Method and device for synchronously recovering lead and zinc from lead-zinc oxide

Abstract

The invention provides a method and device for synchronously recovering lead and zinc from lead-zinc oxide, and belongs to the field of metal production or refining, and the method comprises the following steps: providing a lead-zinc oxide powdery material; the lead-zinc oxide powdery material is fed into a reaction zone in a flash smelting furnace, CO plasma jet is applied to the lead-zinc oxide powdery material in the falling process of the lead-zinc oxide powdery material, and lead-zinc steam and lead-containing molten slag are obtained; obtaining a crude lead-zinc alloy; and the lead-containing molten slag falling into a molten pool area in the flash smelting furnace is smelted in the molten pool area in the flash smelting furnace, and liquid lead is obtained. According to the method, the lead-zinc oxide is treated through a flash smelting furnace smelting treatment + CO plasma jet technology, and efficient and synchronous recovery of lead and zinc in the lead-zinc oxide is achieved; wherein the lead recovery rate is gt; 96%; the zinc recovery rate is gt; 94%. And the method has the characteristics of short process flow, short time required by the whole process, cleanness and low consumption. The corresponding device is simple in structure, easy and convenient to operate and wide in application range.

Description

Technical Field

[0001] The present invention belongs to the field of metal production or refining, and in particular relates to a method and device for synchronously recovering lead and zinc from lead-zinc oxides. Background Art

[0002] Lead-zinc oxides are important secondary resources generated during lead-zinc smelting. Their efficient recovery is crucial for resource recycling and environmental protection. Traditional methods for treating lead-zinc oxides primarily include pyrolysis and hydrolysis, but both have significant limitations.

[0003] However, wet processing techniques for treating complex lead-zinc oxide resources have certain limitations. They primarily utilize pyrometallurgical processes to recover lead or zinc from lead-zinc oxides through carbon-thermal reduction. This process is slow and highly dependent on coal resources. The resulting metal also contains a high carbon content, requiring further refining, which increases processing steps and costs. Furthermore, the addition of reducing agents such as coke consumes a lot of energy and easily produces harmful gases such as lead-zinc smoke and sulfur dioxide.

[0004] In summary, there is an urgent need to develop a green and efficient method to achieve the simultaneous reduction and separation of lead and zinc in lead-zinc oxide, so as to break through the bottleneck of lengthy traditional technical processes and low metal recovery rates. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method and device for simultaneously recovering lead and zinc from lead-zinc oxides, aiming to solve the problem that it is difficult to achieve efficient simultaneous recovery of lead and zinc from lead-zinc oxides using existing technologies.

[0006] To achieve the above object, the present invention provides a method for simultaneously recovering lead and zinc from lead-zinc oxide, comprising the steps of:

[0007] Provide lead zinc oxide powder material.

[0008] The lead-zinc oxide powder material is fed into a reaction zone in a flash smelting furnace, and a CO plasma jet is applied to the lead-zinc oxide powder material during its falling process to obtain lead-zinc vapor and lead-containing molten slag.

[0009] The lead-zinc vapor is captured and recovered to obtain a crude lead-zinc alloy.

[0010] The lead-containing molten slag falling into the flash smelting furnace is smelted in the molten pool area, and the mixed slag-lead liquid obtained by the smelting is separated to obtain liquid lead.

[0011] Furthermore, the temperature of the CO plasma jet is 1200-1800° C.; the arc power of the CO plasma jet is 300-500 kW.

[0012] Furthermore, the particle size of the lead-zinc oxide powder material is ≤200 mesh; and the water content of the lead-zinc oxide powder material is <2wt%.

[0013] Furthermore, the lead-zinc oxide powder material includes the following components in mass percentage: Zn 5-30wt%, Pb 5-20wt%, Fe 5-20wt%, SiO2 20-30wt%, CaO 5-20wt%.

[0014] Furthermore, sources of the lead-zinc oxide powder material include desulfurization products of lead-zinc sulfide ore and secondary metallurgical slag.

[0015] Furthermore, the temperature of the smelting treatment is 1300-1500°C.

[0016] Furthermore, in the step of feeding the lead-zinc oxide powder material into the reaction zone in the flash smelting furnace, the feeding rate of the lead-zinc oxide powder material is 0.5-10 kg / min.

[0017] Furthermore, the capture and recovery method is liquid lead rain spray capture; wherein, the temperature of the liquid lead rain is 590-610°C.

[0018] The present invention also provides a device for simultaneously recovering lead and zinc from lead-zinc oxides, comprising a flash smelting furnace body and a plasma flash smelting lance arranged on the upper part of the flash smelting furnace body.

[0019] The flash smelting furnace body includes a reaction tower at the top and an electric smelting furnace at the bottom; a powder nozzle is provided at the top of the reaction tower, and the plasma flash smelting lance is symmetrically installed on the side wall of the reaction tower; the plasma flash smelting lance generates a CO plasma jet, which is applied to the lead-zinc oxide powder material falling in the reaction tower to obtain lead-zinc vapor and lead-containing molten slag.

[0020] The electric smelting furnace comprises a furnace, a liquid lead discharge pipe and an ascending flue; a heating rod is embedded in the side wall of the furnace, which is used to smelt the lead-containing molten slag falling therein to obtain mixed slag lead liquid, forming an upper smelting slag layer and a lower liquid lead layer; the ascending flue is connected to the furnace.

[0021] Furthermore, the plasma flash smelting torch integrates a gas injection channel and a plasma generating module; the gas injection channel is divided into a first air inlet pipe and a second air inlet pipe, the first air inlet pipe is passed through an Ar or N2 protective gas, and the second air inlet pipe is passed through a CO reducing gas; the plasma generating module includes an arc excitation unit and an annular water cooling jacket, and the annular water cooling jacket has a built-in water inlet pipe and two water outlet pipes.

[0022] The beneficial effects achieved by the present invention are:

[0023] The method provided by this invention uses a flash smelting furnace smelting process followed by a CO plasma jet to treat lead-zinc oxide, achieving efficient and simultaneous recovery of lead and zinc from the oxide. The lead recovery rate is >96%, and the zinc recovery rate is >94%. This method also features a short process flow and a short overall duration, while also being clean and energy-efficient.

[0024] The device provided by the present invention for simultaneously recovering lead and zinc from lead-zinc oxides includes a flash smelting furnace body and a plasma flash smelting lance arranged on the upper part of the flash smelting furnace body. The device has a simple structure, is easy to operate, and has a wide range of applications. The device can be used to efficiently and simultaneously recover lead and zinc from lead-zinc oxides, effectively solving the problems of insufficient primary resources and low recycling rate of solid waste resources, and contributing to the green and sustainable development of the circular economy and the metallurgical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0026] Figure 1 This is a schematic structural diagram of an apparatus for simultaneously recovering lead and zinc from lead-zinc oxides according to an optional embodiment of the present invention;

[0027] Figure 2 This is a comparison chart of the recovery rates of lead and zinc using different lead-zinc recovery processes in Analysis Example 1 of the present invention;

[0028] Figure 3 This is a characterization diagram of the microstructure and phase composition of the molten slag after reduction in Analysis Example 2 of the present invention; wherein, Figure 3 (a) Scanning electron microscope (SEM) image of quenched slag; Figure 3 (b) is the scanning electron microscope (SEM) image of the slowly cooled slag; Figure 3 (c) Figure 3 (b) Point scanning combined with energy spectrum analysis (EDS) diagram of the corresponding points.

[0029] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments may be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention.

[0032] Unless otherwise defined, all technical and scientific terms used in the present invention and those skilled in the art are familiar with the prior art and the present invention. Any method, equipment and material of the prior art similar or equivalent to the methods, equipment and materials described in the embodiments of the present invention can also be used to realize the present invention. When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. The test methods for the following examples without specifying specific conditions are usually based on conventional conditions or according to the conditions recommended by each manufacturer. The materials or reagents required in the following examples are commercially available unless otherwise specified.

[0033] In order to solve the problem that it is difficult to achieve efficient and simultaneous recovery of lead and zinc from lead-zinc oxides using existing technologies, the present invention provides a method for simultaneously recovering lead and zinc from lead-zinc oxides, comprising the steps of:

[0034] Provide lead zinc oxide powder material.

[0035] Lead-zinc oxide powder is fed into the reaction zone of a flash smelting furnace, and a CO plasma jet is applied to the lead-zinc oxide powder as it falls, producing lead-zinc vapor and lead-containing molten slag. Specifically, the CO plasma jet, in the form of activated free radicals such as CI, C II, and O II, reacts with the lead-zinc oxide powder fed into the reaction zone of the flash smelting furnace in a plasma-induced reaction. The main reactions that may occur include:

[0036] CO2(g)+C=2CO(g)

[0037] ZnCO3=ZnO+CO2(g)

[0038] ZnO+CO(g)=Zn+CO2(g)

[0039] Zn2SiO4+2C=2Zn(g)+2CO(g)+SiO2

[0040] Zn2SiO4+2CO(g)=2Zn(g)+2CO2(g)+SiO2(s)

[0041] ZnFe2O4+2CO(g)=Zn(g)+2FeO+2CO2(g)

[0042] CO(g)→C II+O II

[0043] Zn2SiO4 + C II → 2Zn II + SiO2· + CO2 (g)

[0044] 2ZnO + C II → 2Zn II + CO2 (g)

[0045] 2Zn II→2Zn(g)

[0046] The lead-zinc vapor is captured and recovered to obtain a crude lead-zinc alloy.

[0047] The lead-containing molten slag that falls into the molten pool of the flash smelting furnace is smelted, and the mixed slag-lead liquid obtained from the smelting is separated and processed to obtain liquid lead. Specifically, the main reactions that may occur include:

[0048] PbCO3=PbO+CO2(g)

[0049] PbO+CO(g)=Pb+CO2(g)

[0050] PbO+C=Pb+CO2(g)

[0051] 2Fe3O4+C=6FeO+CO2(g)

[0052] Fe3O4+4CO(g)=3Fe+4CO2(g)

[0053] FeO+CO(g)=Fe+CO2(g)

[0054] CO(g)→C II+O II

[0055] 2PbO + C II → 2Pb II + CO2 (g)

[0056] 2FeO+C II=2Fe II+CO2(g)

[0057] 2Pb II→2Pb(l)2Fe II→2Fe

[0058] That is, the lead-zinc oxide powder material contacts the CO plasma jet during the falling process, and the strong interaction flow field makes the lead-zinc oxide powder material to be reacted fully contact with the high-temperature plasma torch in the reaction zone, thereby enhancing the heat transfer, mass transfer, and transmission processes. During the free-falling stage of the lead-zinc oxide powder material, the reduction of zinc ferrite, zinc oxide, lead oxide and other phases is completed in seconds, and the reduced metallic zinc is finally volatilized as lead-zinc vapor, and the lead penetrates into the bottom layer of the mixed slag lead liquid, realizing deep enrichment of the liquid lead. In an optional embodiment, the slag layer after the separation treatment can be discharged and then enter the water quenching device for vitrification and harmless treatment. In another optional embodiment, the waste heat generated by the method of simultaneously recovering lead and zinc from lead-zinc oxide can be collected through the flue for steam power generation; the tail gas after zinc capture is subjected to dust removal treatment to achieve the secondary utilization of reducing gases such as CO.

[0059] The method provided by this invention uses a flash smelting furnace smelting process followed by a CO plasma jet to treat lead-zinc oxide, achieving efficient and simultaneous recovery of lead and zinc from the oxide. The lead recovery rate is >96%, and the zinc recovery rate is >94%. This method also features a short process flow and a short overall duration, while also being clean and energy-efficient.

[0060] Furthermore, the temperature of the CO plasma jet is 1200-1800°C; the arc power of the CO plasma jet is 300-500kW. Specifically, the plasma arc is excited by a high-energy current of 300-500kW. During the CO plasma excitation process, high-energy electrons collide with gas molecules, causing the molecules to be excited, dissociated, or ionized, generating highly active atoms and ions, and obtaining a CO plasma jet. The excited state molecules themselves have high energy, and their vibrational energy reduces the activation energy barrier of the reaction during the chemical reaction, thereby accelerating the chemical reaction. Moreover, the temperature of the CO plasma jet is above 1200°C, which can effectively achieve efficient reduction of lead and zinc, providing a new approach for the environmentally friendly and efficient reduction of metal oxides. Preferably, the molar ratio of CO plasma jet to lead-zinc oxide is ≥1.5-2:1.

[0061] Furthermore, the lead-zinc oxide powder has a particle size of ≤200 mesh and a water content of <2 wt %. Specifically, the lead-zinc oxide powder with a particle size of ≤200 mesh has a large specific surface area, effectively increasing the contact area between the lead-zinc oxide powder and the high-energy plasma (CO plasma jet), enhancing the reduction kinetics and ensuring plasma stabilization.

[0062] Furthermore, the lead-zinc oxide powder material includes the following components in mass percentage: Zn 5-30wt%, Pb 5-20wt%, Fe 5-20wt%, SiO2 20-30wt%, and CaO 5-20wt%.

[0063] Furthermore, sources of the lead-zinc oxide powder include desulfurization products of lead-zinc sulfide ores and secondary metallurgical slag. Specifically, the desulfurization products of lead-zinc sulfide ores include oxygen-enriched desulfurized sinter and oxygen-enriched desulfurized roasted material; and the secondary metallurgical slag includes zinc leaching slag, fluidized bed roaster waste slag, top / bottom / side-blown bath furnace waste slag, blast furnace waste slag, and electric furnace waste slag.

[0064] Furthermore, the smelting temperature is 1300-1500° C. Specifically, according to the thermodynamic principle of lead and zinc reduction volatilization, the smelting temperature is maintained at 1300-1500° C. to increase the reduction volatilization rate of valuable metals.

[0065] Furthermore, in the step of feeding the lead-zinc oxide powder material into the reaction zone of the flash smelting furnace, the feed rate of the lead-zinc oxide powder material is 0.5 to 10 kg / min. Specifically, feeding at a feed rate of 0.5 to 10 kg / min can ensure that the lead-zinc oxide powder material is fully contacted with the high-temperature active groups (CI, C II, O II, etc.), ensure temperature field balance, and prevent fine particulate matter from escaping into the flue gas system.

[0066] Furthermore, the capture and recovery method involves spraying liquid lead rain, where the temperature of the liquid lead rain is between 590°C and 610°C. Specifically, experiments have shown that when the temperature of the liquid lead rain is between 590°C and 610°C, the oxidation inhibition rate of lead-zinc vapor reaches a maximum of 98%.

[0067] The present invention also provides a device for simultaneously recovering lead and zinc from lead-zinc oxides, comprising a flash smelting furnace body and a plasma flash smelting lance 1 arranged on the upper portion of the flash smelting furnace body.

[0068] The flash smelting furnace comprises a top reaction tower 5 and a bottom electric smelting furnace 6. A powder nozzle 7 is installed at the top of the reaction tower 5, and a plasma flash smelting lance 1 is symmetrically mounted on the sidewall of the reaction tower 5. The plasma flash smelting lance 1 generates a CO plasma jet, which is applied to the lead-zinc oxide powder falling within the reaction tower 5, producing lead-zinc vapor and lead-containing molten slag. Preferably, the plasma flash smelting lance 1 is tilted relative to the sidewall of the reaction tower 5 at an angle of 30 to 60 degrees. Within this tilt angle range, a strong reducing plasma flame (CO plasma jet) is formed, enhancing the reduction effect on the lead-zinc oxide powder while effectively preventing damage to the lance tip from the plasma torch.

[0069] Specifically, the flash smelting furnace body is formed by coupling the reaction tower 5 at the top and the electric smelting furnace 6 at the bottom; a powder nozzle 7 is provided at the top of the reaction tower 5, and a plasma flash smelting spray gun 1 is symmetrically installed on the side wall of the reaction tower 5. In an optional embodiment, referring to Figure 1 Two plasma flash smelting lances 1 are installed at the same height on each of the left and right sidewalls of the reaction tower 5. In another optional embodiment, the vertical height of the reaction tower 5 is 3 to 8 meters. Preferably, the sidewalls of the reaction tower 5 are equipped with copper-water jackets distributed in a circumferential array; these jackets are equipped with thermometers and alarm systems to enable real-time temperature monitoring.

[0070] The electric smelting furnace 6 comprises a furnace, a liquid lead discharge pipe 14 and an ascending flue 15; a heating rod 8 is embedded in the side wall of the furnace, which is used to smelt the lead-containing molten slag falling therein to obtain mixed slag lead liquid, forming an upper smelting slag layer 12 and a lower liquid lead layer 13; the ascending flue 15 is connected to the furnace.

[0071] Preferably, refer to Figure 1 The outer wall of the electric smelting furnace 6 is composed, from inside to outside, of a refractory layer 9, a copper water-cooled wall 10, and a steel load-bearing layer 11. In one alternative embodiment, the refractory layer 9 is an Al2O3-Cr2O3 composite castable. In another alternative embodiment, the steel load-bearing layer 11 is 316 / 316L / 316LN stainless steel.

[0072] Heating rods 8 are symmetrically embedded in the left and right sidewalls of the electric smelting furnace 6, embedded between the refractory layer 9 and the copper water-cooled wall 10. In an optional embodiment, four sets of silicon carbide heating rods 8 are symmetrically embedded in the sidewalls of the electric smelting furnace 6 to maintain the furnace temperature at 1300-1500°C. Compared to traditional flash smelting furnaces, heating rods 8 are used to maintain the molten slag temperature in the electric smelting furnace 6 to prevent solidification, eliminating the need for electrodes inserted into the melt. Traditional electrode-inserted smelting relies on direct arc contact with the melt to generate heat, which can significantly shorten the electrode life due to high-temperature corrosion and electrochemical erosion. Using non-contact heating methods such as heating rods 8 effectively extends the service life and simplifies the control process.

[0073] A liquid lead discharge pipe 14 is located at the bottom of the furnace, with the top surface of the pipe 14 positioned at a height less than the thickness of the liquid lead layer 13. This means that when the upper smelting slag layer 12 and the lower liquid lead layer 13 are formed, the sidewalls of the furnace just block the smelting slag layer 12 as the liquid lead layer 13 flows out of the pipe 14. In an optional embodiment, the smelting slag layer 12 is a ZnO-(PbO)-FeO-CaO-SiO2 system with a thickness of 400-800 mm.

[0074] The lead-zinc vapor in the reaction tower 5 can be discharged from the ascending flue 15 connected to the top of the furnace and enter the subsequent condensation system. In an optional embodiment, the condensation system uses a liquid lead rain spray at 590-610°C to capture the lead-zinc vapor and form a Zn-Pb alloy.

[0075] The device for simultaneously recovering lead and zinc from lead-zinc oxides provided by the present invention includes a flash smelting furnace body and a plasma flash smelting lance 1 arranged on the upper part of the flash smelting furnace body. The device has a simple structure, is easy to operate, and has a wide range of applications. The device can be used to efficiently and simultaneously recover lead and zinc from lead-zinc oxides, effectively solving the problems of insufficient primary resources and low recycling rate of solid waste resources, and promoting the green and sustainable development of the circular economy and the metallurgical industry.

[0076] Furthermore, the plasma flash smelting torch 1 integrates a gas injection channel 2 and a plasma generation module. The gas injection channel 2 is divided into a first inlet pipe, the first inlet pipe carrying Ar or N2 shielding gas, and a second inlet pipe carrying CO reducing gas. The plasma generation module includes an arc excitation unit 3 and an annular water cooling jacket 4, which has a built-in water inlet pipe and two water outlet pipes. Specifically, N2 or Ar is introduced through the first inlet pipe. After stabilization, the arc excitation unit 3 and the CO controller of the second inlet pipe are activated to inject CO. Then, lead-zinc oxide powder is sprayed into the reaction tower 5 to initiate the reaction. Preferably, the annular water cooling jacket 4 is also equipped with a thermocouple to monitor the temperature in real time and control the cooling efficiency to a temperature difference of ≤5°C. In an optional embodiment, the volume fraction of CO reducing gas in the introduced gas is ≥10%.

[0077] In an alternative embodiment, referring to Figure 1 When using an apparatus for simultaneously recovering lead and zinc from lead-zinc oxides, a lead-zinc oxide powder with a particle size of ≤200 mesh enters a reaction tower 5 through a powder nozzle 7. As the lead-zinc oxide powder falls, a plasma flash smelting lance 1 mounted on the sidewall of the reaction tower 5 injects a CO plasma jet into the reaction zone of the reaction tower 5, producing lead-zinc vapor and lead-containing molten slag. The lead-zinc vapor is discharged through an ascending flue 15 for subsequent zinc capture to produce a crude lead-zinc alloy. The lead-containing molten slag that falls into the hearth of an electric smelting furnace 6 is smelted at a furnace temperature of 1300-1500°C using a heating rod 8 to produce a mixed slag lead liquid, forming an upper slag layer 12 and a lower liquid lead layer 13. The slag layer 12 can be separated by the sidewalls of the electric smelting furnace 6, and the enriched liquid lead is discharged through a liquid lead discharge pipe 14.

[0078] For further understanding of the present invention, now illustrate with examples:

[0079] Example 1

[0080] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 2000g of lead-zinc oxide powder material with the main composition of Zn 25wt%, Pb 5wt%, Fe 7wt%, SiO2 25wt%, CaO 18wt%, and the remainder being a small amount of other oxide impurities; the particle size was 150 mesh and the water content was 2wt%.

[0081] The lead-zinc oxide powder material is added to the powder nozzle 7 through a sealed feeding port, and the plasma flash smelting lance 1 is turned on with an arc power of 500 kW. N2 is introduced through the first air inlet pipe and CO is introduced through the second air inlet pipe of the plasma flash smelting lance 1. The volume fraction of CO in the introduced gases is 20%. After the CO plasma stabilizes, the powder is sprayed into the reaction tower 5 at a feeding rate of 0.5 kg / min. The powder falls into the electric smelting furnace 6 and is deeply reduced for 30 minutes. The reduction temperature in the furnace of the electric smelting furnace 6 is controlled to 1300°C using a heating rod 8, forming an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0082] Liquid lead rain at 590°C is used to spray and capture lead-zinc vapor discharged from the ascending flue 15; liquid lead is collected through the liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 94.1%, and the lead recovery rate reaches 96.4%.

[0083] Example 2

[0084] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 2000g of lead-zinc oxide powder material with the main composition of Zn 30wt%, Pb 20wt%, Fe 5wt%, SiO2 20wt%, CaO 5wt%, and the rest being a small amount of other oxide impurities; its particle size was 200 mesh and water content was 2wt%.

[0085] The lead-zinc oxide powder material is added to the powder nozzle 7 through the sealed feeding port, and the plasma flash smelting spray gun 1 is turned on with an arc power of 300kW. Ar is introduced through the first air inlet pipe of the plasma flash smelting spray gun 1, and CO is introduced through the second air inlet pipe. The volume fraction of CO in the introduced gas is 10%.

[0086] After the CO plasma stabilizes, powder is blown into the reaction tower 5 at a feeding rate of 1 kg / min. The powder falls into the electric smelting furnace 6 and is deeply reduced for 30 minutes. The reduction temperature in the furnace of the electric smelting furnace 6 is controlled to 1400°C by the heating rod 8, forming an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0087] Liquid lead rain at 610°C is used to spray and capture lead-zinc vapor discharged from the ascending flue 15; liquid lead is collected through the liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 90.3%, and the lead recovery rate reaches 89.2%.

[0088] Example 3

[0089] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 4000g of lead-zinc oxide powdery material with the main composition of Zn5wt%, Pb16wt%, Fe10wt%, SiO230wt%, CaO18wt%, and the remainder being a small amount of other oxide impurities; the particle size was 200 mesh, and the water content was 2wt%.

[0090] The lead-zinc oxide powder material is added to the powder nozzle 7 through a sealed feeding port, and the plasma flash smelting lance 1 is turned on with an arc power of 400 kW. N2 is introduced through the first air inlet pipe and CO is introduced through the second air inlet pipe of the plasma flash smelting lance 1. The volume fraction of CO in the introduced gases is 10%. After the CO plasma stabilizes, the powder is sprayed into the reaction tower 5 at a feeding rate of 2 kg / min. The powder falls into the electric smelting furnace 6 and is deeply reduced for 40 minutes. The reduction temperature in the furnace of the electric smelting furnace 6 is controlled to 1300°C using a heating rod 8, forming an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0091] A 600°C liquid lead rain spray is used to capture lead and zinc vapor discharged from the ascending flue 15; liquid lead is collected through a liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 92.3%, and the lead recovery rate reaches 90.2%.

[0092] Comparative Example 1

[0093] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 2000g of a mixture mainly composed of Zn 25wt%, Pb 5wt%, Fe 10wt%, SiO2 30wt%, CaO 18wt%, and the rest being a small amount of other oxide impurities; the particle size was 500 mesh, and the water content was 2wt%.

[0094] The mixed material is added with 200 g of a carbonaceous reducing agent and placed into a smelting furnace for molten pool smelting for 120 minutes. The melt in the smelting furnace is directly heated to 1400° C. using electrodes to form an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0095] A 600°C liquid lead rain spray is used to capture lead and zinc vapor discharged from the ascending flue 15; liquid lead is collected through a liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 90.3%, and the lead recovery rate reaches 89.2%.

[0096] Comparative Example 2

[0097] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 2000g of a mixture mainly composed of Zn 25wt%, Pb 5wt%, Fe 10wt%, SiO2 30wt%, CaO 18wt%, and the rest being a small amount of other oxide impurities; the particle size was 200 mesh, and the water content was 2wt%.

[0098] The mixed material is added to the powder nozzle 7 through the sealed feeding port, and the plasma flash smelting lance 1 is turned on with an arc power of 500 kW. N2 is introduced only through the first air inlet pipe of the plasma flash smelting lance 1, and no gas is introduced through the second air inlet pipe. After the N2 plasma stabilizes, powder is sprayed into the reaction tower 5 at a feeding rate of 0.5 kg / min. The powder falls into the electric smelting furnace 6 and is deeply reduced for 40 minutes. The reduction temperature in the furnace of the electric smelting furnace 6 is controlled to 1400°C by a heating rod 8, forming an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0099] A 600°C liquid lead rain spray is used to capture lead and zinc vapor discharged from the ascending flue 15; liquid lead is collected through a liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 66.3%, and the lead recovery rate reaches 69.5%.

[0100] Comparative Example 3

[0101] The desulfurization product of a domestic lead-zinc sulfide ore was mixed with secondary metallurgical slag in proportion to obtain 2000g of a mixture mainly composed of Zn 25wt%, Pb 5wt%, Fe 10wt%, SiO2 30wt%, CaO 18wt%, and the rest being a small amount of other oxide impurities; the particle size was 200 mesh, and the water content was 2wt%.

[0102] The mixed material was added with 200 g of a carbonaceous reducing agent and added to the powder nozzle 7 through a sealed feeding port. The powder was sprayed into the reaction tower 5 at a feeding rate of 0.5 kg / min. The powder fell into the electric smelting furnace 6 and was deeply reduced for 40 minutes. The reduction temperature in the furnace of the electric smelting furnace 6 was controlled to 1400° C. by a heating rod 8, forming an upper smelting slag layer 12 and a lower liquid lead layer 13.

[0103] A 600°C liquid lead rain spray is used to capture lead and zinc vapor discharged from the ascending flue 15; liquid lead is collected through a liquid lead discharge pipe 14; the slag phase after reduction (smelting slag layer 12) is mainly composed of silicate oxides formed by Ca, Fe, and Si; the zinc recovery rate reaches 72.1%, and the lead recovery rate reaches 68.8%.

[0104] Analysis example 1

[0105] Combined with the lead and zinc recovery conditions of different lead and zinc recovery processes in Examples 1 to 3 and Comparative Examples 1 to 3, a comprehensive analysis was conducted. The comparative results of the lead and zinc recovery rates in Example 1 and Comparative Example 3 are shown in FIG. Figure 2 The comparison table of the duration, energy consumption and waste gas conditions of each process is shown in Table 1.

[0106] Table 1 Comparison of the duration of each process and the lead and zinc recovery rate in Examples 1 to 3 and Comparative Examples 1 to 3

[0107]

[0108] According to Table 1, we can see that:

[0109] As shown by the components of the treated materials in Examples 1 to 3 and Comparative Examples 1 to 3, the slag types are all fusible liquid slag types. From a kinetic perspective, the reduction effect of the fusible liquid slag type is better than that of the solid slag type.

[0110] Utilizing the method for simultaneous recovery of lead and zinc from lead-zinc oxides provided by the present invention (see Examples 1-3), the flash reduction of lead-zinc oxides is enhanced by a CO plasma jet. Highly active intermediate species such as CI, C II, and O II generated by CO ionization can effectively dissociate the stable network structure of lead-zinc silicates, significantly breaking through the kinetic limitations of traditional reduction smelting. Comparative examples demonstrate that, compared with conventional bath smelting (Comparative Example 1), conventional flash smelting (Comparative Example 3), and the reduction effect of an N2 plasma system (Comparative Example 2), Examples 1-3 demonstrate significant superiority in both smelting time and reduction efficiency (lead recovery rate, zinc recovery rate). This method provides a new technical path for the efficient and clean smelting of complex lead-zinc oxides.

[0111] Analysis example 2

[0112] The upper smelting slag layer 12 formed in Example 1 was subjected to characterization and analysis of the microstructure and phase composition of the smelting slag after reduction by cold quenching slag and slow cooling slag. The characterization results are as follows: Figure 3 shown.

[0113] Figure 3 The scanning electron microscope (SEM) image and energy spectrum analysis (EDS) image of the smelting slag after reduction are shown in the figure. Figure 3(a) is the secondary electron (BSE) imaging result of the cold-quenched slag, which retains the uniform amorphous structure formed by rapid cooling of the high-temperature molten state. There is no obvious grain boundary feature on the surface, and the reaction slag has good fluidity. Figure 3 (b) The crystal growth morphology of the slowly cooled slag, the matrix is ​​a calcium silicate iron composite system, combined with the energy spectrum point scanning data, such as Figure 3 (c) The spherical particles are identified as CaSiO3. The absence of Pb and Zn in the slag indicates a good recovery effect.

[0114] In summary, the above technical solutions of the present invention are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for simultaneously recovering lead and zinc from lead-zinc oxides, characterized in that: Including steps: Provide lead zinc oxide powder material; feeding the lead-zinc oxide powder material into a reaction zone in a flash smelting furnace, and applying a CO plasma jet to the lead-zinc oxide powder material during its falling process to obtain lead-zinc vapor and lead-containing molten slag; capturing and recovering the lead-zinc vapor to obtain a crude lead-zinc alloy; The lead-containing molten slag falling into the flash smelting furnace is smelted in the molten pool area, and the mixed slag-lead liquid obtained by the smelting is separated to obtain liquid lead.

2. The method for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 1, wherein: The temperature of the CO plasma jet is 1200-1800° C.; the arc power of the CO plasma jet is 300-500 kW.

3. The method for synchronously recovering lead and zinc from lead-zinc oxide according to claim 1, characterized in that: The particle size of the lead-zinc oxide powder material is ≤200 mesh; the water content of the lead-zinc oxide powder material is <2wt%.

4. The method for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 1, wherein: The lead-zinc oxide powder material includes the following components in mass percentage: Zn 5-30wt%, Pb 5-20wt%, Fe 5-20wt%, SiO2 20-30wt%, and CaO 5-20wt%.

5. The method for synchronously recovering lead and zinc from lead-zinc oxide according to claim 1, characterized in that: The sources of the lead-zinc oxide powder material include desulfurization products of lead-zinc sulfide ore and secondary metallurgical slag.

6. The method for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 1, characterized in that: The smelting temperature is 1300-1500°C.

7. The method for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 1, characterized in that: In the step of feeding the lead-zinc oxide powder material into the reaction zone in the flash smelting furnace, the feeding rate of the lead-zinc oxide powder material is 0.5-10 kg / min.

8. The method for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 1, wherein: The capture and recovery method is liquid lead rain spray capture; wherein, the temperature of the liquid lead rain is 590-610°C.

9. A device for simultaneously recovering lead and zinc from lead-zinc oxides, characterized in that: It comprises a flash smelting furnace body and a plasma flash smelting lance arranged on the upper part of the flash smelting furnace body; The flash smelting furnace body includes a reaction tower at the top and an electric smelting furnace at the bottom; a powder nozzle is provided at the top of the reaction tower, and plasma flash smelting lances are symmetrically installed on the side walls of the reaction tower; the plasma flash smelting lances generate a CO plasma jet, which is applied to the lead-zinc oxide powder material falling in the reaction tower to produce lead-zinc vapor and lead-containing molten slag; The electric smelting furnace comprises a furnace, a liquid lead discharge pipe and an ascending flue; a heating rod is embedded in the side wall of the furnace, which is used to smelt the lead-containing molten slag falling therein to obtain mixed slag lead liquid, forming an upper smelting slag layer and a lower liquid lead layer; the ascending flue is connected to the furnace.

10. The device for simultaneously recovering lead and zinc from lead-zinc oxide according to claim 9, characterized in that: The plasma flash smelting torch is integrated with a gas injection channel and a plasma generation module; The gas injection channel is divided into a first air inlet pipe and a second air inlet pipe, wherein Ar or N2 protective gas flows through the first air inlet pipe, and CO reducing gas flows through the second air inlet pipe; The plasma generating module comprises an arc excitation unit and an annular water cooling jacket, wherein the annular water cooling jacket is built with a water inlet pipe and two water outlet pipes.

Images