CN113355525B - A method for cooperating with copper smelting slag to treat gold-containing waste slag - Google Patents

Abstract

The invention discloses a method for treating gold-containing waste slag with copper smelting slag. Silver-copper matte, flue gas and sulfide slag, described rich in gold-silver-copper matte recover gold, silver and copper through refining; (2) the sulfide slag obtained in step (1) is mixed with copper smelting slag, adding vulcanizing agent 2 to smelt , flotation of the smelted product to obtain copper sulfide, zinc sulfide and lead sulfide. The invention realizes the efficient enrichment and recovery of copper and gold resources in copper blowing slag/copper refining slag and gold-containing waste slag through the coordinated matching of copper smelting slag and gold-containing waste slag; High-efficiency enrichment of copper, lead and zinc in copper smelting slag is achieved.

Description

A method for cooperating with copper smelting slag to treat gold-containing waste slag

technical field

The invention belongs to the field of metallurgical engineering, in particular to a method for treating copper smelting slag and gold-containing waste slag.

Background technique

Copper is an important basic material, and consumption is large and growing continuously. In 2019, China's refined copper production was 9.784 million tons, an increase of 5.5% over 2018, while its apparent Chinese demand was 12.8 million tons, an increase of 2.5% over the same period last year. With the mining of copper resources, the grade of copper ore has reached 0.2%-0.3%, and copper metallurgy is facing severe challenges, so it is more and more important to recover its valuable metals from copper smelting slag. When copper is smelted under oxygen-enriched smelting conditions, a large amount of Fe ₃ O ₄ with high melting point will be produced, which will deteriorate the properties of the slag, resulting in high copper content in the slag. At present, the copper depletion technology only considers the recovery of copper, but does not consider the recovery of valuable metals such as lead and zinc, and almost all of the blowing slag/refining slag with high lead and zinc is returned to the smelting process, and Pb and Zn circulate in the smelting process, resulting in copper The content of matte impurities is high, which reduces the quality of copper matte and increases the impurity removal pressure in the subsequent process.

China's gold production has ranked first in the world for 13 years. In 2019, China's raw material gold production was 380.2 tons, and the imported raw material gold production was 120.19 tons, an increase of 6.57% over 2018. Therefore, it is still imminent to recover gold resources from waste residues. The existing gold extraction process is mainly wet method, and cyanide gold extraction is the most widely used wet method, which produces a large amount of cyanide-containing tailings. The toxic substances in the cyanide tailings are harmful and the content of valuable metals is high, so cleaning treatment is urgently needed.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background art, and to provide a method for cooperating and collocating copper smelting slag with high resource recovery and utilization rate to treat gold-containing waste slag. In order to solve the above-mentioned technical problems, the technical scheme proposed by the present invention is:

A method for cooperating with copper smelting slag for processing gold-containing waste slag, comprising the following steps:

(1) mixing copper smelting slag/copper smelting slag (copper blowing smelting slag and/or copper smelting slag), gold-containing waste slag, and vulcanizing agent 1 to obtain gold-silver-rich copper matte, flue gas and sulfide slag, The described gold-rich copper matte recovers gold, silver (into the anode slime after electrolytic refining) and copper through electrorefining;

(2) mixing the sulfide slag obtained in step (1) with copper smelting slag, adding vulcanizing agent 2 for smelting, and flotation of the smelting product to obtain copper sulfide, zinc sulfide and lead sulfide.

In the above-mentioned method for cooperating with copper smelting slag to treat gold-containing waste slag, preferably, the copper blowing slag/copper refining slag contains Cu with a mass content of 3-30%, Pb with a mass content of 3-10%, and a mass content of 3-30%. 1-6% Zn.

In the above-mentioned method for treating gold-containing waste slag with copper smelting slag, preferably, the gold-containing waste slag includes one or more of gold cyanide tailings, complex gold-copper ore and high-silicon gold ore, and the gold-containing waste slag is The mass content of gold is 0.5-10g/t, and the mass content of silver is 5-200g/t.

In the above-mentioned method for treating gold-containing waste slag with copper smelting slag, preferably, the mass ratio of the copper blowing slag/copper refining slag to the gold-containing waste slag is (5-10):1. The above mass ratio is mainly determined according to the copper content of the raw slag and the composition of the slag, and is determined by considering the synergistic effect of the copper slag and the gold-containing waste slag. Because the gold-containing waste slag contains quartz or silicate phase, and when quartz exists, adding vulcanizing agent 1 can reduce the high-melting iron tetroxide, which is beneficial to improve the properties of the slag. If the above mass ratio is high, the silica content in the system is low, resulting in inconspicuous delamination of copper matte and slag, and high gold content in the slag, it may be necessary to supplement quartz as a flux, so that ferrous oxide and quartz produced by the sulfidation reaction are slag-forming. Reaction; if the above mass ratio is low, it is equivalent to adding excess quartz to the smelting system, which increases the viscosity of the slag and the fluidity, which is not conducive to the capture of precious metals such as gold and silver by the metal phase or the copper matte phase.

In the method for the above-mentioned copper smelting slag to synergistically process gold-containing waste residue, preferably, the vulcanizing agent 1 includes one or more of calcium sulfide, iron sulfide, ferrous sulfide and pyrite, and the amount of the vulcanizing agent 1 is It is 8-15% of the total mass of copper blowing slag/copper refining slag. On the one hand, the choice of vulcanizing agent will not introduce new impurities, and on the other hand, it can improve the fluidity of slag. Too much vulcanizing agent 1 will cause more iron oxides in the system to be vulcanized. If the ferrous oxide content in the smelting system is too low, the viscosity of the slag will increase, resulting in an increase in the copper content of the slag, which will also lead to copper matte If the grade decreases, the ability to capture precious metals such as gold and silver will decrease; if the vulcanizing agent is too small, the existing copper, lead, and zinc metal oxides will not be easily vulcanized, which will affect the next recovery rate.

In the above-mentioned method for treating gold-containing waste slag by cooperative collocation of copper smelting slag, preferably, the copper smelting slag contains Cu with a mass content of 0.5-6%, Pb with a mass content of 0-1%, and a mass content of 0.5-6% Zn.

In the above-mentioned method for cooperating with copper smelting slag to treat gold-containing waste slag, preferably, in the step (1), the smelting temperature is 1200-1320° C., and the smelting time is 1.5-4h. The above reaction temperature is conducive to the mutual synergy between the copper smelting slag and the gold-containing waste slag, so that gold and copper enter the copper matte, and valuable metals are recovered at the same time. The melting temperature in the step (2) is 1150-1250°C. The above reaction temperature is conducive to the mutual synergy between the copper smelting slag and the sulfide slag, and finally realizes the full recovery of metal resources.

In the method for the above-mentioned copper smelting slag synergistic treatment of gold-containing waste slag, preferably, the mass ratio of the copper smelting slag to the sulfide slag is (5-10): 1, the vulcanizing agent 2 is sulfur, and the addition of the sulfur The amount is 2-8% of the total mass of copper smelting slag and sulfide slag. During the smelting process of copper ore, more smelting slag is produced, and the amount of blowing slag and refining slag is small. When various slag types are used in combination, it can be considered to increase the amount of copper smelting slag added. In addition, it is also necessary to consider the synergistic relationship between the copper smelting slag and the sulfide slag to match the composition ratio of the two. Too much sulfur addition will cause waste of resources and generate more SO ₂ gas; too low addition of sulfur will lead to incomplete vulcanization of copper, lead and zinc oxides in the slag, resulting in excessive copper, lead and zinc content in the tailings. In order to improve the degree of sulfidation in step (2), pyrite or pyrite and sulfur can be considered to be synergistically matched.

In the above-mentioned method for treating gold-containing waste slag with copper smelting slag, preferably, the copper blowing slag/copper refining slag is hot slag, and the copper smelting slag is hot slag. In the present invention, the hot slag is used as the raw material, no additional heating is required in the reaction process, and the addition of the vulcanizing agent will supplement the heat and make up for the heat loss of the reaction system.

In the above-mentioned method for cooperating with copper smelting slag to treat gold-containing waste slag, preferably, the vulcanizing agent 2 is added while slowly cooling to 1150° C. in the smelting system. Sulfur is added in the process of slow cooling of the mixture, so as to avoid the volatilization of lead sulfide and zinc sulfide into the gas phase at high temperature, resulting in the loss of lead and zinc.

In the above-mentioned method for treating gold-containing waste slag with copper smelting slag, when copper smelting slag and gold-containing waste slag are cooperatively matched, most of the lead and zinc elements are sulfided into the sulfide slag, and the sulfide slag basically does not contain gold resources, and the flotation tailings It contains 0.1-0.3% copper, 0.01-0.2% lead and 0.2-0.5% zinc.

In the above-mentioned method for cooperating and collocating gold-containing waste slag with copper smelting slag, the specific steps of step (1) are as follows: the hot copper blowing slag/copper refining slag produced in the copper smelting process is poured into the reaction furnace through the slag bag, and the The feeding device adds the gold-containing waste residue and vulcanizing agent 1 into the reaction furnace, and keeps the temperature at 1200-1320 °C. This process does not require additional heat source to supplement heat, because adding vulcanizing agent will release heat. During this process, copper and gold resources are enriched in copper matte. The specific steps of step (2) are as follows: the sulfide slag and the hot copper smelting slag are discharged into the slag bag, the vulcanizing agent 2 is slowly supplemented in the slag bag, and further flotation is performed to obtain copper sulfide, zinc sulfide and lead sulfide.

The chemical equation involved in the present invention is as follows:

CaS+Cu ₂ O=Cu ₂ S+CaO;

CaS+FeO+SiO ₂ =FeS+CaSiO ₃ ;

2ZnO+1.5S ₂ (g)=2ZnS+SO ₂ (g);

2PbO+1.5S ₂ (g)=2PbS+SO ₂ (g);

2Cu ₂ O+S ₂ (g)=Cu ₂ S+SO ₂ (g).

The invention realizes the efficient enrichment and recovery of valuable metals such as copper and gold in the copper smelting slag and the gold-containing waste slag through the co-processing of the copper blowing slag/copper refining slag and the gold-containing waste slag, and the sulfide slag produced in the process can also be smelted with copper. The slag is coordinated to recover copper, lead, zinc and other metals in it, so as to avoid the pollution of the ecological environment caused by its storage. Specifically: (1) It is difficult for noble metal atoms to bond with substances in the slag, so that it is difficult for noble metal atoms or atom clusters to enter the slag phase, and on the contrary, it is easy to be trapped by copper matte. Copper smelting slag and gold-containing waste slag work together to make use of the metal-like properties of copper matte, and the higher the grade of copper matte, the stronger the ability to capture precious metals, and because copper smelting slag contains a part of metal copper element, metal The ability of copper element to capture precious metals is stronger, and the element copper and copper matte work together to recover the precious metals in the gold-containing waste residue to increase the collection capacity of precious metals; in addition, the quartz and other components in the gold-containing waste residue will also affect the Facilitates recovery of copper metal and capture of precious metals. (2) The invention innovatively treats the copper blowing slag/copper refining slag and the gold-containing waste slag in a collaborative manner, avoiding the further dispersion of the valuable metal lead and zinc resources generated in the return smelting stage into the copper matte phase, reducing the quality of the copper matte, By increasing the impurity removal pressure in the subsequent process, it enters the sulfide slag for enrichment, which also avoids the problem of high cost of wet extraction of cyanide slag by using thiourea to extract gold.

Compared with the prior art, the advantages of the present invention are:

1. The present invention innovatively treats copper blowing slag/copper refining slag with gold-containing waste slag, which avoids the further dispersion of valuable metal lead and zinc resources generated in the return smelting stage, and makes it enter the sulfide slag for enrichment.

2. The invention innovatively combines the produced sulfide slag and copper smelting slag for smelting, and further flotation to obtain copper sulfide, zinc sulfide and lead sulfide, which can make full use of the sulfide slag produced in the previous step to realize the matching of copper blowing smelting slag. Slag-free smelting of gold-containing waste slag.

3. The present invention realizes the efficient enrichment and recovery of copper and gold resources in copper blowing slag/copper refining slag and gold-containing waste slag through the coordinated matching of copper smelting slag and gold-containing waste slag; at the same time, the process produces sulfide slag and copper smelting slag synergistically In combination, the efficient enrichment of copper, lead and zinc in copper smelting slag is realized.

4. The invention adopts the pyrotechnic method to extract gold, which has the advantages of low cost, short process, simple process, large processing scale, comprehensive recovery of various metals, and high metal recovery rate.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are For some embodiments of the present invention, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative efforts.

Fig. 1 is the process flow diagram of the present invention.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and in detail below with reference to the accompanying drawings and preferred embodiments of the specification, but the protection scope of the present invention is not limited to the following specific embodiments.

Unless otherwise defined, all technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention.

Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or can be prepared by existing methods.

Example 1:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g hot copper smelting slag as raw material, its main chemical composition includes Cu26.2%, Pb8.9%, Zn3.41%, Fe30.2%, _SiO2 1.56%, CaO8.68%. 30g of gold cyanide tailings were added to the molten copper blowing slag through a feeding device. The chemical composition of the gold cyanide tailings included SiO ₂ 60%, Au5g/t, Ag30.2g/t, Fe7.8%, and 30g was added. The pyrite was kept at 1300 °C for 2 hours to obtain copper matte and sulfide slag. The grade of copper matte is 60.62%; the sulfide slag contains 1% copper, 0.11g/t gold and 0.5g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 3% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.22% copper, 0.06% lead and 0.24% zinc. %.

Example 2:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g copper flash smelting slag as raw material, its main chemical composition includes Cu26.2%, Pb8.9%, Zn3.41%, Fe30.2%, _SiO2 1.56%, CaO8.68%. 50g of gold cyanide tailings were added to the molten copper blowing slag through a feeding device. The chemical composition of the gold cyanide tailings included SiO ₂ 60%, Au5g/t, Ag30.2g/t, Fe7.8%, and 45g was added. The pyrite was kept at 1300 °C for 2 hours to obtain copper matte and sulfide slag. The grade of copper matte is 58.3%; the sulfide slag contains 1.1% copper, 0.14g/t gold, 0.56g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 4% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.18% copper, 0.1% lead and 0.23% zinc. %.

Example 3:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g copper blowing slag as raw material, its main chemical composition includes Cu26.2%, Pb8.9%, Zn3.41%, Fe30.2%, _SiO2 1.56%, CaO8.68%. 50g of gold cyanide tailings were added to the molten copper blowing slag through a feeding device, and the chemical composition of the gold cyanide tailings included SiO ₂ 65.2%, Au 4.5g/t, Ag40.2g/t, Fe 9.8%, and Add 45g of pyrite, keep smelting at 1300℃ for 2h, and obtain copper matte and sulfide slag. The grade of copper matte is 59.62%; the sulfide slag contains 0.82% copper, 0.19g/t gold and 0.39g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 4% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.24% copper, 0.08% lead and 0.26% zinc. %.

Example 4:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g copper refining slag as raw material, its main chemical composition includes Cu29.21%, Pb4.31%, Zn2.58%, Fe28.16%, _SiO2 19.32%. 30g of gold cyanide tailings were added to the molten copper blowing slag through a feeding device. The chemical composition of the gold cyanide tailings included SiO ₂ 65.2%, Au 4.5g/t, Ag51.2g/t, Fe 9.8%, and Add 45g of pyrite, keep smelting at 1300℃ for 2h, and obtain copper matte and sulfide slag. The grade of copper matte is 60.2%; the sulfide slag contains 0.92% copper, 0.18g/t gold and 0.45g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 4% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.18% copper, 0.07% lead and 0.34% zinc. %.

Example 5:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g copper refining slag as raw material, its main chemical composition includes Cu29.21%, Pb4.31%, Zn2.58%, Fe28.16%, _SiO2 19.32%. 30g of gold cyanide tailings were added to the molten copper blowing slag through a feeding device. The chemical composition of the gold cyanide tailings included SiO ₂ 65.2%, Au 4.5g/t, Ag51.2g/t, Fe 9.8%, and Add 45g of pyrite, keep smelting at 1300℃ for 2h, and obtain copper matte and sulfide slag. The grade of copper matte is 60.2%; the sulfide slag contains 0.92% copper, 0.18g/t gold and 0.45g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu5.5%, Pb0.7%, Zn5.2%, Fe39.2%, _SiO2 22.4%, CaO1.38% . The mass of sulfur added to the mixed melt at 1200°C is 4% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.23% copper, 0.07% lead and 0.49% zinc. %.

Comparative Example 1:

As shown in Figure 1, a method for cooperating with copper smelting slag to process gold-containing waste slag includes the following steps:

(1) Using 300g copper blowing slag as raw material, its main chemical composition includes Cu26.2%, Pb8.9%, Zn3.41%, Fe30.2%, _SiO2 1.56%, CaO8.68%. 80g of gold cyanide tailings were added to the molten copper smelting slag through the feeding device. The chemical composition of the gold cyanide tailings included SiO ₂ 60%, Au5g/t, Ag30.2g/t, Fe7.8%, and 30g was added. The pyrite was kept at 1300 °C for 2 hours to obtain copper matte and sulfide slag. The grade of copper matte is 55.8%; the sulfide slag contains 1.8% copper, 0.54g/t gold and 1.89g/t silver, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 6% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.43% copper, 0.06% lead and 0.52% zinc. %.

Comparative Example 2:

A method for treating copper smelting slag, comprising the following steps:

(1) Using 300g copper blowing slag as raw material, its main chemical composition includes Cu26.2%, Pb8.9%, Zn3.41%, Fe30.2%, _SiO2 1.56%, CaO8.68%. Add 45g of pyrite, keep smelting at 1300℃ for 2h, and obtain copper matte and sulfide slag. The grade of copper matte is 56.4%; the sulfide slag contains 2.4% copper, and lead and zinc basically exist in the sulfide state in the sulfide slag.

(2) Mix the hot sulfide slag with the hot smelting slag. The main chemical composition of the smelting slag includes Cu3.03%, Pb0.53%, Zn2.72%, Fe40.31%, _SiO2 21.1%, CaO1.62% . The mass of sulfur added to the mixed melt at 1200°C is 4% of the mass of the mixed melt. After the flotation process, copper sulfide, zinc sulfide and lead sulfide are obtained. The tailings contain 0.68% copper, 0.24% lead and 0.57% zinc. %.

Claims (9)

1. A method for processing gold-containing waste slag by synergistic collocation of copper smelting slag is characterized by comprising the following steps:

(1) mixing copper converting slag/copper refining slag, gold-containing waste slag and a vulcanizing agent 1, and then smelting to obtain gold, silver and copper matte rich in gold, silver and copper, flue gas and vulcanizing slag, wherein the gold, silver and copper matte rich in gold, silver and copper is refined and recovered;

(2) mixing the sulfide slag obtained in the step (1) with copper smelting slag, adding a vulcanizing agent 2 for smelting, and performing flotation on a smelting product to obtain copper sulfide, zinc sulfide and lead sulfide;

the mass ratio of the copper converting slag/copper refining slag to the gold-containing waste slag is (5-10): 1.

2. the method of claim 1, wherein the copper converting slag/copper refining slag contains 3-30% by mass of Cu, 3-10% by mass of Pb, and 1-6% by mass of Zn.

3. The method for the synergistic collocation treatment of gold-containing waste residues according to claim 1, wherein the gold-containing waste residues comprise one or more of cyanidation tailings, complex cuprite and high-silicon gold ores, and the mass content of gold and the mass content of silver in the gold-containing waste residues are 0.5-10g/t and 5-200 g/t.

4. The method for the synergistic collocation treatment of the gold-containing waste residues through the copper smelting slag according to claim 1, wherein the vulcanizing agent 1 comprises one or more of calcium sulfide, iron sulfide, ferrous sulfide and pyrite, and the dosage of the vulcanizing agent 1 is 8-15% of the total mass of the copper converting slag/copper refining slag.

5. The method of claim 1, wherein the copper smelting slag comprises 0.5-6% by mass of Cu, 0-1% by mass of Pb, and 0.5-6% by mass of Zn.

6. The method for the cooperative processing of gold-containing waste slag through copper smelting slag according to any one of claims 1 to 5, wherein the smelting temperature in the step (1) is 1200-1320 ℃, and the smelting time is 1.5-4 h; the smelting temperature in the step (2) is 1150-1250 ℃.

7. The method for the synergistic collocation treatment of gold-containing waste residues through copper smelting slag according to any one of claims 1 to 5, wherein the mass ratio of the copper smelting slag to the vulcanizing slag is (5-10): 1, the vulcanizing agent 2 is sulfur, and the addition amount of the sulfur is 2-8% of the total mass of the copper smelting slag and the vulcanizing slag.

8. The method of co-ordinating copper smelting slag according to any one of claims 1 to 5, wherein the copper converting slag/copper refining slag is hot slag, and the copper smelting slag is hot slag.

9. The method for the synergistic co-ordination of copper smelting slag according to any one of claims 1 to 5, characterized in that the sulfidiser 2 is added while slowly cooling to 1150 ℃ in the smelting system.

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