of traditional pyrometallurgical process affecting furnace conditions, but also avoids the shortcomings of existing wet process with high cost and large amount of wastewater. The whole process magnesium recovery rate is greater than 95%, and the copper recovery rate is greater than 99%, thereby realizing efficient resource recovery of copper and magnesium in copper-containing waste magnesia bricks. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of the present invention;

[0030] Figure 2 This is a flow chart of the crushing and material preparation process of the present invention;

[0031] Figure 3 It is a flow chart of vacuum reduction of the present invention;

[0032] Figure 4 This is a flow chart of copper recovery in the pyrometallurgical smelting process of the present invention;

[0033] Figure 5 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention. Example 1

[0035] See also Figure 1-5 The present invention provides a technical solution: a method for resource utilization of copper-containing waste magnesia bricks, comprising the following steps:

[0036] S1. Crushing and preparing materials: crushing the copper-containing waste magnesia bricks and mixing them with the reducing agent and catalyst in proportion, and then pressing the powder of the copper-containing waste magnesia bricks into blocks or balls;

[0037] In step S1, the crushing and preparation of materials includes the following steps:

[0038] S11. Use a crusher or grinder to crush the copper-containing waste magnesium bricks into particles or powder that meet the particle size requirements; so that they reach a particle size suitable for further processing.

[0039] S12, adding a reducing agent and a catalyst mixed in proportion to the crushed copper-containing waste magnesia bricks, wherein the reducing agent is used to promote the reduction of copper oxide in the copper-containing waste magnesia bricks into metallic copper, and the catalyst is used to increase the reaction rate;

[0040] S13. Uniform mixing: Use a stirring device to fully mix the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst to ensure that the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst are evenly distributed, and that the powdered copper-containing waste magnesia bricks are in full contact with the reducing agent and the catalyst, so that the metal elements in the copper-containing waste magnesia bricks can be effectively extracted;

[0041] S14. Compression molding: The mixed materials are pressed into blocks or balls by applying pressure using a press or extruder to facilitate subsequent processing and transportation.

[0042] In step S1, the maximum particle size of the copper-containing waste magnesia bricks after crushing is less than 100 mesh, and the property requirement of the reducing agent is a powder with a maximum particle size less than 100 mesh. When pressing the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst, the pressure for making blocks or pellets is greater than 2.0 MPa.

[0043] The reducing agent is silicon-calcium alloy or calcium carbide, the catalyst is fluoride salt, and the fluoride salt is calcium fluoride or sodium fluoride; the reducing agent of this solution is silicon-calcium alloy powder.

[0044] The mass ratio of the amount of reducing agent added to the copper-containing waste magnesium bricks is 10-25:100, and the mass ratio of the amount of catalyst added to the copper-containing waste magnesium bricks is 1-3:100.

[0045] S2. Vacuum reduction: Under vacuum conditions, the block or spherical copper-containing waste magnesium bricks are reduced to obtain metallic magnesium and reduction slag; the vacuum environment helps to reduce the impact of oxygen and other impurities on the reduction process and improve the reduction efficiency.

[0046] In step S2, the process of vacuum reduction of magnesium metal is as follows:

[0047] S21. Place the copper-containing waste magnesium bricks in the form of blocks or pellets mixed with the reducing agent and catalyst in a vacuum furnace. The vacuum environment is used to remove oxygen and other impurities that may affect the reduction process, ensuring that the reduction reaction can proceed in a purer and more efficient environment.

[0048] S22, heating the prepared materials in the vacuum furnace to make the temperature in the furnace reach the level required for the reduction reaction, triggering the reduction reaction, and the reducing agent reducing the metal oxides in the copper-containing waste magnesium bricks to metallic magnesium. At the same time, the catalyst promotes the reduction reaction and improves the reduction efficiency;

[0049] S23. Metallic magnesium is extracted from the copper-containing waste magnesium bricks and forms a reduction slag with the substances that did not participate in the reaction. After the reaction is completed, the metallic magnesium is separated from the reduction slag by cooling and separation, and the metallic magnesium is refined and purified.

[0050] In step S2, the vacuum degree in the vacuum furnace is less than 50 Pa, the heating temperature of the reduction reaction in the vacuum furnace is controlled at 1000° C.-1250° C., and the duration of the reduction reaction is 2-4 hours.

[0051] S3. Returning the reducing slag to the pyrometallurgical smelting process to recover copper.

[0052] In step S3, the process of recovering copper from the reducing slag through a pyrometallurgical smelting process includes the following steps:

[0053] S31, crushing the reduced slag into an appropriate particle size, and mixing it with the flux and flux in proportion, and adjusting the composition and melting point of the reduced slag;

[0054] S32, adding the mixed reducing slag to a converter, and blowing air or other oxidants into the converter to cause a reduction reaction of the metal oxides in the reducing slag, and starting smelting under high temperature conditions, so that the metallic copper element is gradually separated from the slag to form a metal phase and a slag phase;

[0055] Kaldo furnace smelting is a more efficient smelting method. It utilizes the high temperatures of the Kaldo furnace to cause the metal oxides in the reducing slag to react with the reducing agent, thereby extracting the copper metal. Kaldo furnace smelting offers advantages such as fast reaction speed, high metal recovery rate, and low energy consumption.

[0056] S33. Separate the metallic copper from the slag by gravity separation, electromagnetic separation or flotation.

[0057] Gravity separation utilizes the density difference between the metal phase and the slag phase for separation; electromagnetic separation utilizes the conductivity of the metal phase to achieve separation through the action of the electromagnetic field; flotation uses flotation agents to form a foam layer in the metal phase or slag phase, thereby achieving separation.

[0058] The composition of copper-containing waste magnesia bricks is shown in the following table:

[0059] element Mg Cu As Fe Si Al Cr No. 1 copper-containing waste magnesia brick% 16.9 13.8 0.2 10.1 4.3 2.39 3.0 No.2 copper-containing waste magnesia brick% 22.5 8.6 0.2 7.2 5.3 3.1 5.4

[0060] The specific operation process is as follows:

[0061] Crushing preparation: Take No. 1 copper-containing waste magnesia brick, crush it with a crusher, sieve it through a 100-mesh screen to obtain copper-containing waste magnesia brick powder, take silicon-calcium alloy, grind it to below 100 mesh, mix 250g of copper-containing waste magnesia brick powder, 35g of silicon-calcium alloy powder, and 7.5g of calcium fluoride, and press it into briquettes with a sample press machine. Control the pressure during briquetting to 25Kg;

[0062] Vacuum reduction: The pressed material was placed in a material boat and sent to a vacuum reduction tank for reduction under vacuum conditions of 25 Pa for 3 hours. The reduction temperature was controlled at 1000°C to obtain 40.5g of metallic magnesium and 243.2g of reduced slag with a magnesium recovery rate of 95.9%. Example 2

[0063] The same as Example 1 will not be repeated here, except that

[0064] The specific operation process is as follows:

[0065] Crushing preparation: Take No. 1 copper-containing waste magnesia brick, crush it with a crusher, sieve it through a 100-mesh screen to obtain copper-containing waste magnesia brick powder, take silicon-calcium alloy, grind it to below 100 mesh, mix 250g of copper-containing waste magnesia brick powder, 40g of silicon-calcium alloy powder, and 6g of calcium fluoride, and press it into briquettes with a sample press machine, controlling the pressure during briquetting to 25Kg;

[0066] Vacuum reduction: The pressed material was placed in a material boat and sent to a vacuum reduction tank for reduction under vacuum conditions of 32 Pa for 4 hours. The reduction temperature was controlled at 1100°C to obtain 40.9g of metallic magnesium and 247.8g of reduced slag, with a magnesium recovery rate of 96.8%. Example 3

[0067] The same points as in Example 1 and Example 2 are not described in detail.

[0068] The specific operation process is as follows:

[0069] Crushing preparation: Take No. 2 copper-containing waste magnesia brick, crush it with a crusher, sieve it through a 100-mesh screen to obtain copper-containing waste magnesia brick powder, take silicon-calcium alloy, grind it to below 100 mesh, mix 250g of copper-containing waste magnesia brick powder, 50g of silicon-calcium alloy powder, and 6g of sodium fluoride, and press it into briquettes with a sample press machine, controlling the pressure during briquetting to 25Kg;

[0070] Vacuum reduction: The pressed material was placed in a material boat and sent to a vacuum reduction tank for reduction under vacuum conditions of 40 Pa for 3.5 hours. The reduction temperature was controlled at 1150°C to obtain 54.8g of metallic magnesium and 241.5g of reduced slag, with a magnesium recovery rate of 97.4%. Example 4

[0071] The same points as in Example 1 to Example 3 are not described in detail.

[0072] The specific operation process is as follows:

[0073] Crushing preparation: Take No. 2 copper-containing waste magnesia brick, crush it with a crusher, sieve it through a 100-mesh screen to obtain copper-containing waste magnesia brick powder, take silicon-calcium alloy, grind it to below 100 mesh, mix 250g of copper-containing waste magnesia brick powder, 60g of silicon-calcium alloy powder, and 7.5g of sodium fluoride, and press it into briquettes with a sample press machine. Control the pressure during briquetting to 25Kg;

[0074] Vacuum reduction: The pressed material was placed in a material boat and sent to a vacuum reduction tank for reduction under vacuum conditions of 48 Pa for 4 hours. The reduction temperature was controlled at 1250°C to obtain 55.1g of metallic magnesium and 247.4g of reduced slag, with a magnesium recovery rate of 98.0%.

[0075] In summary, the present invention uses "waste preparation - vacuum reduction to extract metallic magnesium - return the reduced slag to pyrometallurgical smelting to recover copper" as the main process to treat copper-containing waste magnesium bricks, thereby realizing the resource recovery of copper and magnesium in copper-containing waste magnesium bricks. The process flow is short and the recovery efficiency is high. It not only solves the problem of traditional pyrometallurgical process affecting the furnace condition, but also avoids the shortcomings of existing wet process with high cost and large amount of wastewater. The magnesium recovery rate of the whole process is greater than 95%, and the copper recovery rate is greater than 99%, realizing the efficient resource recovery of copper and magnesium in copper-containing waste magnesium bricks.

[0076] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for resource utilization of copper-containing waste magnesia bricks, characterized by: The steps include: S1. Crushing and preparing materials: crushing the copper-containing waste magnesia bricks and mixing them with the reducing agent and catalyst in proportion, and then pressing the powder of the copper-containing waste magnesia bricks into blocks or balls; The reducing agent is silicon-calcium alloy or calcium carbide, the catalyst is fluoride salt, and the fluoride salt is calcium fluoride or sodium fluoride; The mass ratio of the reducing agent added to the copper-containing waste magnesium bricks is 10-25:100, and the mass ratio of the catalyst added to the copper-containing waste magnesium bricks is 1-3:

100. S2. Vacuum reduction: Under vacuum conditions, the block or spherical copper-containing waste magnesium bricks are reduced to obtain metallic magnesium and reduction slag; The vacuum degree in the vacuum furnace is less than 50 Pa, the heating temperature of the reduction reaction in the vacuum furnace is controlled at 1000°C-1250°C, and the duration of the reduction reaction is 2-4 hours; S3. Returning the reducing slag to the pyrometallurgical smelting process to recover copper.

2. The method for resource utilization of copper-containing waste magnesia bricks according to claim 1, characterized in that: In step S1, the crushing and preparation of materials includes the following steps: S11. Use a crusher or grinder to crush the copper-containing waste magnesium bricks into particles or powder that meet the particle size requirements; S12, adding a reducing agent and a catalyst mixed in proportion to the crushed copper-containing waste magnesia bricks, wherein the reducing agent is used to promote the reduction of copper oxide in the copper-containing waste magnesia bricks into metallic copper, and the catalyst is used to increase the reaction rate; S13. Uniform mixing: Use a stirring device to fully mix the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst to ensure that the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst are evenly distributed and that the powdered copper-containing waste magnesia bricks are in full contact with the reducing agent and the catalyst; S14, compression molding: The mixed materials are pressed into blocks or balls by applying pressure using a press or an extruder.

3. The method for resource utilization of copper-containing waste magnesia bricks according to claim 2, characterized in that: In step S1, the maximum particle size of the copper-containing waste magnesia bricks after crushing is less than 100 mesh, and the property requirement of the reducing agent is a powder with a maximum particle size less than 100 mesh. When pressing the powdered copper-containing waste magnesia bricks, the reducing agent and the catalyst, the pressure for making blocks or pellets is greater than 2.0 MPa.

4. The method for resource utilization of copper-containing waste magnesia bricks according to claim 1, characterized in that: In step S2, the process of vacuum reduction of magnesium metal is as follows: S21, placing the lump or spherical copper-containing waste magnesium bricks mixed with a reducing agent and a catalyst in a vacuum furnace; S22, heating the prepared materials in the vacuum furnace to trigger a reduction reaction, wherein the reducing agent reduces the metal oxides in the copper-containing waste magnesium bricks to metallic magnesium. At the same time, the catalyst promotes the reduction reaction to improve the reduction efficiency; S23. Metallic magnesium is extracted from the copper-containing waste magnesium bricks and forms a reduction slag with the substances that did not participate in the reaction. After the reaction is completed, the metallic magnesium is separated from the reduction slag by cooling and separation, and the metallic magnesium is refined and purified.

5. The method for resource utilization of copper-containing waste magnesia bricks according to claim 1, characterized in that: In step S3, the process of recovering copper from the reducing slag through a pyrometallurgical smelting process includes the following steps: S31, crushing the reduced slag into an appropriate particle size, and mixing it with the flux and flux in proportion, and adjusting the composition and melting point of the reduced slag; S32, adding the mixed reducing slag to a converter, and blowing air or other oxidants into the converter to cause a reduction reaction of the metal oxides in the reducing slag, and starting smelting under high temperature conditions, so that the metallic copper element is gradually separated from the slag to form a metal phase and a slag phase; S33. Separate the metallic copper from the slag by gravity separation, electromagnetic separation or flotation.

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