Treatment method of sludge containing copper and nickel

Abstract

The invention discloses a method for recovering copper and nickel from electroplating sludge containing copper and nickel. The sludge containing copper and nickel is fully mixed with additives such as a reducing agent, a slag former, a vulcanizing agent and an alkaline flux according to a certain proportion, the mixture is granulated and then added into a smelting furnace, and by controlling the furnace temperature and blowing in oxygen-enriched air for smelting, more than 95% of copper and more than 90% of nickel can be recycled, and meanwhile 99% of chromium enters smelting slag; and harmless treatment of Cr in the slag is realized through slow cooling of the slag.

Description

Technical Field

[0001] The present invention relates to the pyrometallurgical process in the metallurgical field, and particularly to a method capable of simultaneously realizing the recovery of valuable metals in copper-nickel-containing sludge and the harmless treatment of slag. Technical Background

[0002] Electroplating sludge is a flocculent precipitate produced by treating electroplating wastewater, and has characteristics such as high water content, strong mobility of heavy metal components, and low crystallinity. It is not only a hazardous solid waste but also a secondary resource with great recycling value. At present, the recovery methods of valuable metals in electroplating sludge include wet process, pyrometallurgical process, and pyrometallurgical-wet process combined technology.

[0003] Chinese Patent [A method for comprehensively recovering valuable metals in electroplating sludge, CN108754150A] leaches electroplating sludge with sulfuric acid, then separates the acid leaching residue and acid leaching solution. Iron powder is added to the acid leaching solution for replacement filtration separation to obtain copper powder and mother liquor. Then, hydrogen peroxide, sodium carbonate solution, and composite flocculant are added to the mother liquor to control the pH to form hydroxide precipitates of iron and chromium ions, and the chromium-iron slag and the mother liquor containing zinc and nickel are separated and then zinc and nickel are separated by extraction. However, it is difficult to separate chromium and iron in the wet leaching solution of electroplating sludge. To solve this problem, Chinese Patent [A method for recovering chromium in electroplating sludge by sub-molten salt method, CN109280776B] proposes a pyrometallurgical-wet process combined technology. This process fully stirs and mixes electroplating sludge with an alkali solution (NaOH or KOH solution) to form a sludge slurry, then dries it to dry sludge with a water content of less than 20%, roasts it at 280-580°C, and then leaches and recovers chromium with water or weak acid aqueous solution, and the recovery rate of chromium can be greater than 90%.

[0004] The wet process and the combined pyro-hydrometallurgical process can effectively extract valuable elements from electroplating sludge, but there are problems such as high toxicity of leaching residues and difficult wastewater treatment. The pyro-metallurgical process has the characteristics of simple process and large processing capacity, and can effectively recycle valuable elements from low-chromium electroplating sludge [Gong Ao et al., Carbothermal reduction-low-carbon refining treatment of copper-containing sludge to separate and enrich valuable metals. The Chinese Journal of Nonferrous Metals, 2020; 30: 2178-2189]. However, the presence of high-melting-point elements such as Cr and Ni in copper-nickel electroplating sludge makes smelting treatment difficult. Aiming at the problem of difficult smelting of copper-nickel electroplating sludge, the Chinese patent [A method for harmless treatment of electroplating sludge, CN110951966A] mixes electroplating sludge, quartz sand and a reducing agent in a certain proportion, and conducts reduction smelting at a high temperature of 1350-1600°C. More than 90% of Cu and Ni can be enriched in the alloy, but Cr and Fe also enter the alloy synchronously, resulting in difficult subsequent separation. Chinese patents [A method for treating electroplating sludge with gypsum slag, CN111826522A; A method for treating electroplating sludge by bottom-blown bath smelting process, CN111041213A] adopt the method of adding a large amount of fluxes containing Fe, Si and Ca to reduce the influence of high-melting-point metals such as Cr and Ni on the smelting system, and can smelt and treat electroplating sludge between 1050-1350°C, but no reduction treatment is achieved. Aiming at the problem of too high smelting temperature of nickel-containing electroplating sludge, the Chinese patent [A method for sulfurizing roasting-alkaline smelting to separate nickel from nickel-containing sludge, CN111394597A] uses sulfur slag as a sulfurizing agent, conducts sulfurizing roasting to obtain roasted ore, and the tail gas is absorbed by sodium hydroxide solution, and sodium salt crystals and mother liquor are obtained by crystallization separation. Then, the crystals are mixed with the roasted ore, sodium hydroxide and pulverized coal for alkaline smelting, and the Ni recovery rate reaches more than 97%. Although this method reduces the smelting temperature, it will produce alkali slag at the same time, and its environmental toxicity is difficult to guarantee. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for recovering valuable metals from copper-nickel electroplating sludge by low-temperature pyro-metallurgy and simultaneously realizing harmless disposal of the sludge.

[0006] The technical solution adopted by the present invention to achieve the above purpose is: mixing copper-nickel electroplating sludge with additives such as a reducing agent, a slag-forming agent, a sulfurizing agent and an alkaline substance for batching, then placing it in a smelting furnace for alkaline matte smelting, and separating matte and smelting slag after slow cooling. After further treatment of the matte, separation and purification are realized, and high-efficiency recovery of Cu and Ni is achieved. The leaching toxicity of the slag meets the national standard and can be used as a building material.

[0007] The specific process and technical parameters are as follows:

[0008] 1. Batching

[0009] Weigh the copper-nickel electroplating sludge together with additives such as reducing agents, slag-forming agents, sulfiding agents, and alkaline fluxes. Control the mass of the reducing agent added to be 3-8% of the mass of the electroplating sludge. The mass of the slag-forming agent added should meet the initial requirements of the smelting slag type, with the mass ratio of FeO to SiO2 being 1.0-2.0:1 and the mass ratio of CaO to SiO2 being 0.3-0.8:1. Control the addition amount of the sulfiding agent to be 3-10% of the mass of the electroplating sludge, and control the addition amount of the alkaline flux to be 20-40% of the mass of the electroplating sludge. Control the mass ratio of Na to S in the mixture of the electroplating sludge and additives to be 1-6:1. Then, fully mix the electroplating sludge and additives evenly and granulate, controlling the mass percentage of water in the granulated material to be 8-15%.

[0010] 2. Alkaline matte smelting

[0011] Add the granulated material into the smelting furnace, control the temperature to be 800-1250°C, control the liquid level height of the matte layer in the lower layer of the furnace to be 200-400 mm, and the liquid level height of the slag layer in the upper layer of the furnace to be 400-800 mm. Inject an oxygen-enriched air with a volume concentration of natural gas and oxygen of 70-85% at a position 50-100 mm above the interface between the smelting slag layer and the matte layer. The volume-mass ratio of the injected natural gas to the granulated material is 60-100 NM 3 / t, and the volume-mass ratio of oxygen to the granulated material is 120-200 Nm 3 / t. Set a secondary tuyere 600-800 mm above the smelting furnace and inject an oxygen-enriched air with an oxygen volume concentration of 23-50%. The amount of oxygen-enriched air is 150-220 Nm 3 / t. Smelt for 2-6 h under the above conditions, and then discharge the matte and slag into a matte ladle and a slag ladle respectively. The reactions occurring in this process are as follows:

[0012] Cu2O + S + C = Cu2S + CO↑ (1)

[0013] 3NiO + 2S + 3C = Ni3S2 + 3CO↑ (2)

[0014] Fe2O3 + S + 3C = Fe2S + 3CO↑ (3)

[0015] 2Na2CO3 + 2S + C = 2Na2S + 3CO2↑ (4)

[0016] CH4 + 2O2 = CO2↑ + 2H2O↑ (5)

[0017] C + O2 = CO↑ (6)

[0018] 3. Slow cooling of slag

[0019] Slowly cool the slag, control the cooling rate of the slag to be 2-5°C / min until it cools to room temperature.

[0020] The reducing agent is one or more of pulverized coal or coke, wherein the particle size of the pulverized coal is required to be 0.1 - 5 mm, and the fixed carbon content by mass percentage is ≥ 55%; the particle size of the coke is required to be 3 - 20 mm, and the fixed carbon content by mass percentage is ≥ 80%.

[0021] The slag former is one or more of quartz sand and limestone, wherein the mass percentage content of SiO2 in the quartz sand is ≥ 90%, and the mass percentage content of CaO in the limestone is ≥ 99%.

[0022] The sulfiding agent is one or more of sulfur or sulfur-containing slag, with an S content ≥ 80%.

[0023] The basic flux is one or more of sodium hydroxide, sodium carbonate, sodium silicate, and sodium sulfate.

[0024] The mass content range of elements in the copper-nickel electroplating sludge described is as follows: Fe 10.0% - 25.0%, Cu 0.5% - 15.0%, Ni 0.5% - 20.0%, Cr 4% - 18.0%, Si 0.5% - 5.0%, Ca 0.5% - 15.0%, Zn 0.1% - 5.0%, Al 0.5% - 5.0%, Pb 0.5% - 2.0%, S 0.5% - 5.0%, Na 0.5% - 5.0%.

[0025] The present invention has the following advantages compared with other pyrometallurgical treatment technologies for electroplating sludge:

[0026] (1) By controlling the smelting atmosphere and regulating the composition of the smelting system, basic copper-nickel matte smelting of copper-nickel electroplating sludge is carried out, and the smelting temperature can be reduced to below 1250 °C, reducing the energy consumption during the smelting process;

[0027] (2) Realize the reduction treatment of copper-nickel electroplating sludge and the enrichment of valuable elements. Among them, the matte enriches more than 95% of Cu and more than 90% of Ni, and the slag enriches more than 99% of Cr, improving the subsequent separation efficiency;

[0028] (3) By slow cooling of the slag, Cu, Ni, and Cr in the slag are stored in the spinel phase, realizing the harmlessness of the basic smelting slag. The TCLP test results of the smelting slag show that it is lower than the standard value of "Identification Standard for Toxicity of Leaching of Hazardous Wastes - GB5085.3 - 2007";

[0029] (4) The raw materials of the present invention have strong adaptability, high recovery efficiency of valuable metals, and low labor intensity. Description of the Drawings

[0030] Figure 1 XRD diagram of the smelting slag in Example 1 of the present invention

[0031] Figure 2 SEM image of the smelting slag in Example 1 of the present invention

[0032] Figure 3 Micro-area composition table of the smelting slag in Example 1 of the present invention Detailed implementation manners

[0033] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the specific implementation manners of the present invention are not limited thereto.

[0034] Example 1

[0035] Composition of electroplating sludge: Fe 20.7%, Cu 4.0%, Ni 7.3%, Cr 4.1%, Si 2.2%, Ca 10.2%, S 2.9%, Na 1.2%.

[0036] The reducing agent is pulverized coal with a carbon content of 55.4%; the sulfurizing agent is sulfur with a sulfur content of 95.0%; the quartz sand has a SiO2 content of 91.6%; both iron oxide and calcium oxide are industrial grade with a content > 99%; the basic flux is industrial grade sodium carbonate with a content > 99%.

[0037] Weigh and proportion the electroplating sludge with additives such as reducing agent, slag-forming agent, sulfurizing agent and basic flux. Control the weight of the pulverized coal added to be 4% of the weight of the electroplating sludge, the weight of sulfur to be 8% of the weight of the electroplating sludge, and the weight of sodium carbonate to be 38% of the weight of the electroplating sludge. Control the mass ratio of Na and S in the mixed material of electroplating sludge and additives to be 1.7:1. The addition amounts of iron oxide, quartz sand and calcium oxide meet the initial requirements of the smelting slag type, with the mass ratio of FeO to SiO2 being 1.5:1 and the mass ratio of CaO to SiO2 being 0.8:1. Then, mix the electroplating sludge with pulverized coal, slag-forming agent, sulfur and sodium carbonate evenly for batching and granulation. Add the granulated material into the smelting furnace, control the temperature at 1200 °C, control the liquid level height of the lower matte layer in the furnace at 200 mm, and the liquid level height of the upper slag layer in the furnace at 400 mm. Inject oxygen-enriched air with a volume concentration of 70% of natural gas and oxygen 50 mm above the interface between the smelting slag layer and the matte layer. The volume-mass ratio of the injected natural gas to the granulated material is 60 NM 3 / t, and the volume-mass ratio of oxygen to the granulated material is 120 Nm 3 / t. Set a secondary air inlet 600 mm above the smelting furnace and inject oxygen-enriched air with an oxygen volume concentration of 23%. The amount of oxygen-enriched air is 150 Nm 3 / t. Smelt for 2 h under the above conditions, and then discharge the matte and slag in sequence. Control the cooling rate of the slag at 3 °C / min until room temperature.

[0038] In this example, 95.1% of copper and 90.1% of nickel are enriched in the matte, and 99.3% of Cr is enriched in the slag.

[0039] The composition of the matte produced in this example is shown in Table 1-1.

[0040] Table 1-1

[0041]

[0042] The composition of the smelting slag produced in this example is shown in Table 1-2.

[0043] Table 1-2

[0044]

[0045] TCLP tests were carried out on the main metal elements in the smelting slag according to HJT 299-2007 "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method", indicating that the smelting slag is no longer a hazardous waste. The results are shown in Table 5. Cu, Ni, and Cr in the slag are hosted in the spinel phase, and the basic glassy slag does not contain Cu, Ni, and Cr. The results are as Figure 2 and Figure 3 shown.

[0046] Example 2

[0047] Composition of electroplating sludge: Fe 24.0%, Cu 6.5%, Ni 17.8%, Cr 9.4%, Si 2.5%, Ca 10.1%, S 1.3%, Na 2.2%.

[0048] The reducing agent is pulverized coal with a carbon content of 55.4%; quartz sand with a SiO2 content of 91.6%; iron oxide and calcium oxide are both industrial grade with a content > 99%; the basic flux is industrial grade sodium sulfate with a content > 99%, and it is also the sulfur source in this system.

[0049] The electroplating sludge is weighed and proportioned with additives such as reducing agent, slag-forming agent, sulfiding agent, and basic flux. The weight of the pulverized coal added is controlled to be 12% of the weight of the electroplating sludge, and the weight of sodium sulfate is 36.6% of the weight of the electroplating sludge. The mass ratio of Na and S in the mixed material of electroplating sludge and additives is controlled to be 1.5:1. The addition amounts of iron oxide, quartz sand, and calcium oxide meet the initial requirements of the smelting slag type with a mass ratio of FeO to SiO2 of 1.5:1 and a mass ratio of CaO to SiO2 of 0.6:1. Then, the electroplating sludge is mixed evenly with pulverized coal, slag-forming agent, and sodium sulfate for pelletizing. The pellets are added into the smelting furnace, the temperature is controlled at 1250 °C, the liquid level height of the matte layer in the lower layer of the furnace is controlled at 400 mm, and the liquid level height of the slag layer in the upper layer of the furnace is 800 mm. Oxygen-enriched air with a volume concentration of 85% of natural gas and oxygen is blown in 100 mm above the interface between the smelting slag layer and the matte layer. The volume-mass ratio of the natural gas introduced to the pellets is 100 NM 3 / t, the volume mass ratio of oxygen to the granular material is 200 Nm 3 / t. A secondary tuyere is set 800 mm above the smelting furnace, and oxygen-enriched air with an oxygen volume concentration of 50% is blown in, and the amount of oxygen-enriched air is 220 Nm 3 / t. Smelt for 3.5 h under the above conditions. Then, matte and slag are discharged in sequence, and the cooling rate of the slag is controlled at 3.5 °C / min until room temperature.

[0050] In this Example 95.4% of copper and 90.3% of nickel are enriched in the matte, and 99.6% of Cr is enriched in the slag.

[0051] The composition of the matte produced in this Example is shown in Table 2-1.

[0052] Table 2-1

[0053]

[0054] The composition of the smelting slag produced in this Example is shown in Table 2-2.

[0055] Table 2-2

[0056]

[0057] The TCLP test is carried out on the main metal elements in the smelting slag according to HJT 299-2007 "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method", indicating that the smelting slag is no longer a hazardous waste, and the results are shown in Table 5.

[0058] Example 3

[0059] Composition of electroplating sludge: Fe 20.3%, Cu 7.1%, Ni 13.5%, Cr 9.4%, Si 3.7%, Ca 14.1%, S 0.6%, Na 3.5%.

[0060] The reducing agent is coke with a carbon content of 82.1%; the sulfiding agent is sulfur with a sulfur content of 95.0%; both iron oxide and calcium oxide are industrial grade with a content of >99%; the basic flux is industrial grade sodium silicate with a content of >99%.

[0061] Weigh and proportion the electroplating sludge with additives such as reducing agent, slag-forming agent, sulfurizing agent and alkaline flux. Control the weight of coke added to be 3% of the weight of the electroplating sludge, the weight of sulfur to be 10% of the weight of the electroplating sludge, and the weight of sodium silicate to be 25% of the weight of the electroplating sludge. Control the mass ratio of Na and S in the mixture of electroplating sludge and additives to be 1.3:1. The addition amounts of iron oxide, quartz sand and calcium oxide meet the initial requirements of the smelting slag type, with the mass ratio of FeO to SiO2 being 1.5:1 and the mass ratio of CaO to SiO2 being 0.5:1. Then, mix the electroplating sludge evenly with pulverized coal, slag-forming agent and sodium silicate for batching. Add the granulated materials into the smelting furnace, control the temperature at 800 °C, control the liquid level height of the lower matte layer in the furnace to be 300 mm, and the liquid level height of the upper slag layer in the furnace to be 600 mm. Blow in oxygen-enriched air with a volume concentration of 80% of natural gas and oxygen 70 mm above the interface of the smelting slag layer and the matte layer. The volume-mass ratio of the natural gas introduced to the granular material is 800 NM 3 / t, and the volume-mass ratio of oxygen to the granular material is 160 Nm 3 / t. Set a secondary tuyere 700 mm above the smelting furnace and blow in oxygen-enriched air with an oxygen volume concentration of 40%. The amount of oxygen-enriched air is 180 Nm 3 / t. Smelt under the above conditions for 6 h, and then discharge the matte and slag in sequence. Control the cooling rate of the slag to be 4 °C / min until room temperature.

[0062] In this example, 95.8% of copper and 91.1% of nickel are enriched in the matte, and 99.5% of Cr is enriched in the slag.

[0063] The composition of the matte produced in this example is shown in Table 3-1.

[0064] Table 3-1

[0065]

[0066] The composition of the smelting slag produced in this example is shown in Table 3-2.

[0067] Table 3-2

[0068]

[0069] Perform TCLP tests on the main metal elements in the smelting slag according to HJT 299-2007 "Solid Waste Leaching Toxicity Leaching Method - Sulfuric Acid and Nitric Acid Method", indicating that the smelting slag is no longer a hazardous waste. The results are shown in Table 5.

[0070] Example 4

[0071] Composition of electroplating sludge: Fe 15.6%, Cu 7.8%, Ni 14.3%, Cr 6.5%, Si 2.0%, Ca 8.2%, S 1.9%, Na 4.2%.

[0072] The reducing agent is coke with a carbon content of 82.1%; the sulfiding agent is sulfur with a sulfur content of 95.0%; the quartz sand has a SiO2 content of 91.6%; both iron oxide and calcium oxide are of industrial grade with a content > 99%; the basic flux is industrial grade sodium carbonate with a content > 99%.

[0073] Weigh and proportion the electroplating sludge with additives such as reducing agent, slag-forming agent, sulfiding agent, and basic flux. Control the weight of added coke to be 6% of the weight of the electroplating sludge, the weight of sulfur to be 6% of the weight of the electroplating sludge, and the weight of sodium carbonate to be 32.5% of the weight of the electroplating sludge. Control the mass ratio of Na and S in the mixture of electroplating sludge and additives to be 2.4:1. The addition amounts of iron oxide, quartz sand, and calcium oxide meet the initial requirements of the smelting slag type, with the mass ratio of FeO to SiO2 being 1.7:1 and the mass ratio of CaO to SiO2 being 0.5:1. Mix the electroplating sludge, coke, slag-forming agent, sulfur, and sodium carbonate evenly for batching and granulation. Add the granulated material into the smelting furnace, control the temperature at 1150 °C, control the liquid level height of the lower matte layer in the furnace at 350 mm, and the liquid level height of the upper slag layer in the furnace at 500 mm. Blow in a rich oxygen air with a volume concentration of 75% of natural gas and oxygen 65 mm above the interface between the smelting slag layer and the matte layer. The volume-mass ratio of the introduced natural gas to the granular material is 90 NM 3 / t, and the volume-mass ratio of oxygen to the granular material is 130 Nm 3 / t. Set a secondary tuyere 700 mm above the smelting furnace and blow in a rich oxygen air with an oxygen volume concentration of 45%. The amount of rich oxygen air is 160 Nm 3 / t. Smelt under the above conditions for 4 h, then discharge the matte and slag in sequence, and control the cooling rate of the slag at 2.5 °C / min until room temperature.

[0074] In this example, 95.0% of copper and 90.3% of nickel are enriched in the matte, and 99.2% of Cr is enriched in the slag.

[0075] The composition of the matte produced in this example is shown in Table 4-1.

[0076] Table 4-1

[0077]

[0078] The composition of the smelting slag produced in this example is shown in Table 4-2.

[0079] Table 4-2

[0080]

[0081] TCLP tests were conducted on the main metal elements in the smelting slag according to HJT 299-2007 "Solid Waste - Extraction Procedure for Toxicity Characteristic - Sulfuric Acid and Nitric Acid Method", indicating that the smelting slag is no longer a hazardous waste, and the results are shown in Table 5.

[0082] Table 5

[0083]

Claims

1. A treatment method for copper-nickel sludge, characterized in that, It includes the following steps: (a) Weigh the copper-nickel-containing sludge and additives such as reducing agents, slag-forming agents, sulfiding agents, and alkaline fluxes. Then, fully mix the sludge and additives evenly and granulate them, controlling the mass percentage of water in the pellets to be 8-15%. (b) Add the granulated materials into the smelting furnace, control the temperature at 800-1250°C, control the liquid level height of the matte layer in the lower layer of the furnace to be 200-400 mm, and the liquid level height of the slag layer in the upper layer of the furnace to be 400-800 mm. Inject natural gas and oxygen-enriched air at a position 50-100 mm above the interface between the smelting slag layer and the matte layer; set a secondary tuyere 600-800 mm above the smelting furnace and inject oxygen-enriched air. Smelt under the above conditions for 2-6 h, and then discharge the matte and slag into a matte ladle and a slag ladle respectively. (c) Slowly cool the slag, controlling the cooling rate of the slag to be 2-5°C / min until it cools to room temperature.

2. The treatment method of copper-nickel sludge according to claim 1, characterized in that, The mass content range of elements in the copper-nickel-containing sludge described in step (a) is as follows: Fe 10.0%-25.0%, Cu 0.5%-15.0%, Ni 0.5%-20.0%, Cr 4%-18.0%, Si 0.5%-5.0%, Ca 0.5%-15.0%, Zn 0.1%-5.0%, Al 0.5%-5.0%, Pb 0.5%-2.0%, S 0.5%-5.0%, Na 0.5%-5.0%.

3. The treatment method of copper-nickel sludge as described in claim 1, wherein The reducing agent described in step (a) is one or more of pulverized coal or coke, and its addition amount is 3-8% of the mass of the sludge. Among them, the particle size of the pulverized coal is required to be 0.1-5 mm, and the fixed carbon content by mass percentage is ≥55%; the particle size of the coke is required to be 3-20 mm, and the fixed carbon content by mass percentage is ≥80%.

4. A method for treating copper-nickel sludge according to claim 1, characterized in that, The slag-forming agent described in step (a) is one or more of quartz sand and limestone, and its added mass meets the initial requirements of the smelting slag type, with the mass ratio of FeO to SiO2 being 1.0-2.0:1 and the mass ratio of CaO to SiO2 being 0.3-0.8:

1. Among them, the mass percentage of SiO2 in the quartz sand is ≥90%, and the mass percentage of CaO in the limestone is ≥99%.

5. The treatment method of copper-nickel sludge according to claim 1, characterized in that, The sulfiding agent described in step (a) is one or more of sulfur or sulfur-containing slag, with an S content ≥80%, and its addition amount is 3-10% of the mass of the sludge.

6. The treatment method of copper-nickel sludge according to claim 1, characterized in that, The alkaline flux described in step (a) is one or more of sodium hydroxide, sodium carbonate, sodium silicate, and sodium sulfate, and its addition amount is 20-40% of the mass of the sludge, and the mass ratio of Na to S in the mixed material of the sludge and additives is 1-6:

1.

7. A treatment method for copper-nickel sludge as described in claim 1, characterized in that, The volume concentration of oxygen in the oxygen-enriched air injected at a position 50 to 100 mm above the interface between the smelting slag layer and the matte layer described in step (b) is 70 to 85%, and the volume-mass ratio of the natural gas introduced to the granular material is 60 to 100 NM 3 / t, and the volume-mass ratio of oxygen to the granular material is 120 to 200 Nm 3 / t.

8. A treatment method for copper-nickel sludge as described in claim 1, characterized in that, A secondary tuyere is arranged at a position 600 - 800 mm above the smelting furnace in step (b), and the volume concentration of oxygen in the oxygen-enriched air blown in is 23 - 50%, and the amount of oxygen-enriched air is 150 - 220 Nm 3 / t.

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