Method for comprehensively recovering copper-nickel concentrate

Abstract

The invention discloses a comprehensive recovery method for copper-nickel concentrate, which comprises the following steps: smelting the copper-nickel concentrate to obtain smelting slag and high-nickel copper matte which are layered up and down; performing side-blowing converting on the air-quenched and granulated high-nickel copper matte to obtain high-nickel converting slag which is layered up and down and qualified crude copper; the liquid smelting slag and the high-nickel converting slag are mixed for two-step reduction smelting, iron slag and copper-nickel alloy which are layered up and down are obtained through weak reduction, and reducing slag and molten iron which are layered up and down are obtained through strong reduction. According to the method disclosed by the invention, one-step removal of the Ni element is realized through side-blowing reinforced stirring of the granulated copper matte, so that application of the high-nickel copper concentrate to large-scale continuous copper smelting becomes possible. And meanwhile, through cooperative treatment of the smelting slag and the converting slag, short-process comprehensive recovery of Cu, Ni and Fe elements is achieved. The deeply depleted tailings are subjected to water quenching to form a calcium-silicon glass body which has a curing effect on heavy metal ions and is a high-quality building raw material, high-valued and full-quality utilization of mineral resources is realized, and the method is a brand-new technical route for widening the application range of raw materials, reducing cost and improving efficiency in a copper smelting plant.

Description

Technical Field

[0001] The invention belongs to the field of nonferrous metal smelting, and in particular relates to a method for comprehensive recovery of copper-nickel concentrate. Background Art

[0002] China is highly dependent on foreign mineral resources, and high-quality copper resources are decreasing. The impurities such as arsenic, lead, zinc, and nickel are becoming increasingly high. Technological innovation is necessary to improve the adaptability of the copper smelting system to complex raw materials. Metallic nickel is one of the common associated elements in copper concentrate. In the conventional copper pyrometallurgical smelting process, the migration direction of nickel is: concentrate-copper matte-blister copper-anode copper, and finally enters the electrolytic refining system. The Ni content in high-quality copper concentrate is usually <0.02%. Although the Ni element is enriched to varying degrees during smelting, blowing, and refining, the nickel content in anode copper can usually be controlled below 0.5%, which can meet the requirements of the electrolytic refining process.

[0003] The Ni content in copper-nickel ore is more than 100 times that of ordinary copper concentrate, usually containing more than 1% Ni. Some secondary copper-nickel materials, such as secondary copper concentrate obtained by high-nickel matte beneficiation, have a Ni content of more than 3%. During the smelting process, Ni is enriched in matte, which not only affects the normal slag formation during the matte blowing process, but also causes the Ni content of the anode plate to exceed the standard by a large margin, which has a significant impact on the electrolytic refining process. During the electrolysis of high-nickel copper anodes, problems such as anode passivation, difficulty in anode mud sedimentation, and granulation and easy oxidation and blackening of the cathode copper surface are prone to occur. At the same time, the load of nickel removal in electrolyte purification will also increase significantly. In response to the smelting difficulties of this type of high-nickel copper concentrate, a domestic company has developed a top-blowing refining followed by a Kaldo furnace refining process, which can deeply blow and remove nickel from the nickel-containing crude copper, and can reduce the Ni content in the crude copper to 0.6%, meeting the requirements of subsequent processes. However, the obvious disadvantages of this process are its small processing capacity and cyclical operation, making it difficult to adapt to large-scale continuous copper smelting systems. At the same time, the copper-nickel slag produced during the refining process is returned to the nickel smelting system for treatment, so it is only suitable for companies engaged in copper-nickel joint smelting. For individual copper smelting companies, the issue of Ni element recovery still needs to be considered.

[0004] Therefore, the realization of large-scale and continuous smelting of copper-nickel concentrate, deep separation of Ni element in the material, and comprehensive recovery of valuable elements in copper-nickel slag are technical problems that need to be solved urgently in the industry. Summary of the invention

[0005] The purpose of the present invention is to provide a method for comprehensive recovery of copper-nickel concentrate, to realize continuous smelting of copper-nickel concentrate by using oxygen-enriched molten pool enhanced smelting process, to realize deep separation of nickel by means of reaction kinetic conditions of side-blowing blowing, and to comprehensively recover valuable metal elements Cu, Ni and Fe in copper-nickel slag, so that copper-nickel concentrate can be applied to large-scale continuous industrial production, and to improve the adaptability of copper smelting enterprises to low-quality complex raw materials.

[0006] The present invention provides a method for comprehensive recovery of copper-nickel concentrate, comprising the following steps:

[0007] S1. Add the raw copper-nickel concentrate, fuel and acid flux into the smelting furnace, blow in oxygen-rich air, adjust the ratio of oxygen to fuel, and adjust the reaction atmosphere to an oxidizing atmosphere for smelting. After the smelting is completed, smelting slag and high-nickel copper matte with upper and lower layers are obtained. The high-nickel copper matte is discharged from the matte port and then quenched and granulated to obtain granular high-nickel copper matte; the smelting slag is discharged from the slag port and introduced into the double-zone depletion furnace to recover copper and iron in the slag;

[0008] S2. Add the granular high-nickel copper matte obtained in step S1 into a blowing furnace, then add a mixed flux to make slag, blow oxygen-enriched air from a side-blowing lance for blowing, and obtain upper and lower layered copper-nickel slag and low-nickel crude copper after the blowing is completed. The low-nickel crude copper melt is discharged from the copper mouth and sent to the anode furnace for further refining;

[0009] S3. The smelting slag obtained in step S1 and the copper-nickel slag obtained in step S2 are introduced into a double-zone depletion furnace, and then oxygen-enriched air and fuel are respectively blown into the two reaction zones, and the reaction atmosphere in the first reaction zone is adjusted to a weak reducing atmosphere for reduction smelting by adjusting the ratio of oxygen to fuel. After the weak reduction is completed, iron slag and copper-nickel alloy with upper and lower layers are obtained; the iron slag overflows to the second reaction zone, and the reaction atmosphere is adjusted to a strong reducing atmosphere for reduction smelting, and alkaline flux is added to adjust the slag shape. After the strong reduction is completed, reducing slag and molten iron with upper and lower layers are obtained.

[0010] Furthermore, in step S1, the copper-nickel concentrate contains 8-10% H2O, 20-26% Cu, 1-2% Ni, 28-32% S and 25-35% Fe on a dry basis.

[0011] In order to maintain the stability of the charge structure, copper-nickel concentrate is generally blended with multiple types of copper concentrates with inconsistent nickel content so that the composition of the mixed material falls within the above range.

[0012] Furthermore, in step S1, the fuel is granular coal; the acidic flux is silica; the Fe / SiO2 in the smelting slag is controlled at 1.8-2.0, the slag contains Cu 1.5-2%, Ni 0.2-0.3%; the high-nickel copper matte contains Cu 68-72%, Ni 4-6%, and Fe 1-3%.

[0013] Furthermore, in step S1, the process conditions involved in smelting include: oxygen concentration of 80-90%, oxygen-to-material ratio controlled at 280-320 Nm 3 / t, coal rate is 1-2%, flux rate is 5-8%, smelting temperature is maintained at 1250-1300℃, and smelting time is 3-3.5h.

[0014] Among them, the oxygen-to-charge ratio refers to the ratio of the oxygen flow rate to the mass of the mixed charge, the coal rate refers to the ratio of the mass of the fuel to the mass of the mixed charge, and the flux rate refers to the ratio of the mass of the flux to the mass of the mixed charge.

[0015] Furthermore, in step S1, the high-nickel copper matte is discharged from the matte mouth and then subjected to wind quenching and granulation treatment to prepare copper matte particles with a particle size of less than 5 mm.

[0016] Furthermore, in step S2, the process conditions of side blowing are: oxygen enrichment concentration is 21-60%, oxygen-to-material ratio is controlled at 150Nm 3 / t, the flux rate is 4-6%, the blowing temperature is maintained at 1250-1300℃, and the blowing time is 15-20h.

[0017] Among them, the oxygen-to-material ratio refers to the ratio of the oxygen flow rate to the mass of the hot copper matte, and the flux rate refers to the ratio of the mass of the flux to the mass of the hot copper matte.

[0018] There are two main advantages of using small-particle copper matte for side-blowing refining: 1) The particle size of wind-quenched high-nickel copper matte is usually <5mm, and its density is not much different from that of the slag. It sinks slowly in the slag layer. The melt and solid particles in the slag are quickly and fully contacted with oxygen under the vigorous stirring of the oxidizing gas, which is beneficial to the deep removal of Ni and Fe impurity elements. At the same time, the copper liquid layer below the side-blowing spray gun is relatively static, and the diffusion of the slag-gold interface is slowed down, which can effectively inhibit the secondary melting of Ni in the slag; 2) The continuous operation of side-blowing refining is conducive to large-scale production.

[0019] Furthermore, in step S2, the mixed flux is a mixture of limestone and silica; after the mixed flux is added, the CaO / Fe in the copper-nickel slag generated is controlled at 0.2-0.4, the SiO2 / Fe is controlled at 0.5-0.7, and the slag contains Cu 25-35% and Ni 18-20%.

[0020] During the blowing process, oxygen-rich air is blown into the slag layer to form a bubble layer. Oxygen rapidly reacts with Fe, Ni, and Cu in the high-nickel copper matte to produce FeO, Fe3O4, NiO, Cu2O and other oxides. Some Cu2O reacts with Cu2S to form crude copper and sink. The remaining oxides react with CaO and SiO2 in the mixed flux to form slag, eventually forming Cu2O-NiO-Fe x O-CaO-SiO2 five-element blowing slag. The blowing slag floats on the upper layer of the blowing furnace, overflows and is discharged regularly, and is added to the double-zone depletion furnace through the chute for reduction smelting.

[0021] Furthermore, in step S2, the blowing endpoint controls the content of Cu≥98.5%, Ni≤0.5%, and S≤0.05% in the crude copper.

[0022] The crude copper is continuously discharged through the siphon port at the bottom of the converting furnace and sent to the conventional anode furnace for refining to prepare anode plates.

[0023] Furthermore, in step S3, the fuel is pulverized coal or natural gas.

[0024] Furthermore, in step S3, the process conditions for reduction smelting in the first reaction zone include: hot smelting slag and blowing slag flow into the dual-zone depletion furnace through a chute, and the weak reducing atmosphere in the first reaction zone refers to controlling the volume ratio of CO / (CO+CO2) in the atmosphere to be 50-70%; the coal rate is 10-15%, the oxygen excess coefficient is controlled at 0.65-0.75, the temperature of reduction smelting is controlled at 1300-1350°C, and the time of reduction smelting is 1 to 3 hours.

[0025] Among them, the coal rate refers to the ratio of the mass of fuel to the mass of slag.

[0026] Under the reduction smelting conditions, Cu and Ni in the mixed slag are reduced to metal elements to form a copper-nickel alloy and sink to the lower layer. The copper-nickel alloy can be directly sold after casting, and further refined to produce copper-nickel alloy products of different grades. The slag type is transformed into FeO-CaO-SiO2 ternary iron slag.

[0027] Furthermore, in step S3, the process conditions for reduction smelting in the second reaction zone include: the strong reducing atmosphere in the second reaction zone refers to controlling the volume ratio of CO / (CO+CO2) in the atmosphere to be >70%; the coal rate is 30-35%, the oxygen excess coefficient is controlled at <0.65, the temperature of reduction smelting is controlled at 1450-1500°C, the flux rate is 15-20%, and the reduction smelting time is 1 to 3 hours.

[0028] Among them, the coal rate refers to the ratio of the mass of fuel to the mass of iron slag, and the flux rate refers to the ratio of the mass of flux to the mass of iron slag.

[0029] Under the reduction smelting conditions, Fe in the slag is reduced to a single metal substance, forming molten iron that sinks to the lower layer, and the slag is transformed into a CaO-SiO2 binary slag with a binary basicity of CaO / SiO2 mass ratio of 0.8-1.2. The reduced slag contains Cu≤0.4%, Ni≤0.1%, and Fe≤3%. The reduced slag is regularly discharged from the slag outlet and quenched with water before being sold as a raw material for building material preparation.

[0030] Furthermore, the flue gas generated in steps S1 and S2 is sent to the acid-making process after waste heat recovery, dust collection and purification, and the flue gas generated in step S3 is discharged after waste heat recovery, dust collection and purification meet the standards.

[0031] Principle of the present invention:

[0032] In the smelting stage of step S1, most of the main impurity Fe element in the raw material is converted into FeO and Fe3O4. These oxides react with the acidic flux and enter the slag phase, while absorbing Al2O3, PbO, ZnO, etc. into the slag; the sulfur element is partially oxidized to produce SO2 and enter the flue gas; Cu and the remaining S element are deposited in the lower layer in the form of Cu2S, and dissolve Ni3S2 and a small amount of FeS to form high-nickel copper matte. Due to the presence of FeS in the copper matte in the smelting section, NiO in the slag is easily dissolved back into the copper matte phase by secondary sulfidation, resulting in poor oxidative slag removal effect at this stage, and more than 90% of the Ni element is enriched in the copper matte phase, which brings difficulties to the next step of deep nickel removal. Therefore, the high-nickel copper matte is released and then quenched and granulated, and the deep oxidation and impurity removal is carried out by enhanced stirring of the gas-liquid-solid three-phase in the side-blowing blowing slag layer in the next step. The main valuable metals in the smelting slag are Fe and Cu elements. The molten slag is introduced into the reduction depletion furnace and mixed with the blowing slag for smelting;

[0033] In the side-blowing refining stage of step S2, granular high-nickel copper matte is added to the refining furnace, and then oxygen-rich air is blown into the slag layer by the side-blowing lance. Since the wind-quenched high-nickel copper matte has a small particle size and a density that is not much different from that of the molten slag, it sinks slowly in the slag layer. The melt and solid particles in the slag are quickly and fully contacted with oxygen under the vigorous stirring of the oxidizing gas, thereby achieving the melting of the solid particles and the oxidation of the impurity elements. Most of the Fe and Ni in the high-nickel copper matte are converted into oxidized phases and dissolved into the upper slag layer. The Cu element generates metallic copper through the interactive reaction of Cu2S and Cu2O and sinks to form crude copper with qualified composition. The use of small-particle copper matte for oxidative blowing strengthens the kinetic conditions of the reaction process, inhibits the interactive reaction of Ni3S2 and Cu2O to generate metallic nickel under the direct blowing conditions of liquid copper matte, and effectively reduces the Ni content in the crude copper. The qualified crude copper produced at the end of the blowing enters the conventional pyro-refining process to manufacture anode copper, and the copper-nickel slag produced enters the next step of depletion and recovery;

[0034] In the reduction smelting stage of step S3, the copper-nickel slag is regularly discharged from the slag outlet of the blowing furnace and flows into the dual-zone depletion furnace through the chute, and then oxygen-enriched air and fuel are respectively blown into the two reaction zones. By adjusting the ratio of oxygen to fuel, the reaction atmosphere in the first reaction zone is adjusted to a weak reducing atmosphere for reduction smelting. The main phases in the slag are Cu2O, NiO, Fe3O4, SiO2, etc. According to the order of metal element activity, the metal activity of Cu and Ni elements is relatively weak and the two are relatively close. In the weak reducing atmosphere, they are preferentially reduced to liquid alloys and sink to form a copper-nickel alloy layer. The iron oxides in the slag are converted into low-valent oxides FeO and SiO2 to form iron slag; the iron slag overflows to the second reaction zone, and the reaction atmosphere is adjusted to a strong reducing atmosphere for reduction smelting. At the same time, alkaline flux CaCO3 or CaO is added to adjust the slag type, the Fe element is reduced to form molten iron, and the reduction slag type is adjusted to a CaO-SiO2 binary slag system.

[0035] Beneficial effects of the present invention:

[0036] (1) The method of the present invention granulates the high-nickel copper matte obtained by smelting by air quenching, and separates copper and nickel by side-blowing the small-particle copper matte. The melt and solid particles in the slag are rapidly and fully contacted with oxygen under the vigorous stirring of the oxidizing gas, thereby achieving deep removal of the Ni element. At the same time, the copper liquid layer below the side-blowing lance is relatively static, and the diffusion of the slag-gold interface is slowed down, which can effectively inhibit the secondary melting of Ni in the slag and ensure that the quality of the crude copper meets the standards.

[0037] (2) The method of the present invention does not require the addition of periodically operated crude copper nickel removal equipment at the back end of the blowing process, and the side-blowing blowing process can realize large-scale continuous operation, making it possible to apply high-nickel copper concentrate to large-scale continuous copper smelting;

[0038] (3) The method of the present invention treats the smelting slag containing Cu and Fe in coordination with the blowing slag containing Cu, Fe and Ni, first extracting the copper-nickel alloy and then extracting the pig iron, thereby eliminating the steps of slow cooling of the smelting slag and slag selection and returning the blowing slag to the ingredients in the traditional process, thereby realizing the short-process comprehensive recovery of Cu, Ni and Fe elements;

[0039] (4) In the method of the present invention, the tailings after deep depletion are quenched with water to form a calcium-silicon glass body, which has a good solidification effect on residual heavy metal ions and is a high-quality raw material for the preparation of building materials, thus realizing the high-value and full-quality utilization of mineral resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the comprehensive recovery process of copper-nickel concentrate in Example 1. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0042] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0043] The oxygen-enriched side-blown smelting furnace used in the embodiment of the present invention includes a furnace body; the furnace body is a rectangular structure, and a solid charge feeding port and a flue are arranged on the top thereof, and the rear end of the flue is connected to a flue gas treatment system; a plurality of submerged side-blowing air ports are arranged in the middle part of the furnace side wall; a secondary air port is arranged on the upper part of the furnace side wall; a slag port is arranged in the middle part of the end wall, and a matte port is arranged in the lower part, and the matte port is connected to a wind quenching granulation device. The solid charge feeding port is used to add copper-nickel concentrate mixture and flux, block fuel, etc.; the flue gas treatment system can recover waste heat and capture smoke and dust; the plurality of submerged side-blowing air ports are used to blow in oxygen-enriched air, and the stirring intensity of the slag layer is changed by adjusting the oxygen concentration; the secondary air port is used to ignite sulfur and other combustible components in the flue gas to suppress slagging in the flue.

[0044] The side-blowing converting furnace used in the embodiment of the present invention includes a furnace body; the furnace body is a rectangular structure, and a solid charge feeding port and a flue are arranged on the top, and the rear end of the flue is connected to the flue gas treatment system; a plurality of submerged side-blowing air ports are arranged in the middle of the furnace side wall; a slag port is arranged in the middle of the end wall, and a siphon copper port is arranged at the lower part, and the copper port is connected to the anode refining furnace through a chute. The solid charge feeding port is used to add granular copper matte and flux, etc.; the flue gas treatment system can recover waste heat and capture smoke and dust; the plurality of submerged side-blowing air ports are used to blow oxygen-enriched air into the slag layer, and the stirring intensity of the slag layer is changed by adjusting the oxygen concentration.

[0045] The dual-zone depletion furnace used in the embodiment of the present invention is a rectangular furnace body, and the molten pool area at the bottom of the furnace is separated into a first reaction zone and a second reaction zone by a partition wall. The first reaction zone and the second reaction zone share the same smelting device, and the smelting device is functionally divided into a weak reduction zone and a strong reduction zone. The weak reduction zone is the first reaction zone, and the strong reduction zone is the second reaction zone. The upper gas phase area of ​​the smelting device is connected and provided with a secondary air port, and the secondary air port is used to ignite combustible components such as CO in the flue gas; a plurality of partition wall channels are provided on the partition wall, so that after removing Cu and Ni The molten slag enters the second reaction zone through the partition wall channel; a melt feeding port and an alloy discharge port are provided on the end wall on one side of the first reaction zone, a first reaction zone solid feeding port is provided on the upper part of the first reaction zone, and a second reaction zone solid feeding port is provided on the upper part of the second reaction zone. Side blowing spray guns are provided on the side walls of the first reaction zone and the second reaction zone for introducing oxygen and fuel into the smelting device to adjust different reducing atmospheres; a slag outlet and an iron outlet are provided on the end wall on one side of the second reaction zone, the slag outlet is an outflow channel for the reducing slag, the iron outlet is an outflow channel for the molten iron, and the slag outlet is arranged above the iron outlet.

[0046] Example 1

[0047] The present invention provides a method for comprehensive recovery of copper-nickel concentrate, the schematic diagram of which is as follows: Figure 1 As shown, the following steps are included:

[0048] The copper-nickel concentrate mixed charge and granular coal are added to the oxygen-enriched side-blown smelting furnace through the upper charging port via a belt conveyor. The copper-nickel concentrate mixed charge contains 8% H2O, 22% Cu, 1.6% Ni, 28% S, and 35% Fe on a dry basis. Oxygen-enriched air is blown in from the side-blown tuyere for smelting, with an oxygen concentration of 85% and an oxygen-to-charge ratio of 300 Nm 3 / t, coal rate is 1.5%, and silica flux is added from the upper feeding port to make slag, flux rate is 7%, smelting temperature is 1250℃, smelting is 3h, and smelting slag and high nickel copper matte are obtained. The high nickel copper matte contains Cu 68.5%, Ni 4.6%, Fe 3%; Fe / SiO2 in the smelting slag is 2.0, and the slag contains Cu 1.6%, Ni0.2%. After smelting, the slag is discharged from the slag port and introduced into the double-zone depletion furnace through the chute for reduction smelting. The high nickel copper matte is granulated by wind quenching to make copper matte particles <5mm.

[0049] The high-nickel copper matte particles are added to the charging port of the side-blowing refining furnace for refining. During refining, oxygen-enriched air is blown in through the side-blowing lance set at the height of the furnace wall slag layer. The oxygen-enriched concentration is 30% and the oxygen-to-fuel ratio is 150Nm 3 / t, the blowing temperature is 1250℃, and limestone and silica flux are added into the furnace through the charging port set on the top of the furnace to make slag, wherein the mass of limestone accounts for 1.8% of the mass of high-nickel copper matte, and the mass of silica accounts for 3.5% of the mass of high-nickel copper matte. The copper liquid generated by blowing contains Cu 98.5%, Ni 0.5%, and S 0.04%. The crude copper is continuously discharged through the lower siphon port and sent to the anode furnace for refining and preparation of anode plates.

[0050] The blowing slag has CaO / Fe=0.2, SiO2 / Fe=0.5, and contains 30% Cu and 18% Ni. After the blowing slag is discharged, it is added to the weak reduction zone of the double-zone depletion furnace through a chute for reduction smelting together with the smelting slag. In the weak reduction zone, the volume ratio of CO / (CO+CO2) in the atmosphere is controlled to be 50%, the coal rate is 12%, and the reduction temperature is 1320°C. Cu and Ni in the slag are reduced to liquid copper-nickel alloy, and the iron oxide in the slag is reduced to FeO. The slag is transformed into FeO-CaO-SiO2 ternary iron slag. The iron slag enters the strong reduction zone, and the volume ratio of CO / (CO+CO2) in the atmosphere is adjusted to 75%, the coal rate is 32%, and the reduction temperature is 1450°C. 15% limestone flux is added to make slag, and the Fe in the slag is reduced to molten iron and sinks to the lower layer. The binary basicity CaO / SiO2 mass ratio in the reduced slag is 0.9, containing 0.36% Cu, 0.08% Ni, and 2.9% Fe.

[0051] After testing, the copper-nickel alloy obtained contains Cu 57.69%, Ni 40.31%; the molten iron contains Fe 94.49%, C3.85%; the comprehensive recovery rate of major metals is Cu 99.2%, Ni 97.3%, and Fe 92.1%.

[0052] Example 2

[0053] The copper-nickel concentrate mixed charge and granular coal are added to the oxygen-enriched side-blown smelting furnace through the upper charging port via a belt conveyor. The copper-nickel concentrate mixed charge contains 10% H2O, 25% Cu, 1.2% Ni, 30% S, and 30% Fe on a dry basis. Oxygen-enriched air is blown in from the side-blown tuyere for smelting, with an oxygen concentration of 89% and an oxygen-to-charge ratio of 320Nm 3 / t, coal rate is 1.8%, and silica flux is added from the upper feeding port to make slag, flux rate is 5%, smelting temperature is 1280℃, smelting is 3.2h, and smelting slag and high-nickel copper matte are obtained. The high-nickel copper matte contains Cu 70.5%, Ni 5.1%, and Fe 2.2%; Fe / SiO2 in the smelting slag is 1.8, and the slag contains Cu1.5% and Ni 0.25%. After smelting, the slag is discharged from the slag port and introduced into the double-zone depletion furnace through the chute for reduction smelting. The high-nickel copper matte is granulated by wind quenching to make copper matte particles <5mm.

[0054] The high-nickel copper matte particles are added to the charging port of the side-blowing refining furnace for refining. During refining, oxygen-enriched air is blown in through the side-blowing lance set at the height of the furnace wall slag layer. The oxygen-enriched concentration is 45%, and the oxygen-to-fuel ratio is 150Nm 3 / t, the blowing temperature is 1270℃, and limestone and silica flux are added into the furnace through the charging port set on the top of the furnace to make slag, wherein the mass of limestone accounts for 1.4% of the mass of high-nickel copper matte, and the mass of silica accounts for 3.2% of the mass of high-nickel copper matte. The copper liquid generated by blowing contains Cu 98.6%, Ni 0.49%, and S 0.045%. The crude copper is continuously discharged through the lower siphon port and sent to the anode furnace for refining and preparation of anode plates.

[0055] The blowing slag contains CaO / Fe=0.3, SiO2 / Fe=0.6, and contains 33% Cu and 20% Ni. After the blowing slag is discharged, it is added to the weak reduction zone of the double-zone depletion furnace through a chute for reduction smelting together with the smelting slag. The CO / (CO+CO2) volume ratio in the weak reduction zone is controlled to be 60%, the coal rate is 10%, and the reduction temperature is 1300°C. The Cu and Ni in the slag are reduced to liquid copper-nickel alloy. The iron oxide in the slag is reduced to FeO, and the slag is transformed into FeO-CaO-SiO2 ternary iron slag. The iron slag enters the strong reduction zone, and the CO / (CO+CO2) volume ratio in the atmosphere is adjusted to 77%, the coal rate is 30%, and the reduction temperature is 1480°C. 17% limestone flux is added to make slag, and the Fe in the slag is reduced to molten iron and sinks to the lower layer. The binary basicity CaO / SiO2 mass ratio in the reduced slag is 1.0, containing 0.38% Cu, 0.09% Ni, and 2.8% Fe.

[0056] After testing, the obtained copper-nickel alloy contains Cu 58.09%, Ni 40.82%; the molten iron contains Fe 94.23%, C3.77%; the comprehensive recovery rate of major metals is Cu 99.1%, Ni 97.1%, and Fe 92.8%.

[0057] Example 3

[0058] The copper-nickel concentrate mixed charge and granular coal are added to the oxygen-enriched side-blown smelting furnace through the upper charging port via a belt conveyor. The copper-nickel concentrate mixed charge contains 9% H2O, 26% Cu, 1.9% Ni, 22% S, and 26% Fe on a dry basis. Oxygen-enriched air is blown in from the side-blown tuyere for smelting, with an oxygen concentration of 82% and an oxygen-to-charge ratio of 280Nm 3 / t, coal rate is 1.2%, and silica flux is added from the upper feeding port to make slag, flux rate is 8%, smelting temperature is 1300℃, smelting is 3.5h, and smelting slag and high-nickel copper matte are obtained. The high-nickel copper matte contains Cu 71.6%, Ni 5.8%, and Fe 2.6%; Fe / SiO2 in the smelting slag is 1.9, and the slag contains Cu1.8% and Ni 0.28%. After smelting, the slag is discharged from the slag port and introduced into the double-zone depletion furnace through the chute for reduction smelting. The high-nickel copper matte is granulated by wind quenching to make copper matte particles <5mm.

[0059] The high-nickel copper matte particles are added to the charging port of the side-blowing refining furnace for refining. During refining, oxygen-enriched air is blown in through the side-blowing lance set at the height of the furnace wall slag layer. The oxygen-enriched concentration is 55%, and the oxygen-to-fuel ratio is 150Nm 3 / t, the blowing temperature is 1300℃, and limestone and silica flux are added into the furnace through the charging port set on the top of the furnace to make slag, wherein the mass of limestone accounts for 1.9% of the mass of high-nickel copper matte, and the mass of silica accounts for 3.7% of the mass of high-nickel copper matte. The copper liquid generated by blowing contains Cu 98.7%, Ni 0.45%, and S 0.045%. The crude copper is continuously discharged through the lower siphon port and sent to the anode furnace for refining and preparation of anode plates.

[0060] The blowing slag contains CaO / Fe=0.4, SiO2 / Fe=0.7, 35% Cu, and 19% Ni. After the blowing slag is discharged, it is added to the weak reduction zone of the double-zone depletion furnace through a chute for reduction smelting together with the smelting slag. The CO / (CO+CO2) volume ratio in the weak reduction zone is controlled to be 65%, the coal rate is 14%, and the reduction temperature is 1350°C. The Cu and Ni in the slag are reduced to liquid copper-nickel alloy. The iron oxide in the slag is reduced to FeO, and the slag type is transformed into FeO-CaO-SiO2 ternary iron slag. The iron slag enters the strong reduction zone, and the CO / (CO+CO2) volume ratio in the atmosphere is adjusted to 80%, the coal rate is 35%, and the reduction temperature is 1500°C. 19% limestone flux is added to make slag, and the Fe in the slag is reduced to molten iron and sinks to the lower layer. The binary basicity CaO / SiO2 mass ratio in the reduced slag is 0.2, containing 0.35% Cu, 0.07% Ni, and 2.7% Fe.

[0061] After testing, the copper-nickel alloy obtained contains Cu 57.33%, Ni 41.25%; the molten iron contains Fe 94.68%, C3.25%; the comprehensive recovery rate of major metals is Cu 99.3%, Ni 97.4%, and Fe 93.0%.

[0062] Comparative Example 1

[0063] According to the current conventional nickel-containing copper concentrate smelting process, an immersed single-lance top-blown furnace is usually used for self-heating smelting (this process is recorded in Chapter 9 of "China Nickel-Cobalt Metallurgy"), the smelting temperature is 1250℃, and the resulting crude copper contains 91% Cu, 4% Ni, and 3% S. Since the anode furnace has almost no effect on the removal of Ni, the crude copper needs to be periodically oxidized and blown by the Kaldo furnace to remove nickel, oxidize the crude copper into crude copper containing 98.5% Cu, 0.6% Ni, and 0.06% S, and then enter the anode furnace for refining. The Kaldo furnace in this process has an operating cycle of 2-2.5h, and the loading capacity of each furnace is only about 15t. It is suitable for processing small-scale production lines and is difficult to cooperate with the current large-scale and continuous production. At the same time, the gas-liquid mixed dynamic conditions of the single-gun top-blown furnace autothermal smelting are not good, making it difficult to achieve deep removal of Ni from crude copper. The produced slag contains 10% Cu and 5% Ni, which needs to be returned to the smelting link, resulting in the cyclic enrichment of Ni in the system, which increases the pressure of nickel removal in the subsequent smelting sulfur-making and blowing copper-making processes.

Claims

1. A method for comprehensive recovery of copper-nickel concentrate, characterized in that: The following steps are involved: S1. Add the raw copper-nickel concentrate, fuel and acid flux into the smelting furnace, blow in oxygen-rich air, adjust the ratio of oxygen to fuel, and adjust the reaction atmosphere to an oxidizing atmosphere for smelting. After the smelting is completed, smelting slag and high-nickel copper matte with upper and lower layers are obtained. The high-nickel copper matte is discharged from the matte port and then quenched and granulated to obtain granular high-nickel copper matte; the smelting slag is discharged from the slag port and introduced into the double-zone depletion furnace to recover copper and iron in the slag; S2. Add the granular high-nickel copper matte obtained in step S1 into a blowing furnace, then add a mixed flux to make slag, blow oxygen-enriched air from a side-blowing lance for blowing, and obtain upper and lower layered copper-nickel slag and low-nickel blister copper melt after the blowing is completed. The low-nickel blister copper melt is discharged from the copper mouth and sent to the anode furnace for further refining; S3. The copper-nickel slag obtained in step S2 is introduced into a double-zone depletion furnace, and then oxygen-enriched air and fuel are respectively blown into the two reaction zones, and the reaction atmosphere in the first reaction zone is adjusted to a weak reducing atmosphere for reduction smelting by adjusting the ratio of oxygen to fuel. After the weak reduction is completed, iron slag and copper-nickel alloy with upper and lower layers are obtained; the iron slag overflows to the second reaction zone, and the reaction atmosphere is adjusted to a strong reducing atmosphere for reduction smelting, and alkaline flux is added to adjust the slag shape. After the strong reduction is completed, reducing slag and molten iron with upper and lower layers are obtained.

2. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S1, the copper-nickel concentrate contains 8-10% H2O, 20-26% Cu, 1-2% Ni, 8-32% S2, and 25-35% Fe on a dry basis; the fuel is granular coal; the acidic flux is silica; 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; the high-nickel copper matte contains 68-72% Cu, 4-6% Ni, and 1-3% Fe; the high-nickel copper matte is discharged from the matte mouth and then subjected to wind quenching and granulation treatment to prepare copper matte particles with a particle size of less than 5 mm.

3. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S1, the process conditions involved in smelting include: oxygen concentration of 80-90%, oxygen-to-material ratio controlled at 280-320 Nm 3 / t, coal rate is 1-2%, flux rate is 5-8%, smelting temperature is maintained at 1250-1300℃, and smelting time is 3-3.5h.

4. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S2, the process conditions of side blowing are: oxygen enrichment concentration is 21-60%, oxygen-to-material ratio is controlled at 150Nm 3 / t, the flux rate is 4-6%, the blowing temperature is maintained at 1250-1300℃, and the blowing time is 15-20h.

5. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S2, the mixed flux is a mixture of limestone and silica; after the mixed flux is added, the CaO / Fe ratio of the copper-nickel slag generated is controlled at 0.2-0.4, the SiO2 / Fe ratio is controlled at 0.5-0.7, and the slag contains Cu 25-35% and Ni 18-20%.

6. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S2, the blowing endpoint controls the content of Cu≥98.5%, Ni≤0.5%, and S≤0.05% in the crude copper.

7. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S3, the fuel is pulverized coal or natural gas.

8. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S3, the process conditions for reduction smelting in the first reaction zone include: hot smelting slag and blowing slag flow into the double-zone depletion furnace through a chute, the weak reducing atmosphere in the first reaction zone refers to controlling the volume ratio of CO / (CO+CO2) in the atmosphere to be 50-70%; the coal rate is 10-15%, the oxygen excess coefficient is controlled at 0.65-0.75, the temperature of reduction smelting is controlled at 1300-1350°C, and the time of reduction smelting is 1 to 3 hours.

9. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: In step S3, the process conditions for reduction smelting in the second reaction zone include: the strong reducing atmosphere in the second reaction zone refers to controlling the volume ratio of CO / (CO+CO2) in the atmosphere to be >70%; the coal rate is 30-35%, the oxygen excess coefficient is controlled at <0.65, the temperature of reduction smelting is controlled at 1450-1500°C, the flux rate is 15-20%, and the reduction smelting time is 1 to 3 hours.

10. The method for comprehensive recovery of copper-nickel concentrate according to claim 1, characterized in that: The flue gas generated in steps S1 and S2 is sent to the acid-making process after waste heat recovery, dust collection and purification, and the flue gas generated in step S3 is discharged after waste heat recovery, dust collection and purification meet the standards.

Images