A method for continuous smelting of a nickel-containing copper concentrate in a short process

Abstract

This invention discloses a short-process continuous smelting method for nickel-copper concentrate. The method includes: 1) smelting the nickel-copper concentrate to obtain smelting slag and high-nickel copper matte with upper and lower layers; 2) performing suspension blowing on the high-nickel copper matte to obtain nickel-copper blowing slag and crude copper with upper and lower layers; 3) performing reduction smelting on the nickel-copper blowing slag to obtain reduction slag and copper-nickel alloy with upper and lower layers. This invention, by adjusting the reaction kinetics and slag structure in the blowing section, enables efficient separation of copper and nickel elements in the high-nickel copper concentrate during the blowing section. The resulting crude copper meets the requirements of subsequent pyrometallurgical refining and electrolytic refining, eliminating the need for a denicking stage at the downstream end. This shortens the smelting process and makes it possible to apply high-nickel copper concentrate to large-scale continuous copper smelting. The reduction of nickel-copper blowing slag to copper-nickel alloy eliminates the traditional process of returning the blowing slag to the batching process, achieving short-process recovery of Ni element and solving the problem of Ni element cyclic enrichment in the system. This is a new technical route for copper smelters to broaden the scope of raw material applications and reduce costs and increase efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of non-ferrous metal smelting, and particularly relates to a short-process continuous smelting method for a nickel-containing copper concentrate. BACKGROUND

[0002] Copper is the second most produced metal among the ten non-ferrous metals, and is widely used in the fields of electricity, machinery, transportation, electronics, aerospace, etc. due to its good electrical conductivity, thermal conductivity, ductility and corrosion resistance. At present, the raw material for primary copper metal smelting is mainly copper concentrate, and the self-sufficiency rate of copper concentrate in China is less than 30%, which is heavily dependent on imports. With the rising price of imported copper concentrate and the shrinking space for processing fees, the supply of high-grade and high-quality copper concentrate is becoming increasingly scarce, and the increasing impurity content in the future copper smelting raw material is an inevitable trend.

[0003] Metal nickel is one of the common associated elements in copper concentrate. In the pyrometallurgical process which dominates the field of copper smelting, nickel element usually enters the electrolytic system along the path of concentrate-copper matte-rough copper-anode copper. In the case of low initial content (generally 0.01-0.02%), Ni has little effect on the pyrometallurgical system itself, but if the raw material contains high nickel (>1%), Ni is enriched in the copper matte during the smelting process, which will affect the slag making process of the copper matte. Since the anode furnace refining process commonly used in the industry has almost no effect on the removal of Ni element, most of the Ni in the rough copper enters the anode plate, which has a significant impact on the production of cathode copper in the electrolytic refining process. In the high-nickel copper anode electrolysis process, problems such as anode passivation, anode mud settlement difficulty, and cathode copper surface particle formation and easy oxidation to blackening are prone to occur.

[0004] Industry technical personnel have conducted some statistics and research on the migration rule of Ni element in the smelting process of nickel-containing copper concentrate, and found that in the smelting process, due to the presence of FeS in the copper matte product, NiO in the slag is easily dissolved into the copper matte, so more than 90% of the Ni element enters the converting link with the copper matte, which is difficult to remove by slagging. The impact of different processes in the converting link on the distribution of Ni element is quite different. For example, in the flash converting process, 70% of the Ni element is distributed in the rough copper, which is difficult to remove effectively. Although the Ausmelt converting furnace can oxidize 70% of the Ni element into slag, it cannot reduce the nickel content in the rough copper to a reasonable range when the raw material contains high nickel. A certain enterprise developed a unique treatment process for high-nickel secondary copper concentrate, which connects the top-blown converting with the Kaldo furnace refining process to deeply convert and remove nickel from the high-nickel rough copper. The Ni content in the rough copper can be reduced to 0.6%, which meets the requirements of the subsequent process. However, the obvious disadvantage of this process is that the long process leads to multiple material transfers, the Kaldo furnace has small processing capacity and is operated periodically, which is difficult to adapt to large-scale continuous copper smelting systems. Therefore, it is an urgent technical problem in the industry to realize short-process and continuous smelting of high-nickel copper concentrate. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a short process continuous smelting method for nickel-containing copper concentrate based on the reaction principle of nickel-containing copper concentrate oxidation smelting and converting and the melting characteristics of high-nickel slag, aiming to realize copper-nickel separation by oxygen-enriched molten pool continuous converting process without increasing the complexity of the smelting process, so that high-nickel copper concentrate can be applied to large-scale continuous industrial production, and the adaptability of copper smelting enterprises to low-quality complex raw materials is improved.

[0006] The short process continuous smelting method for nickel-containing copper concentrate provided by the present application comprises the following steps:

[0007] 1) The raw material nickel-containing copper concentrate and fuel and acid flux are added into a smelting furnace, oxygen-enriched air is blown in, the proportion of oxygen and fuel is adjusted, the reaction atmosphere is adjusted to an oxidizing atmosphere for smelting, and after smelting, upper and lower layered smelting slag and high-nickel copper matte are obtained;

[0008] 2) The high-nickel copper matte obtained in step 1) is introduced into a converting furnace, then mixed flux is added for slagging, and oxygen-enriched gas flow is blown in for suspension converting, and after converting, upper and lower layered nickel-copper converting slag and crude copper are obtained;

[0009] 3) The nickel-copper converting slag obtained in step 2) is introduced into a depletion furnace, then oxygen-enriched air and fuel are blown in, the proportion of oxygen and fuel is adjusted, the reaction atmosphere is adjusted to a weak reducing atmosphere for reduction smelting, and after reduction smelting, upper and lower layered reduction slag and copper-nickel alloy are obtained.

[0010] In the smelting stage of step 1), most of the main impurity Fe element in the raw material is converted into oxides, which react with the flux to enter the slag phase, and at the same time, Al2O3, PbO, ZnO, etc. are absorbed into the slag; sulfur is partially oxidized to produce SO2 into the flue gas; Cu and the remaining part of S element are deposited in the lower layer in the form of Cu2S, and most of Ni3S2 and a small amount of FeS are dissolved to form high-nickel copper matte.

[0011] In the suspension converting stage of step 2), the high-nickel copper matte is periodically discharged from the lower outlet of the smelting furnace, then flows into the converting furnace through the launder, and then the oxygen-rich gas stream is blown in. Under the intense stirring of the oxidizing gas, the Fe and Ni in the high-nickel copper matte are mostly converted into oxidized phases. These oxidized phases are combined with the mixed flux to form slag and float on the upper layer of the hearth. The Cu element is generated into metallic copper through the interactive reaction of Cu2S and Cu2O and then precipitates in the lower layer of the hearth to form a copper liquid layer (blister copper). Ni3S2 reacts with Cu2O to generate part of the metallic nickel and dissolve in the blister copper. In the late stage of the converting, due to the reduction of the activity of the metallic nickel in the blister copper, Cu and Ni are simultaneously oxidized into the slag phase, and S element is oxidized into SO2 and enters the flue gas. The qualified blister copper produced at the end of the converting process enters the conventional pyro-refining process to produce anode copper, and the nickel-copper converting slag enters the next process for depletion and recovery.

[0012] In the reduction smelting stage of step 3), the nickel-copper converting slag is periodically discharged from the slag port of the converting furnace, then flows into the depletion furnace through the launder, and then the oxygen-rich air and pulverized coal are blown in. By adjusting the ratio of oxygen to fuel, the reaction atmosphere is adjusted to a weak reducing atmosphere for reduction smelting. The Cu, Ni and a small amount of Fe elements in the nickel-copper converting slag are reduced to metallic elements to form a copper-nickel alloy melt and precipitate in the lower layer, which is periodically discharged from the lower outlet as a copper-nickel alloy preparation raw material for sale. The Fe element is converted into low-valence oxides, and the slag system is converted from a five-element system slag to a three-element system slag, which is periodically discharged from the slag port and can be directly water quenched as a building material preparation raw material.

[0013] Preferably, in step 1), the nickel-copper concentrate contains 8-10% of H2O, 20-26% of Cu, 1-2% of Ni, 28-32% of S and 25-35% of Fe on a dry basis.

[0014] In order to maintain the stability of the charge structure, the nickel-copper concentrate generally uses a mixed material of different batches and different types of nickel-copper concentrate. Here, different batches and different types of nickel-copper concentrate refer to the copper concentrate with inconsistent nickel content used by the production enterprise. By ore blending, the composition of the mixed material falls within the above range.

[0015] Preferably, in step 1), the fuel is granular coal. Granular coal has a wide source and low cost.

[0016] Preferably, in step 1), the smelting involves the following process conditions: the oxygen concentration is 80-90%, the oxygen-to-material ratio is controlled at 300 Nm 3 / t, the coal rate is 1-2%, the flux rate is 5-8%, the smelting temperature is maintained at 1250-1300℃, and the smelting time is 2.5-3h. Here, the oxygen-to-material ratio refers to the ratio of oxygen flow to the mass of mixed charge, the coal rate refers to the mass of fuel to the mass of mixed charge, and the flux rate refers to the mass of flux to the mass of mixed charge.

[0017] Preferably, in step 1), the acid flux is silica. In the smelting process, the Fe element in the raw material is mostly oxidized into FeO and Fe3O4, which form slag with SiO2 in the acid flux to form smelting slag. The Fe / SiO2 in the smelting slag is controlled at 1.8-2.0, and the slag contains 1.5-2% Cu and 0.2-0.3% Ni. After the smelting is completed, the smelting slag is discharged from the slag port and sent to the slow-cooling slag selection for recovering the Cu therein.

[0018] Preferably, in step 1), the high-nickel copper matte contains 68-72% Cu, 4-6% Ni, and 1-3% Fe.

[0019] Preferably, in step 1), the smelting furnace is an oxygen-enriched side-blown smelting furnace. The oxygen-enriched side-blown smelting furnace includes a furnace body. The furnace body has a rectangular structure, and a solid charge inlet and a flue are arranged at the top of the furnace body. The rear end of the flue is connected to a flue gas treatment system. A plurality of submerged side-blown tuyeres are arranged at the middle part of the side wall of the furnace chamber. A secondary air inlet is arranged at the upper part of the side wall of the furnace chamber. A slag port is arranged at the middle part of the end wall, and a copper matte port is arranged at the lower part of the end wall. The oxygen-enriched side-blown smelting furnace is connected to the feed inlet of the converting furnace through a chute. The solid charge inlet is used for adding nickel-copper concentrate mixture, flux, block fuel, etc. The flue gas treatment system can recover waste heat and capture flue dust. The plurality of submerged side-blown tuyeres are used for blowing oxygen-enriched air with different concentrations to flexibly control the oxygen partial pressure in the furnace by adjusting the ratio of oxygen to fuel. The secondary air inlet is used for igniting the combustible components such as sulfur in the flue gas to inhibit the slagging of the flue.

[0020] Preferably, in step 2), the process conditions involved in the suspension converting include: the oxygen-enriched concentration is 25-30%, the oxygen-to-material ratio is controlled at 150 Nm 3 / t, the flux rate is 4-6%, the converting temperature is maintained at 1250-1300°C, and the converting time is 14-16h. The oxygen-to-material ratio here refers to the ratio of oxygen flow to the mass of hot copper matte, and the flux rate refers to the ratio of the mass of flux to the mass of hot copper matte.

[0021] The suspension converting has two advantages: 1) the hot material continuously enters and exits, which saves the material transfer between multiple devices, fully utilizes the physical heat of the hot copper matte, saves energy consumption, and continuous operation is conducive to large-scale production; 2) the oxygen lance of the suspension converting is not immersed in the molten pool, and the service life of the oxygen lance can be effectively prolonged.

[0022] Preferably, in step 2), the mixed flux is a mixture of limestone and silica. In the converting process, the high-pressure oxygen stream rapidly reacts with Fe, Ni, and Cu in the high-nickel copper matte to generate oxides such as FeO, Fe3O4, NiO, and Cu2O. These oxides form slag with CaO and SiO2 in the mixed flux, and finally form a Cu2O-NiO-Fex O-CaO-SiO2 quinary system copper-nickel converting slag. The CaO / Fe in the copper-nickel converting slag is controlled at 0.2-0.4, the SiO2 / Fe is controlled at 0.5-0.7, the slag contains Cu 25-35%, Ni 18-20%. The copper-nickel converting slag floats on the upper layer of the converting furnace hearth, is periodically overflowed and discharged, and is added into the reduction smelting furnace via a spout.

[0023] Preferably, in step 2), the Cu content in the blister copper is controlled to be ≥98.5%, the Ni content is ≤0.6%, and the S content is ≤0.1%. The blister copper is continuously discharged through the lower siphon of the converting furnace and is sent to a conventional anode furnace for refining to prepare anode plates. The continuous converting process belongs to a superheated state, and fuel is not needed to be added, and solid copper such as a residual electrode can be added according to the furnace condition to adjust the furnace temperature.

[0024] Preferably, in step 2), the converting furnace is a multi-lance top-blown continuous converting furnace; the converting furnace comprises a furnace body, wherein the cross section of the furnace body is a rectangular structure; a copper water jacket is arranged at the slag line area of the molten pool of the converting furnace, and a white copper matte inlet, a blister copper discharge port, a slag discharge port and an emergency discharge port are arranged on the furnace wall; a plurality of top-blown lances are arranged on the top of the furnace, the lance body is liftable and rotatable, and high-pressure oxygen-enriched air can be blown into the lances to perform suspended blowing above the liquid surface; a flue and a solid furnace charge inlet are arranged on the top of the furnace, and the flue is connected with the furnace body and a waste heat boiler. The solid furnace charge inlet can be used for adding fluxes, solid furnace charges and the like.

[0025] Preferably, in step 3), the fuel is pulverized coal or natural gas. The pulverized coal or natural gas is widely available and is convenient to be blown by the lances.

[0026] Preferably, in step 3), the process conditions of the reduction smelting include that the volume ratio of CO / (CO+CO2) in the weak reducing atmosphere is controlled to be 50-70%, the coal rate is 10-15%, the oxygen excess coefficient is controlled to be 0.65-0.75, the temperature of the reduction smelting is controlled to be 1300-1350°C, and the time of the reduction smelting is 1-3h. Here, the coal rate refers to the mass ratio of the fuel to the converting slag. Under the reduction smelting conditions, Cu and Ni in the copper-nickel converting slag are reduced to metal elements, form a copper-nickel alloy and sink to the lower layer, and the iron oxides in the slag are reduced to FeO, and the slag type is changed to FeO-CaO-SiO2 ternary system reduction slag. The Cu content in the reduction slag is ≤0.4%, and the Ni content is ≤0.1%. The reduction slag is periodically discharged from the slag port, is water quenched and is sold as a building material preparation raw material. The copper-nickel alloy can be directly sold after being cast, and is further refined to prepare copper-nickel alloy products of different grades.

[0027] Preferably, in step 3), the lean furnace is a side-blown reduction furnace; the side-blown reduction furnace includes a furnace body, which is a rectangular structure. A liquid feed port is located on the upper part of one side end wall, and a solid charge feed port and a flue are located on the top. The rear end of the flue is connected to a flue gas treatment system. Several submerged side-blown nozzles are located on the lower part of the furnace side wall, and the nozzles are made of multiple layers of concentric sleeves. A secondary air inlet is located on the upper part of the furnace side wall. A slag discharge port and a siphon port are located on the furnace end wall. The solid charge feed port is used to add flux, lumpy fuel, etc.; the flue gas treatment system is used for waste heat recovery and dust collection; the several submerged side-blown nozzles can be used to simultaneously blow in oxygen-enriched air and fuels such as pulverized coal / natural gas; the secondary air inlet is used to ignite combustible components such as CO in the flue gas.

[0028] Preferably, the flue gas generated in steps 1) and 2) contains SO2, so it is sent to the acid production process after waste heat recovery, dust collection and purification.

[0029] Preferably, the flue gas generated in step 3) is discharged after waste heat recovery, dust collection, and purification to meet the standards.

[0030] The beneficial effects of this invention are as follows: 1) By adjusting the reaction kinetics and slag structure in the blowing section, copper and nickel elements in high-nickel copper concentrate are efficiently separated in the blowing section. The resulting crude copper can meet the requirements of subsequent pyrometallurgical refining and electrolytic refining. There is no need to add periodically operated denickelization equipment at the back end, shortening the smelting process and reducing the number of furnace charge transfers, making it possible to apply high-nickel copper concentrate to large-scale continuous copper smelting. 2) The high-nickel and high-copper blowing slag is reduced to a copper-nickel alloy, eliminating the traditional step of returning the blowing slag to the batching process. This achieves short-process recovery of Ni element and solves the problem of Ni element circulating and accumulating in the system with the molten slag. 3) The main smelting equipment is basically the same as that of a conventional molten pool copper smelting production line. Only one blowing slag depletion furnace needs to be added to achieve comprehensive recovery of copper and nickel raw materials. Therefore, the engineering application difficulty is low, making it a new technical route for copper smelters to broaden the scope of raw material application and reduce costs and increase efficiency. Attached Figure Description

[0031] Figure 1 This is a flow chart of the short-process continuous smelting process for nickel-copper concentrate in Example 1. Detailed Implementation

[0032] Example 1

[0033] according to Figure 1 The process shown involves feeding a nickel-copper concentrate mixture and granular coal into an oxygen-enriched side-blown smelting furnace via a belt conveyor through the top feed port. The nickel-copper concentrate mixture contains 10% H₂O and, on a dry basis, 26% Cu, 1.8% Ni, 30% S, and 35% Fe. Oxygen-enriched air is blown in through the side tuyeres, with an oxygen concentration of 85% and an oxygen-to-material ratio controlled at 300 Nm³.3 The coal content is 1.5%, and silica flux is added from the top feed port to form slag with a flux content of 6.5%. The smelting temperature is 1250℃, and the smelting time is 3 hours, yielding smelting slag and high-nickel copper matte. The high-nickel copper matte contains 68.9% Cu, 4.9% Ni, and 3% Fe; the smelting slag has an Fe / SiO2 ratio of 2.0 and contains 1.6% Cu and 0.2% Ni. After smelting, the slag is discharged from the slag outlet and sent to a slow-cooling slag separator to recover Cu. The high-nickel copper matte flows through a chute into the feed port of a multi-lance top-blown furnace for suspension blowing. During blowing, oxygen-enriched air is blown in through lances set on the furnace top, with an oxygen concentration of 25% and an oxygen-to-material ratio controlled at 150 Nm³. 3 The furnace operates at a blowing temperature of 1300℃. Simultaneously, limestone and silica flux are added to the furnace through a charging port located on the furnace top to form slag. The limestone accounts for 1.8% of the mass of the high-nickel copper matte, and the silica accounts for 3.8%. Oxygen from the oxygen-enriched air rapidly reacts with the Fe, Ni, and Cu in the high-nickel copper matte, undergoing a violent oxidation reaction, ultimately forming Cu₂O-NiO-Fe. x The O-CaO-SiO2 pentagonal slag has a CaO / Fe ratio of 0.2 and a SiO2 / Fe ratio of 0.6. The slag contains 30% Cu and 19% Ni. After being discharged, the slag is fed into a reduction furnace via a chute for reduction smelting. The resulting molten copper (crude copper) contains 98.5% Cu, 0.6% Ni, and 0.1% S. The crude copper is continuously discharged through a lower siphon and sent to a conventional anode furnace for refining to prepare anode plates. (Cu2O-NiO-Fe) x After the O-CaO-SiO2 pentagonal slag is added to the side-blown reduction furnace, oxygen-enriched air and pulverized coal are blown into the furnace through the side-blown nozzle. The ratio of oxygen to pulverized coal is adjusted to control the CO / (CO+CO2) volume ratio in the atmosphere to be 55%, the coal ratio to be 15%, and the reduction temperature to be 1350℃. Cu and Ni in the slag are reduced to liquid copper-nickel alloy, and iron oxides in the slag are reduced to FeO. The slag type is transformed into FeO-CaO-SiO2 ternary reduction slag. The reduction slag contains 0.36% Cu and 0.08% Ni, and the recovery rates of Cu and Ni are both >99%. The copper-nickel alloy can be sold externally for further refining to produce copper-nickel alloy products of different grades.

[0034] Example 2

[0035] according to Figure 1 The process shown involves feeding a mixed nickel-copper concentrate charge and granular coal into an oxygen-enriched side-blown smelting furnace via a belt conveyor through the top feed port. The mixed nickel-copper concentrate charge contains 9% H₂O and, on a dry basis, 24% Cu, 1.6% Ni, 29% S, and 35% Fe. Oxygen-enriched air is blown in through the side tuyeres for smelting, with an oxygen concentration of 85% and an oxygen-to-material ratio controlled at 300 Nm³. 3The coal content was 1.6%, and silica flux was added from the top feed port to form slag at a flux rate of 7%. The smelting temperature was 1260℃, and the smelting time was 3 hours, yielding smelting slag and high-nickel copper matte. The high-nickel copper matte contained 70% Cu, 4.5% Ni, and 2.8% Fe. The smelting slag had an Fe / SiO2 ratio of 2.0 and contained 1.7% Cu and 0.2% Ni. After smelting, the slag was discharged from the slag outlet and sent to a slow-cooling slag separator to recover Cu. The high-nickel copper matte flowed through a chute into the feed port of a multi-lance top-blown furnace for suspension blowing. During blowing, oxygen-enriched air was blown in through lances located at the top of the furnace, with an oxygen concentration of 27% and an oxygen-to-material ratio controlled at 150 Nm³. 3 The furnace operates at a blowing temperature of 1300℃. Simultaneously, limestone and silica flux are added to the furnace through a charging port located on the furnace top to form slag. The limestone accounts for 1.6% of the mass of the high-nickel copper matte, and the silica accounts for 3.6%. Oxygen from the oxygen-enriched air rapidly reacts with the Fe, Ni, and Cu in the high-nickel copper matte, undergoing a violent oxidation reaction, ultimately forming Cu₂O-NiO-Fe. x The O-CaO-SiO2 pentagonal slag has a CaO / Fe ratio of 0.2 and a SiO2 / Fe ratio of 0.58. The slag contains 31% Cu and 18% Ni. After being discharged, the slag is fed into a reduction furnace via a chute for reduction smelting. The resulting molten copper (crude copper) contains 98.8% Cu, 0.58% Ni, and 0.08% S. The crude copper is continuously discharged through a lower siphon and sent to a conventional anode furnace for refining to prepare anode plates. (Cu2O-NiO-Fe) x After the O-CaO-SiO2 pentagonal slag is added to the side-blown reduction furnace, oxygen-enriched air and pulverized coal are blown into the furnace through the side-blown nozzle. The ratio of oxygen to pulverized coal is adjusted to control the CO / (CO+CO2) volume ratio in the atmosphere to be 55%, the coal yield to be 15%, and the reduction temperature to be 1350℃. Cu and Ni in the slag are reduced to liquid copper-nickel alloy, and iron oxides in the slag are reduced to FeO. The slag type is transformed into FeO-CaO-SiO2 ternary reduction slag. The reduction slag contains 0.38% Cu and 0.09% Ni, and the recovery rates of Cu and Ni are both >99%. The copper-nickel alloy can be sold externally for further refining to produce copper-nickel alloy products of different grades.

[0036] Example 3

[0037] according to Figure 1 The process shown involves feeding a nickel-copper concentrate mixture and granular coal into an oxygen-enriched side-blown smelting furnace via a belt conveyor through the top feed port. The nickel-copper concentrate mixture contains 8% H₂O and, on a dry basis, 21% Cu, 1.4% Ni, 28% S, and 33% Fe. Oxygen-enriched air is blown in through the side tuyeres for smelting, with an oxygen concentration of 85% and an oxygen-to-material ratio controlled at 300 Nm³. 3The coal content was 1.8%, and silica flux was added from the top feed port to form slag with a flux ratio of 7.5%. The smelting temperature was 1280℃, and the smelting time was 3 hours, yielding smelting slag and high-nickel copper matte. The high-nickel copper matte contained 72% Cu, 4.2% Ni, and 2.5% Fe; the smelting slag had an Fe / SiO2 ratio of 2.0 and contained 1.9% Cu and 0.3% Ni. After smelting, the slag was discharged from the slag outlet and sent to a slow-cooling slag separator to recover Cu. The high-nickel copper matte flowed through a chute into the feed port of a multi-lance top-blown furnace for suspension blowing. During blowing, oxygen-enriched air was blown in through lances located on the furnace top, with an oxygen concentration of 29% and an oxygen-to-material ratio controlled at 150 Nm³. 3 The furnace operates at a blowing temperature of 1280℃. Simultaneously, limestone and silica flux are added to the furnace through a charging port located on the furnace top to form slag. The limestone accounts for 1.5% of the mass of the high-nickel copper matte, and the silica accounts for 3.2%. Oxygen from the oxygen-enriched air rapidly reacts with the Fe, Ni, and Cu in the high-nickel copper matte, undergoing a violent oxidation reaction, ultimately forming Cu₂O-NiO-Fe. x The O-CaO-SiO2 pentagonal slag has a CaO / Fe ratio of 0.21 and a SiO2 / Fe ratio of 0.53. The slag contains 34% Cu and 19.5% Ni. After being discharged, the slag is fed into a reduction furnace via a chute for reduction smelting. The resulting molten copper (crude copper) contains 98.9% Cu, 0.55% Ni, and 0.07% S. This crude copper is continuously discharged through a lower siphon and sent to a conventional anode furnace for refining to prepare anode plates. (Cu2O-NiO-Fe) x After the O-CaO-SiO2 pentagonal slag is added to the side-blown reduction furnace, oxygen-enriched air and pulverized coal are blown into the furnace through the side-blown lance. The ratio of oxygen to pulverized coal is adjusted to control the CO / (CO+CO2) volume ratio in the atmosphere to be 55%, the coal yield to be 15%, and the reduction temperature to be 1300℃. Cu and Ni in the slag are reduced to liquid copper-nickel alloy, and iron oxides in the slag are reduced to FeO. The slag type is transformed into FeO-CaO-SiO2 ternary reduction slag. The reduction slag contains 0.4% Cu and 0.1% Ni, and the recovery rates of Cu and Ni are both >99%. The copper-nickel alloy can be sold externally and further refined to produce copper-nickel alloy products of different grades.

[0038] Comparative Example 1

[0039] The conventional smelting process for nickel-copper concentrate typically employs a submerged single-lance top-blown furnace for autothermal smelting (this process is described in Chapter 9 of "Chinese Nickel-Cobalt Metallurgy") at a smelting temperature of 1250℃. The resulting crude copper contains 91% Cu, 4% Ni, and 3% S. Since the anode furnace has almost no effect on Ni removal, this crude copper needs to be periodically oxidized and blown in a Kaldo furnace to remove nickel, oxidizing the crude copper to a content of 98.5% Cu, 0.6% Ni, and 0.06% S before it enters the anode furnace for refining. The Kaldo furnace in this process operates for 2-2.5 hours per cycle, with a charge of only about 15 tons per furnace. This is suitable for small-scale production lines and is difficult to integrate with current large-scale, continuous production lines. Meanwhile, the self-heating gas-liquid hybrid chemistry of the single-gun top-blown furnace is not ideal, making it difficult to achieve deep removal of Ni from crude copper. The resulting slag contains 10% Cu and 5% Ni, which needs to be returned to the smelting process. This results in the cyclic enrichment of Ni in the system, increasing the pressure on nickel removal in subsequent smelting sulfur production and blowing copper production processes.

[0040] This invention achieves efficient separation of copper and nickel in nickel-containing copper concentrate by adjusting the reaction kinetics and slag structure in the blowing section. This eliminates the need for periodically operated denickelization equipment at the downstream end, shortening the smelting process and enabling the application of high-nickel copper concentrate in large-scale continuous copper smelting. Simultaneously, the high-nickel, high-copper blowing slag is reduced to a copper-nickel alloy, eliminating the traditional step of returning the blowing slag to the batching process. This achieves short-process recovery of Ni and solves the problem of Ni circulating and accumulating within the system along with the molten slag.

[0041] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A method for short-process continuous smelting of nickel-copper concentrate, comprising the following steps: 1) Add the raw material nickel-copper concentrate, fuel, and acidic flux into the smelting furnace, blow in oxygen-enriched air, and adjust the reaction atmosphere to an oxidizing atmosphere by adjusting the ratio of oxygen to fuel for smelting. After smelting, smelting slag with upper and lower layers and high-nickel copper matte are obtained. 2) The high-nickel copper matte obtained in step 1) is introduced into the blowing furnace, then mixed flux is added to form slag, and oxygen-enriched flow is blown in for suspension blowing. After the blowing is completed, nickel-copper slag and crude copper with upper and lower layers are obtained. 3) Introduce the nickel-copper smelting slag obtained in step 2) into the depletion furnace, then blow in oxygen-enriched air and fuel. By adjusting the ratio of oxygen to fuel, the reaction atmosphere is adjusted to a weakly reducing atmosphere for reduction smelting. After the reduction smelting is completed, the upper and lower layers of reduction slag and copper-nickel alloy are obtained. The nickel-copper concentrate contains 8-10% H2O, and on a dry basis contains 20-26% Cu, 1-2% Ni, 28-32% S, and 25-35% Fe. In step 1), the smelting process conditions include: oxygen concentration of 80-90%, coal ratio of 1-2%, flux ratio of 5-8%, smelting temperature maintained at 1250-1300℃, and smelting time of 2.5-3 hours; the Fe / SiO2 ratio in the smelting slag is controlled at 1.8-2.0, and the slag contains 1.5-2% Cu and 0.2-0.3% Ni; the high-nickel copper matte contains 68-72% Cu, 4-6% Ni, and 1-3% Fe; and the oxygen-to-material ratio is controlled at 300 Nm. 3 / t; where the coal ratio refers to the ratio of fuel mass to mixed charge mass, the flux ratio refers to the ratio of flux mass to mixed charge mass, and the oxygen-to-charge ratio refers to the ratio of oxygen flow rate to mixed charge mass; In step 2), the CaO / Fe ratio in the copper-nickel smelting slag is controlled at 0.2-0.4, the SiO2 / Fe ratio is controlled at 0.5-0.7, and the slag contains 25-35% Cu and 18-20% Ni; the crude copper contains ≥98.5% Cu, ≤0.6% Ni, and ≤0.1% S; the process conditions involved in suspension blowing include: an oxygen enrichment concentration of 25-30% and an oxygen-to-material ratio controlled at 150 Nm. 3 / t, flux rate 4-6%, blowing temperature maintained at 1250-1300℃, blowing time 14-16h; wherein, the oxygen-to-material ratio refers to the ratio of oxygen flow rate to hot copper matte mass, and flux rate refers to the ratio of flux mass to hot copper matte mass; In step 3), the process conditions for reduction smelting include: a weak reducing atmosphere refers to controlling the volume ratio of CO / (CO+CO2) in the atmosphere to be 50-70%.

2. The method according to claim 1, characterized in that, In step 1), the fuel is granular coal; the acidic flux is silica.

3. The method according to claim 1, characterized in that, In step 2), the mixed flux is a mixture of limestone and silica.

4. The method according to claim 1, characterized in that, In step 3), the fuel is pulverized coal or natural gas; the process conditions for reduction smelting include: coal ratio of 10-15%, excess oxygen coefficient controlled at 0.65-0.75, reduction smelting temperature controlled at 1300-1350℃, and reduction smelting time of 1-3 hours; wherein, coal ratio refers to the ratio of the mass of fuel to the mass of smelting slag.

5. The method according to claim 1, characterized in that, In step 3), the reducing residue contains Cu ≤ 0.4% and Ni ≤ 0.1%.

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