Method for synergistically and comprehensively recovering copper and zinc smelting slag

Abstract

The invention provides a method for synergistically and comprehensively recovering copper and zinc smelting slag, which comprises the following steps: adding raw materials including hot copper smelting slag and high-sulfur zinc slag into a smelting furnace, blowing oxygen-enriched air and pulverized coal fuel into the furnace, and performing first smelting to generate first flue gas, sulfide melt and first smelting slag; and the sulfide melt and the first smelting slag are separated, the obtained first smelting slag serves as a raw material, a calcium flux is added, and molten iron, second smelting slag and second flue gas are generated through second smelting. According to the process, waste is treated with waste, a slag former, a vulcanizing agent and the like do not need to be additionally added, energy consumption is greatly reduced, the content of Fe, Cu, Pb and Zn in tailings is low, pollution risks are avoided, the comprehensive recovery rate of Cu, Pb, Fe and Zn is high, meanwhile, the separation effect of products on valuable metal elements is good, the grade of all the products is high, and the difficulty of follow-up secondary separation and recovery of the valuable metal is lowered.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of comprehensive utilization of non-ferrous metallurgical solid waste, and particularly relates to a method for cooperatively and comprehensively recovering copper and zinc smelting slag. BACKGROUND

[0002] Copper is an important non-ferrous metal in the development of national economy, and its output is only inferior to that of electrolytic aluminum. The main solid waste produced in the copper pyrometallurgical process is the tailing after flotation recovery of copper smelting slag, and about 2.5-3 tons of copper slag are produced for each ton of crude copper. The main valuable metal elements in the copper smelting slag are copper and iron, and the copper content in the smelting slag is significantly different according to different smelting processes. The copper content in the flash smelting slag and the oxygen-enriched side-blown smelting slag is about 1.5%, and the copper content in the oxygen-enriched bottom-blown smelting slag is about 4-6%, which all need to be recovered for the second time. The FeO-SiO2 binary system slag type is usually used in the copper smelting process, so the iron content in the slag can reach more than 40%, and in addition, the slag generally contains Pb 0.2-0.6% and Zn 1.0-5.5%. At present, only a small amount of Fe is recovered in industrial production, and Pb and Zn are not effectively recovered.

[0003] The order of copper and iron recovery in copper slag is currently copper first and then iron. After the smelting slag is discharged from the furnace, it is placed in a slag ladle, and the copper sulfide grains in the slag are fully grown by adopting the mode of air slow cooling + water cooling. Then, the smelting slag is crushed and ground for flotation, and the copper concentrate obtained contains about 30% of copper. The copper recovery rate is greater than 90% when returning to the batching link. The flotation tailings are the main waste slag produced by the current copper smelting. At present, the research object of most copper slag iron recovery is the flotation tailings. Since the iron element in the flotation tailings is mainly in the form of fayalite, the direct magnetic separation recovery rate is low. If a modification treatment method such as magnetization roasting or direct reduction is used, the iron-containing phase is converted into magnetite or elemental iron at high temperature, and then the beneficiation is carried out. The already cooled flotation tailings need to be heated again, which has high energy consumption. At the same time, the high impurity content of the recovered product leads to a low price, and the overall economic rationality is not reasonable. Therefore, at present, most of the researches are still in the experimental stage, and it is difficult to be industrialized.

[0004] The mainstream industrialized treatment method of copper smelting slag at present requires that the smelting slag must be subjected to slow cooling treatment, the heat contained in the slag is not utilized, the glass content in the slow cooling tail slag is low, the solidification effect of heavy metals and harmful elements is poor, and there is a high risk of environmental pollution. If the tail slag after flotation is subjected to comprehensive recovery of Fe, Pb, Zn and other elements, the copper slag needs to be heated to a high temperature state again, and the energy consumption is high. Therefore, the technical ideas need to be adjusted, and the recovery methods and recovery sequence of Cu, Fe, Pb and Zn in the copper smelting slag are comprehensively considered, so that the physical heat of the smelting slag is fully utilized, and the influence of the lean tailing on the environment is minimized. In recent years, the reduction sulfidation method which is more studied in the field of solid waste disposal has the potential to treat multi-metal copper slag. The basic method is to use pyrite, Na2SO4, CaSO4 and other sulfidation agents to form copper matte with Cu, Pb and part of Fe, Zn elements in the copper slag under high temperature conditions, so that large particle size copper matte particles are formed in the cooling process, which is easy to separate slag and matte. Patents such as CN202411293066.4, CN202411292671.X and CN202510322485.4 have proposed such methods, but there are still some problems: 1. After adding the sulfidation agent, the slow cooling separation technical route is still used, which does not essentially solve the problems of deep separation of Fe, Zn and other elements and low glass content in the tailing of the original process; 2. The addition of a large proportion of primary minerals such as pyrite increases the amount of tailing, which does not meet the idea of waste slag reduction.

[0005] CN202111283859.4 discloses a method for collaborative treatment of lead-zinc smelting slag and copper-containing materials. The method uses FeO-SiO2-CaO ternary system as the main lead-zinc smelting slag, copper-containing materials as the raw material, and copper smelting slag as the solvent. After batching, 0.1-2wt% of sulfidation agent is added, the mixture and coal powder are added into a side-blown reduction furnace for reduction smelting, and smoke, copper sulfide and reduction smelting slag are produced. After dust collection, lead and zinc oxide dust is obtained. After water quenching of copper matte and reduction smelting slag, granular copper matte and water quenching slag are obtained. The recovery rate of each metal in the process still needs to be improved, the heavy metal content in the tailing is too high, in addition, the sulfidation agent needs to be added extra, and the copper smelting slag needs to be added extra to adjust the slag type, which increases the amount of slag and does not meet the requirement of waste slag reduction, and the energy consumption is relatively high.

[0006] As can be seen from the above, there are still many problems in the comprehensive recovery process of valuable metals in copper smelting slag, which cannot meet the current requirements of low-carbon, high-efficiency, full-quality utilization and environmental protection in solid waste disposal. SUMMARY

[0007] The present application aims to solve the above-mentioned problems of the prior art, and the purpose is to provide a method for collaborative comprehensive recovery of copper and zinc smelting slag.

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: Applicants have found that the high-sulfur zinc residue produced by the oxygen pressure leaching zinc process can be directly used to treat hot copper smelting residue as a sulfidizing agent without additional addition of sulfidizing residue, slag forming agent and other raw materials, and can simultaneously achieve enrichment and recovery of Cu, Pb, Zn and Fe elements, thereby eliminating the processes of slow cooling and sorting of hot residue and secondary heating modification in the traditional process, solving the technical problems of high energy consumption and ineffective recovery of Pb and Zn in copper residue comprehensive recovery, and achieving high metal recovery rate and good metal separation effect, and the obtained products have relatively high grade, which is conducive to subsequent accurate separation and recovery of valuable metals, wherein the recovery rates of Fe, Cu and Pb are all above 95%, the comprehensive recovery rate of Fe can be as high as 98.5%, the comprehensive recovery rate of Cu can be as high as 98.9%, the comprehensive recovery rate of Pb can be as high as 99.3%, and the recovery rate of Zn is above 90%, for example, can be as high as 92.1%, and the heavy metal content in the final obtained residue is low, and the water-quenched harmless residue can be used as a building material raw material.

[0009] The application provides a method for cooperatively and comprehensively recovering copper and zinc smelting residues, comprising: adding raw materials of hot copper smelting residue and high-sulfur zinc residue into a smelting furnace, blowing oxygen-rich air and carbonaceous fuel into the furnace, and performing first smelting to generate first flue gas, sulfide melt and first smelting residue; most of Zn and a small part of Pb in the raw materials enter the first flue gas, most of Cu, most of Pb and part of Fe enter the sulfide melt, and most of Fe enters the first smelting residue; separating the sulfide melt and the first smelting residue, and adding a calcium-based solvent into the obtained first smelting residue as raw materials, and performing second smelting to generate molten iron, second smelting residue and second flue gas.

[0010] Further, the temperature of the hot copper smelting residue is 1200-1300℃.

[0011] Further, the hot copper smelting residue comprises Cu element 0.7-5.0%, Fe element 35-45%, Zn element 1.0-5.5% and Pb element 0.2-0.6% according to mass percentage.

[0012] Further, the temperature of the first smelting is 1300-1350℃.

[0013] Further, the duration of the first smelting is 2.5-3.5h.

[0014] Further, the smelting furnace of the first smelting is a side-blown smelting furnace.

[0015] Further, in the first smelting, the oxygen concentration in the oxygen-rich air is 60-90vol%.

[0016] Further, in the first smelting, the ratio of the volume of CO to the total volume of CO and CO2 in the first flue gas is 40-70%.

[0017] Further, in the first smelting, the carbonaceous fuel is pulverized coal; the amount of the carbonaceous fuel is 1-5% of the total mass of the hot-state copper smelting slag and the high-sulfur zinc slag.

[0018] Further, in the first smelting, the mass of the high-sulfur zinc slag is 10-30% of the mass of the hot-state copper slag.

[0019] Further, the high-sulfur zinc slag contains, in terms of mass percentage, 1.5-5.5% of Zn element, 2.5-6.5% of Pb element, 2.0-6.0% of Fe element, 0.2-0.6% of Cu element, and 50-80% of S element.

[0020] Further, the high-sulfur zinc slag has a water content of 15-18 wt%.

[0021] Further, in the first smelting slag, the content of Cu element is 0.1% or less, the content of Zn element is 0.4% or less, and the content of Pb element is 0.01% or less.

[0022] Further, in the second smelting slag, the content of Fe element is 1.2% or less, the content of Cu element is 0.095% or less, the content of Pb element is 0.01% or less, and the content of Zn element is 0.38% or less.

[0023] Further, the temperature of the second smelting is 1450-1550℃.

[0024] Further, the duration of the second smelting is 1.5-2h.

[0025] Further, the second smelting is side-blown reduction smelting, and the equipment for the second smelting is a side-blown reduction furnace.

[0026] Further, in the second smelting, the ratio of the volume of CO to the total volume of CO and CO2 in the second flue gas is controlled to be VCO / (VCO+VCO2)≥70%.

[0027] Further, the main component of the calcareous solvent is at least one of lime and limestone; and the amount of the calcareous solvent is determined according to the equivalent mass of CaO in the calcareous solvent, which is 25-30% of the mass of the first smelting slag.

[0028] Further, in the second smelting, oxygen-rich air and carbonaceous fuel are blown into the furnace.

[0029] Further, the carbonaceous fuel is pulverized coal; and the coal rate of the pulverized coal is 30-35%.

[0030] Further, the first flue gas is ignited by the upper secondary air port of the hearth to remove combustible gas, and then is cooled by the waste heat recovery system and sent to the dust collection device, and the dust after dust removal is sent to the secondary zinc oxide leaching system for treatment to separate Pb and Zn in oxygen.

[0031] Further, the sulfide melt is discharged from the discharge port of the furnace body, and the obtained ingot is sent to the copper smelting system after crushing.

[0032] Further, the second smelting slag is used as a building material raw material. Further, the mass content of Cu in the molten iron is below 0.2%.

[0033] Further, the second flue gas is ignited by the upper secondary air port of the hearth to remove combustible gas, and then is cooled by the waste heat recovery system and sent to the dust collection device, and the dust after dust removal is sent to the secondary zinc oxide leaching system for treatment to separate Pb and Zn in oxygen.

[0034] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: (1) The waste slag produced by copper smelting and zinc smelting is disposed cooperatively, the high-sulfur zinc slag can completely replace the primary mineral as a sulfidizing agent, waste is treated with waste, and part of the S combustion heat significantly reduces system fuel consumption, not only realizing low-carbon disposal of copper slag and significantly reducing energy consumption, but also without the need for additional sulfidizing agent and slagging agent.

[0035] (2) Compared with the copper slag slow cooling separation process currently widely used in large-scale industrial applications, the hot copper slag is directly smelted and stepwise extracted, and then water quenched, which can fully recover Cu, Pb, Zn and Fe elements in the slag without secondary heating modification, fully utilizes the physical heat of high-temperature molten slag, and effectively improves the energy utilization efficiency; and the Fe, Cu, Pb and Zn contents in the reduced slag are very low, which can be directly water quenched and solidified for treatment, so that it can be widely used in building material preparation.

[0036] (3) The process has high comprehensive recovery rate of Cu, Zn, Pb and Fe, and the recovery rate of Fe, Cu and Pb is above 95%, the comprehensive recovery rate of Fe can be as high as 98.5%, the comprehensive recovery rate of Cu can be as high as 98.9%, the comprehensive recovery rate of Pb can be as high as 99.3%, and the recovery rate of Zn is above 90%, and the heavy metal content in the obtained smelting slag is low, which can be used as a building material raw material. The process realizes full extraction of valuable metals and harmless disposal of tailings, without the risk of environmental pollution.

[0037] (4) The process has good separation effect of the recovered products, primary flue dust, lead matte and molten iron Pb, Zn, Cu and Fe, by optimizing part of the associated process parameters, the grade of each product is high, for example, the concentration of ZnO in the primary flue dust is high, the grade of copper sulfide in the lead matte is high and the total iron content is relatively low, the content of copper and other elements in the molten iron is low, which is conducive to reducing the difficulty of subsequent secondary separation and recovery of the above valuable metals, reducing energy consumption and reagent consumption, and simplifying the complexity of the subsequent separation process. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0039] Figure 1 The process flow diagram for the comprehensive recovery of copper and zinc smelting slag. DETAILED DESCRIPTION

[0040] In order to further improve the comprehensive recovery level of copper smelting slag and at the same time improve the utilization efficiency of heat in copper slag, the present application proposes a method for the comprehensive recovery of copper and zinc smelting slag, which uses high-sulfur zinc slag produced by the oxygen pressure leaching full-wet zinc smelting process as a sulfidizing agent for molten pool smelting and multi-phase separation. On the one hand, the slag contains 55-80% of sulfur, which is mainly combustible sulfur element and can be used as a sulfidizing agent and fuel, so it can achieve copper making and heat supplementing at the same time. On the other hand, the high-sulfur zinc slag itself is a kind of dangerous solid waste. The applicant found through research that the elements of Pb, Zn, Cu and Fe in the slag can also be deeply depleted during the cooperative smelting process, and finally a highly glassy CaO-SiO2 system water-quenched slag is produced, realizing full-quality utilization without the need for additional slag-making agents and sulfidizing agents. The present application proposes a technical scheme of hot copper slag + cold zinc slag cooperative copper making and smelting-heat slag smelting reduction for iron production, which produces secondary zinc oxide dust, matte, molten iron and water-quenched slag, realizes low-carbon and efficient recovery of main metal elements, and has important significance for improving the comprehensive recovery technical level of copper smelting enterprises.

[0041] Some embodiments of the present application provide a method for the comprehensive recovery of copper and zinc smelting slag, which comprises: Step (1), adding raw materials of hot copper smelting slag and high-sulfur zinc slag into a smelting furnace, blowing rich-oxygen air and carbonaceous fuel into the furnace, carrying out first smelting, and producing flue gas, copper matte at the lower part of the molten pool and first smelting slag at the upper part of the molten pool.

[0042] In this step, most of the zinc and a small amount of Pb in the raw material enter the flue gas, and secondary oxidation in the upper part of the hearth and the flue forms zinc suboxide dust, which is recovered by the dust collection system and then sent to the zinc suboxide wet leaching system for further separation of Pb and Zn; most of the Cu, most of the Pb and part of the Fe are reduced and sulfidized to form copper sulfide, which is deposited in the lower layer of the molten pool, and the high-valence iron oxides in the two kinds of slag are reduced to FeO, and most of the Fe and the original FeO, SiO2, CaO, etc. in the slag form the first smelting slag, which floats on the upper layer of the molten pool. During the feeding process, hot smelting slag is first added from the liquid feeding port of the side-blown smelting furnace, and then solid materials are added through the solid feeding port arranged on the top of the furnace. In this step, the pulverized coal mainly acts as a reducing agent, which adjusts the smelting atmosphere with oxygen-enriched air to provide a reducing atmosphere for the smelting process.

[0043] In some preferred embodiments, the temperature of the hot copper smelting slag is 1200-1300°C, such as 1200°C, 1250°C, 1300°C, etc.

[0044] In some preferred embodiments, the hot copper smelting slag comprises, in terms of mass percentage, 0.7-5.0% of Cu element, 35-45% of Fe element, 1.0-5.5% of Zn element and 0.2-0.6% of Pb element.

[0045] In some preferred embodiments, in step (1), the temperature of the first smelting is 1300-1350°C.

[0046] In some preferred embodiments, in step (1), the duration of the first smelting is 2.5-3.5h, such as 2.5h, 3h, 3.5h, etc.

[0047] In some preferred embodiments, in step (1), the first smelting is side-blown smelting, specifically, oxygen-enriched air and pulverized coal are blown in through side-blown lances.

[0048] In some preferred embodiments, in step (1), the smelting furnace for the first smelting is a side-blown smelting furnace.

[0049] In some preferred embodiments, in step (1), in the first smelting, the oxygen concentration in the oxygen-enriched air is 60-90vol%, such as 60vol%, 65vol%, 70vol%, 75vol%, 80vol%, 85vol%, 90vol%, etc.

[0050] In some preferred embodiments, in step (1), in the first smelting, the carbonaceous fuel includes but is not limited to pulverized coal; the coal rate of the pulverized coal is 1-5%, such as 1%, 2%, 3%, 4%, 5%, etc. Coal rate (%) = (added coal weight / total weight of treated smelting slag and high-sulfur zinc slag) × 100%.

[0051] In some preferred embodiments, in step (1), the ratio of the volume of CO to the total volume of CO and CO2 in the flue gas in the first smelting is 40-70%, such as 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc. The applicant has found through research that, by controlling the atmosphere, the selective reduction of Zn, Pb and Cu elements can be ensured, and Fe element mainly exists in the form of FeO and is not reduced to elemental metal.

[0052] In some preferred embodiments, the high-sulfur zinc slag contains, by mass percentage, 1.5-5.5% of Zn element, 2.5-6.5% of Pb element, 2.0-6.0% of Fe element, 0.2-0.6% of Cu element and 50-80% of S element.

[0053] More than 90% of the S element in the high-sulfur zinc slag is in the form of elemental combustible sulfur. The heat released by combustion keeps the temperature of the molten slag at 1300-1350°C, providing better thermodynamic conditions for the reduction and volatilization of Zn element.

[0054] In some preferred embodiments, the high-sulfur zinc slag has a water content of 15-18wt%. After the high-sulfur zinc slag is dewatered by pressure filtration, the water content is controlled to be 15-18wt%. If the water content of the slag is too high, it has two main hazards. On the one hand, water is converted into steam and absorbs a large amount of heat, increasing coal consumption. On the other hand, if the water content is too high, the flue gas entering the acid-making system is prone to cause corrosion of the equipment by dilute acid, increase the working load of the drying tower and disturb the water balance. Therefore, the water content needs to be strictly controlled.

[0055] After the first smelting reaction is performed for 2.5-3h, most of the Zn element in the molten slag is volatilized into zinc oxide dust, and most of the Cu and Pb elements are sulfurized with part of the Fe element to form copper matte. The high-valence iron oxide in the slag is reduced to FeO, forming a FeO-SiO2-CaO ternary system slag. Due to the relatively low Fe content in the high-sulfur zinc slag and the migration of part of the Fe element to the copper matte phase during the process, the iron-silicon ratio in the smelting slag is lower than that in the copper slag entering the furnace, but complete melting can be achieved due to the increase in temperature. After the flue gas is ignited at the secondary air port at the upper part of the hearth to remove the combustible gas, it is cooled by the waste heat recovery system and sent to the dust collection device. The purified flue gas can be used for acid making. The Zn element is enriched in the dust, which can be sent to the zinc oxide wet leaching system for further recovery.

[0056] In some preferred embodiments, in step (1), the mass of the high-sulfur zinc slag in the first smelting is 10-30% of the mass of the hot copper slag, such as 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, etc. If the proportion is too low, the heat is insufficient and the coal consumption increases. If the proportion is too high, the Fe element is easily sulfurized in large quantities, resulting in a decrease in the grade of the obtained copper matte.

[0057] In step (1), after the end of the matte smelting stage, the copper matte is discharged from a straight discharge port provided at the lower part of the end wall, and after the ingot is broken, it can be sent to the copper smelting system as raw material for copper smelting. The smelting slag is discharged from the slag port provided in the middle part of the end wall, and flows into the side-blown reduction furnace liquid feeding port through the chute.

[0058] In step (2), the copper and sulfur are separated, and the obtained first smelting slag is subjected to second smelting, in which lime is mixed in the first smelting slag, to produce molten iron and second smelting slag.

[0059] In this stage, the proportion of fuel blown by the side-blown lance is increased, and the second-stage smelting is performed in a strong reducing atmosphere. The smelting slag is discharged from the slag port in the middle part of the end wall of the side-blown smelting furnace, flows into the liquid feeding port of the side-blown reduction furnace through the chute, and the calcareous flux (lime flux) is added from the solid feeding port at the top of the furnace to form slag, the effective component of the calcareous flux being CaO, and other common substitutes being limestone, the effective component of which being CaCO3. Oxygen-enriched air and pulverized coal are blown into the slag layer from the side-blown lance. After the iron oxides in the slag are deeply reduced, molten iron is produced and settled at the bottom of the hearth, and is discharged from the siphon port. The ingot is sold as a product. The upper smelting slag is converted from the FeO-SiO2-CaO ternary system to the CaO-SiO2 system, that is, the residence time of the melt flowing from the liquid feeding port to the slag port is controlled, and the reduction endpoint can be judged by testing the iron content of the reduced slag. The reduced slag is discharged from the slag port provided in the other end wall, and is simultaneously water-quenched and granulated to form water-quenched slag, which can be sold as a high-quality raw material for building materials. After the combustible gas is removed by igniting the flue gas through the secondary air port at the upper part of the hearth, the flue gas is cooled by the waste heat recovery system and sent to the dust collection device.

[0060] In some preferred embodiments, in step (2), the temperature of the second smelting is 1450-1550°C, for example, 1450°C, 1500°C, 1550°C, etc. The optimized second smelting ensures that the smelting slag after Fe element removal is fully molten and rapidly separated from the generated metal droplets.

[0061] In some preferred embodiments, in step (2), the duration of the second smelting is 1.5-2h.

[0062] In some preferred embodiments, in step (2), the second smelting is side-blown reduction smelting, and the equipment for the second smelting is a side-blown reduction furnace.

[0063] In some preferred embodiments, in step (2), during the second smelting, the VCO / (VCO+VCO2) in the flue gas is controlled to be ≥70%, preferably 70-90%, for example, 70%, 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, etc.

[0064] In some preferred embodiments, in step (2), the amount of lime added is 25-30% of the mass of the first smelting slag. The main role of adding lime is to adjust the slag structure after the Fe element is largely removed from the original slag, to reduce the melting temperature of the slag, and to maintain a certain fluidity.

[0065] In some preferred embodiments, in step (2), during the second smelting, oxygen-enriched air and pulverized coal are blown into the furnace. The molar ratio of oxygen to carbon is ≤0.65.

[0066] In some preferred embodiments, in step (2), the coal rate of the pulverized coal is 30-35%. The partial combustion of the pulverized coal releases heat to maintain the temperature of the molten slag at 1450-1550°C, ensuring that the molten slag after the removal of the Fe element is fully molten and rapidly separates from the generated metal droplets.

[0067] In order to facilitate the understanding of the present application, the following will combine the description of the drawings and the preferred embodiments to make a more comprehensive and detailed description of the present application, but the protection scope of the present application is not limited to the following specific embodiments.

[0068] Unless otherwise defined, all the professional terms used in the following have the same meaning as generally understood by those skilled in the art. The professional terms used in this paper are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0069] Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0070] The oxygen-enriched side-blown smelting furnace used in each embodiment of the present application is a conventional side-blown smelting furnace in the art, the furnace body is of rectangular structure, the upper part of the end wall is provided with a liquid charging port for adding molten copper slag, the top is provided with a solid charging port and a flue, the solid charging port is used to add high-sulfur zinc slag, etc., the rear end of the flue is connected to a flue gas treatment system for waste heat recovery and dust capture, and the purified flue gas enters an acid making system. Since smelting slag and copper matte are produced during the process of copper matte making and smelting, there are two layers of melt in the hearth, and a plurality of submerged side-blown lances arranged at the slag layer position on the side wall of the furnace chamber are used to ensure the full agitation and heating of the molten slag. The lances are of concentric sleeve structure, the inner layer can blow in pulverized fuel, and the outer layer can blow in oxygen-enriched air with different concentrations, to ensure that the oxygen-enriched air, pulverized coal and molten slag are fully mixed. A secondary air port is arranged at the upper part of the side wall of the furnace chamber for igniting combustible components such as CO in the flue gas. A slag port and a matte port are arranged in the middle and lower part of the other end wall, respectively, for normal slag and matte discharge, and the matte port is connected to a ingot casting disc through a chute, and the slag port is connected to the liquid charging port of the side-blown reduction furnace through a chute.

[0071] The side-blown reduction furnace used in the embodiment of the present application is a conventional side-blown reducing agent in the field, the body is of a rectangular structure, a liquid feeding port is arranged at the upper part of one side end wall for adding liquid smelting slag, a solid feeding port and a flue are arranged at the top, the feeding port is used for adding flux, block fuel and the like, the rear end of the flue is connected with a flue gas treatment system to perform waste heat recovery and dust capture, a plurality of submerged side-blown lances are arranged at the middle part of the side wall of the hearth, the lances are made of a plurality of concentric sleeves and can simultaneously blow in oxygen-enriched air and powdered fuel, a secondary air port is arranged at the upper part of the side wall of the hearth for igniting combustible components such as CO in the flue gas, a slag outlet and a metal siphon are arranged at the other side end wall of the furnace body, the slag outlet is connected with a water quenching granulation device, and the siphon is connected with a ingot casting disc through a chute.

[0072] Comparative Example 1 The copper smelting slag is slowly cooled and separated, that is, the smelting slag is first slowly cooled, crushed and ground to an average particle size of less than 75 μm, and then subjected to beneficiation, the obtained primary tailings are further ground to an average particle size of less than 45 μm, and then subjected to beneficiation again, the copper content in the secondary tailings is reduced to less than 0.2%, the beneficiation is performed by flotation, and copper is recovered by flotation; the tailings are added into a molten reduction device (which can be an electric resistance furnace, an induction furnace or a smelting furnace) for secondary melting, and iron is extracted by reduction at 1500°C, the consumption of anthracite for treating each ton of slag is 150 kg higher than that in the embodiment, and the product is a copper-containing pig iron with a Cu content of 2% in the molten iron, which does not meet the requirements of general steelmaking pig iron and needs to be further de-coppered and refined.

[0073] Example 1 The method for cooperatively and comprehensively recovering copper and zinc smelting slag comprises the following steps: 1) First, hot copper smelting slag is added from a liquid feeding port arranged at the end wall of the oxygen-enriched side-blown smelting furnace, high-sulfur zinc slag after pressure filtration dehydration is added into the furnace from a solid feeding port arranged at the top of the furnace, oxygen-enriched air and powdered coal fuel are blown into the furnace from the side-blown lances to perform first-stage reduction and smelting, the reducing atmosphere is controlled in this stage, most of the Cu elements and part of the Pb and Fe elements are reduced and sulfidized to form copper matte phase and sink in the lower layer of the smelting pool, the high-valence iron oxides in the two kinds of slag are reduced to FeO and the original FeO, SiO2, CaO and the like to form slag and float in the upper layer of the smelting pool. Most of the Zn elements and a small part of the Pb elements are reduced and volatilized into the flue gas, and are secondarily oxidized in the upper part of the hearth and the flue to form zinc suboxide dust, which is recovered by the dust collection system and then sent to a zinc suboxide wet leaching system for further separation of Pb and Zn therein.

[0074] 2) After the end of the matte smelting stage, the copper matte is discharged from the straight outlet arranged at the lower part of the end wall, and after the ingot is broken, it can be sent to the copper smelting system as raw material for copper smelting. The smelting slag is discharged from the slag port arranged in the middle part of the end wall, flows into the side-blown reduction furnace liquid feeding port through the chute, the proportion of fuel blown by the side-blown lance is increased in this stage, and the second stage smelting is carried out in a strong reducing atmosphere, and at the same time, the calcium flux is added from the solid feeding port at the top of the furnace to form slag. After the iron oxide in the slag is deeply reduced, molten iron is generated and settled at the bottom of the hearth, and is discharged from the siphon port, and the ingot is sold as a product. The upper slag is transformed from the FeO-SiO2-CaO ternary system into the CaO-SiO2 system, and is discharged from the slag port arranged at the other side end wall, and is simultaneously water quenched and granulated, and the water quenched slag formed can be sold as a building material raw material.

[0075] In the step 1), firstly, hot copper smelting slag is added from the liquid charging port of the side-blown smelting furnace, with a slag temperature of 1250-1300 DEG C, and the slag containing Cu 0.7-5.0%, Fe 35-45%, Zn 1.0-5.5%, and Pb 0.2-0.6%. After the high-sulfur zinc slag is dewatered by pressure filtration, the water content is controlled to 15-18%, and the slag contains Zn 1.5-5.5%, Pb 2.5-6.5%, Fe 2.0-6.0%, Cu 0.2-0.6%, and S 50-80%. The high-sulfur zinc slag is fed into the furnace through the solid charging port arranged at the top of the furnace, and the mass ratio of the high-sulfur zinc slag to the hot copper slag is kept at 10-30%. If the ratio is too low, the heat is insufficient, and the coal consumption increases. If the ratio is too high, the Fe element is largely sulfidized, resulting in a decrease in the matte grade. Oxygen-rich air and pulverized coal are blown from the side-blown lance. The oxygen concentration can be adjusted between 60-90%, and the pulverized coal is mainly used as a reducing agent to provide a reducing atmosphere for the smelting process. The coal rate is controlled at 1-5%, and the CO / (CO+CO2) ratio in the flue gas is kept at 40-70%. Under this atmosphere, the selective reduction of Zn, Pb and Cu elements can be ensured, and the Fe element exists in the form of FeO and is not reduced to elemental metal. More than 90% of the S element in the high-sulfur zinc slag is in the form of elemental combustible sulfur. The combustion releases heat to keep the molten slag temperature at 1300-1350 DEG C, providing better thermodynamic conditions for the volatilization of Zn element. After the smelting reaction is performed for 2.5-3h, most of the Zn element in the molten slag is volatilized into zinc dross, and most of the Cu and Pb elements are sulfidized with part of the Fe element to form matte. The high-valence iron oxide in the slag is reduced to FeO, forming a primary smelting slag of the FeO-SiO2-CaO ternary system. The content of Cu in the first smelting slag is less than 0.1%, the content of Zn is less than 0.4%, and the content of Pb is less than 0.01%. Due to the relatively low Fe content in the high-sulfur zinc slag and the migration of part of the Fe element to the matte during the copper-making process, the iron-silicon ratio in the smelting slag is reduced compared with that in the copper slag fed into the furnace, but the temperature is increased, so that complete melting can be achieved. After the flue gas is ignited through the secondary air port at the upper part of the hearth to remove combustible gases, the flue gas is cooled by the waste heat recovery system and sent to the dust collection device. The purified flue gas can be used for acid production. The Zn element is enriched in the dust, which can be sent to the zinc dioxides leaching system for further recovery.

[0076] In the step 2), the once-smelted slag is discharged from the slag port in the middle of the end wall of the side-blown smelting furnace, and flows into the liquid feeding port of the side-blown reduction furnace through a chute. In this stage, a strong reducing atmosphere is formed, and the CO / (CO+CO2) is adjusted to be greater than 70% by controlling the oxygen / coal ratio, and the molar ratio of oxygen to carbon is less than 0.65. At this time, the second-stage smelting is performed. Meanwhile, lime flux is added through the solid feeding port in the upper part of the furnace, and the effective component of the lime flux is CaO. Other common substitutes are limestone, and the effective component of the limestone is CaCO3. The amount of the lime added accounts for 25-30% of the amount of the treated slag, so as to ensure that the binary basicity of the reduced slag is between 1.0 and 1.2. Oxygen-enriched air and pulverized coal are blown into the slag layer from the side-blown lance, and the coal rate is 30-35%. The partial combustion of the pulverized coal releases heat, so as to keep the temperature of the molten slag at 1450-1550 DEG C, and to ensure that the molten slag after the removal of Fe element is fully molten and quickly separated from the generated metal liquid drops. The molten iron generated after the deep reduction of the iron oxides in the slag sinks to the bottom of the hearth, and is discharged from the siphon port to be sold as ingots. The upper molten slag is gradually changed from the first smelted slag of the FeO-SiO2-CaO system to the second smelted slag of the CaO-SiO2 system. The content of Fe element in the second smelted slag is less than 1.2%, the content of Cu element is less than 0.095%, the content of Pb element is less than 0.01%, and the content of Zn element is less than 0.38%. The reduction time is 1.5-2h, that is, the residence time of the molten slag flowing from the liquid feeding port to the slag port is controlled. The reduction endpoint can be judged by testing the iron content in the reduced slag. The reduced slag is discharged from the slag port, and can be used as a high-quality raw material for building materials after water quenching and cooling. After the combustible gas is removed by igniting the flue gas through the secondary air port in the upper part of the hearth, the flue gas is cooled by the waste heat recovery system, and is sent into the dust collection device.

[0077] Example 2 (1) The hot copper smelted slag contains Cu 1.5%, Fe 42%, Zn 3.5%, and Pb 0.5%, and the slag temperature is 1250 DEG C. The high-sulfur zinc slag contains water 15%, Zn 2.4%, Pb 2.6%, Fe 5.6%, Cu 0.2%, and S 62%. The high-sulfur zinc slag is 30% of the mass of the hot copper slag, and is added into the furnace body from the liquid feeding port of the side-blown smelting furnace. Oxygen-enriched air and pulverized coal fuel are blown into the furnace from the side-blown lance, the oxygen-enriched concentration is 80% (that is, the oxygen concentration in the oxygen-enriched air is 80%), the coal rate is 1.2%, the CO / (CO+CO2) in the flue gas is 40%, the smelting temperature is 1350 DEG C, and the smelting time is 3h.

[0078] The Zn element in the raw material slag is mostly reduced and volatilized to form a zinc suboxide dust containing 53.5% of ZnO and 6.9% of PbO; the Cu and Pb elements are mostly sulfidized with part of the Fe element to form lead matte containing 9.87% of Cu2S, 5.0% of PbS, 300 g / t of Ag and 49.3% of Fe; the obtained primary smelting slag is a ternary system slag of FeO-SiO2-CaO, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.1%, 0.4% and 0.01% respectively. After the end of the copper-making smelting stage, the lead matte is discharged from a straight discharge port arranged at the lower part of the end wall, and after the cast ingot is broken, it can be sent to the copper smelting system as raw material for copper smelting. The smelting slag is discharged from a slag port arranged at the middle part of the end wall and flows into the liquid feeding port of the side-blown reduction furnace through a chute.

[0079] (2) The two-stage reduction smelting process is carried out in the side-blown reduction furnace, the side-blown lance blows oxygen-enriched air and pulverized coal into the side-blown reduction furnace, the proportion of the pulverized coal is increased, the CO / (CO+CO2) is controlled to be 70%, the lime addition amount accounts for 25% of the amount of the treated slag (the primary smelting slag), the lime is added for slagging through the solid feeding port at the top of the furnace, the basicity of the reduction slag is 1.05, the coal rate is 31.8%, the smelting temperature is 1500°C, the reduction time is 1.5h, the output molten iron contains 0.2% of Cu, and the contents of Cu, Zn, Pb and Fe in the obtained secondary smelting slag are 0.09%, 0.32%, 0.009% and 1.05% respectively. After the iron oxides in the slag are deeply reduced, the molten iron is generated and settled at the bottom of the hearth and is discharged from the siphon port, and the cast ingot is sold as a product; the reduction slag is discharged from the slag port arranged at one side of the end wall and is simultaneously water quenched and granulated to form water quenched slag, the water quenched slag is quenched to form almost 100% of glass phase, has a significant solidification effect on heavy metal ions, and the leaching toxicity can meet the requirements of a general solid waste of the first class, and is sold as a high-quality raw material for building materials. After the flue gas is ignited through the secondary air port at the upper part of the hearth to remove combustible gases, the flue gas is cooled through the waste heat recovery system and is sent into the dust collection device.

[0080] The comprehensive recovery rates of the Fe, Cu, Pb and Zn elements are 98.5%, 98.9%, 99.3% and 92.1% respectively, the energy consumption of the comprehensive recovery of copper and iron is reduced by 30% compared with the secondary heating iron extraction process after the copper slag is slowly cooled, and the comprehensive recovery of Pb and Zn is simultaneously realized.

[0081] Example 3 (1) The hot copper smelting slag contains Cu 4.5%, Fe 35%, Zn 5.5%, Pb 0.5%, and the slag temperature is 1250℃. The high-sulfur zinc slag contains water 15%, and the slag contains Zn 2.4%, Pb 2.6%, Fe 5.6%, Cu 0.2%, and S 62%. The high-sulfur zinc slag is 10% of the mass of the hot copper slag, the hot copper smelting slag is added into the furnace body from the liquid feeding port of the side-blown smelting furnace, the high-sulfur zinc slag is added into the furnace from the solid feeding port at the top of the furnace, the oxygen-enriched air and the pulverized coal fuel are blown into the furnace from the side-blown lance, the oxygen-enriched concentration is 80% (i.e. the oxygen concentration in the oxygen-enriched air is 80%), the coal rate is 3.5%, the CO / (CO+CO2) in the flue gas is maintained at 55%, the smelting temperature is 1300℃, and the smelting time is 3.5h.

[0082] Most of the Zn element in the raw material molten slag is reduced and volatilized to form zinc suboxide dust containing ZnO 53.45% and PbO 6.89%; most of the Cu and Pb elements are sulfidized with part of the Fe element to form lead matte, and the lead matte contains Cu2S 12.3%, PbS 5.0%, Ag 310g / t, and Fe 45.2; the obtained primary smelting slag is a FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn, and Pb in the slag can be reduced to 0.097%, 0.38%, and 0.0095% respectively. After the end of the copper-making smelting stage, the lead matte is discharged from the straight discharge port arranged at the lower part of the end wall, and after the cast ingot is broken, it can be sent to the copper smelting system as the raw material for copper smelting. The smelting slag is discharged from the slag port arranged in the middle part of the end wall and flows into the liquid feeding port of the side-blown reduction furnace through the chute.

[0083] (2) The secondary reduction smelting process is carried out in the side-blown reduction furnace, the oxygen-enriched air and the pulverized coal are blown into the side-blown reduction furnace from the side-blown lance, the proportion of the pulverized coal is increased, the CO / (CO+CO2) is controlled at 70%, the lime addition amount accounts for 25% of the amount of the treated slag (the primary smelting slag), the lime is added for slagging from the solid feeding port at the top of the furnace, the reduction slag has a binary basicity of 1.05, the coal rate is 31.8%, the smelting temperature is 1500℃, the reduction time is 1.5h, the molten iron contains Cu 0.12%, and the contents of Cu, Zn, Pb, and Fe in the obtained secondary smelting slag are 0.092%, 0.35%, 0.0091%, and 1.1% respectively. After the iron oxides in the slag are deeply reduced, the molten iron is generated and settled at the bottom of the hearth, is discharged from the siphon port, and the cast ingot is sold as a product; the reduction slag is discharged from the slag port arranged at one side of the end wall and is simultaneously water-quenched and granulated to form water-quenched slag which can be sold as a high-quality raw material for building materials. After the flue gas is ignited through the secondary air port at the upper part of the hearth to remove the combustible gas, the flue gas is cooled through the waste heat recovery system and is sent into the dust collection device.

[0084] The comprehensive recovery rates of Fe, Cu, Pb and Zn elements are 98.8%, 99.0%, 99.5% and 91.8% respectively, the comprehensive recovery energy consumption of copper and iron is reduced by 30% compared with the copper slag slow cooling and secondary heating iron extraction process, and the comprehensive recovery of Pb and Zn is realized at the same time.

[0085] Example 4 (1) The hot copper smelting slag contains Cu 1.5%, Fe 42%, Zn 3.5%, Pb 0.5%, and the slag temperature is 1250°C. The high-sulfur zinc slag contains water content 15%, Zn 2.4%, Pb 2.6%, Fe 5.6%, Cu 0.2%, and S 62%. The high-sulfur zinc slag is 20% of the mass of the hot copper slag, and the hot copper smelting slag is added into the furnace body through the liquid feeding port of the side-blown smelting furnace, the high-sulfur zinc slag is added into the furnace through the solid feeding port at the top of the furnace, the oxygen-enriched air and pulverized coal fuel are blown into the furnace through the side-blown lance, the oxygen-enriched concentration is 80% (i.e. the oxygen concentration in the oxygen-enriched air is 80%), the coal rate is 4.5%, the CO / (CO+CO2) in the flue gas is maintained at 70%, the smelting temperature is 1325°C, and the smelting time is 2.5h.

[0086] Most of the Zn element in the raw material molten slag is reduced and volatilized to form zinc suboxide dust containing ZnO 50.2% and PbO 7.5%; most of the Cu and Pb elements are sulfidized with part of the Fe element to form lead matte containing Cu2S 9.5%, PbS 4.8%, Ag 290g / t and Fe 45.6%; the obtained primary smelting slag is a FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.094%, 0.35% and 0.0087% respectively. After the end of the copper matte smelting stage, the lead matte is discharged through the straight discharge port arranged at the lower part of the end wall, and after the ingot is broken, it can be sent to the copper smelting system as the raw material for copper smelting. The smelting slag is discharged through the slag port arranged in the middle part of the end wall and flows into the liquid feeding port of the side-blown reduction furnace through the chute.

[0087] (2) The two-stage reduction smelting process is carried out in the side-blown reduction furnace, the side-blown lance blows oxygen-enriched air and pulverized coal into the side-blown reduction furnace, the proportion of the pulverized coal is increased, the CO / (CO+CO2) is controlled to be 70%, the lime addition amount accounts for 25% of the amount of the treated slag (the first smelting slag), the lime is added into the side-blown reduction furnace through the solid feeding port at the top of the furnace to form slag, the binary basicity of the reduction slag is 1.05, the coal rate is 31.8%, the smelting temperature is 1500 DEG C, the reduction time is 1.5 h, the molten iron obtained contains 0.16% of Cu, the contents of Cu, Zn, Pb and Fe in the secondary smelting slag are 0.085%, 0.36%, 0.0097% and 1.05% respectively. After the iron oxides in the slag are deeply reduced, the molten iron is generated and settled at the bottom of the hearth, is discharged through the siphon port and is cast into ingots as products for sale; the reduction slag is discharged through the slag port arranged at one side of the end wall and is granulated by water quenching to form water-quenched slag which can be used as high-quality raw material for building materials for sale. After the combustible gas is removed through the secondary air port at the upper part of the hearth, the flue gas is cooled through the waste heat recovery system and is sent into the dust collection device.

[0088] The comprehensive recovery rates of Fe, Cu, Pb and Zn elements are 98.5%, 98.9%, 99.3% and 92.1% respectively, the energy consumption of the copper-iron comprehensive recovery is reduced by 30% compared with the secondary heating iron extraction process after the copper slag is slowly cooled, and the comprehensive recovery of Pb and Zn is realized simultaneously.

[0089] Comparative Example 2 The difference between the present comparative example and Example 2 is that, in step (1), the process parameters are different, specifically, the high-sulfur zinc slag accounts for 8% of the mass of the hot copper slag, the coal rate is 6.3%, the amount of the oxygen-enriched air is adjusted to keep the CO / (CO+CO2) in the flue gas to be 40%, the smelting temperature is 1350 DEG C and the smelting time is 3 h.

[0090] In step (1), the secondary zinc oxide dust containing 48.5% of ZnO and 5.8% of PbO is obtained, and the lead matte containing 11.2% of Cu2S, 3.5% of PbS, 280 g / t of Ag and 49.1% of Fe is obtained, the first smelting slag is the FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.18%, 0.25% and 0.015% respectively.

[0091] In step (2), the molten iron contains 0.25% of Cu, and the contents of Zn, Pb, Cu and Fe in the secondary smelting slag are 0.46%, 0.013%, 0.024% and 0.974% respectively. The comprehensive recovery rates of Fe, Cu, Pb and Zn elements are 96.8%, 94.2%, 96.1% and 92.8% respectively, and the energy consumption of the copper-iron comprehensive recovery is reduced by 22% compared with the secondary heating iron extraction process after the copper slag is slowly cooled.

[0092] The energy saving effect is poor in the comparative example, and because the amount of flue gas increases and the contents of Zn and Pb in the raw material decrease, the contents of ZnO and PbO in the smoke dust decrease; the amount of lead matte significantly decreases, the grade of Cu in the obtained lead matte increases, but more iron enters the slag, resulting in an increase in the amount of slag, and the Cu and Pb entering the slag increase, and the comprehensive recovery rate of Cu, Pb and Fe decreases due to the increase in the amount of slag, and the contents of Cu and Pb in the molten iron increase, resulting in a decrease in the grade of the molten iron.

[0093] Comparative Example 3 The difference between the present comparative example and Example 2 is only that in step (1), the process parameters are different, specifically, the high-sulfur zinc slag is 35.8% of the mass of the hot copper slag, the smelting temperature is 1400°C, and the other process parameters remain unchanged.

[0094] In step (1), the secondary zinc oxide dust containing ZnO 54.0% and PbO 7.2% is obtained, and the lead matte containing Cu2S 8.1%, PbS 5.3%, Ag 320 g / t and Fe 53.0% is obtained, and the obtained primary smelting slag is FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.095%, 0.38% and 0.009% respectively.

[0095] In step (2), the molten iron obtained contains Cu 0.18%, and the contents of Zn, Pb, Fe and Cu in the secondary smelting slag obtained are 0.34%, 0.009%, 1.08% and 0.05% respectively. The comprehensive recovery rates of Fe, Cu, Pb and Zn elements in the present method are 98.2%, 98.6%, 99.0% and 93.6% respectively, and the energy consumption of copper-iron comprehensive recovery is reduced by 28% compared with the copper slag slow cooling and secondary heating iron extraction process.

[0096] The increase in the content of iron in the matte reduces the grade of the matte and increases the cost of the subsequent lead matte treatment process; at the same time, the increase in the temperature increases the contents of Zn and Pb entering the smoke dust, resulting in the volatilization of metal sulfides, which not only increases the amount of secondary zinc oxide dust treatment process slag, but also further reduces the metal separation effect of the next step of smoke dust, resulting in an increase in the difficulty of subsequent metal separation and recovery.

[0097] Comparative Example 4 The difference between the present comparative example and Example 2 is only that in step (1), the high-sulfur zinc slag is 20% of the mass of the hot copper slag, and the smelting temperature is maintained at 1250°C and the smelting time is 4h.

[0098] In step (1), the secondary zinc oxide dust containing ZnO 45.2%, PbO 5.0% is obtained, and the lead matte containing Cu2S 10.12%, PbS 4.2%, Ag 270 g / t, Fe 44.5% is obtained, and the primary smelting slag is FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.13%, 0.60% and 0.012% respectively.

[0099] In step (2), the obtained molten iron contains Cu 0.22%, and the contents of Zn, Pb, Fe and Cu in the secondary smelting slag are 0.48%, 0.011%, 1.40% and 0.08% respectively. The comprehensive recovery rates of Fe, Cu, Pb and Zn elements in the method are 96.5%, 97.0%, 97.8% and 88.0% respectively, and the energy consumption of copper-iron comprehensive recovery is reduced by 20% compared with the secondary heating iron extraction process after the copper slag slow cooling.

[0100] The reduction of smelting temperature will cause the reduction effect of zinc to be poor, the zinc content in the secondary zinc oxide to be reduced, and the economic efficiency of the subsequent processing process of the secondary zinc oxide to be reduced; the yield of the lead matte is reduced, the Pb and Fe grades in the matte are reduced, the amount of the primary smelting slag is increased, the contents of Zn, Fe and Cu in the slag are increased, the contents of Cu, Zn and Pb in the primary smelting slag are increased, the contents of Cu, Pb and Zn in the obtained molten iron are increased after the secondary reduction smelting, and the metal content in the secondary smelting slag is increased due to the increase of the slag amount, thereby reducing the comprehensive recovery rate of each element.

[0101] Comparative Example 5 The difference between the present comparative example and Example 2 is that in step (1), the CO / (CO+CO2) in the flue gas is controlled to be 35% by adjusting the rich oxygen air.

[0102] In step (1), the secondary zinc oxide dust containing ZnO 46.8%, PbO 5.5% is obtained, and the lead matte containing Cu2S 10.2%, PbS 3.8%, Ag 320 g / t, Fe 47.2% is obtained, and the primary smelting slag is FeO-SiO2-CaO ternary system slag, and the contents of Cu, Zn and Pb in the slag can be reduced to 0.14%, 0.58% and 0.014% respectively.

[0103] In step (2), the obtained molten iron contains Cu 0.24%, and the contents of Zn, Pb, Fe and Cu in the secondary smelting slag are 0.45%, 0.012%, 1.38% and 0.11% respectively. The comprehensive recovery rates of Fe, Cu, Pb and Zn elements in the method are 96.2%, 96.8%, 97.5% and 87.2% respectively, and the energy consumption of copper-iron comprehensive recovery is reduced by 27% compared with the secondary heating iron extraction process after the copper slag slow cooling.

[0104] The volatilization effect of zinc and lead oxides is poor with the decrease of CO partial pressure, and the content of Zn and Pb in the fume is reduced; the total amount of lead matte is reduced, and the grade of Cu in the lead matte is increased, the content of Pb and Fe is reduced, the primary smelting slag is increased, the content of Cu, Zn and Pb in the primary smelting slag is increased, and the content of iron, copper, lead and zinc in the tail slag is also increased, and the content of Cu, Pb and Zn in the molten iron is increased.

[0105] Comparative Example 6 The difference between the present comparative example and Example 2 is that in step (1), the CO / (CO+CO2) in the flue gas is controlled to be 75% by adjusting the oxygen-enriched air.

[0106] In step (1), the secondary zinc oxide dust containing 54.5% of ZnO and 7.4% of PbO is obtained, and the lead matte containing 8.5% of Cu2S, 4.7% of PbS, 340 g / t of Ag and 57.5% of Fe is obtained, and the primary smelting slag is FeO-SiO2-CaO ternary system slag, and the content of Cu, Zn and Pb in the slag can be reduced to 0.090%, 0.34% and 0.009% respectively.

[0107] In step (2), the molten iron obtained contains 0.17% of Cu, and the content of Zn, Pb, Fe and Cu in the secondary smelting slag is 0.32%, 0.0085%, 1.05% and 0.06% respectively. The comprehensive recovery rate of Fe, Cu, Pb and Zn elements in the present method is 98.3%, 98.7%, 99.5% and 94.8% respectively, and the energy consumption of copper-iron comprehensive recovery is reduced by 23% compared with the copper slag slow cooling and secondary heating iron extraction process.

[0108] The concentration of ZnO and PbO in the secondary zinc oxide dust is increased, the content of Fe in the lead matte is increased, and part of the reduced iron reduces the copper element in the slag interface to form elemental copper, and then forms iron-copper alloy, which suppresses the sulfidation path of copper, so that pure Cu2S phase is difficult to form, and a mixture of metal iron alloy phase (containing Fe, Cu, Pb, etc.) and a small amount of sulfide phase is formed, the content of Cu2S and PbS in the original lead matte is reduced, the content of Fe is changed in form due to the generation of metal iron, which leads to the decrease of the quality of lead matte and the significant increase of the subsequent recovery difficulty.

[0109] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A method for synergistic comprehensive recovery of copper and zinc smelting slag, characterized in that, The application relates to a method for producing molten iron and molten zinc from hot copper smelting slag and high-sulfur zinc slag. The method comprises the following steps: adding the raw material hot copper smelting slag and the high-sulfur zinc slag into a smelting furnace, blowing oxygen-rich air and carbonaceous fuel into the furnace, and performing first smelting to generate first flue gas, sulfide melt and first smelting slag; Separating the sulfide melt and the first smelting slag, taking the obtained first smelting slag as raw material, adding calcium flux, and performing second smelting to generate molten iron, second smelting slag and second flue gas.

2. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The temperature of the hot copper smelting slag is 1200-1300 DEG C. The hot copper smelting slag comprises 0.7-5.0% of Cu element, 35-45% of Fe element, 1.0-5.5% of Zn element and 0.2-0.6% of Pb element according to mass percentage.

3. The method for comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The temperature of the first smelting is 1300-1350 DEG C. The first smelting lasts for 2.5-3.5 hours. The smelting furnace of the first smelting is a side-blown smelting furnace.

4. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The oxygen concentration in the oxygen-rich air in the first smelting is 60-90 vol%. The ratio of the CO volume to the total volume of CO and CO2 in the first smelting is 40-70%. The carbonaceous fuel in the first smelting is pulverized coal; the mass of the carbonaceous fuel is 1-5% of the total mass of the raw material hot copper smelting slag and the high-sulfur zinc slag. The mass of the high-sulfur zinc slag in the first smelting is 10-30% of the mass of the hot copper slag.

5. The method for comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The high-sulfur zinc slag comprises 1.5-5.5% of Zn element, 2.5-6.5% of Pb element, 2.0-6.0% of Fe element, 0.2-0.6% of Cu element and 50-80% of S element according to mass percentage. The water content of the high-sulfur zinc slag is 15-18 wt%. The content of Cu element in the first smelting slag is below 0.1%, the content of Zn element is below 0.4% and the content of Pb element is below 0.01%. The content of Fe element in the second smelting slag is below 1.2%, the content of Cu element is below 0.095%, the content of Pb element is below 0.01% and the content of Zn element is below 0.38%.

6. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The temperature of the second smelting is 1450-1550 DEG C. The second smelting lasts for 1.5-2 hours. The second smelting is side-blown reduction smelting. The equipment of the second smelting is a side-blown reduction furnace. The ratio of the CO volume to the total volume of CO and CO2 in the second smelting is controlled to be greater than or equal to 70%.

7. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, The main component of the calcium flux is at least one of lime and limestone; the equivalent mass of the calcium flux is determined according to the CaO content in the calcium flux and is 25-30% of the mass of the first smelting slag.

8. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, Oxygen-rich air and carbonaceous fuel are blown into the furnace from the side in the second smelting. The carbonaceous fuel is pulverized coal; the coal rate of the pulverized coal is 30-35%.

9. The method for synergic comprehensive recovery of copper and zinc smelting slag according to claim 1, characterized in that, After the first flue gas is ignited by a secondary air inlet point at the upper part of the hearth to remove combustible gas, the first flue gas is cooled by a waste heat recovery system and is sent into a dust collecting device; the flue gas after dust removal is used for acid production; the obtained dust is sent to a secondary zinc oxide leaching system for treatment to separate Pb and Zn in oxygen. The sulfide melt is discharged from a discharge port of the furnace body, and the obtained ingot is sent to a copper smelting system after crushing. The second smelting slag is used as a building material raw material; The mass content of Cu in the molten iron is below 0.2%; The second flue gas is ignited after combustible gas is removed through a secondary sealing point at the upper part of the hearth, cooled through a waste heat recovery system, and then sent to a dust collecting device. The gas after dust collection is purified and then exhausted.

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