Method and device for recovering metal zinc from zinc hydrometallurgy slag

Abstract

The invention provides a method and a device for recovering metal zinc from zinc hydrometallurgy slag, and belongs to the field of metal production or refining. According to the method, one or more plasma-state active substances of N2 + CH4, CO, CO2 and carbon powder act on a wet-process zinc smelting slag powdery material in a side blowing manner, so that metal zinc is efficiently obtained from the wet-process zinc smelting slag powdery material. By the adoption of the method, metal zinc can be recycled from the zinc hydrometallurgy slag within 20-60 min; and the recovery rate of the metal zinc is as high as 97.4%. And the technological process is simple, meanwhile, the carbon emission can be greatly reduced, and the application prospect is wide. The corresponding device is mainly composed of a molten pool smelting furnace and a plasma generating device arranged on the side wall of the molten pool smelting furnace. A porous carbon material is arranged on the inner wall of the end, close to the hearth, of the recovery flue, and the strong reducing atmosphere condition is guaranteed to inhibit oxidation of zinc steam. The device is simple in structure, and can be used for efficiently treating the zinc hydrometallurgy slag powdery material in batches so as to recover metal zinc in the zinc hydrometallurgy slag powdery material.

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 recovering metallic zinc from hydrometallurgical zinc slag. Background Art

[0002] The treatment of hydrometallurgical zinc slag produced during the hydrometallurgical zinc smelting process has always been a technical challenge in the industry. Currently, the mainstream pyrometallurgical treatment processes for hydrometallurgical zinc slag are the rotary kiln volatilization method and the fuming furnace method. These processes involve high-temperature reduction, which volatilizes zinc, lead, and other metals into the dust, achieving a recovery rate of approximately 90%. The rotary kiln volatilization method is widely used in China due to its mature technology and adaptability to raw materials.

[0003] However, pyrometallurgical treatment processes have demonstrated several limitations in industrial applications. While the rotary kiln volatilization method can volatilize metals like zinc and lead into dust through high-temperature reduction, the utilization rate of coke or pulverized coal during the process is generally low. Due to density differences, the reducing agent cannot fully contact the metal oxides within the melt, resulting in carbon consumption as high as 40-50% of the mass of the incoming kiln material, resulting in a waste of resources. Furthermore, pyrometallurgical treatment processes have long reaction times. For example, the rotary kiln volatilization method requires a multi-stage process (drying-precalcination-reduction-volatilization), with a single treatment cycle lasting 3-4 hours. The kiln temperature must be maintained at 1100-1300°C, resulting in high energy costs. Furthermore, the large amount of coal coke reacts with sulfides to produce gases such as CO and SO₂, requiring complex exhaust gas treatment facilities, further increasing operating costs. Summary of the Invention

[0004] The main purpose of the present invention is to provide a method and device for recovering metallic zinc from hydrometallurgical zinc slag, aiming to solve the problems of complex process flow, high carbon consumption and environmental pollution in recovering metallic zinc from hydrometallurgical zinc slag using existing technologies.

[0005] To achieve the above object, the present invention provides a method for recovering metallic zinc from hydrometallurgical zinc slag, comprising the steps of:

[0006] Provide hydrometallurgical zinc slag powder material.

[0007] The powdered material of the wet zinc smelting slag is fed into a molten pool smelting furnace, and plasma active substances are blown into the furnace from both sides of the molten pool smelting furnace to react and obtain zinc-containing vapor; wherein the source of the plasma active substances includes N2, and one or more of CH4, CO, CO2 and carbon powder.

[0008] The zinc-containing vapor is captured and recovered to obtain metallic zinc.

[0009] Furthermore, the plasma active material is a plasma torch generated by a plasma generating device; and the power of the plasma torch is 300-500kW.

[0010] Furthermore, the reaction time of the side-blowing plasma active material step is 20 to 60 minutes.

[0011] Furthermore, the particle size of the hydrometallurgical zinc slag powder material ranges from 47 to 5000 μm.

[0012] Furthermore, the hydrometallurgical zinc slag powder material includes the following components in mass percentage: 5-30wt% zinc, 1-10wt% lead, 10-40wt% iron, 5-20wt% silicon, 0-3wt% copper, 1-10wt% sulfur and 0-5% calcium.

[0013] Furthermore, the source of the hydrometallurgical zinc slag powder material includes one or more of intermediate leaching residue, acid leaching residue, goethite slag, iron vitriol slag and lead-silver slag.

[0014] Furthermore, in the step of side-blowing the plasma active material, the side-blowing gas flow rate required for each kilogram of the hydrometallurgical zinc slag powder material is 10 to 100 L / min.

[0015] The mass of the side-blown carbon powder required for each kilogram of the hydrometallurgical zinc slag powder material is 0.15-0.25 kg.

[0016] Furthermore, the capture and recovery method is liquid zinc rain spray capture; wherein, the temperature of the liquid zinc rain is 500-700°C.

[0017] The present invention also provides an apparatus for recovering metallic zinc from hydrometallurgical zinc slag, which is used to implement any of the aforementioned methods for recovering metallic zinc from hydrometallurgical zinc slag. The apparatus for recovering metallic zinc from hydrometallurgical zinc slag comprises a molten pool smelting furnace, a plasma generator, and a zinc condensing device; the plasma generator is arranged on the side wall of the molten pool smelting furnace; and the zinc condensing device is connected to the top of the molten pool smelting furnace.

[0018] The molten pool smelting furnace includes a furnace, a closed charging port, a recovery flue and a slag discharge port; the closed charging port and the recovery flue are respectively arranged at the two ends of the top of the molten pool smelting furnace, and the closed charging port and the recovery flue are both connected to the furnace; the slag discharge port is opened near the bottom of the molten pool smelting furnace.

[0019] The inner wall of the recovery flue close to the furnace is provided with a porous carbon material; the pore diameter of the porous carbon material is 20 to 100 mm; the height of the porous carbon material is 1 to 5 m; the end of the recovery flue away from the furnace is connected to the zinc condensation device.

[0020] The number of the plasma generating devices is no less than two; and the ejection directions of the plasma active substances generated by the plasma generating devices are all directed towards a position near the bottom of the furnace.

[0021] Furthermore, the side wall material of the molten pool smelting furnace includes refractory bricks.

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

[0023] The present invention provides a method for recovering metallic zinc from hydrometallurgical zinc slag. This method involves side-blowing a plasma-active substance (N₂ + one or more of CH₄, CO, CO₂, and carbon powder) onto the hydrometallurgical zinc slag powder to efficiently recover metallic zinc. This method can recover metallic zinc from the hydrometallurgical zinc slag in 20 to 60 minutes, achieving a zinc recovery rate of up to 97.4%. This method has a simple process flow, and the ultra-high temperature and reducing active groups generated by the plasma-active substance significantly improve the efficiency of the reduction reaction while significantly reducing carbon emissions, offering broad application prospects.

[0024] The device for simultaneously recovering lead and zinc from lead-zinc oxides provided by the present invention is designed for the method of recovering metallic zinc from hydrometallurgical zinc slag provided by the present invention. It mainly consists of a molten pool smelting furnace and a plasma generator arranged on its side wall; and a recovery flue is provided on the top of the molten pool smelting furnace. The inner wall of the recovery flue near one end of the furnace is provided with a porous carbon material (pore size of 20 to 100 mm and height of 1 to 5 m), which can completely convert CO2 in the atmosphere into CO, ensuring a strong reducing atmosphere to inhibit the oxidation of zinc vapor, and directly recovering it as elemental zinc without returning to the hydrometallurgical treatment process. The device has a simple structure and can be used to efficiently process hydrometallurgical zinc slag powder in batches to recover the metallic zinc therein. 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 recovering metallic zinc from hydrometallurgical zinc slag according to an optional embodiment of the present invention;

[0027] Figure 2 This is a scanning electron microscope (SEM) image of the slag phase of Example 1 of the present invention;

[0028] Figure 3This is an energy dispersive X-ray spectrometer (EDS) image corresponding to the scanning electron microscope (SEM) image of the slag phase of Example 1 of the present invention;

[0029] Figure 4 This is a scanning electron microscope (SEM) image of the slag phase of Example 2 of the present invention;

[0030] Figure 5 This is an energy dispersive X-ray spectrometer (EDS) image corresponding to the scanning electron microscope (SEM) image of the slag phase of Example 2 of the present invention;

[0031] Figure 6 This is a scanning electron microscope (SEM) image of the slag phase of Example 3 of the present invention;

[0032] Figure 7 This is an energy dispersive X-ray spectrometer (EDS) image corresponding to a scanning electron microscope (SEM) image of the slag phase of Example 3 of the present invention;

[0033] Figure 8 This is a scanning electron microscope (SEM) image of the slag phase of Example 4 of the present invention;

[0034] Figure 9 This is an energy dispersive X-ray spectrometer (EDS) image corresponding to a scanning electron microscope (SEM) image of the slag phase of Example 4 of the present invention;

[0035] Figure 10 is an X-ray diffractometer (XRD) diagram of the slag phase of Comparative Example 1 of the present invention;

[0036] Figure 11 This is an X-ray diffractometer (XRD) diagram of the furnace wall dust of Comparative Example 2 of the present invention;

[0037] Figure 12 This is a scanning electron microscope (SEM) image of the slag phase of Comparative Example 3 of the present invention;

[0038] Figure 13 This is an energy dispersive X-ray spectrometer (EDS) image corresponding to the scanning electron microscope (SEM) image of the slag phase in Comparative Example 3 of the present invention.

[0039] 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

[0040] 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.

[0041] 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.

[0042] 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.

[0043] In order to solve the problems of complex process flow, high carbon consumption, and environmental pollution in recovering metallic zinc from hydrometallurgical zinc slag using the existing technology, the present invention provides a method for recovering metallic zinc from hydrometallurgical zinc slag, comprising the following steps:

[0044] A powdery material of wet zinc smelting slag is provided. Specifically, the wet zinc smelting slag is dried, crushed and ground in sequence to obtain the powdery material of wet zinc smelting slag.

[0045] Powdered hydrometallurgical zinc slag is fed into a molten pool smelting furnace, and plasma-active substances are blown into the furnace from both sides to react and produce zinc-containing vapor. The sources of the plasma-active substances include nitrogen (N2) and one or more of CH4, CO, CO2, and carbon powder. Preferably, the volume ratio of N2 to one or more of CH4, CO, and CO2 is 10:1-3. Experimental results show that when the sources of the plasma-active substances are all gases, the zinc recovery rate is highest when the volume ratio of nitrogen (N2) to the other gases (one or more of CH4, CO, and CO2) is 10:1-3, which can be stabilized at over 90%.

[0046] The zinc-containing vapor is captured and recovered to obtain metallic zinc.

[0047] The present invention provides a method for recovering metallic zinc from hydrometallurgical zinc slag. This method involves side-blowing a plasma-active substance (N₂ + one or more of CH₄, CO, CO₂, and carbon powder) onto the hydrometallurgical zinc slag powder to efficiently recover metallic zinc. This method can recover metallic zinc from the hydrometallurgical zinc slag in 20 to 60 minutes, achieving a zinc recovery rate of up to 97.4%. This method has a simple process flow, and the ultra-high temperature and reducing active groups generated by the plasma-active substance significantly improve the efficiency of the reduction reaction while significantly reducing carbon emissions, offering broad application prospects.

[0048] Furthermore, the plasma-active material is a plasma torch generated by the plasma generator 1; and the power of the plasma torch is 300-500 kW. Specifically, the plasma torch with a power of 300-500 kW has high-temperature energy, which can meet the temperature and energy consumption of the entire process of the method for recovering metallic zinc from hydrometallurgical zinc slag of the present invention, without the need for additional energy sources such as sulfide ore and coal coke. After the plasma torch with a power of 300-500 kW is side-blown into the molten pool smelting furnace, the following reaction will occur:

[0049] The main components of hydrometallurgical zinc slag are metal oxides (MeO) and metal sulfates (MeSO4):

[0050] 2MeO+C·=2Me+CO2(g)

[0051] MeO+CO - =Me+CO2(g)

[0052] MeSO4+2C·=Me+S 2- +2CO2(g)

[0053] MeSO4+4CO - =Me+S 2- +4CO2(g)

[0054] Furthermore, the reaction time of the side-blowing plasma active material step is 20 to 60 minutes. Specifically, when the reaction time of the side-blowing plasma active material step is 20 to 60 minutes, the final zinc recovery rate is stabilized at more than 90%.

[0055] Furthermore, the particle size of the hydrometallurgical zinc slag powder ranges from 47 to 5000 μm. Specifically, experiments revealed that in order for the plasma-activated substances introduced by the side-blown reaction to effectively react with the hydrometallurgical zinc slag, the hydrometallurgical zinc slag must be crushed and ground to a particle size of 47 to 5000 μm (300 mesh to 5 mm). If the particle size after crushing and grinding is too small, less than 300 mesh, the material will be blown onto the furnace walls during the plasma injection process, reducing the reduction effect. If the particle size is greater than 5 mm, the reaction within the material particles will not be complete within a short period of time.

[0056] Furthermore, the powdered material of the hydrometallurgical zinc slag includes the following components by weight: 5-30 wt% zinc, 1-10 wt% lead, 10-40 wt% iron, 5-20 wt% silicon, 0-3 wt% copper, 1-10 wt% sulfur, and 0-5 wt% calcium. Specifically, the reduction reaction of the ZnFe2O4 component and the metal sulfate component in the hydrometallurgical zinc slag during conventional pyrometallurgical treatment consumes a large amount of heat, resulting in low reaction efficiency and the formation of ZnS that is difficult to further reduce. The present method efficiently reduces the ZnFe2O4 component to elemental zinc and iron oxides while avoiding the formation of ZnS.

[0057] Furthermore, the source of the hydrometallurgical zinc slag powder material includes one or more of intermediate leaching residue, acid leaching residue, goethite slag, iron vitriol slag and lead-silver slag.

[0058] Furthermore, during the side-blowing step of generating plasma-active material, the required side-blowing gas flow rate is 10 to 100 L / min per kilogram of hydrometallurgical zinc slag powder. Specifically, when the gas flow rate is less than 10 L / min, the number of active groups generated is small, resulting in incomplete reduction reaction. When the gas flow rate is greater than 100 L / min, the excessive gas flow rate easily disperses the material particles, reducing the reduction effect, and the excess active groups are wasted.

[0059] The required side-blown carbon powder mass for every kilogram of hydrometallurgical zinc slag powder is 0.15-0.25 kg. Specifically, when the carbon powder mass is less than 0.15 kg, the reduction is insufficient and the reduction rate is low. When the carbon powder mass is greater than 0.25 kg, the carbon powder is excessive, the reduction effect is not significantly increased, and the excess carbon powder is wasted.

[0060] Furthermore, the capture and recovery method is to spray and capture the liquid zinc rain; wherein, the temperature of the liquid zinc rain is 500-700°C. Specifically, when the temperature is less than 500°C, the liquid zinc easily solidifies into a solid state; when the temperature is greater than 700°C, the condensation effect of the zinc vapor is reduced, and some zinc vapor is not completely condensed.

[0061] Reference Figure 1The present invention also provides an apparatus for recovering metallic zinc from hydrometallurgical zinc slag, which is used to implement any of the aforementioned methods for recovering metallic zinc from hydrometallurgical zinc slag. The apparatus for recovering metallic zinc from hydrometallurgical zinc slag comprises a molten bath smelting furnace, a plasma generator 1, and a zinc condensing device 7; the plasma generator 1 is arranged on the side wall of the molten bath smelting furnace; and the zinc condensing device 7 is connected to the top of the molten bath smelting furnace.

[0062] The molten pool smelting furnace includes a furnace, a sealed charging port 2, a recovery flue 6, and a slag tapping port 4. The sealed charging port 2 and the recovery flue 6 are respectively located at opposite ends of the top of the molten pool smelting furnace and are both connected to the furnace. The slag tapping port 4 is located near the bottom of the molten pool smelting furnace. Specifically, the slag tapping port 4 is located near the bottom of the molten pool smelting furnace to facilitate the recovery of the iron-containing liquid slag after the reaction.

[0063] The inner wall of the recovery flue 6 at one end near the furnace is provided with a porous carbon material 3; the pore diameter of the porous carbon material 3 is 20 to 100 mm; the height of the porous carbon material 3 is 1 to 5 meters; the end of the recovery flue 6 away from the furnace is connected to the zinc condensation device 7. Specifically, in the molten pool smelting furnace, the hydrometallurgical zinc slag powder material in the furnace reacts instantaneously with the plasma-state active material injected by the plasma generator 1 from the side, causing the gaseous volatile components (including zinc vapor) reduced from the hydrometallurgical zinc slag powder material to escape rapidly. However, CO2 is also present in the gaseous volatile components, which decomposes into CO and O2 at high temperatures, resulting in an increase in oxygen potential, which easily causes the zinc vapor to be oxidized, thereby interfering with the subsequent recovery of metallic zinc. Therefore, in order to solve this technical problem, a porous carbon material 3 with a pore size of 20 to 100 mm and a height of 1 to 5 m was obtained after multiple experimental adjustments, which was set on the inner wall of the recovery flue 6 close to the furnace. The CO2 was completely converted into CO through the Boudouard reaction CO2+C=2CO. Maintaining the reducing atmosphere of CO can prevent the oxidation of zinc vapor, thereby further improving the zinc recovery rate of the metallic zinc captured by the final zinc condensation device 7.

[0064] There are at least two plasma generators 1, and the plasma-state active substances generated by the plasma generators 1 are ejected toward a position near the bottom of the furnace. Preferably, the plasma generator 1 includes a first generator and a second generator; the first generator is used to inject nitrogen dioxide, and the second generator is used to inject one or more of methane, carbon dioxide, carbon dioxide, and carbon powder. In an optional embodiment, the first and second generators are first activated; then, hydrometallurgical zinc smelting slag powder is added to the molten bath smelting furnace through the sealed feed port 2, and the sealed feed port 2 is closed. The vent valve of the first generator of the plasma generator 1 is opened to perform an nitrogen purge operation; then, the vent valve of the second generator of the plasma generator 1 is opened to side-blow one or more of the plasma-state active substances selected from the group consisting of methane, carbon dioxide, carbon dioxide, and carbon powder into the molten bath smelting furnace. When the carrier substances in the second generator are all gases, the volume ratio of the gas injected from the first generator to the gas injected from the second generator is 10:1 to 3. In another optional embodiment, the plasma generating device 1 has a mixing module, and the substances entering the plasma generating device 1 can be mixed into a mixture in a specified proportion under the control of the mixing module, and the specified flow rate can be controlled to be sprayed; wherein, when the substances entering the plasma generating device 1 are all gases, the volume ratio of N2 to other gases (one or more of CH4, CO and CO2) in the mixture is 10:1~3.

[0065] Furthermore, the sidewalls of the molten pool smelting furnace are made of refractory bricks 5. Specifically, the refractory bricks 5 can withstand high temperatures and melt corrosion, protecting the metal structure of the furnace; and the refractory bricks 5 have low thermal conductivity, which can reduce heat loss in the furnace and improve thermal efficiency.

[0066] The device for simultaneously recovering lead and zinc from lead-zinc oxides provided by the present invention is designed for the method of recovering metallic zinc from hydrometallurgical zinc slag provided by the present invention. It mainly consists of a molten pool smelting furnace and a plasma generator arranged on its side wall; and a recovery flue is provided on the top of the molten pool smelting furnace. The inner wall of the recovery flue near one end of the furnace is provided with a porous carbon material (pore size of 20 to 100 mm and height of 1 to 5 m), which can completely convert CO2 in the atmosphere into CO, ensuring a strong reducing atmosphere to inhibit the oxidation of zinc vapor, and directly recovering it as elemental zinc without returning to the hydrometallurgical treatment process. The device has a simple structure and can be used to efficiently process hydrometallurgical zinc slag powder in batches to recover the metallic zinc therein.

[0067] For further understanding of the present invention, now illustrate with examples:

[0068] Example 1

[0069] (1) First, the obtained zinc leaching residue sample is dried, crushed, ground into powder, and sieved through 100 mesh (150 μm) to obtain 100 g of wet zinc smelting slag powder material with the main components of Zn, Fe, Pb, S, Si, Ca, and Cu being 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%), and the rest being other oxide impurities. The mixed material is added into the molten pool smelting furnace through the closed feeding port 2.

[0070] (2) Turn on the plasma generator 1, adjust the power of the plasma torch to 350 kW, and control the side blowing gas flow rate to 60 L / min. The side blowing gas is a mixture of N2:CO with a volume ratio of 10:1. Use the plasma torch to perform a plasma reaction on the wet zinc smelting slag powder material fed into the molten pool smelting furnace.

[0071] (3) The reaction lasted 25 minutes, yielding a gaseous volatile component. The main components detected in the gaseous volatile component were Pb and Zn. Zinc vapor was collected through a recovery flue 6, whose inner wall had a porous carbon material 3 (pore diameter 80 mm, height 1 m), and then transferred to a zinc condenser 7 (zinc rain temperature 700°C), yielding metallic zinc with a zinc recovery rate of 95.7%.

[0072] The slag phase was collected from the slag outlet 4. After testing, the main components of the slag phase were silicate oxides formed by calcium, iron and silicon, and a certain amount of iron liquid was reduced. The zinc content in the slag phase was 1.14% and the lead content was 1.11% (Table 1).

[0073] Table 1 Surface scanning spectrum of slag phase in Example 1

[0074]

[0075]

[0076] The slag phase was tested by energy dispersive X-ray spectroscopy (EDS), and the results of scanning electron microscopy (SEM) of the slag phase were as follows: Figure 2 As shown, the SEM image of the slag phase ( Figure 2 ) The corresponding EDS test results are as follows Figure 3 As shown. Combined Figure 2 and Figure 3 It can be seen that the slag phase is mainly iron oxide, metallic iron phase and metal sulfide.

[0077] Example 2

[0078] (1) First, the obtained zinc leaching slag sample is dried, crushed, ground into powder, and sieved through 200 mesh (74 μm) to obtain 100 g of wet zinc smelting slag powder material with the main components of Zn, Fe, Pb, S, Si, Ca, and Cu being 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%), and the rest being other oxide impurities. The mixed material is added into the molten pool smelting furnace through the closed feeding port 2.

[0079] (2) Turn on the plasma generator 1, adjust the power of the plasma torch to 400 kW, and control the side blowing gas flow rate to 65 L / min. The side blowing gas is a mixture of N2:CH4 in a volume ratio of 10:3. Use the plasma torch to perform a plasma reaction on the wet zinc smelting slag powder material fed into the molten pool smelting furnace.

[0080] (3) The reaction time was 35 minutes, and a gaseous volatile component was obtained. The main components detected in the gaseous volatile component were Pb and Zn. Zinc vapor was collected through a recovery flue 6 with a porous carbon material 3 (pore diameter 20 mm, height 5 m) on the inner wall and sent to a zinc condenser 7 (zinc rain temperature 500°C) to obtain metallic zinc. The zinc recovery rate was 97.4%.

[0081] The slag phase was collected from the slag outlet 4, and the scanning electron microscope (SEM) test results of the slag phase were as follows: Figure 4 As shown, the SEM image of the slag phase ( Figure 4 ) The corresponding EDS test results are as follows Figure 5 As shown. Combined Figure 4 and Figure 5 It can be seen that the main components of the slag phase are silicate oxides formed by calcium and silicon and iron phase. The zinc content in the slag phase is 0.63% and the lead content is 1.2% (Table 2).

[0082] Table 2 Surface scanning spectrum of slag phase in Example 2

[0083]

[0084]

[0085] Example 3

[0086] (1) First, the obtained zinc leaching slag sample is dried, crushed, ground into powder, and sieved through 300 mesh (50 μm) to obtain 100 g of wet zinc smelting slag powder material with the main components of Zn, Fe, Pb, S, Si, Ca, and Cu being 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%), and the rest being other oxide impurities. The mixed material is added into the molten pool smelting furnace through the closed feeding port 2.

[0087] (2) Turn on the plasma generator 1, adjust the power of the plasma torch to 500 kW, and control the side blowing gas flow rate to 100 L / min. The side blowing gas is a mixture of N2:CO2:CH4 in a volume ratio of 10:1:2. Use the plasma torch to perform a plasma reaction on the wet zinc smelting slag powder material fed into the molten pool smelting furnace.

[0088] (3) The reaction time was 30 minutes, and a gaseous volatile component was obtained. The main components detected in the gaseous volatile component were Pb and Zn. Zinc vapor was collected through a recovery flue 6 with a porous carbon material 3 (pore diameter 60 mm, height 3 m) on the inner wall and sent to a zinc condenser 7 (zinc rain temperature 600°C) to obtain metallic zinc. The zinc recovery rate was 93.2%.

[0089] The slag phase was collected from the slag outlet 4, and the scanning electron microscope (SEM) test results of the slag phase were as follows: Figure 6 As shown, the SEM image of the slag phase ( Figure 6 ) The corresponding EDS test results are as follows Figure 7 As shown. Combined Figure 6 and Figure 7 It can be seen that the main components of the slag phase are silicate oxides formed by calcium, silicon and iron and silicon, and a certain amount of iron liquid is reduced. The precipitated metal phase is mainly iron phase. The zinc content in the slag phase is 1.81% and the lead content is 1.48% (Table 3).

[0090] Table 3 Surface scanning spectrum of slag phase in Example 3

[0091]

[0092] Example 4

[0093] (1) First, the obtained zinc leaching residue sample is dried, crushed, ground into powder and sieved through 10 mesh (2000 μm) to obtain 100 g of wet zinc smelting slag powder material with the main composition of Zn, Fe, Pb, S, Si, Ca, and Cu being 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%), and the rest being other oxide impurities. The mixed material is added into the molten pool smelting furnace through the closed feeding port 2.

[0094] (2) Turn on the plasma generator 1, adjust the power of the plasma torch to 300 kW, control the side blowing gas flow rate to 55 L / min, the side blowing gas is N2, and simultaneously spray carbon powder at a rate of 1.2 g / min.

[0095] The plasma torch is used to carry out plasma reaction on hydrometallurgical zinc slag powder material fed into a molten pool smelting furnace.

[0096] (3) The reaction time was 20 minutes, and a gaseous volatile component was obtained. The main components detected in the gaseous volatile component were Pb and Zn. Zinc vapor was collected through a recovery flue 6 with a porous carbon material 3 (pore diameter 80 mm, height 4 m) on the inner wall and sent to a zinc condenser 7 (zinc rain temperature 500°C) to obtain metallic zinc. The zinc recovery rate was 96.1%.

[0097] The slag phase was collected from the slag outlet 4, and the scanning electron microscope (SEM) test results of the slag phase were as follows: Figure 8 As shown, the SEM image of the slag phase ( Figure 8 ) The corresponding EDS test results are as follows Figure 9 As shown. Combined Figure 8 and Figure 9 It can be seen that the main components of the slag phase are silicate oxides formed by calcium, iron and silicon, and a certain amount of iron liquid is reduced. The precipitated metal phase is mainly iron phase. The zinc content in the slag phase is 1.57% and the lead content is 0.87% (Table 4).

[0098] Table 4 Surface scanning spectrum of slag phase in Example 4

[0099]

[0100] Comparative Example 1

[0101] (1) The zinc leaching residue sample was dried, crushed, ground into powder, and sieved through 100 mesh (150 μm) to obtain 100 g of hydrometallurgical zinc slag powder material with a main composition of 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%) of Zn, Fe, Pb, S, Si, Ca, and Cu, with the remainder being other oxide impurities. An electromagnetic induction heating device was used to control the temperature in the furnace tube at 1250±50°C, and N2 and O2 (7:3) were introduced into the furnace at a gas flow rate of 100 mL / min.

[0102] (2) The wet zinc smelting slag powder was mixed with 35% (wt.%) coke and added into a high-temperature horizontal furnace through a closed charging port. After reduction for 90 minutes, the product was taken out and the zinc and lead contents in the product were determined using an inductively coupled plasma-optical emission spectrometer (ICP-OES).

[0103] (3) After roasting, the residual lead content in the slag phase was 1.3%, the zinc content was 2.16%, and the zinc recovery rate was 89.7%. The slag phase was tested by X-ray diffractometer (XRD), and the test results were as follows: Figure 10 shown. Figure 10 It shows that the zinc-lead phases in the slag phase are ZnS and Pb, and the iron-containing phases are Fe2SiO4, FeO, FeS and Fe.

[0104] Comparative Example 2

[0105] Compared with Example 1, only the particle size of the reaction material in step (1) was changed, and the remaining steps were the same as Example 1. The zinc leaching residue sample was dried, crushed, ground into powder, and sieved through 400 mesh (38 μm) to obtain 100 g of a wet zinc smelting slag powder material having a main composition of 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%) of Zn, Fe, Pb, S, Si, Ca, and Cu, with the remainder being other oxide impurities. The mixed material was added to the molten pool smelting furnace through the closed feed port 2.

[0106] The unreacted zinc leaching slag powder was collected on the side wall of the furnace and the powder was subjected to X-ray diffraction (XRD) analysis. The test results are as follows: Figure 11 As shown; the main component of the powder is ZnFe2O4.

[0107] Due to the excessively fine particle size of the material, some zinc leaching slag particles that did not participate in the reaction were blown to the side wall of the furnace. The slag phase in the furnace and the unreacted material particles on the side wall of the furnace were mixed and crushed, and then measured using ICP-OES. The total zinc recovery rate was 74.5%.

[0108] Comparative Example 3

[0109] Compared with Example 1, only the particle size of the reaction material in step (1) was changed, and the remaining steps were the same as Example 1. The zinc leaching slag sample was dried and crushed to 8 mm to obtain 100 g of a wet zinc smelting slag powder material having a main composition of 18.3%, 25.3%, 5.53%, 4.9%, 7.3%, 1.9%, and 0.6% (wt.%) of Zn, Fe, Pb, S, Si, Ca, and Cu, with the remainder being other oxide impurities. The mixed material was added to the molten pool smelting furnace through the sealed feed port 2.

[0110] The final zinc recovery rate for the metallic zinc was 53.7%. The slag phase was collected from the slag outlet 4. After testing, the main components of the slag phase were silicate oxides formed by unreacted ZnFe2O4, Ca, and Si. The zinc content in the slag phase was 11.3% and the lead content was 1.8% (Table 5).

[0111] Table 5 Surface scanning spectrum of slag phase in comparative example 3

[0112]

[0113]

[0114] The slag phase was examined by scanning electron microscopy (SEM), and the test results were as follows: Figure 12 As shown; SEM image of the slag phase ( Figure 12 ) The corresponding energy dispersive X-ray spectrometer (EDS) test results are as follows Figure 13 As shown. Combined Figure 12 and Figure 13 It can be seen that the slag phase is mainly ZnFe2O4 and silicate.

[0115] Comparative Example 1 is a laboratory simulation of molten pool smelting reduction, with 35% coke added. After a reaction time of 90 minutes, the zinc recovery rate is 89.7%, and the generated ZnS is difficult to volatilize further; in Comparative Example 2, the zinc leaching slag powder is ground to 38 μm and then CO plasma is used for spray reduction. During the reaction process, due to the fine particle size of the material, part of the powder is blown to the side wall of the furnace and not completely reacted, resulting in a decrease in the total zinc recovery rate; in Comparative Example 3, the zinc leaching slag particles are crushed to 8 mm and then CO plasma is used for spray reduction. During the reaction process, due to the large particle size of the material, the interior of the particles is not completely reduced within the same reaction time, which reduces the total zinc recovery rate.

[0116] 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 recovering metallic zinc from hydrometallurgical zinc slag, characterized in that: Including steps: Provide hydrometallurgical zinc slag powder material; The hydrometallurgical zinc slag powder material is fed into a molten pool smelting furnace, and plasma active substances are blown into the furnace from both sides of the molten pool smelting furnace to react and produce zinc-containing vapor; wherein the source of the plasma active substances includes nitrogen, and one or more of methane, carbon dioxide, carbon dioxide, and carbon powder; The zinc-containing vapor is captured and recovered to obtain metallic zinc.

2. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, characterized in that: The plasma active material is a plasma torch generated by a plasma generating device; and the power of the plasma torch is 300-500kW.

3. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, wherein the reaction time of the side-blowing plasma active material step is 20 to 60 minutes.

4. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, wherein: The particle size range of the wet zinc smelting slag powder material is 47 to 5000 μm.

5. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, characterized in that: The wet zinc smelting slag powder material includes the following components in mass percentage: 5-30wt% zinc, 1-10wt% lead, 10-40wt% iron, 5-20wt% silicon, 0-3wt% copper, 1-10wt% sulfur and 0-5% calcium.

6. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, characterized in that: The source of the hydrometallurgical zinc slag powder material includes one or more of intermediate leaching residue, acid leaching residue, goethite slag, iron vitriol slag and lead-silver slag.

7. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, characterized in that: In the step of side-blowing the plasma active material, the side-blowing gas flow rate required for each kilogram of the hydrometallurgical zinc slag powder material is 10 to 100 L / min; The mass of the side-blown carbon powder required for each kilogram of the hydrometallurgical zinc slag powder material is 0.15-0.25 kg.

8. The method for recovering metallic zinc from hydrometallurgical zinc slag according to claim 1, characterized in that: The capture and recovery method is liquid zinc rain spray capture; wherein, the temperature of the liquid zinc rain is 500-700°C.

9. An apparatus for recovering metallic zinc from hydrometallurgical zinc slag, used for implementing the method for recovering metallic zinc from hydrometallurgical zinc slag according to any one of claims 1 to 8, characterized in that: The device for recovering metallic zinc from hydrometallurgical zinc slag comprises a molten pool smelting furnace, a plasma generator, and a zinc condensing device; the plasma generator is arranged on the side wall of the molten pool smelting furnace; the zinc condensing device is connected to the top of the molten pool smelting furnace; The molten pool smelting furnace includes a furnace, a sealed charging port, a recovery flue, and a slag tapping port; the sealed charging port and the recovery flue are respectively arranged at two ends of the top of the molten pool smelting furnace, and the sealed charging port and the recovery flue are both connected to the furnace; the slag tapping port is opened near the bottom of the molten pool smelting furnace; The inner wall of the recovery flue close to the furnace is provided with a porous carbon material; the pore diameter of the porous carbon material is 20 to 100 mm; the height of the porous carbon material is 1 to 5 m; the end of the recovery flue away from the furnace is connected to the zinc condensing device; The number of the plasma generating devices is no less than two; and the ejection directions of the plasma active substances generated by the plasma generating devices are all directed towards a position near the bottom of the furnace.

10. The device for recovering metallic zinc from hydrometallurgical zinc slag according to claim 9, characterized in that: The side wall material of the molten pool smelting furnace includes refractory bricks.

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