A hydrogen-rich reduction and recovery system and method for fine-grained multi-metal materials in a multi-chamber furnace

Abstract

The present application relates to the technical field of metal smelting, and discloses a multi-chamber furnace hydrogen-rich reduction and recovery system and method for fine-grained multi-metal materials, which comprises an oxidizing roasting pretreatment unit, a multi-chamber furnace staged hydrogen-rich reduction unit, a staged trapping unit, a reduction flue gas recovery unit and a cooling and heat recovery unit, and the oxidizing roasting pretreatment unit is further connected to an oxidizing flue gas purification unit. The oxidizing roasting pretreatment unit is used for oxidizing desulfurization and arsenic removal by using a medium-temperature hydrogen-rich synthesis gas; the multi-chamber furnace staged hydrogen-rich reduction unit is used for reverse reduction of fine-grained oxidized materials and super-high-temperature hydrogen-rich synthesis gas; the staged trapping unit is used for flue gas reduction of oxidized materials by using a reverse U-shaped or reverse V-shaped cavity; the reduction flue gas recovery unit is used for obtaining lead and / or zinc powder and purified synthesis gas by cooling, filtering and washing; and the cooling and heat recovery unit is used for recovering the waste heat of reduction products. The present application realizes pre-removal of harmful elements, quality purification of flue gas, and differential continuous reduction, improves reduction efficiency, recovers lead and zinc metal powder, and realizes multiple utilization of heat.

Description

Technical Field

[0001] This invention relates to the field of metal smelting technology, specifically to a multi-hearth furnace hydrogen-rich reduction and recovery system and method for fine-grained polymetallic materials. Background Technology

[0002] Copper smelting slag, iron-containing metallurgical slag, and some low-grade iron-containing powders usually contain valuable metal components such as iron, copper, lead, and zinc, and may also contain harmful elements such as sulfur and arsenic.

[0003] Existing gas-based direct reduction technologies typically use iron ore powder or iron ore pellets as raw materials, employing hydrogen, carbon monoxide, or mixtures thereof as reducing gases to convert iron oxides into metallic iron within a reduction reactor. Gas-based vertical shaft furnace reduction processes generally require raw materials with good particle size and strength, often necessitating pelletizing or the selection of high-grade oxide pellets. Fluidized bed reduction processes can handle powder raw materials, but under high-temperature reduction conditions, fine iron oxide particles may agglomerate, cluster, or lose flow, affecting gas-solid contact and continuous operation. Multi-hearth furnaces, through rake arms pushing the material downwards through each hearth and allowing it to contact and react with reducing gases, can extend the residence time of powder materials within the furnace, making them suitable for gas-solid reduction of powder materials within a certain particle size range. Chinese invention patent application CN119979797A discloses a method and system for the direct reduction of iron ore powder using a gas-based multi-hearth furnace. This method involves reducing iron ore powder with H2 and / or CO reducing gases within a multi-hearth furnace reactor to obtain reduced metallic iron, and discloses the structure of the multi-hearth furnace reactor, gas supply device, and tail gas treatment device. This type of technology is mainly aimed at the direct reduction of iron ore powder to prepare metallic iron. The tail gas treatment is usually aimed at cooling, dust removal, drying, compression and CO2 removal before recycling.

[0004] However, existing gas-based multi-hearth furnace direct reduction technology is mainly applicable to the preparation of metallic iron from high-grade iron ore powder, focusing on avoiding pelletizing and fluidized bed loss. But for fine-grained copper smelting slag containing sulfur, arsenic, and multi-metallic components such as lead, zinc, copper, and iron, problems remain, including harmful elements entering the reduction tail gas, mismatched reduction residence times for different particle sizes, disordered entrainment of fine powder by the airflow, difficulty in recovering volatile lead and zinc, and insufficient utilization of high-temperature materials and tail gas heat. Therefore, the actual technical problem this invention aims to solve is: how to achieve continuous and synergistic processing of complex fine-grained metallurgical materials in a gas-based multi-hearth furnace powder reduction system, including pre-purification of complex fine-grained metallurgical materials, flue gas purification, particle size reduction, lead and / or zinc recovery, and heat reuse, thereby achieving continuous and efficient hydrogen-rich reduction of complex fine-grained metallurgical materials and improving resource recovery rate. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a multi-hearth furnace hydrogen-rich reduction and recovery system and method for fine-grained polymetallic materials. The specific technical solution is as follows: A multi-hearth furnace hydrogen-rich reduction and recovery system for fine-grained polymetallic materials is characterized in that the recovery system includes: an oxidative roasting pretreatment unit, an oxidative flue gas purification unit, a multi-hearth furnace staged hydrogen-rich reduction unit, a staged collection unit, a reduction flue gas recovery unit, and a cooling and reheating unit. The oxidative roasting pretreatment unit is introduced with medium-temperature hydrogen-rich syngas and fine-particle polymetallic materials to carry out an oxidation reaction, so as to produce oxidized flue gas and fine-particle oxide materials. The oxidation flue gas purification unit introduces oxidation flue gas for cooling and washing to purify the oxidation flue gas; The multi-hearth furnace staged hydrogen-rich reduction unit is fed with fine-particle oxide feedstock and ultra-high temperature hydrogen-rich syngas flowing in opposite directions to carry out a reduction reaction, so as to form oxide feedstock flue gas and fine-particle reduction products. The graded collection unit forms an inverted U-shaped cavity or an inverted V-shaped cavity to introduce oxide flue gas for reduction reaction, resulting in reduced flue gas and fine-particle reduction products. The reducing flue gas recovery unit introduces reducing flue gas for sequential cooling, filtration, and washing to obtain lead-zinc metal powder and purified synthesis gas; The cooling and reheating unit is fed with low-temperature hydrogen-rich syngas and fine-particle reduction products for convective heat exchange, so as to form high-temperature hydrogen-rich syngas and cooled fine-particle reduction products.

[0006] Furthermore, the oxidative roasting pretreatment unit includes an oxidative roasting rotary kiln and a hydrogen-rich syngas burner connected to the oxidative roasting rotary kiln. The hydrogen-rich syngas burner introduces medium-temperature hydrogen-rich syngas and oxygen for combustion to maintain the operating temperature of the oxidative roasting rotary kiln and to react with sulfur and / or arsenic in fine-particle polymetallic materials; wherein the hydrogen-rich syngas includes hydrogen and carbon monoxide. The rotary kiln for oxidative roasting forms an oxidation flue gas outlet for discharging oxidative flue gas and an oxidation discharge outlet for discharging fine-particle oxide materials. The oxidation flue gas outlet is connected to the oxidation flue gas purification unit, and the oxidation discharge outlet is connected to the multi-hearth furnace staged hydrogen-rich reduction unit.

[0007] Furthermore, the oxidation flue gas purification unit includes a first waste heat boiler and a desulfurization and arsenic removal purifier connected to the first waste heat boiler. The first waste heat boiler forms a first cavity to contain the oxidizing flue gas, so as to absorb the sensible heat of the oxidizing flue gas and perform gas-solid separation of the oxidizing flue gas, thereby obtaining sulfur-containing gas and oxidizing waste residue. The desulfurization and arsenic removal purifier consists of a desulfurization and arsenic removal inlet and a condensation and scrubbing component. The desulfurization and arsenic removal inlet is connected to the exhaust port of the first waste heat boiler and the condensation and scrubbing component, respectively, so as to introduce sulfur-containing gas into the condensation and scrubbing component.

[0008] Furthermore, the multi-hearth furnace staged hydrogen enrichment unit includes: The multi-layer multi-hearth furnace has a feed inlet and exhaust channel at the top, a discharge outlet at the bottom, and several hydrogen-rich synthesis gas inlets along the height of the side. A feed distribution unit is installed at the feed inlet to regulate the falling rate of fine oxide particles; The rake arm, located inside the multi-layer, multi-hearth furnace, pushes the fine oxide material downwards from hearth to hearth. During this downward movement, ultra-high temperature hydrogen-rich syngas is introduced through the hydrogen-rich syngas inlet to create vertical convection with the fine oxide material.

[0009] Furthermore, it also includes a graded collection unit, which includes several cyclone dust collectors. Each cyclone dust collector is connected to the exhaust channel through an inverted V-shaped pipe to form an inverted V-shaped cavity for the reduction reaction of the oxide flue gas. An inverted V-shaped tube consists of a connected riser and a faller.

[0010] Furthermore, the flue gas recovery unit includes: The second waste heat boiler forms a second cavity to contain the reducing flue gas, so as to absorb the sensible heat of the reducing flue gas and perform gas-solid separation on the reducing flue gas, thereby obtaining lead and / or zinc flue gas. A bag filter connected to the exhaust port of the second cavity filters and cools lead and / or zinc flue gas to obtain lead and / or zinc powder and filtered synthesis gas; the exhaust port of the bag filter is connected to the cooling and washing unit to pass the filtered synthesis gas into the cooling and washing unit to form purified synthesis gas. A gas holder connected to the exhaust port of the cooling and washing unit to store purified syngas, which includes hydrogen and carbon monoxide.

[0011] Furthermore, the cooling and reheating unit includes a cooling rotary kiln, which forms a solid inlet. The solid inlet is connected to the main discharge channel, which is connected to the outlet of the cyclone dust collector and the discharge outlet of the multi-layer multi-hearth furnace, so as to transfer the fine-particle reduction product into the solid inlet. The cooling rotary kiln has a low-temperature hydrogen-rich syngas inlet and a high-temperature hydrogen-rich syngas outlet, so that the low-temperature hydrogen-rich syngas can exchange heat with the fine-particle reduction products through convection, thereby forming high-temperature hydrogen-rich syngas. The high-temperature hydrogen-rich syngas outlet is fed into the reduction flue gas recovery unit to recover the sensible heat of the high-temperature hydrogen-rich syngas.

[0012] A method comprising the following steps: Fine-grained polymetallic materials are fed into an oxidation roasting pretreatment unit for oxidation reaction to obtain oxidized flue gas and fine-grained oxide materials. The oxidizing flue gas is passed into the oxidizing flue gas purification unit to recover sensible heat and perform cooling and washing to obtain exhaust gas that can be discharged. The fine oxide material is moved down one chamber at a time in the multi-hearth furnace staged hydrogen-rich reduction unit to undergo several convective heat exchange and reduction reactions with high-temperature hydrogen-rich syngas at different heights, so as to obtain oxide flue gas and the first fine reduction product. The oxide flue gas is passed into the staged collection unit to carry out the reduction reaction, and reduced flue gas and second fine particle reduction product are obtained. The reducing flue gas is passed into the reducing flue gas recovery unit for heat absorption and filtration to obtain lead and / or zinc powder, which is then cooled and washed to obtain purified syngas. The first and second fine-particle reduction products are fed into a cooling and reheating unit and exchanged heat with low-temperature hydrogen-rich syngas to obtain cooled fine-particle reduction products and high-temperature hydrogen-rich syngas. High-temperature hydrogen-rich syngas is passed into a reduction flue gas recovery unit to obtain purified syngas; The cooled fine-particle reduction product was ground and magnetically separated to obtain elemental iron and elemental copper.

[0013] As can be seen from the above technical solution, the present invention has the following beneficial effects: This invention utilizes an oxidative roasting pretreatment unit to introduce hydrogen-rich syngas and fine-particle multi-metal materials for oxidation reaction, pre-removing harmful elements such as sulfur and arsenic. The oxidative flue gas purification unit then cools and washes the flue gas to achieve graded purification. A multi-hearth furnace staged hydrogen-rich reduction unit and a staged collection unit utilize ultra-high temperature hydrogen-rich syngas in counter-current contact with the materials, along with inverted U-shaped or inverted V-shaped cavity structures, to achieve differentiated and continuous reduction of materials of different particle sizes, improving reduction efficiency. A reduction flue gas recovery unit recovers lead-zinc metal powder and purifies the syngas through cooling, filtration, and washing. A cooling and reheating unit utilizes hydrogen-rich syngas to absorb the waste heat from high-temperature materials and the sensible heat from the high-temperature hydrogen-rich syngas, achieving multiple utilizations of system heat. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 for Figure 1 Enlarged view of section A in the image; Figure 3 This is a flowchart illustrating Embodiment 2 of the present invention.

[0015] In the diagram: 1. Oxidation roasting pretreatment unit; 11. Oxidation roasting rotary kiln; 12. Hydrogen-rich syngas burner; 2. Oxidation flue gas purification unit; 21. First waste heat boiler; 22. Desulfurization and arsenic removal purifier; 3. Multi-hearth furnace staged hydrogen-rich reduction unit; 31. Multi-layer multi-hearth furnace; 32. Material distribution unit; 33. Hydrogen-rich syngas inlet; 34. Rake arm; 35. Exhaust channel; 36. Discharge outlet; 4. Staged collection unit; 41. Cyclone dust collector; 42. Ascending pipe; 43. Downcomer; 5. Reduction flue gas recovery unit; 51. Second waste heat boiler; 52. Bag filter; 53. Cooling and washing unit; 54. Gas holder; 6. Main discharge channel; 7. Cooling and reheating unit; 71. Cooling rotary kiln. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0018] Example 1 In this embodiment, the fine-grained polymetallic material is an iron-copper smelting slag, wherein FeO accounts for 30%–45%; SiO2 accounts for 30%–35%; CaO accounts for 2%–10%; Al2O3 accounts for 2%–8%; Cu accounts for 0.5%–4.5%; Zn, Pb, S, and As each account for 1%–3%; MgO, Cr2O3, Ni, Co, Au, and Ag are all trace amounts. S, As, Pb, Cu, and Zn can all react with O2 to form oxides; when Pb oxides and Zn oxides are heated to 650 degrees Celsius under normal pressure, they volatilize to form lead and zinc volatile gases; iron ions form reduced iron under a reducing atmosphere. Furthermore, the hydrogen-rich synthesis gas consists of 65% H2, 28% CO, and 7% inert gases. Secondly, the temperature of ultra-high temperature hydrogen-rich synthesis gas is 1300℃, which can be raised to this temperature by an electromagnetic heating device; low temperature hydrogen-rich synthesis gas is 40℃; medium temperature hydrogen-rich synthesis gas is 650℃; and high temperature hydrogen-rich synthesis gas is 800℃.

[0019] like Figure 1As shown, fine-grained multi-metallic material at 25°C is continuously fed into the interior of the oxidative roasting pretreatment unit 1, and then heat-dissipating hydrogen-rich synthesis gas is introduced into it. This heat-dissipating hydrogen-rich synthesis gas flows from the bottom of the multi-layer multi-hearth furnace 31, through the interlayer between the rake arm 34 and the central shaft inside the multi-layer multi-hearth furnace 31, thereby dissipating heat from the rake arm 34 and the central shaft, and then flows out from the top of the central shaft and enters the interior of the oxidative roasting pretreatment unit 1. The heat-dissipating hydrogen-rich synthesis gas is ignited inside the oxidative roasting pretreatment unit 1. The rate of introduction of the hydrogen-rich synthesis gas and the intensity of the oxidation reaction are adjusted to maintain the interior of the oxidative roasting pretreatment unit 1 at 650°C. Secondly, sulfides (such as cuprous sulfide) react with oxygen to produce sulfur dioxide, thereby achieving desulfurization of fine-grained polymetallic materials and yielding metal oxides. The sulfur dioxide forms part of the oxidizing flue gas. Arsenides (such as arsenopyrite FeAsS) react with oxygen to produce sulfur dioxide and arsenic trioxide, thereby achieving arsenic removal from fine-grained polymetallic materials and yielding metal oxides. The arsenic trioxide forms part of the oxidizing flue gas, thus achieving pre-impurity removal of fine-grained polymetallic materials and preventing harmful elements from entering the fine oxide material, affecting metal recovery. The metal oxides include at least PbO, ZnO, CuO, FeO, and Fe3O4.

[0020] Next, the oxidizing flue gas is introduced into the oxidizing flue gas purification unit 2, which includes a desulfurization and arsenic removal purifier 22, comprising a condenser and a scrubbing tower. The condenser is typically a shell-and-tube type, which can rapidly cool the oxidizing flue gas, causing arsenic trioxide to condense into a solid substance. The scrubbing tower uses a liquid (usually an alkaline solution) to countercurrently contact the oxidizing flue gas, absorbing sulfur dioxide and washing away residual dust through physical or chemical processes (such as NaOH solution), thereby achieving the fractional purification of the oxidizing flue gas, obtaining purified oxidizing flue gas, which is then discharged into the atmosphere.

[0021] Secondly, the internal temperature of the oxidation roasting pretreatment unit 1 is maintained at 650°C, ensuring that the temperature of the fine oxide material formed after the oxidation reaction of the fine polymetallic material is maintained at 650°C. This fine oxide material is fed into the distribution section 32 at the top of the multi-hearth furnace staged hydrogen-rich reduction unit 3 at a feed rate of 25 tons per hour. The distribution section 32 then regulates the falling rate of the fine oxide material at the top of the multi-hearth furnace staged hydrogen-rich reduction unit 3. Simultaneously, ultra-high temperature hydrogen-rich syngas is introduced into the distribution section 32 through the hydrogen-rich syngas inlet 33 on the side of the distribution section 32. The ultra-high temperature hydrogen-rich syngas flows upward, while the fine oxide material falls downward, resulting in convection. Due to the significant temperature difference between the two, contact heat transfer occurs. Furthermore, the ultra-high temperature hydrogen-rich syngas reacts with the metal oxides in the fine oxide material, such as... PbO undergoes reduction reactions with H2 and CO, respectively, to produce Pb (vapor) and water vapor, and Pb (vapor) and carbon dioxide, thus yielding four metallic elements: lead (vapor), zinc (vapor), copper (solid), and iron (solid), as well as water vapor. The lead (vapor) and zinc (vapor) then flow together with ultra-high temperature hydrogen-rich syngas towards the staged collection unit 4. Next, ultrafine particles (e.g., larger than 280 mesh) of the oxide material float to the surface under the influence of the ultra-high temperature hydrogen-rich syngas, forming part of the oxide material flue gas, and continuously undergo reduction reactions with the ultra-high temperature hydrogen-rich syngas. Then, fine particles (e.g., larger than 200 mesh) of the oxide material flow towards the staged collection unit 4 under the influence of the ultra-high temperature hydrogen-rich syngas and undergo reduction reactions, yielding fine-particle reduction products, thereby achieving particle-graded reduction. In this process, it is necessary to maintain the material processing capacity of the multi-layer multi-hearth furnace 31 at its maximum capacity to avoid affecting its processing efficiency. Secondly, both ultrafine and fine particles are mixed with ultra-high temperature hydrogen-rich syngas and flow towards the staged collection unit 4, forming oxide flue gas, thereby increasing the reaction area and improving reduction efficiency. Next, large particles (particles that cannot float, such as particles smaller than 200 mesh) of fine oxide particles continue to descend inside the staged hydrogen-rich reduction unit 3 of the multi-hearth furnace, continuing to undergo convection and reduction reactions with the ultra-high temperature hydrogen-rich syngas. After multiple reactions, the fine oxide particles undergo complete reduction, yielding granular fine reduction products (such as elemental copper and elemental iron), achieving highly efficient hydrogen-rich reduction of fine oxide particles.

[0022] The method for distinguishing between large, fine, and ultrafine particles is as follows: Ultra-high temperature hydrogen-rich syngas is introduced at the same flow rate, and convective heat is exchanged with the fine oxide particles. The total amount of fine oxide particles falling per unit time is calculated by detecting the accumulation height of the falling particles. The total amount of falling particles representing ultrafine particles is greater than the total amount of falling particles representing fine particles, and the total amount of falling particles representing ultrafine particles does not exceed the maximum processing capacity of the multi-layer multi-hearth furnace 31. Furthermore, based on production requirements, the staff defines the range of the total amount of falling particles representing ultrafine particles and the range of the total amount of falling particles representing fine particles, thereby achieving flexible adjustment of particle size reduction and improving hydrogen-rich reduction efficiency.

[0023] Secondly, the graded collection unit 4 includes a cyclone dust collector 41, an ascending pipe 42, and a descending pipe 43. The ascending pipe 42 and the descending pipe 43 are interconnected, and the connection position is an inverted V-shape or U-shape. Both are hollow pipes, thus forming an inverted U-shaped cavity or an inverted V-shaped cavity. Next, under the collection of the cyclone dust collector 41, the oxide flue gas first rises along the ascending pipe 42 and then descends along the descending pipe 43, mixing with the ultra-high temperature hydrogen-rich synthesis gas to undergo a complete reduction reaction, obtaining particulate fine reduction products. These products are then filtered through the cyclone dust collector 41, allowing only gas to pass through, thus forming reduction flue gas. Finally, the reduction flue gas enters the reduction flue gas recovery unit 5. The oxide flue gas includes ultra-fine particles of fine oxides and fine particles of fine oxides, while the reduction flue gas includes unreacted ultra-high temperature hydrogen-rich synthesis gas, lead vapor, and zinc vapor. First, the reducing flue gas interacts with water inside the reducing flue gas recovery unit 5, and the heat is gradually dissipated. Lead and zinc vapors condense and are cooled to 160℃-180℃, or are further cooled by water mist spraying to between 160℃ and 180℃. Then, it flows through the filtration device (bag filter 52) of the reducing flue gas recovery unit 5 for filtration, realizing the recovery of lead and zinc, and separating the unreacted high-temperature hydrogen-rich synthesis gas from lead and zinc. Second, the unreacted high-temperature hydrogen-rich synthesis gas is passed into the cooling and scrubbing unit 53, which includes a condenser and a scrubbing tower, to remove residual dust and residual impurity gases (such as trace amounts of sulfur dioxide), resulting in purified synthesis gas containing hydrogen and carbon monoxide, thereby improving the recovery rate of metal resources, hydrogen, and carbon monoxide.

[0024] The working temperature of the bag filter 52 is 160℃-180℃.

[0025] Secondly, the fine oxide material moves down through the multi-hearth furnace staged hydrogen-rich reduction unit 3, eventually yielding blocky high-temperature fine-particle reduction products at a temperature of 1200℃. Next, the high-temperature fine-particle reduction products and the granular fine-particle reduction products generated by the staged collection unit 4 are fed into the cooling and reheating unit 7. Low-temperature hydrogen-rich syngas is then introduced into the cooling and reheating unit 7, where all the fine-particle reduction products and the low-temperature hydrogen-rich syngas undergo convective heat exchange, thereby cooling the fine-particle reduction products and heating the low-temperature hydrogen-rich syngas. This results in cooled fine-particle reduction products and high-temperature hydrogen-rich syngas, facilitating subsequent grinding and magnetic separation of the cooled fine-particle reduction products to obtain iron and copper. It also facilitates the introduction of the high-temperature hydrogen-rich syngas into the reduction flue gas recovery unit 5, where it absorbs heat to generate steam for power generation, thus achieving heat recovery and improving the heat recovery efficiency.

[0026] Secondly, the material distribution unit 32 is equipped with a material level detector to monitor the accumulation rate of fine oxide materials that fail to float after convection with ultra-high temperature hydrogen-rich syngas. This allows for the adjustment of the falling speed of the fine oxide materials and the flow rate of the ultra-high temperature hydrogen-rich syngas, ensuring that the total amount of fine oxide materials falling into the multi-layer multi-hearth furnace 31 does not exceed the processing limit of the multi-layer multi-hearth furnace 31, thus achieving material reduction by particle size.

[0027] Furthermore, the oxidative roasting pretreatment unit 1 includes an oxidative roasting rotary kiln 11 and a hydrogen-rich syngas burner 12 connected to the oxidative roasting rotary kiln 11; the hydrogen-rich syngas burner 12 introduces medium-temperature hydrogen-rich syngas and oxygen for combustion to maintain the operating temperature of the oxidative roasting rotary kiln 11 and to induce oxidation reactions with sulfur and arsenic; the oxidative roasting rotary kiln 11 forms an oxidation flue gas outlet for discharging oxidative flue gas and an oxidation discharge outlet for discharging fine-particle oxide materials, the oxidation flue gas outlet is connected to the oxidation flue gas purification unit 2, and the oxidation discharge outlet is connected to the multi-hearth furnace staged hydrogen-rich reduction unit 3.

[0028] Specifically, the rotary kiln 11 for oxidation roasting is a commonly used piece of equipment in this field. It includes a screw feeder at the kiln tail, a discharge device (screw discharge device) at the kiln head, a steel cylinder inside the kiln, a hydrogen-rich syngas burner 12 connected to the kiln head, and an oxygen supply pipe (which can supply air or oxygen) connected to the steel cylinder. Next, the fine-grained polymetallic material is fed into the screw feeder and enters the steel cylinder. The steel cylinder is placed at an incline and rotates slowly. The medium-temperature hydrogen-rich syngas is fed into the hydrogen-rich syngas burner 12 for combustion. The combustion products are then fed into the kiln, thereby maintaining the kiln temperature at 650°C. At the same time, it promotes the oxidation reaction between oxygen and the fine-grained polymetallic material, thereby desulfurizing and dearsenicizing the fine-grained polymetallic material, and thus obtaining sulfur-free and arsenic-free fine-grained oxide material.

[0029] Secondly, as is known, the kiln tail is higher than the kiln head, and the airflow floats upward. Fine-grained polymetallic materials flow downward along the inclined inner surface of the steel cylinder, thus forming an oxidation exhaust port at the kiln tail and an oxidation discharge port at the kiln head. This allows the medium-temperature hydrogen-rich syngas to be introduced into the hydrogen-rich syngas burner 12 connected to the kiln head for combustion. The resulting oxidation flue gas enters the kiln and floats upward, then exits from the oxidation exhaust port at the kiln tail and enters the oxidation flue gas purification unit 2. First, its sensible heat is absorbed, and then it is cooled and washed again. At the same time, the generated fine-grained oxide material flows downward and is discharged from the oxidation discharge port at the kiln head, and then sent to the multi-hearth furnace staged hydrogen-rich reduction unit 3 for reduction reaction.

[0030] Furthermore, the oxidation flue gas purification unit 2 includes a first waste heat boiler 21 and a desulfurization and dearsenic removal purifier 22 connected to the first waste heat boiler 21; the first waste heat boiler 21 forms a first cavity to accommodate the oxidation flue gas, so as to absorb the sensible heat of the oxidation flue gas and perform gas-solid separation on the oxidation flue gas, thereby obtaining sulfur-containing gas and oxidation waste residue; the desulfurization and dearsenic removal purifier 22 forms a desulfurization and arsenic removal vent and a condensation and scrubbing element, the desulfurization and arsenic removal vent is connected to the exhaust port of the first waste heat boiler 21 and the condensation and scrubbing element respectively, so as to introduce the sulfur-containing gas into the condensation and scrubbing element.

[0031] Specifically, the first waste heat boiler 21 is connected to the oxidation flue gas outlet at the kiln tail, which is a commonly used device in the field. The first waste heat boiler 21 is a gas-water heat exchanger, which can absorb heat to generate steam for power generation. Secondly, the oxidation flue gas at 650°C is introduced into the first cavity of the first waste heat boiler 21. Some particles fall under the action of gravity. The gaseous sulfides (sulfur dioxide) and gaseous arsenides (arsenic trioxide) exchange heat with the water in the first waste heat boiler 21 to achieve preliminary cooling and condensation, thereby cooling down to below 200°C. Alternatively, a spray tower can be used to cool both down to below 200°C to obtain steam, arsenic-containing powder or arsenic-containing particles, and gaseous sulfides. Next, a bag filter 52 is used to filter the arsenic-containing powder or arsenic-containing particles to achieve arsenic removal. The gaseous sulfides are then discharged through the exhaust port of the first waste heat boiler 21 and introduced into the condensing and washing components, namely the condenser and washing tower, through the desulfurization and arsenic inlet, thereby achieving final condensation and washing, and thus obtaining sulfur-free and arsenic-free waste gas, which is then discharged into the atmosphere.

[0032] like Figure 2As shown, the multi-hearth furnace staged hydrogen enrichment unit includes: a multi-layer multi-hearth furnace 31, with a feed inlet and exhaust channel 35 formed at the top of the multi-layer multi-hearth furnace 31, a discharge outlet 36 formed at the bottom of the multi-layer multi-hearth furnace 31, and several hydrogen-rich syngas inlets 33 formed along the height direction on the side of the multi-layer multi-hearth furnace 31, with several hydrogen-rich syngas inlets 33 connected to each other along the height direction; a feed distribution component 32 set at the feed inlet to adjust the falling rate of fine oxide material; and a rake arm 34 set inside the multi-layer multi-hearth furnace 31, which pushes the fine oxide material down chamber by chamber. During the down-moving process, ultra-high temperature hydrogen-rich syngas is introduced into the hydrogen-rich syngas inlet 33 to form an upward and downward convection with the fine oxide material inside the multi-layer multi-hearth furnace 31.

[0033] Specifically, the multi-layer multi-hearth furnace 31 forms ten furnace layers, and a material distribution component 32 is installed on the top. The material distribution component 32 is a commonly used device in the art, which includes a tank for receiving fine oxide materials, an opening regulator for the discharge port installed at the bottom of the tank, and an exhaust port connected to the downcomer 43. The opening regulator controls the falling rate of the fine oxide materials, thereby regulating the convection velocity between the fine oxide materials and the ultra-high temperature hydrogen-rich synthesis gas. Secondly, a central shaft is installed inside the multi-layer multi-hearth furnace 31, and ten rake arms 34 are installed along the height direction on the side of the central shaft. The rake arms 34 are located between the upper and lower furnace layers. Each rake arm 34 has several rake teeth installed below it. The rake arms 34 rotate around the central axis to push the fine oxide material falling into the lower furnace layer down one chamber at a time, while simultaneously performing preliminary grinding on the fine oxide material. Next, eight hydrogen-rich synthesis gas inlets 33 are evenly formed circumferentially on the side sections of the 1st, 3rd, 5th, 7th, and 9th layers of the multi-layer multi-hearth furnace 31. Ultra-high temperature hydrogen-rich synthesis gas is divided into 5 portions and introduced into them, which convect with the fine oxide material located in the material distribution unit 32, thereby causing the fine oxide particles to float upward. Then, the rake arms 34 transfer the fine oxide material located in the 9th layer to the 10th layer, and then the 1200°C blocky fine reduction product falls from the discharge outlet 36.

[0034] Secondly, exhaust channels 35 are formed on the top left and right sides of the multi-layer multi-hearth furnace 31, which are connected to the graded collection unit 4 respectively, so that the floating fine oxide material enters the graded collection unit 4. At the same time, the ultra-high temperature hydrogen-rich synthesis gas also enters the graded collection unit 4 through the exhaust channel 35, and undergoes a reduction reaction with the fine oxide material. Then, iron oxide, copper oxide, zinc oxide and lead oxide react with hydrogen and carbon monoxide respectively to obtain particulate fine reduction products, lead (volatile gas), zinc (volatile gas), water vapor and carbon dioxide. The particulate fine reduction products are discharged to the main discharge channel 6 by the cyclone dust collector 41, and the remaining material forms reduction flue gas, which is directed to the reduction flue gas recovery unit 5.

[0035] Furthermore, it also includes a graded collection unit 4, which includes several cyclone dust collectors 41. Each cyclone dust collector 41 is connected to the exhaust channel 35 through an inverted V-shaped pipe to form an inverted V-shaped cavity for the reduction reaction of oxide flue gas.

[0036] Specifically, the riser pipe 42 and the downcomer pipe 43 are integrally formed or connected by a V-joint to form an inverted V-shaped pipe. The bottom end of the riser pipe 42 is connected to the exhaust channel 35 at the top of the multi-layer multi-hearth furnace 31 and the exhaust port of the material distribution component 32. The bottom end of the downcomer pipe 43 is connected to the corresponding cyclone dust collector 41, so that the cyclone dust collector 41 can generate negative pressure to drive the oxide flue gas entering the multi-layer multi-hearth furnace 31 or the material distribution component 32 into the exhaust channel 35 or exhaust port, the riser pipe 42, the downcomer pipe 43 and the cyclone dust collector 41 in sequence. The reaction time (residence time) of the oxide flue gas in the riser pipe 42 and the downcomer pipe 43 is controlled at 10-15 seconds, so that the fine oxide particles in the oxide flue gas can fully undergo the reduction reaction, thereby achieving particle-level collection and improving reduction efficiency.

[0037] Furthermore, the reduction flue gas recovery unit 5 includes: a second waste heat boiler 51, which forms a second cavity to accommodate the reduction flue gas, so as to absorb the sensible heat of the reduction flue gas and perform gas-solid separation on the reduction flue gas to obtain lead and / or zinc flue gas; a bag filter 52 connected to the exhaust port of the second cavity to filter the cooled lead and / or zinc flue gas to obtain lead and / or zinc powder and filtered synthesis gas; the exhaust port of the bag filter 52 is connected to a cooling scrubbing element 53 to pass the filtered synthesis gas into the cooling scrubbing element 53 to form purified synthesis gas; and a gas holder 54 connected to the exhaust port of the cooling scrubbing element 53 to store the purified synthesis gas, which includes hydrogen and carbon monoxide.

[0038] Specifically, the cyclone dust collector 41 sends the captured reducing flue gas into the interior of the second waste heat boiler 51, forming a second cavity. This cavity allows the reducing flue gas to be placed and exchange heat with low-temperature water, continuously cooling it until it reaches below 200°C. The lead and zinc flue gas then flows upwards through the exhaust port to the bag filter 52 for condensation. The bag filter 52 collects the condensed lead and zinc powder through its filter bags. Next, the filtered syngas is passed through a condenser and a scrubbing tower to remove dust and trace amounts of sulfur dioxide. After demisting to remove moisture, clean, purified syngas is obtained and stored in the gas holder 54, improving the utilization rate of hydrogen and carbon monoxide.

[0039] Secondly, the first waste heat boiler 21 and the second waste heat boiler 51 absorb the sensible heat of the gas to form steam, which is then fed into the steam turbine to generate electricity, thereby improving energy utilization.

[0040] Furthermore, the cooling and reheating unit 7 includes a cooling rotary kiln 71, which forms a solid inlet. The solid inlet is connected to the main discharge channel 6, which is connected to the outlet of the cyclone dust collector 41 and the discharge outlet 36 of the multi-layer multi-hearth furnace 31, so as to transfer fine-particle reduction products into the solid inlet. The cooling rotary kiln 71 has a low-temperature hydrogen-rich synthesis gas inlet and a high-temperature hydrogen-rich synthesis gas outlet, so that the low-temperature hydrogen-rich synthesis gas and the fine-particle reduction products can exchange heat through convection, thereby forming high-temperature hydrogen-rich synthesis gas. The high-temperature hydrogen-rich synthesis gas outlet is introduced into the reduction flue gas recovery unit 5 to recover the sensible heat of the high-temperature hydrogen-rich synthesis gas.

[0041] Specifically, the cooling rotary kiln 71 is a commonly used device in the field. Its main structure is an inclined and slowly rotating steel cylinder, which causes the material to tumble and move forward continuously inside the cylinder as it rotates. Among them, the 1200°C blocky fine-particle reduction product from the multi-layer multi-hearth furnace 31 and the granular fine-particle reduction product from the cyclone dust collector 41 enter from the solid inlet (high end) of the cooling rotary kiln 71. Under the action of inclination and rotation, the fine-particle reduction product slowly moves towards the solid outlet (low end) of the cooling rotary kiln 71. Simultaneously, low-temperature hydrogen-rich syngas at 40°C is blown in from the lower end, flowing counter-currently with the fine-particle reduction products. Under the action of the lifting plates inside the steel cylinder, the fine-particle reduction products are repeatedly lifted, fully contacting the counter-flowing cold gas for efficient heat exchange. This ensures that the temperature of the fine-particle reduction products at the solid outlet does not exceed 80°C. After absorbing heat, the low-temperature hydrogen-rich syngas forms high-temperature hydrogen-rich syngas, which then flows through the high-temperature hydrogen-rich syngas outlet to the second waste heat boiler 51 to absorb its sensible heat. It then flows to the bag filter 52 for filtration and to the cooling and washing unit 53 for condensation and washing, resulting in purified syngas containing hydrogen and carbon monoxide, thereby improving the utilization rate of hydrogen and carbon monoxide.

[0042] Example 2 like Figure 3As shown, this embodiment is a method based on a rotary system, which includes the following steps: Fine-grained polymetallic materials are fed into an oxidation roasting pretreatment unit 1 for oxidation reaction, yielding oxidation flue gas and fine-grained oxide materials; the oxidation flue gas is passed into an oxidation flue gas purification unit 2 to recover sensible heat and perform cooling and washing, yielding exhaust gas that can be discharged; the fine-grained oxide materials are moved down through the multi-hearth furnace staged hydrogen-rich reduction unit 3, sequentially undergoing several convective heat exchange and reduction reactions with high-temperature hydrogen-rich syngas at different heights, yielding oxide material flue gas and the first fine-grained reduction product; the oxide material flue gas is then passed into a staged collection unit. 4. A reduction reaction is carried out to obtain reduction flue gas and a second fine-particle reduction product. The reduction flue gas is passed into the reduction flue gas recovery unit 5 for heat absorption and filtration to obtain lead and / or zinc powder, which is then cooled and washed to obtain purified syngas. The first and second fine-particle reduction products are sent to the cooling and reheating unit 7 and exchanged with the low-temperature hydrogen-rich syngas via convection to obtain cooled fine-particle reduction products and high-temperature hydrogen-rich syngas. The high-temperature hydrogen-rich syngas is passed into the reduction flue gas recovery unit 5 to obtain purified syngas. The cooled fine-particle reduction products are ground and magnetically separated to obtain elemental iron and elemental copper.

[0043] Specifically, both the first and second fine-particle reduction products are granular fine-particle reduction products. Next, hydrogen-rich syngas and oxygen are fed into the hydrogen-rich syngas burner 12 for combustion, and the combustion products are then introduced into the kiln to increase the temperature of the oxidative roasting rotary kiln 11 to 650°C and increase the oxygen concentration. Copper smelting slag at 25°C is fed into the oxidative roasting rotary kiln 11 and undergoes an oxidation reaction with oxygen to obtain sulfur- and arsenic-containing oxidized flue gas and fine-particle oxide material containing metal oxides. Next, the oxidized flue gas is sent to the first waste heat boiler 21 for continuous cooling, filtering and condensing the arsenic-containing particles to remove arsenic. It is then sent to the desulfurization and arsenic removal purifier 22, where sulfur in the oxidized flue gas is removed through a chemical reaction, forming harmless waste gas that is then discharged into the atmosphere. Simultaneously, the fine-particle oxide material is fed into the multi-layer multi-hearth furnace 31, which... As the material falls from the bottom, the high-temperature hydrogen-rich syngas introduced from the side of the multi-layer multi-hearth furnace 31 continuously convects with the fine-particle oxide material moving down through each hearth, thereby causing a reduction reaction and carrying away ultrafine particles and fine particles of the fine-particle oxide material. This results in the formation of fine-particle reduction products (first fine-particle reduction products) discharged from the bottom and oxide flue gas discharged from the side. These flue gas then enter the cyclone dust collector 41 through the riser pipe 42 and the downcomer pipe 43. The cyclone dust collector 41 collects the fine-particle reduction products (second fine-particle reduction products) generated by the reduction reaction in the inverted V-shaped cavity. These fine-particle reduction products enter the solid inlet of the cooling rotary kiln 71 through the main discharge channel 6, where they undergo convective heat exchange with the 40°C hydrogen-rich syngas.

[0044] Secondly, the cyclone dust collector 41 sequentially sends the captured reduction tail gas into the second waste heat boiler 51 for continuous cooling, the bag dust collector 52 captures the condensed lead and zinc metal powder, and the cooling and washing unit 53 cools and washes the unreacted high-temperature hydrogen-rich synthesis gas, thereby obtaining lead and zinc powder and purified synthesis gas. Secondly, the main discharge channel 6 can be a screw feeder, whose discharge port is connected to the solid inlet (high end) of the cooling rotary kiln 71, thereby sending all the fine-particle reduction products into the cooling rotary kiln 71 to provide heat; at the same time, low-temperature hydrogen-rich synthesis gas at 40°C is introduced into the solid outlet (low end) of the cooling rotary kiln 71, and the gas and solid undergo convective heat exchange to obtain high-temperature hydrogen-rich synthesis gas and cooled fine-particle reduction products. The high-temperature hydrogen-rich synthesis gas then flows through the second waste heat boiler 51, bag filter 52, cooling washing unit 53 and gas holder 54 in sequence. The cooled fine-particle reduction products are discharged from the solid outlet (low end) of the cooling rotary kiln 71 and enter the grinding device and magnetic separation device to be ground and magnetically separated, thereby obtaining elemental copper and elemental iron.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0046] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A multi-hearth furnace hydrogen-rich reduction and recovery system for fine-grained multimetallic materials, characterized in that, The recovery system includes: an oxidation roasting pretreatment unit (1), an oxidation flue gas purification unit (2), a multi-hearth furnace staged hydrogen-rich reduction unit (3), a staged collection unit (4), a reduction flue gas recovery unit (5), and a cooling and reheating unit (7); The oxidation roasting pretreatment unit (1) introduces medium-temperature hydrogen-rich synthesis gas and fine-particle polymetallic materials for oxidation reaction to produce oxidized flue gas and fine-particle oxide materials. The oxidation flue gas purification unit (2) introduces the oxidation flue gas for cooling and washing to purify the oxidation flue gas; The multi-hearth furnace staged hydrogen-rich reduction unit (3) is fed with fine-particle oxide material and ultra-high temperature hydrogen-rich synthesis gas flowing in opposite directions to carry out a reduction reaction to form oxide material flue gas and fine-particle reduction products. The graded collection unit (4) forms an inverted U-shaped cavity or an inverted V-shaped cavity to introduce the oxide flue gas for reduction reaction, thereby obtaining reduced flue gas and fine-particle reduction products. The reducing flue gas recovery unit (5) introduces the reducing flue gas for sequential cooling, filtration and washing to obtain lead-zinc metal powder and purified synthesis gas; The cooling and reheating unit (7) introduces low-temperature hydrogen-rich syngas and the fine-particle reduction product for convective heat exchange to form high-temperature hydrogen-rich syngas and cooled fine-particle reduction product.

2. The recycling system according to claim 1, characterized in that: The oxidative roasting pretreatment unit (1) includes an oxidative roasting rotary kiln (11) and a hydrogen-rich synthesis gas burner (12) connected to the oxidative roasting rotary kiln (11). The hydrogen-rich syngas burner (12) introduces the medium-temperature hydrogen-rich syngas and oxygen for combustion to maintain the working temperature of the oxidative roasting rotary kiln (11) and to react with sulfur and / or arsenic in the fine-particle polymetallic material; wherein the hydrogen-rich syngas includes hydrogen and carbon monoxide; The rotary kiln (11) for oxidizing and roasting forms an oxidation exhaust port for discharging the oxidizing flue gas and an oxidation discharge port for discharging the fine oxide material. The oxidation exhaust port is connected to the oxidation flue gas purification unit (2), and the oxidation discharge port is connected to the multi-hearth furnace staged hydrogen-rich reduction unit (3).

3. The recycling system according to claim 2, characterized in that: The oxidation flue gas purification unit (2) includes a first waste heat boiler (21) and a desulfurization and arsenic removal purifier (22) connected to the first waste heat boiler (21); The first waste heat boiler (21) forms a first cavity to accommodate the oxidizing flue gas, so as to absorb the sensible heat of the oxidizing flue gas and perform gas-solid separation on the oxidizing flue gas, thereby obtaining sulfur-containing gas and oxidizing waste residue; The desulfurization and arsenic removal purifier (22) forms a desulfurization and arsenic removal vent and a condensation and washing component. The desulfurization and arsenic removal vent is connected to the exhaust port of the first waste heat boiler (21) and the condensation and washing component, respectively, so as to introduce the sulfur-containing gas into the condensation and washing component.

4. The recycling system according to claim 1, characterized in that: The multi-hearth furnace staged hydrogen enrichment unit includes: A multi-layer multi-hearth furnace (31) is provided with a feed inlet and an exhaust channel (35) at the top, a discharge outlet (36) at the bottom, and several hydrogen-rich synthesis gas inlets (33) along the height direction on the side of the multi-layer multi-hearth furnace (31). The feed distribution component (32) is installed at the feed inlet to adjust the falling rate of the fine oxide material; The rake arm (34) installed inside the multi-layer multi-hearth furnace (31) pushes the fine oxide material down chamber by chamber. During the process of moving down chamber by chamber, the hydrogen-rich synthesis gas inlet (33) introduces the ultra-high temperature hydrogen-rich synthesis gas to form an upward and downward convection with the fine oxide material.

5. The recycling system according to claim 4, characterized in that, It also includes a graded collection unit (4), which includes several cyclone dust collectors (41). Each cyclone dust collector (41) is connected to the exhaust channel (35) through an inverted V-shaped pipe to form an inverted V-shaped cavity for the reduction reaction of the oxide flue gas. The inverted V-shaped tube includes a connected ascending tube (42) and a descending tube (43).

6. The recycling system according to claim 1, characterized in that: The reducing flue gas recovery unit (5) includes: The second waste heat boiler (51) forms a second cavity to accommodate the reducing flue gas, so as to absorb the sensible heat of the reducing flue gas and perform gas-solid separation on the reducing flue gas, thereby obtaining lead and / or zinc flue gas. A bag filter (52) connected to the exhaust port of the second cavity filters the cooled lead and / or zinc flue gas to obtain lead and / or zinc powder and filtered synthesis gas; the exhaust port of the bag filter (52) is connected to a cooling and washing component (53) to pass the filtered synthesis gas into the cooling and washing component (53) to form purified synthesis gas; A gas holder (54) connected to the exhaust port of the cooling and washing unit (53) is provided for storing the purified synthesis gas, which includes hydrogen and carbon monoxide.

7. The recycling system according to claim 5, characterized in that: The cooling and reheating unit (7) includes a cooling rotary kiln (71), which forms a solid inlet. The solid inlet is connected to the main discharge channel (6), which is connected to the outlet of the cyclone dust collector (41) and the discharge outlet (36) of the multi-layer multi-hearth furnace (31) to transfer the fine-particle reduction product into the solid inlet. The cooling rotary kiln (71) has a low-temperature hydrogen-rich syngas inlet and a high-temperature hydrogen-rich syngas outlet, so that the low-temperature hydrogen-rich syngas and the fine-particle reduction product exchange heat through convection, thereby forming the high-temperature hydrogen-rich syngas. The high-temperature hydrogen-rich synthesis gas outlet is fed into the reducing flue gas recovery unit (5) to recover the sensible heat of the high-temperature hydrogen-rich synthesis gas.

8. A method for a recycling system according to any one of claims 1 to 7, characterized in that, Includes the following steps: Fine-grained polymetallic materials are fed into an oxidation roasting pretreatment unit for oxidation reaction to obtain oxidized flue gas and fine-grained oxide materials. The oxidation flue gas is passed into an oxidation flue gas purification unit to recover sensible heat and perform cooling and washing to obtain exhaust gas that can be discharged. The fine oxide material is moved down one chamber at a time in the multi-hearth furnace staged hydrogen-rich reduction unit to undergo several convective heat exchange and reduction reactions with high-temperature hydrogen-rich syngas at different heights, so as to obtain oxide flue gas and the first fine reduction product. The oxide flue gas is passed into the graded collection unit to carry out a reduction reaction, resulting in reduced flue gas and a second fine-particle reduction product. The reduction flue gas is passed into the reduction flue gas recovery unit for heat absorption and filtration to obtain lead and / or zinc powder, which is then cooled and washed to obtain purified synthesis gas. The first fine-particle reduction product and the second fine-particle reduction product are fed into a cooling and reheating unit and exchanged with low-temperature hydrogen-rich syngas via convective heat exchange to obtain cooled fine-particle reduction product and high-temperature hydrogen-rich syngas. The high-temperature hydrogen-rich syngas is passed into the reducing flue gas recovery unit to obtain the purified syngas; The cooled fine-particle reduction product was ground and magnetically separated to obtain elemental iron and elemental copper.

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