Preparation method of a heat-stable reducing agent for copper smelting

Abstract

The application discloses a preparation method of a heat-stable reducing agent for copper smelting. The heat-stable reducing agent for copper smelting is prepared by taking iron-containing materials as aggregates, carbon-containing materials as fine materials, crushing and screening the two kinds of materials respectively, uniformly mixing the two kinds of materials according to a proportion, adding a certain amount of high-temperature binder as a filler, continuously stirring and uniformly mixing, and then pressing and forming. The reducing agent obtained by the method has a certain heat stability at a high temperature of 1100-1350 DEG C. Meanwhile, the specific particle size distribution of the reducing agent can make the reducing agent obtain a larger crack density and a higher crack network degree, so that the reducing agent can reduce the occurrence of pulverization and fragmentation when suddenly falling from normal temperature to a high-temperature melt of 1300 DEG C, improve the utilization rate of the reducing agent, and significantly improve the efficiency of reducing ferric oxide in copper smelting.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a method for preparing a reducing agent for thermally stable copper smelting. Background Technology

[0002] Modern pyrometallurgical copper smelting employs oxygen-enriched smelting processes. During this process, a large amount of high-melting-point iron(III) oxide (Fe3O4) particles are inevitably generated in the molten pool, leading to increased slag viscosity, decreased fluidity, higher copper content in the slag, and poor separation of copper matte from the slag. In production, solid reducing agents are typically added to reduce Fe3O4 to ferrous oxide for slag formation, thereby mitigating the negative effects of Fe3O4. For example, Chinese patent "A Method for Efficiently Eliminating Fe3O4 in Copper Smelting Slag" (CN 115369259A) uses a mixture of two or more of metallic iron, carbon, quartz, and pyrite as a reducing agent to reduce the influence of Fe3O4. However, these composite reducing agents are prone to pulverization and fragmentation during use due to sudden temperature changes and the significant impact force generated when added to the molten pool from a height. Therefore, providing a reducing agent with good thermal stability for copper smelting is of practical necessity and engineering application significance. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a thermally stable reducing agent for copper smelting. The method involves simple steps and mild preparation conditions. The prepared reducing agent exhibits certain thermal stability at high temperatures of 1100~1350 ℃, and its specific particle size distribution enables it to achieve a large crack density and a high degree of crack network. This reduces the splashing phenomenon that occurs when the reducing agent is suddenly dropped from room temperature into a high-temperature melt at 1300 ℃, improves the utilization rate of the reducing agent, and thus improves the reduction efficiency of ferric oxide in copper slag.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for preparing a thermally stable reducing agent for copper smelting involves using iron-containing materials as aggregates and carbon-containing materials as fines. The aggregates are crushed and sieved separately, then mixed evenly in a certain proportion. A high-temperature binder, used as a filler, is heated to a flowable state and added to the mixed powder. After stirring and mixing, the resulting mixture is pressed into shape and cooled to obtain a thermally stable block reducing agent for copper smelting.

[0006] Furthermore, the iron-containing material is one or more of the following: low-grade iron ore, iron-containing dust, iron-containing slag, and iron filings.

[0007] Furthermore, the carbon-containing material is one or more of the following: anthracite, coke, bituminous coal, and carbon powder.

[0008] Furthermore, after crushing and screening, the particle size range of iron-containing materials is -0.15 to +0.074 mm, and the particle size range of carbon-containing materials is -0.074 to +0.01 mm.

[0009] Furthermore, the mass ratio of the iron-containing material to the carbon-containing material is 1:1 to 3.

[0010] Furthermore, the mixing time for iron-containing and carbon-containing materials is 5 to 15 minutes.

[0011] Furthermore, the high-temperature adhesive is one or more of asphalt, coal tar, rubber, and resin.

[0012] Furthermore, the amount of the high-temperature binder is 5% to 10% of the weight of the mixed powder.

[0013] Furthermore, the mixing time for adding the high-temperature binder is 10-20 minutes.

[0014] Furthermore, the pressure for the pressing and molding process is 10~30 MPa.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] This invention controls the particle size distribution of the reducing agent raw material for copper smelting, enabling the resulting reducing agent to have certain thermal stability at high temperatures of 1100~1350℃. At the same time, its specific particle size distribution also allows the reducing agent lumps to obtain a large crack density and a high degree of crack network when they suddenly drop from room temperature to a high-temperature melt of 1300℃, which can further improve the thermal stability of the reducing agent lumps. This reduces the occurrence of reducing agent pulverization and fragmentation, improves the utilization rate of reducing agent lumps, and reduces the content of iron(III) oxide in copper slag. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the structural changes of the reducing agent obtained in this invention after high-temperature thermal shock. Detailed Implementation

[0018] A method for preparing a thermally stable reducing agent for copper smelting involves crushing and sieving iron-containing materials and carbon-containing materials separately to a particle size range of -0.15 to +0.074 mm for the iron-containing materials and -0.074 to +0.01 mm for the carbon-containing materials. The two materials are then mixed at a mass ratio of 1:1 to 3 and stirred for 5 to 15 minutes until homogeneous. A high-temperature binder, at 5% to 10% of the weight of the mixed powder, is heated to a flowable state and added to the mixed powder. The mixture is then stirred for another 10 to 20 minutes. The resulting mixture is then pressed into shape at 10 to 30 MPa and finally cooled to obtain a thermally stable block reducing agent for copper smelting.

[0019] The iron-containing material is one or more of the following: low-grade iron ore, iron-containing dust, iron-containing slag, and iron filings.

[0020] The carbon-containing material is one or more of the following: anthracite, coke, bituminous coal, and carbon powder.

[0021] The high-temperature adhesive is one or more of asphalt, coal tar, rubber, and resin.

[0022] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0023] Example 1:

[0024] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, the pyrite was first crushed and screened to a particle size range of -0.15 mm to +0.074 mm, and the anthracite was crushed and screened to a particle size range of -0.074 mm to +0.01 mm. The pyrite and anthracite were then mixed at a mass ratio of 1:2 for 10 minutes, resulting in a total mixed powder mass of 90 g. 9 g of bitumen was placed in a medium-temperature electric furnace and heated while stirring until the liquid became viscous. This was then poured into the mixed powder, and the mixture was stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 20 MPa to form a cylindrical reducing agent. After cooling, this yielded a cylindrical reducing agent.

[0025] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1 The temperature was raised to 1250 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. The reducing agent sample was then removed from the crucible. The results showed that the surface of the blocky reducing agent had abundant microcracks, but it still maintained its overall shape.

[0026] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1 The temperature was raised to 1250 ℃ and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. After removing the crucible and allowing it to cool naturally, the copper slag was cut in half along the height of the crucible. One portion of the copper slag sample was then cut radially along the crucible to divide the slag layer in two. The content of iron(III) oxide in the upper slag sample was tested. The results showed that the content of iron(III) oxide in the upper copper slag after reduction decreased to 12%.

[0027] Example 2:

[0028] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, the pyrite was first crushed and screened to a particle size range of -0.15 mm to +0.074 mm, and the anthracite was crushed and screened to a particle size range of -0.074 mm to +0.01 mm. The pyrite and anthracite were then mixed at a mass ratio of 1:3 for 10 minutes, resulting in a total mixed powder mass of 90 g. 9 g of bitumen was placed in a medium-temperature electric furnace and heated while stirring until the liquid became viscous. This was then poured into the mixed powder, and the mixture was stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 20 MPa to form a cylindrical reducing agent. After cooling, this yielded a cylindrical reducing agent.

[0029] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1 The temperature was raised to 1250 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 3 meters, and the reducing agent sample was removed from the crucible. The results showed that the surface of the blocky reducing agent had abundant microcracks, which were relatively deep but still maintained their overall shape.

[0030] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1 The temperature was raised to 1250 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 3 meters. The crucible was removed and allowed to cool naturally. The copper slag was then cut in half along the height of the crucible. One portion of the copper slag sample was cut radially along the crucible to divide the slag layer in two. The content of iron(III) oxide in the upper layer of the sample was tested. The results showed that the content of iron(III) oxide in the upper layer of reduced copper slag decreased to 12.8%.

[0031] Comparative Example 1:

[0032] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, pyrite and anthracite were first crushed and sieved to a particle size range of -0.5 mm to +0.15 mm. Then, the resulting pyrite and anthracite were mixed at a mass ratio of 1:2 for 10 minutes, yielding a total mixed powder of 90 g. 9 g of bitumen was placed in a medium-temperature electric furnace and heated while stirring until the liquid became viscous. This was then poured into the mixed powder, and the mixture was stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 20 MPa to form a cylindrical reducing agent. After cooling, this yielded a cylindrical reducing agent.

[0033] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1The temperature was raised to 1250 ℃ and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters, and the reducing agent sample was removed from the crucible. The results showed that because the crushed particle size of the aggregate and fine materials did not meet the limit, the pyrite and anthracite mainly relied on the binder to bind with each other. Therefore, the prepared blocky reducing agent pulverized during the addition process and was difficult to maintain its overall shape.

[0034] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1 The temperature was raised to 1250 ℃ and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. The crucible was removed and allowed to cool naturally. The copper slag was then cut in half along the height of the crucible. One half of the copper slag sample was cut radially along the crucible to divide the slag layer in two. The content of iron(III) oxide in the upper layer of the sample was tested. The results showed that the content of iron(III) oxide in the upper layer of copper slag after reduction decreased to 22.3%.

[0035] Comparative Example 2:

[0036] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, the pyrite and anthracite were first crushed and sieved to a particle size range of -0.01 to +0.0013 mm. Then, the resulting pyrite and anthracite were mixed at a mass ratio of 1:2 for 10 minutes, yielding a total mixed powder of 90 g. 9 g of bitumen was heated and stirred in a medium-temperature electric furnace until it became viscous. This viscous liquid was then poured into the mixed powder and stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 20 MPa. After cooling, cylindrical reducing agent was obtained. However, due to the excessively fine particle size and high viscosity of the raw material, the powder easily clumped on the mold during pressing, causing problems such as mold jamming or difficulty in demolding the reducing agent. This resulted in a loss of 0.8 g of reducing agent due to adhesion during demolding.

[0037] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1 The temperature was raised to 1250 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. The reducing agent sample was then removed from the crucible. The results showed that the block of reducing agent maintained its overall shape, and although there were microcracks on its surface, the number of cracks was relatively small.

[0038] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1The temperature was raised to 1250 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. The crucible was removed and allowed to cool naturally. The copper slag was then cut in half along the height of the crucible. One half of the copper slag sample was cut radially along the crucible to divide the slag layer in two. The content of iron(III) oxide in the upper layer of the sample was tested. The results showed that the content of iron(III) oxide in the upper layer of reduced copper slag decreased to 16%.

[0039] Comparative Example 3:

[0040] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, the pyrite and anthracite were first crushed and sieved to a particle size range of -0.15 mm to +0.074 mm. Then, the pyrite and anthracite were mixed at a mass ratio of 1:2 for 10 minutes, resulting in a total mixed powder mass of 90 g. 9 g of bitumen was placed in a medium-temperature electric furnace and heated while stirring until the liquid became viscous. This was then poured into the mixed powder, and the mixture was stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 20 MPa to form a cylindrical reducing agent. After cooling, this yielded a cylindrical reducing agent.

[0041] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1 The temperature was raised to 1350 °C and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. The reducing agent sample was then removed from the crucible. The results showed that the prepared block of reducing agent cracked during the addition process, but microcracks appeared on the surface.

[0042] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1 The temperature was raised to 1350 ℃ and held for 10 min, with argon gas introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. After removing the crucible and allowing it to cool naturally, the copper slag was cut in half along the height of the crucible. One portion of the copper slag sample was then cut radially along the crucible, dividing the slag layer in two. The content of iron(III) oxide in the upper layer of the sample was tested. The results showed that the content of iron(III) oxide in the upper layer of reduced copper slag decreased to 14%.

[0043] Comparative Example 4:

[0044] Using pyrite as aggregate, anthracite as fines, and bitumen as binder, the pyrite was first crushed and screened to a particle size range of -0.5 mm to +0.15 mm, and the anthracite was crushed and screened to a particle size range of -0.01 mm to +0.0013 mm. The pyrite and anthracite were then mixed at a mass ratio of 1:2 for 10 minutes, resulting in a total mixed powder mass of 90 g. 9 g of bitumen was placed in a medium-temperature electric furnace and heated while stirring until the liquid became viscous. This was then poured into the mixed powder, and the mixture was stirred rapidly for 1-2 minutes, followed by continuous stirring for 15 minutes. 5 g of the mixture was then poured into a 20 mm diameter tablet press mold and pressed under 10 MPa to form a cylindrical reducing agent. After cooling, this yielded a cylindrical reducing agent.

[0045] Place the graphite crucible in the furnace and heat it at 5 °C·min. -1 The temperature was raised to 1350 ℃ and held for 10 min. Argon gas was introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters, and the reducing agent sample was removed from the crucible. The results showed that the blocky reducing agent broke into multiple pieces during the reaction, and the cracks were relatively deep.

[0046] Weigh 200 g of copper slag (containing 30% iron oxide) and place it in a corundum crucible. Heat at 5 °C·min -1 The temperature was raised to 1350 ℃ and held for 10 min, with argon gas introduced to provide a protective atmosphere. Then, a piece of the prepared reducing agent was dropped into the crucible from a height of 2 meters. After removing the crucible and allowing it to cool naturally, the copper slag was cut in half along the height of the crucible. One portion of the copper slag sample was then cut radially along the crucible, dividing the slag layer in two. The content of iron(III) oxide in the upper layer of the sample was tested. The results showed that the content of iron(III) oxide in the upper layer of reduced copper slag decreased to 20%.

[0047] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a reducing agent for thermally stable copper smelting, characterized in that, Iron-containing materials are used as aggregates and carbon-containing materials are used as fine materials. After crushing and screening them separately, they are mixed evenly in a certain proportion. Then, a high-temperature binder used as a filler is heated to a flowable state and added to the above mixed powder. After stirring and mixing, the resulting mixture is pressed into shape and cooled to obtain a reducing agent for copper smelting with thermal stability. The iron-containing material is one or more of the following: low-grade iron ore, iron-containing dust, iron-containing slag, and iron filings, and its particle size range after crushing and screening is -0.15 to +0.074 mm. The carbon-containing material is one or more of anthracite, coke, bituminous coal and carbon powder, and its particle size range after crushing and screening is -0.074 to +0.01 mm. The mass ratio of iron-containing materials to carbon-containing materials is 1:1~3.

2. The method for preparing a reducing agent for thermally stable copper smelting according to claim 1, characterized in that: The high-temperature adhesive is one or more of asphalt, coal tar, rubber, and resin.

3. The method for preparing a reducing agent for thermally stable copper smelting according to claim 1, characterized in that: The amount of the high-temperature binder is 5% to 10% of the weight of the mixed powder.

4. A method for preparing a reducing agent for thermally stable copper smelting according to claim 1, characterized in that: The pressure for compression molding is 10~30 MPa.

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