Refining agent for impurity removal of scrap copper and application method of refining agent

Abstract

The invention belongs to the technical field of scrap copper refining and impurity removal, and particularly discloses a refining agent for scrap copper impurity removal and an application method of the refining agent. The refining comprises an iron-containing component and a non-iron component, the valence state of an iron element in the iron-containing component is greater than or equal to 2, and the non-iron component comprises SiO2 and Al2O3; and the mass content of an iron-containing component in the refining agent for removing the impurities of the scrap copper is 10-96%. The application method of the refining agent comprises the following steps: drying the refining agent with certain fineness, heating and melting scrap copper, adding a certain amount of the refining agent into molten copper, controlling the smelting temperature to be 1150-1300 DEG C, blowing oxygen to smelt for a period of time, and slagging off, so that the content of impurity elements in the molten copper can be effectively reduced. The refining agent is remarkable in effect of removing impurity elements in the scrap copper, low in price, easy to obtain and environmentally friendly, can provide technical support for high-quality cyclic utilization of the scrap copper, is easy to industrialize and has very wide popularization and application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of refining and removing impurities from scrap copper, and specifically discloses a refining agent for removing impurities from scrap copper and an application method thereof. Background Art

[0002] my country's copper ore reserves account for only 3.97% of the world's total reserves, with a foreign dependence rate of more than 70%, and a low level of resource security. The recycling of scrap copper has the advantages of low production cost, low energy consumption, and low pollution. It is an effective way to alleviate the shortage of copper resources in my country, and it is also an inevitable choice for the green and sustainable development of the copper-based materials industry chain. Scrap copper has a wide range of sources, many types of impurity elements, and a large fluctuation range. How to remove various impurity elements to a reasonable range is an important issue facing the recycled copper industry. The commonly used refining agents for pyrometallurgical refining of scrap copper are quartz sand, glass slag, lime, soda ash, etc. These traditional refining agents have limited effects on the removal of impurity elements, especially for some difficult-to-separate impurity elements. Taking nickel as an example, nickel and copper can be infinitely dissolved by replacing atoms in the grains. When the nickel content in metallic copper is less than 0.3%, nickel exists in the copper matrix in the form of solid solution; during the smelting process, the oxidation of nickel is slow and incomplete, and the generated NiO is distributed between the copper liquid and the slag, which makes it difficult to separate and purify nickel in the copper liquid.

[0003] In order to remove and purify impurity elements in scrap copper, predecessors have developed some new refining agents, but these refining agents are often alloy products or chemical products, with complex preparation processes and high preparation costs. For example, the invention patent "A scrap copper refining agent and its preparation method and application CN 110527860 B" discloses a copper refining agent, which needs electrolytic copper, Cu-Mg alloy, Cu-B alloy, Cu-Ce alloy, Cu-Y alloy, Cu-Pr alloy, Cu-La alloy as raw materials, and maintains a high-purity inert atmosphere and high temperature in a vacuum melting furnace to prepare the copper refining agent, which has high raw material cost and complex preparation process. For another example, the invention patent "An additive for removing nickel / bismuth from purple copper, its preparation method and application CN 115198100B" discloses an additive for removing nickel / bismuth from purple copper and its preparation method, the additive comprising CaF2, MgF2 and CuF2, and it is necessary to add the raw material containing CaF2, the raw material containing MgF2 and the raw material containing CuF2 or substitutes into an induction furnace, and smelt and synthesize the additive at 1400°C, or add the raw material containing CaF2, metal Mg and metal Cu into an induction furnace, and smelt and synthesize the additive at 1400°C; the CaF2 raw material can be fluorite, the MgF2 raw material can be fluormagnesium fluoride, and CuF2 can be replaced by fluorocarbon compounds, antimony pentafluoride or tin fluoride; among these raw materials, CaF2 is relatively cheap and easy to obtain, while MgF2 and CuF2 are not easy to obtain.

[0004] The present invention is proposed to solve the problems of difficulty in removing or purifying the impurities that are difficult to separate in the existing scrap copper, complex refining agent preparation process and high refining agent cost. Summary of the invention

[0005] The first technical problem to be solved by the present invention is to provide a refining agent which is cheap, easy to obtain, has a simple preparation process, is green and environmentally friendly, and can effectively reduce the impurity content in scrap copper, especially the content of impurities that are difficult to separate. The second technical problem to be solved by the present invention is to provide an application method of the refining agent.

[0006] In order to solve the above-mentioned first technical problem, the present invention provides a refining agent for removing impurities from scrap copper, the refining agent comprising an iron-containing component and a non-iron component, the valence state of the iron element in the iron-containing component is greater than or equal to 2, and the non-iron component contains SiO2 and Al2O3; the mass content of the iron-containing component in the refining agent for removing impurities from scrap copper is 10% to 96%.

[0007] As a preferred embodiment, in the refining agent for removing impurities from scrap copper of the present invention, the iron-containing component may be one or more of hematite, limonite, magnetite, siderite and pyrite.

[0008] As a preferred embodiment, the present invention provides a refining agent for removing impurities from scrap copper, wherein the non-ferrous component comprises gangue minerals containing SiO2 and Al2O3.

[0009] As a preferred embodiment, the present invention provides a refining agent for removing impurities from scrap copper, wherein the sum of the mass proportions of iron-containing components and non-iron components of SiO2 and Al2O3 in the refining agent is greater than 80%, preferably greater than 90%.

[0010] As one of the preferred solutions, the present invention provides a refining agent for removing impurities from scrap copper, wherein the mass content of the iron component in the refining agent is 10% to 96%, preferably 15% to 96%.

[0011] As one of the preferred solutions, mined natural iron ore or iron concentrate and iron tailings obtained through ore dressing can be used as the refining agent.

[0012] In order to solve the above-mentioned second technical problem, the present invention provides an application method of a refining agent for removing impurities from scrap copper. After the scrap copper is heated and melted, a dried refining agent is added to the copper liquid, the smelting temperature is controlled to be 1100-1300°C, and the slag is skimmed after oxygen blowing smelting. The single use amount of the refining agent is 0.1%-3% of the mass of the scrap copper.

[0013] The invention discloses an application method of a refining agent for removing impurities from scrap copper. Natural iron ore is crushed to a size of less than or equal to 10 mm and dried for later use. Iron concentrate and iron tailings obtained by artificial sorting can be directly dried for later use.

[0014] The invention discloses an application method of a refining agent for removing impurities from scrap copper, wherein the mass fraction of copper in the scrap copper is greater than 90%, preferably greater than 98%.

[0015] The invention discloses an application method of a refining agent for removing impurities from scrap copper. The single usage amount of the refining agent is 0.5% to 3% of the mass ratio of the scrap copper, preferably 0.5% to 2%.

[0016] As one of the preferred schemes, the present invention provides an application method of a refining agent for removing impurities from scrap copper, wherein the scrap copper is smelted at a temperature of 1150 to 1300° C., preferably 1150 to 1250° C., and the smelting time is 30 to 180 min.

[0017] The present invention discloses an application method of a refining agent for removing impurities from scrap copper. The refining agent can be added in batches. A refining agent with an iron grade of less than 50% is first added for preliminary impurity removal. After oxygen blowing smelting and slag removal, a refining agent with an iron grade of greater than or equal to 50% is added for deep purification of impurities. After oxygen blowing smelting and slag removal, a purified copper liquid is obtained. That is, the iron ore refining agent can be added in batches. A low-grade iron ore refining agent with an iron component mass content of less than 50% is first added for preliminary impurity removal. After oxygen blowing smelting and slag removal, a high-grade iron ore refining agent with an iron component mass content of more than 50% is added again for deep purification of impurities. After oxygen blowing smelting and slag removal, a purified copper liquid is obtained.

[0018] The present invention discloses a method for applying a refining agent for removing impurities from scrap copper, wherein the refining agent is added to the scrap copper liquid for slagging 1 to 3 times. In the present invention, if the amount of the refining agent is too small, the impurity removal effect is obviously weak, and if the amount of the refining agent is too large, the impurity removal cost will increase. If the amount of the high-grade refining agent is too large, the impurity iron content may also increase.

[0019] The scheme of adding in batches is particularly suitable for scrap copper with high content of impurities such as nickel, lead and tin. For example, scrap copper with nickel, lead and tin content greater than 200ppm is very suitable for the scheme of adding in batches.

[0020] A refining agent for removing impurities from scrap copper and its application method using the above technical solution, the technical principle of which is briefly described as follows: for the difficult-to-separate impurity nickel, during the oxygen blowing smelting process of scrap copper, the metal nickel can be oxidized to NiO, but NiO is distributed between the copper liquid and the slag, making it difficult to separate and purify. The iron-containing component in the refining agent is Fe2O3 or is easily converted into Fe2O3 under oxygen blowing smelting conditions, and NiO is easy to combine with Fe2O3 to form nickel-iron spinel NiO·Fe2O3 and enter the smelting slag; at the same time, NiO can also react with the non-iron components in the refining agent, for example, react with SiO2 to form nickel silicate NiO·SiO2 and enter the smelting slag, and react with Al2O3 to form nickel aluminate NiO·Al2O3 and enter the smelting slag. Nickel compounds in the form of NiO·Fe2O3, NiO·SiO2, and NiO·Al2O3 can exist stably in the smelting slag, and the nickel in the scrap copper can be removed by slagging after the smelting is completed. As for the impurities of lead and tin, during the oxygen blowing smelting process of scrap copper, the metal lead and tin can be oxidized to PbO and SnO, and the SiO2 component in the refining agent can react with them to form PbO·SiO2 and SnO·SiO2 and enter the smelting slag. As for the trace impurity iron introduced by the refining agent, during the oxygen blowing smelting process, it is easy to be oxidized to FeO and react with the SiO2 component in the refining agent to form FeO·SiO2 and enter the smelting slag. Therefore, the non-iron components in the refining agent also have the effect of purifying the impurity iron (introduced by the refining agent).

[0021] 4Fe3O4+O2(g)=6Fe2O3

[0022] Fe2O3·nH2O=Fe2O3+nH2O(g)

[0023] 4FeCO3+O2(g)=2Fe2O3+4CO2(g)

[0024] NiO+Fe2O3=NiO·Fe2O3(NiFe2O4)

[0025] 2NiO+SiO2=2NiO·SiO2(Ni2SiO4)

[0026] NiO+Al2O3=NiO·Al2O3(NiAl2O4)

[0027] PbO+SiO2=PbO·SiO2

[0028] SnO+SiO2=SnO·SiO2

[0029] By adopting the refining agent designed by the present invention in combination with the refining process, the Ni content in the product is less than or equal to 80 ppm, and after optimization is less than or equal to 50 ppm; the Pb content is less than or equal to 50 ppm; the Sn content is less than or equal to 50 ppm; and the Fe content is less than or equal to 50 ppm.

[0030] After optimization, the Ni removal rate is greater than or equal to 70% by using the refining agent designed by the present invention in combination with the refining process, and the Ni remaining in the product is less than 50 ppm.

[0031] After optimization, the Pb removal rate is greater than or equal to 90% by using the refining agent designed by the present invention in combination with the refining process, and the Pb remaining in the product is less than 50 ppm. When applied in industry, the higher the Pb content, the higher the Pb removal rate is after the batch addition scheme is used.

[0032] After optimization, the Sn removal rate is greater than or equal to 90% by using the refining agent designed by the present invention in combination with the refining process, and the residual Sn in the product is less than 50 ppm. When applied in industry, the higher the Sn content, the higher the Sn removal rate is after the batch addition scheme is used.

[0033] The advantages of the present invention are:

[0034] 1) Refining agents can be directly obtained from nature or ore dressing plants, are inexpensive, green and environmentally friendly, and are extremely convenient for industrial promotion and application;

[0035] 2) The refining agent composition is reasonable, which can achieve the simultaneous removal and purification of various impurity elements such as nickel, lead, tin, etc. in scrap copper;

[0036] 3) The refining agent has reasonable composition and self-purification effect, which can reduce the introduction of iron impurities as much as possible;

[0037] 4) The refining agent has a simple preparation process and a flexible use method. It can be used in combination according to the impurity content in the scrap copper raw materials or the different smelting stages. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the embodiments.

[0039] Embodiment 1:

[0040] A refining agent for removing impurities from scrap copper, the refining agent is an iron ore obtained from mining, the main iron-containing components of which are hematite (80wt.%) and limonite (15wt.%), the main non-iron components of which are SiO2 (2wt.%), and the remainder of which are other impurities, and the particle size is less than or equal to 10mm. The iron ore does not need to be crushed, and can be directly used as a refining agent for removing impurities from scrap copper after drying. After the scrap copper is melted (the content of Cu in the raw material is 99.89wt.%), a refining agent accounting for 2.0wt.% of the mass ratio of the scrap copper is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200°C, the smelting time is 60min, and after the smelting is completed, the slag is skimmed to obtain a copper liquid after impurities are removed, and the copper content in the copper liquid after reduction and deoxidation is 99.94wt%. The changes in the content of impurity elements before and after the scrap copper is removed are shown in Table 1.

[0041] Table 1 Changes in impurity element content of scrap copper before and after impurity removal

[0042]

[0043] Embodiment 2:

[0044] A refining agent for removing impurities from scrap copper, the refining agent is an iron ore obtained from mining, the main iron-containing components are hematite (62wt.%) and limonite (9wt.%), the main non-iron components are SiO2 (10wt.%) and Al2O3 (6wt.%), the remainder is other impurities, and the iron ore particle size is less than or equal to 30mm. The iron ore can be used as a refining agent for removing impurities from scrap copper after being crushed to a particle size less than or equal to 10mm. After the scrap copper is melted (the content of Cu in the raw material is 99.89wt.%), a refining agent accounting for 2.0wt.% of the mass ratio of the scrap copper is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200℃, the smelting time is 120min, and the slag is skimmed after the smelting is completed to obtain a copper liquid after impurities are removed, and the copper content in the copper liquid after reduction and deoxidation is 99.94wt%. The changes in the content of impurity elements before and after the scrap copper is removed are shown in Table 2.

[0045] Table 2 Changes in impurity element content of scrap copper before and after impurity removal

[0046]

[0047] Embodiment 3:

[0048] A refining agent for removing impurities from scrap copper, the refining agent used is iron ore obtained from mining, the main iron-containing components are siderite (18wt.%) and hematite (limonite) (10wt.%), the main non-iron components are SiO2 (35wt.%) and Al2O3 (10wt.%), the balance is other impurities, and the iron ore particle size is less than or equal to 40mm. The iron ore can be used as a refining agent for removing impurities from scrap copper after being crushed to a particle size less than or equal to 10mm. After the scrap copper is melted (the content of Cu in the raw material is 99.89wt.%), a refining agent accounting for 2.0wt.% of the mass ratio of the scrap copper is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200℃, the smelting time is 180min, and the slag is skimmed after the smelting is completed to obtain a copper liquid after impurities are removed, and the copper content in the copper liquid after reduction and deoxidation is 99.93wt%. The changes in the content of impurity elements before and after the scrap copper is removed are shown in Table 3.

[0049] Table 3 Changes in impurity element content of scrap copper before and after impurity removal

[0050]

[0051] Embodiment 4:

[0052] A refining agent for removing impurities from scrap copper is an iron concentrate obtained by ore dressing, wherein the main iron-containing components are magnetite (80wt.%) and hematite (10wt.%), the main non-iron components are SiO2 (6wt.%), the remainder is other impurities, and the particle size is less than or equal to 0.5mm. The iron concentrate does not need to be ground, and can be directly used as a refining agent for removing impurities from scrap copper after drying. After the scrap copper is melted (the content of Cu in the raw material is 99.89wt.%), a refining agent accounting for 1.0wt.% of the mass ratio of the scrap copper is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1250℃, the smelting time is 120min, and the slag is skimmed after the smelting is completed to obtain a copper liquid after impurities are removed, and the copper content in the copper liquid after reduction and deoxidation is 99.94wt%. The changes in the content of impurity elements before and after the scrap copper is removed are shown in Table 4.

[0053] Table 4 Changes in impurity element content of scrap copper before and after impurity removal

[0054]

[0055]

[0056] Embodiment 5:

[0057] A refining agent for removing impurities from scrap copper, the refining agent used is iron concentrate and iron tailings obtained by ore dressing, wherein the main iron-containing components of the iron concentrate are magnetite (80wt.%) and hematite (10wt.%), the main non-iron component is SiO2 (6wt.%), the particle size is less than or equal to 0.5mm, and the balance is other impurities; the main iron-containing components of the iron tailings are hematite (limonite) (10wt.%) and magnetite (5wt.%), the main non-iron component is SiO2 (62wt.%), the balance is other impurities, and the particle size is less than or equal to 0.5mm. The iron concentrate and iron tailings do not need to be ground, and can be directly used as a refining agent for removing impurities from scrap copper after drying. After the scrap copper is melted (the content of Cu in the raw material is 99.88wt.%), iron tailings accounting for 1.0wt.% of the scrap copper mass ratio are added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1250°C, the smelting time is 90min, and the slag is removed after the smelting is completed. Then, iron concentrate accounting for 1.0wt.% of the scrap copper mass ratio is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200°C, the smelting time is 90min, and the slag is removed after the smelting is completed to obtain the copper liquid after impurities are removed. After reduction and deoxidation, the copper content in the copper liquid is 99.94wt%. The changes in the impurity element content of the scrap copper before and after impurities are removed are shown in Table 5.

[0058] Table 5 Changes in impurity element content of scrap copper before and after impurity removal

[0059]

[0060] Embodiment 6:

[0061] A refining agent for removing impurities from scrap copper, the refining agent used is iron concentrate and iron tailings obtained by ore dressing, wherein the main iron-containing components of the iron concentrate are magnetite (80wt.%) and hematite (10wt.%), the main non-iron component is SiO2 (6wt.%), the particle size is less than or equal to 0.5mm, and the balance is other impurities; the main iron-containing components of the iron tailings are hematite (limonite) (10wt.%) and magnetite (5wt.%), the main non-iron component is SiO2 (62wt.%), the balance is other impurities, and the particle size is less than or equal to 0.5mm. The iron concentrate and iron tailings do not need to be ground, and can be directly used as a refining agent for removing impurities from scrap copper after drying. After the scrap copper is melted (the content of Cu in the raw material is 99.72wt.%), iron tailings accounting for 2.0wt.% of the scrap copper mass ratio are added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1250°C, the smelting time is 90min, and the slag is removed after the smelting is completed. Then, iron concentrate accounting for 2.0wt.% of the scrap copper mass ratio is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200°C, the smelting time is 60min, and the slag is removed after the smelting is completed. Then, iron concentrate accounting for 2.0wt.% of the scrap copper mass ratio is added, oxygen blowing smelting is carried out, the smelting temperature is maintained at 1200°C, the smelting time is 60min, and the slag is removed after the smelting is completed to obtain the copper liquid after impurity removal, and the copper content in the copper liquid after reduction deoxidation is 99.93wt%. The changes in the content of impurity elements before and after the scrap copper is removed are shown in Table 6.

[0062] Table 6 Changes in impurity element content of scrap copper before and after impurity removal

[0063]

[0064] Comparative Example 1:

[0065] Other conditions were consistent with those in Example 1, except that the amount of the refining agent was 0.1%, and the contents of impurities Ni, Pb, Sn, and Fe in the copper liquid after impurity removal were 135 ppm, 81 ppm, 72 ppm, and 18 ppm, respectively.

[0066] Comparative Example 2:

[0067] Other conditions were the same as those in Example 1, except that the refining agent consisted of 50wt.% quartz sand + 50wt.% broken glass, and the contents of impurities Ni, Pb, Sn, and Fe in the copper liquid after impurity removal were 141ppm, 26ppm, 32ppm, and 14ppm, respectively.

[0068] Comparative Example 3:

[0069] The other conditions are the same as those in Example 1, except that the refining agent is chemically pure ferric oxide, and 2.0 wt.% of the refining agent is added to the scrap copper by mass ratio; the contents of impurities Ni, Pb, Sn, and Fe in the copper liquid after impurity removal are 58 ppm, 88 ppm, 74 ppm, and 36 ppm, respectively. By comparing Example 1 with Comparative Example 3, it is found that the effect of removing Pb and Sn by adding pure ferric oxide is general, and the amount of Fe introduced is too high.

Claims

1. A refining agent for removing impurities from scrap copper, characterized in that: The refining agent comprises an iron-containing component and a non-iron component, the valence of the iron element in the iron-containing component is greater than or equal to 2, and the non-iron component comprises SiO2 and Al2O3; the mass content of the iron-containing component in the refining agent for removing impurities from scrap copper is 10% to 96%.

2. A refining agent for removing impurities from scrap copper according to claim 1, characterized in that: The iron-containing component is selected from one or more of hematite, limonite, magnetite, siderite, and pyrite; the non-iron component includes gangue minerals containing SiO2 and Al2O3.

3. A refining agent for removing impurities from scrap copper according to claim 1, characterized in that: The sum of the mass proportions of the iron-containing components and the non-iron components of SiO2 and Al2O3 in the refining agent is greater than 80%, preferably greater than 90%.

4. A refining agent for removing impurities from scrap copper according to claim 1, characterized in that: The mass content of the iron component in the refining agent is 15% to 96%.

5. The refining agent for removing impurities from scrap copper according to claim 1, characterized in that: Mined natural iron ore or iron concentrate and iron tailings obtained through ore dressing can be used as the refining agent.

6. A method for using the refining agent for removing impurities from scrap copper as claimed in any one of claims 1 to 5, characterized in that: After the scrap copper is heated and melted, a dry refining agent is added to the copper liquid, the smelting temperature is controlled to be 1100-1300°C, and the slag is skimmed after oxygen blowing smelting. The single use amount of the refining agent is 0.1%-3% of the mass of the scrap copper, preferably 0.5%-3%, and more preferably 0.5%-2%.

7. The method for using a refining agent for removing impurities from scrap copper according to claim 7, characterized in that: For natural iron ore, it is crushed to less than or equal to 10mm and dried for later use. For iron concentrate and iron tailings obtained by artificial sorting, they can be directly dried for later use.

8. The method for using a refining agent for removing impurities from scrap copper according to claim 6, characterized in that: The mass fraction of copper in the scrap copper is greater than 90%, preferably greater than 98%.

9. The method for using a refining agent for removing impurities from scrap copper according to claim 6, characterized in that: The smelting temperature of the scrap copper is 1150-1300° C., preferably 1150-1250° C., and the smelting time is 30-180 min.

10. The method for using a refining agent for removing impurities from scrap copper according to claim 6, characterized in that: The refining agent can be added in batches. First, a refining agent with an iron grade of less than 50% is added for preliminary impurity removal. After oxygen blowing smelting and slag removal, a refining agent with an iron grade of greater than or equal to 50% is added for deep purification of impurities. After oxygen blowing smelting and slag removal again, purified copper liquid is obtained.

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