Method and system for producing aluminum oxide by using aluminum-rich coal gangue

Abstract

The invention discloses a method and a system for producing aluminum oxide by using aluminum-rich coal gangue, and belongs to the field of secondary resource quality-divided utilization and nonferrous metallurgy. The method comprises the following steps: crushing and screening an aluminum-rich coal gangue raw material to obtain aluminum-rich coal gangue powder; pyrolyzing the aluminum-rich coal gangue powder under the carrying of hot air to obtain a pyrolyzed material; carrying out primary separation on the pyrolysis material to obtain a high-temperature oil-gas mixture and a solid product; carrying out an activation reaction on the solid product under the carrying of carrying gas to obtain calcined aluminum-rich coal gangue; carrying out secondary separation on the calcined aluminum-rich coal gangue to obtain reaction tail gas and high-temperature active silicon-aluminum oxide; performing heat exchange cooling on the high-temperature active silicon-aluminum oxide to obtain cooled active silicon-aluminum oxide; carrying out pre-desilicication treatment on the cooled active silicon-aluminum oxide to obtain a treated product; and extracting aluminum from the treated product to obtain aluminum oxide. The method disclosed by the invention is simple in process, low in energy consumption, reasonable in energy utilization, high in extraction rate and capable of reducing the cost and can be industrially applied on a large scale.

Description

Technical Field

[0001] The present application relates to the technical fields of secondary resource fractionation and nonferrous metal metallurgy, and in particular to a method and system for producing alumina by utilizing aluminum-rich coal gangue. Background Art

[0002] Gangue is solid waste generated during coal mining, washing and processing. Large amounts of gangue piled up will not only occupy land but also pollute the environment. In order to make full use of gangue, at present, gangue is mainly used to produce building materials (such as bricks, cement, etc.) or for power generation. However, using gangue to produce building materials can only use gangue with low added value, especially the aluminum in aluminum-rich gangue, which is a serious waste of valuable elements. Using gangue for power generation will lead to problems such as low combustion efficiency and difficulty in controlling pollutant emissions.

[0003] Alumina is a key raw material for the aluminum industry and is widely used in electrolytic aluminum production, ceramics, refractory materials and other industries. At present, alumina production mainly relies on bauxite resources. It is urgent to find new sources of raw materials for alumina production and develop efficient, economical and environmentally friendly production technologies.

[0004] Since aluminum-rich coal gangue contains abundant aluminum, the method of extracting aluminum from aluminum-rich coal gangue is becoming more and more widespread. However, the existing coal gangue aluminum extraction process faces the problems of complex process, high energy consumption, low extraction rate, high cost, and difficulty in large-scale industrial application, which limits the resource utilization of coal gangue in the aluminum industry. Summary of the invention

[0005] The embodiments of the present application provide a method and system for producing alumina using aluminum-rich coal gangue, which can solve the problems faced by the existing coal gangue aluminum extraction process, such as complex process, high energy consumption, low extraction rate, high cost, and difficulty in large-scale industrial application.

[0006] In order to achieve the above object, the technical solution of the embodiment of the present invention is:

[0007] In a first aspect, an embodiment of the present invention provides a method for producing alumina using aluminum-rich coal gangue, comprising:

[0008] The aluminum-rich coal gangue raw material is crushed and screened to obtain aluminum-rich coal gangue powder;

[0009] Pyrolyzing the aluminum-rich coal gangue powder under the influence of hot air to obtain a pyrolysis material;

[0010] The pyrolysis material is first separated to obtain a high-temperature oil-gas mixture and a solid product, wherein the high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar;

[0011] The solid product is activated by a carrier gas to obtain calcined aluminum-rich coal gangue;

[0012] The calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide;

[0013] Cooling the high temperature active silicon aluminum oxide by heat exchange to obtain a cooling active silicon aluminum oxide;

[0014] The cooling active silicon-aluminum oxide is subjected to a pre-desiliconization treatment to obtain a treated product;

[0015] The treated product is subjected to aluminum extraction to obtain aluminum oxide.

[0016] In combination with the first aspect, in a possible implementation, the pyrolysis material is first separated to obtain a high-temperature oil-gas mixture and a solid product, wherein the high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar, and further includes:

[0017] The hot air and the low-temperature oil-gas mixture are obtained by exchanging heat with the cold air through the high-temperature oil-gas mixture;

[0018] The low-temperature oil-gas mixture is separated three times to obtain normal-temperature tar and normal-temperature coal gas.

[0019] In combination with the first aspect, in a possible implementation, the aluminum-rich coal gangue powder is pyrolyzed under the influence of hot air to obtain a pyrolysis material, further comprising:

[0020] The room temperature coal gas is used to supplement the heat source for pyrolysis.

[0021] In combination with the first aspect, in a possible implementation, the solid product is activated by a carrier gas to obtain calcined aluminum-rich coal gangue, further comprising:

[0022] The room temperature coal gas is used to supplement the heat source for the activation reaction.

[0023] In combination with the first aspect, in a possible implementation, after the low-temperature oil and gas mixture is separated three times to obtain room-temperature tar and room-temperature coal gas, the method further includes:

[0024] The room temperature coal gas is used for waste heat power generation.

[0025] In combination with the first aspect, in a possible implementation, after the calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide, the method comprises:

[0026] Dedusting the reaction tail gas to obtain high-temperature flue gas;

[0027] The high-temperature flue gas is used for waste heat power generation.

[0028] In combination with the first aspect, in a possible implementation, the high temperature active silicon aluminum oxide is subjected to heat exchange cooling to obtain the temperature-reduced active silicon aluminum oxide, comprising:

[0029] The high temperature active silicon aluminum oxide is cooled by heat exchange with cold air to obtain cooling active silicon aluminum oxide and second hot air;

[0030] The second hot air is used for activation reaction, and / or the second hot air is used for preheating the aluminum-rich coal gangue powder.

[0031] In combination with the first aspect, in a possible implementation manner, the oxygen concentration of the pyrolysis is less than 5%, and the temperature is 300°C to 800°C.

[0032] In combination with the first aspect, in a possible implementation, the aluminum content of the aluminum-rich coal gangue raw material is greater than or equal to 40%, and the particle size range of the aluminum-rich coal gangue powder is 0 mm to 3 mm.

[0033] In a second aspect, another embodiment of the present invention provides a system for producing alumina using aluminum-rich coal gangue, comprising a pretreatment mechanism, a pyrolysis mechanism, a first separation mechanism, a thermal activation mechanism, a second separation mechanism, a heat exchange mechanism, a desiliconization mechanism, and an aluminum extraction mechanism;

[0034] The pretreatment mechanism is used to crush and screen the aluminum-rich coal gangue raw material to obtain aluminum-rich coal gangue powder;

[0035] The pyrolysis mechanism is connected to the pretreatment mechanism, and the aluminum-rich coal gangue powder output by the pretreatment mechanism is input into the pyrolysis mechanism under the influence of hot air for pyrolysis to obtain pyrolysis material;

[0036] The first separation mechanism is connected to the pyrolysis mechanism, and the pyrolysis material output by the pyrolysis mechanism is input to the first separation mechanism for primary separation to obtain a high-temperature oil-gas mixture and a solid product, wherein the oil-gas mixture includes high-temperature coal gas and high-temperature tar;

[0037] The thermal activation mechanism is connected to the first separation mechanism, and the solid product output by the first separation mechanism is input into the thermal activation mechanism under the carrying gas for activation reaction to obtain calcined aluminum-rich coal gangue;

[0038] The second separation mechanism is connected to the thermal activation mechanism, and the calcined aluminum-rich coal gangue output by the thermal activation mechanism is input into the second separation mechanism for secondary separation to obtain reaction tail gas and high-temperature active silicon aluminum oxide;

[0039] The heat exchange mechanism is connected to the second separation mechanism, and the high-temperature active silicon-aluminum oxide output by the second separation mechanism is input into the heat exchange mechanism for heat exchange cooling to obtain the temperature-reduced active silicon-aluminum oxide;

[0040] The desiliconization mechanism is connected to the heat exchange mechanism, and the cooling active silicon-aluminum oxide output by the heat exchange mechanism is input into the desiliconization mechanism for pre-desiliconization treatment to obtain a treated product;

[0041] The aluminum extraction mechanism is connected to the desiliconization mechanism, and the treated product output by the desiliconization mechanism is input into the aluminum extraction mechanism to extract aluminum to obtain aluminum oxide.

[0042] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0043] The method for producing alumina using aluminum-rich coal gangue provided in the embodiment of the present invention adopts a pyrolysis-thermal activation-aluminum extraction integrated process. During the pyrolysis and thermal activation process, the aluminum silicate structure in the aluminum-rich coal gangue powder is initially decomposed, which not only provides favorable conditions for subsequent desiliconization and aluminum extraction, but also can recycle and utilize the generated energy products such as coal gas and tar, and can effectively extract the aluminum element in the aluminum-rich coal gangue, realize efficient resource utilization, high-value utilization of coal gangue resources, increase resource added value, provide a new source of raw materials for the aluminum industry, and alleviate the tense situation of bauxite resources. In addition, the method of the present application has a simple process, low energy consumption, and reasonable use of energy, a high extraction rate, and reduced costs, and can be applied on a large scale in industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0045] Figure 1 Schematic diagram of a system for producing alumina using aluminum-rich coal gangue provided in an embodiment of the present application Figure 1 ;

[0046] Figure 2 Schematic diagram of a system for producing alumina using aluminum-rich coal gangue provided in an embodiment of the present application Figure 2 .

[0047] Icons: 1-pyrolysis mechanism; 2-first separation mechanism; 3-first heat exchange mechanism; 4-oil washing mechanism; 5-thermal activation mechanism; 6-second separation mechanism; 7-dust removal mechanism; 8-second heat exchange mechanism; 9-pretreatment mechanism; 10-desiliconization mechanism; 11-aluminum extraction mechanism; 12-power generation mechanism. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0049] In the description of the embodiments of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0050] The embodiment of the present invention provides a method for producing alumina by using aluminum-rich coal gangue, which includes steps 1 to 8. The numbers after the steps do not represent the order of execution.

[0051] Step 1: crushing and screening the aluminum-rich coal gangue raw materials to obtain aluminum-rich coal gangue powder.

[0052] Optionally, the aluminum content of the aluminum-rich coal gangue raw material is greater than or equal to 40%, and the particle size range of the aluminum-rich coal gangue powder is 0mm to 3mm, so as to ensure that the subsequent pyrolysis reaction can be fully carried out and the pyrolysis effect is good.

[0053] Step 2: Pyrolyze the aluminum-rich coal gangue powder under the influence of hot air to obtain a pyrolysis material.

[0054] Optionally, the oxygen concentration of pyrolysis is less than 5%, and the temperature is 300°C to 800°C (typical but non-limiting temperatures such as 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, etc.), so as to achieve a better pyrolysis effect.

[0055] During the pyrolysis reaction, aluminum-rich coal gangue powder undergoes complex physical and chemical changes, producing coal gas, tar, solid products, etc. Among them, gas products such as coal gas, solid products and liquid products such as tar enter the subsequent steps for separation.

[0056] Step 3: The pyrolysis material (the temperature of the pyrolysis material is 300°C to 600°C at this time) is first separated to obtain a high-temperature oil-gas mixture and a solid product. The high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar.

[0057] Step 4: The solid product is activated by a carrying gas to obtain calcined aluminum-rich coal gangue.

[0058] like Figure 1 and Figure 2 As shown, the carrying gas can be the hot air obtained by heat exchange of the first heat exchange mechanism 3 , or it can be the normal temperature coal gas output by the oil washing mechanism 4 .

[0059] Step 5: The calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide.

[0060] Step 6: Cool the high-temperature active silicon-aluminum oxide by heat exchange to obtain the cooled active silicon-aluminum oxide.

[0061] Step 7: The cooled active silicon aluminum oxide is pre-desiliconized to obtain a treated product, thereby selectively removing part of the silicon element to improve the subsequent aluminum extraction efficiency and product quality.

[0062] Step 8: Extract aluminum from the treated product to obtain aluminum oxide. Specifically, the treated product is subjected to the Bayer process, and a series of processes such as dissolution, separation, crystallization, and calcination are performed to extract aluminum to obtain aluminum oxide.

[0063] After pre-desiliconization treatment, the product is processed by the Bayer process to finally obtain high-quality alumina products. The product quality meets the relevant national standards and industry specifications and can be widely used in many fields such as electrolytic aluminum production, ceramics, refractory materials, etc.

[0064] The method for producing alumina using aluminum-rich coal gangue provided in the embodiment of the present invention adopts a pyrolysis-thermal activation-aluminum extraction integrated process. During the pyrolysis and thermal activation process, the aluminum silicate structure in the aluminum-rich coal gangue powder is initially decomposed, which not only provides favorable conditions for subsequent desiliconization and aluminum extraction, but also can recycle and utilize the generated energy products such as coal gas and tar, and can effectively extract the aluminum element in the aluminum-rich coal gangue, realize efficient resource utilization, high-value utilization of coal gangue resources, increase resource added value, provide a new source of raw materials for the aluminum industry, and alleviate the tense situation of bauxite resources. In addition, the method of the present application has a simple process, low energy consumption, and reasonable use of energy, a high extraction rate, and reduced costs, and can be applied on a large scale in industrialization.

[0065] Further, step 3: firstly separating the pyrolysis material to obtain a high-temperature oil-gas mixture and a solid product, wherein the high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar, further comprising:

[0066] Step A: The high-temperature oil-gas mixture is used to exchange heat with cold air to obtain hot air and low-temperature oil-gas mixture, which not only cools the high-temperature oil-gas mixture, but also uses the heat energy of the high-temperature oil-gas mixture to heat the cold air, making rational use of heat energy. This heat exchange is indirect heat exchange, such as a shell and tube heat exchanger. Figure 1 and Figure 2 As shown, the hot air carries the aluminum-rich coal gangue powder for pyrolysis, or, as Figure 1 As shown, hot air carries solid products to undergo activation reaction, thereby realizing energy recovery and utilization.

[0067] Step B: Separate the low-temperature oil and gas mixture three times to obtain room-temperature tar and room-temperature coal gas.

[0068] Furthermore, step B: after the low-temperature oil and gas mixture is separated three times to obtain room-temperature tar and room-temperature coal gas, the process further includes: using the room-temperature coal gas for waste heat power generation. This not only saves energy consumption and makes rational use of resources, but also the coal gas does not pollute the environment.

[0069] Optionally, step 2: pyrolyzing the aluminum-rich coal gangue powder under the influence of hot air to obtain a pyrolysis material, further includes: supplementing the heat source for the pyrolysis by using normal temperature coal gas, thereby rationally utilizing the coal gas.

[0070] Optionally, step 4: the solid product is activated by a carrying gas to obtain calcined aluminum-rich coal gangue, and further includes: supplementing the heat source for the activation reaction by normal temperature coal gas, thereby rationally utilizing the coal gas.

[0071] Further, step 5: after the calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide, it comprises:

[0072] Step M: removing dust from the reaction tail gas to obtain high-temperature flue gas. The reaction tail gas contains a small amount of dust and incompletely reacted gas components, and the reaction tail gas is removed from the dust to obtain high-temperature flue gas.

[0073] Step N: Use the high-temperature flue gas for waste heat power generation, thereby making reasonable use of the heat in the high-temperature flue gas.

[0074] Optionally, step 6: cooling the high temperature active silicon aluminum oxide by heat exchange to obtain the cooling active silicon aluminum oxide, comprising:

[0075] Step X: Cooling the high-temperature active silicon-aluminum oxide by heat exchange with cold air to obtain cooling active silicon-aluminum oxide and second hot air. Recover the heat of the high-temperature active silicon-aluminum oxide by heat exchange with cold air.

[0076] Step Y: using the second hot air for activation reaction, and / or using the second hot air for preheating aluminum-rich coal gangue powder, thereby reasonably recovering and utilizing heat.

[0077] In the method for producing alumina using aluminum-rich coal gangue provided by the embodiment of the present invention, the heat of the high-temperature oil-gas mixture and the high-temperature active silicon-aluminum oxide is fully recovered and utilized during the entire production process. The recycling of hot air provides part of the heat for pyrolysis and thermal activation reactions, reducing the input of external energy. At the same time, the excess coal gas is used for waste heat power generation, and the heat recovered by the multi-stage cooling mechanism is also reasonably utilized, further improving the energy utilization efficiency and significantly reducing the energy consumption of the entire production process.

[0078] The coal gas and reaction exhaust gas produced by pyrolysis are reasonably treated. The coal gas is used for waste heat power generation, reducing waste gas emissions. After dust removal, the content of pollutants such as dust in the reaction exhaust gas meets environmental protection standards, and the high-temperature flue gas is used for waste heat power generation, achieving harmlessness and resource utilization of exhaust gas and achieving environmental friendliness.

[0079] The embodiment of the present invention provides an innovative method for producing alumina from aluminum-rich coal gangue. Through a series of process steps such as pyrolysis, thermal activation and aluminum extraction of aluminum-rich coal gangue powder, efficient extraction of aluminum element can be achieved, the added value of resources can be increased, and the environmental pollution problem of coal gangue can be solved. It can not only help to alleviate the shortage pressure of bauxite resources and promote the sustainable development of the aluminum industry, but also open up new ways for the resource utilization of aluminum-rich coal gangue and achieve a win-win situation for the economy and the environment.

[0080] Another embodiment of the present invention provides a system for producing alumina using aluminum-rich coal gangue, including a pretreatment mechanism 9, a pyrolysis mechanism 1, a first separation mechanism 2, a thermal activation mechanism 5, a second separation mechanism 6, a second heat exchange mechanism 8, a desiliconization mechanism 10 and an aluminum extraction mechanism 11.

[0081] The pretreatment mechanism 9 is used to crush and screen the aluminum-rich coal gangue raw material to obtain aluminum-rich coal gangue powder.

[0082] The pyrolysis mechanism 1 is connected to the pretreatment mechanism 9, and the aluminum-rich coal gangue powder output by the pretreatment mechanism 9 is input into the pyrolysis mechanism 1 at a stable and controllable feeding rate under the hot air for pyrolysis to obtain a pyrolysis material. The pyrolysis mechanism 1 can be a pyrolysis furnace, which is equipped with heating elements and a precise temperature control system. Under the condition of strictly controlling the oxygen content below 5%, the pyrolysis temperature can be precisely controlled in the range of 300°C to 800°C. During the pyrolysis process, high-precision temperature sensors, pressure sensors and other monitoring equipment are installed in the pyrolysis furnace to monitor and feedback various key parameters in the pyrolysis process in real time to ensure that the reaction is always in the best state. The coal gas generated by pyrolysis is discharged through a dedicated pipeline and enters the subsequent first separation mechanism 2.

[0083] The first separation mechanism 2 is connected to the pyrolysis mechanism 1. The pyrolysis material output by the pyrolysis mechanism 1 is rapidly input into the first separation mechanism 2 through a high-temperature resistant and well-insulated pipeline for initial separation to obtain a high-temperature oil-gas mixture and solid products. The oil-gas mixture includes high-temperature coal gas and high-temperature tar.

[0084] The tar is efficiently collected by a specially designed tar collection device (such as a tar tank) for subsequent professional oil washing treatment. The generated powdered coke is discharged by a special discharge device (such as a star discharger) and stored as a high-quality heat source for the thermal activation mechanism 5.

[0085] The thermal activation mechanism 5 is connected to the first separation mechanism 2. The solid product outputted from the first separation mechanism 2 is carried by the carrying gas and inputted into the thermal activation mechanism 5 at a stable conveying rate for activation reaction to obtain calcined aluminum-rich coal gangue.

[0086] like Figure 1 and Figure 2 As shown, the carrying gas can be hot air output by the first heat exchange mechanism 3, or can be room temperature coal gas output by the oil washing mechanism 4. The thermal activation mechanism 5 can be a rotary kiln, a conveyor bed or a fluidized bed, which is selected according to actual needs, and the temperature range of the activation reaction is 700°C to 1200°C. During the activation reaction, the minerals in the solid product further undergo decomposition, oxidation and other reactions to obtain calcined aluminum-rich coal gangue.

[0087] During the activation process, the thermal activation mechanism 5 is equipped with advanced temperature monitoring, gas flow rate monitoring and material fluidization state monitoring equipment to monitor the reaction progress in real time, ensuring that the material can be evenly heated and fully reacted in the thermal activation mechanism 5, thereby achieving efficient decomposition and oxidation conversion of minerals.

[0088] The second separation mechanism 6 is connected to the thermal activation mechanism 5, and the calcined aluminum-rich coal gangue output by the thermal activation mechanism 5 is input to the second separation mechanism 6 for secondary separation to obtain reaction tail gas and high-temperature active silicon aluminum oxide.

[0089] The second heat exchange mechanism 8 is connected to the second separation mechanism 6, and the high-temperature active silicon-aluminum oxide output by the second separation mechanism 6 is input to the second heat exchange mechanism 8 for heat exchange cooling to obtain the temperature-reduced active silicon-aluminum oxide.

[0090] The second heat exchange mechanism 8 cools the high temperature active silicon aluminum oxide by heat exchange with cold air to obtain the cooled active silicon aluminum oxide and the second hot air. The second hot air is used for activation reaction and / or the second hot air is used for preheating aluminum-rich coal gangue powder to achieve comprehensive utilization of energy.

[0091] The second heat exchange mechanism 8 is a combination of one or more of a cyclone cooler and a rotary cooler, and the temperature of the finally cooled active silicon aluminum oxide is 25°C to 300°C.

[0092] The desiliconization mechanism 10 is connected to the second heat exchange mechanism 8, and the cooling active silicon aluminum oxide output by the second heat exchange mechanism 8 is input to the desiliconization mechanism 10 for pre-desiliconization treatment to obtain a treated product.

[0093] The aluminum extraction mechanism 11 is connected to the desiliconization mechanism 10, and the treated product output by the desiliconization mechanism 10 is input to the aluminum extraction mechanism 11 for aluminum extraction to obtain aluminum oxide.

[0094] The system for producing alumina using aluminum-rich coal gangue provided in the embodiment of the present application also includes: a heat exchange mechanism and an oil washing mechanism 4. The heat exchange mechanism is connected to the first separation mechanism 2, and the high-temperature oil-gas mixture output by the first separation mechanism 2 is quickly output to the first heat exchange mechanism 3 through a high-temperature resistant and well-insulated pipeline to exchange heat with cold air to obtain hot air and a low-temperature oil-gas mixture.

[0095] The oil washing mechanism 4 is connected to the first heat exchange mechanism 3. The low-temperature oil-gas mixture output by the first heat exchange mechanism 3 is quickly input into the oil washing mechanism 4 through a high-temperature resistant and well-insulated pipeline for three separations to obtain room-temperature tar and room-temperature coal gas. After the low-temperature oil-gas mixture is processed by the oil washing mechanism 4, organic chemical raw materials such as benzene and naphthalene can be recovered. Room-temperature tar is transported to the oil washing mechanism 4 through a dedicated pipeline at a stable flow rate for deep processing to recover high-value organic components.

[0096] The system for producing alumina using aluminum-rich coal gangue provided in the embodiment of the present application further includes: a power generation mechanism 12. The power generation mechanism 12 is connected to the oil washing mechanism 4. The normal temperature coal gas output by the oil washing mechanism 4 is input to the power generation mechanism 12 for waste heat power generation, thereby making full use of thermal energy.

[0097] Optional, such as Figure 1 and Figure 2 As shown, the oil washing mechanism 4 is connected to the pyrolysis mechanism 1. The normal temperature coal gas output by the oil washing mechanism 4 is input to the pyrolysis mechanism 1 to supplement the heat source for pyrolysis.

[0098] Optional, such as Figure 1 As shown, the oil washing mechanism 4 is connected to the thermal activation mechanism 5. The normal temperature coal gas output by the oil washing mechanism 4 is input to the thermal activation mechanism 5 to supplement the heat source for the activation reaction.

[0099] Furthermore, the system for producing alumina using aluminum-rich coal gangue provided in the embodiment of the present application also includes: a dust removal mechanism 7.

[0100] The dust removal mechanism 7 is connected to the second separation mechanism 6. The reaction tail gas (temperature of 700°C to 1000°C) output by the second separation mechanism 6 is quickly input to the dust removal mechanism 7 through a high temperature resistant pipeline for dust removal to obtain high temperature flue gas.

[0101] The power generation mechanism 12 is connected to the dust removal mechanism 7. The high-temperature flue gas output by the dust removal mechanism 7 is input to the power generation mechanism 12 for waste heat power generation.

[0102] The dust removal mechanism 7 is a combination of one or more types of a high-efficiency cyclone dust collector and an interception dust collector.

[0103] The system for producing alumina using aluminum-rich coal gangue provided by the embodiment of the present invention can realize the integrated process of pyrolysis-thermal activation-aluminum extraction. During the pyrolysis and thermal activation process, the aluminum silicate structure in the aluminum-rich coal gangue powder is initially decomposed, which not only provides favorable conditions for subsequent desiliconization and aluminum extraction, but also can recycle and utilize the generated energy products such as coal gas and tar, and can effectively extract the aluminum element in the aluminum-rich coal gangue, realize efficient resource utilization, high-value utilization of coal gangue resources, increase resource added value, provide a new source of raw materials for the aluminum industry, and alleviate the tense situation of bauxite resources. In addition, the method of the present application is simple in process, low in energy consumption, and reasonable in energy utilization, with a high extraction rate, reduced costs, and can be applied on a large scale in industrialization.

[0104] In the whole production process, the heat of high-temperature oil-gas mixture and high-temperature active silicon-aluminum oxide is fully recovered and utilized. The circulation of hot air provides part of the heat for pyrolysis and thermal activation reaction, reducing the input of external energy. At the same time, the excess gas is used for waste heat power generation, and the heat recovered by the multi-stage cooling mechanism is also reasonably utilized, further improving the energy utilization efficiency and significantly reducing the energy consumption of the whole production process.

[0105] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0106] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A method for producing alumina using aluminum-rich coal gangue, characterized in that: include: The aluminum-rich coal gangue raw material is crushed and screened to obtain aluminum-rich coal gangue powder; Pyrolyzing the aluminum-rich coal gangue powder under the influence of hot air to obtain a pyrolysis material; The pyrolysis material is first separated to obtain a high-temperature oil-gas mixture and a solid product, wherein the high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar; The solid product is activated by a carrier gas to obtain calcined aluminum-rich coal gangue; The calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide; Cooling the high temperature active silicon aluminum oxide by heat exchange to obtain a cooling active silicon aluminum oxide; The cooling active silicon-aluminum oxide is subjected to a pre-desiliconization treatment to obtain a treated product; The treated product is subjected to aluminum extraction to obtain aluminum oxide.

2. The method for producing alumina using aluminum-rich coal gangue according to claim 1, characterized in that: The pyrolysis material is first separated to obtain a high-temperature oil-gas mixture and a solid product, wherein the high-temperature oil-gas mixture includes high-temperature coal gas and high-temperature tar, and further includes: The hot air and the low-temperature oil-gas mixture are obtained by exchanging heat with the cold air through the high-temperature oil-gas mixture; The low-temperature oil-gas mixture is separated three times to obtain normal-temperature tar and normal-temperature coal gas.

3. The method for producing alumina using aluminum-rich coal gangue according to claim 2, characterized in that: The aluminum-rich coal gangue powder is pyrolyzed under the influence of hot air to obtain a pyrolysis material, and further comprises: The room temperature coal gas is used to supplement the heat source for pyrolysis.

4. The method for producing alumina using aluminum-rich coal gangue according to claim 2, characterized in that: The solid product is activated by a carrier gas to obtain calcined aluminum-rich coal gangue, and the process further comprises: The room temperature coal gas is used to supplement the heat source for the activation reaction.

5. The method for producing alumina using aluminum-rich coal gangue according to any one of claims 2 to 4, characterized in that: After the low-temperature oil-gas mixture is separated three times to obtain normal-temperature tar and normal-temperature coal gas, the method further comprises: The room temperature coal gas is used for waste heat power generation.

6. The method for producing alumina using aluminum-rich coal gangue according to claim 1, characterized in that: After the calcined aluminum-rich coal gangue is subjected to secondary separation to obtain reaction tail gas and high-temperature active silicon-aluminum oxide, the method comprises: Dedusting the reaction tail gas to obtain high-temperature flue gas; The high-temperature flue gas is used for waste heat power generation.

7. The method for producing alumina using aluminum-rich coal gangue according to claim 1, characterized in that: The high temperature active silicon aluminum oxide is subjected to heat exchange cooling to obtain the temperature-lowering active silicon aluminum oxide, comprising: The high temperature active silicon aluminum oxide is cooled by heat exchange with cold air to obtain cooling active silicon aluminum oxide and second hot air; The second hot air is used for activation reaction, and / or the second hot air is used for preheating the aluminum-rich coal gangue powder.

8. The method for producing alumina using aluminum-rich coal gangue according to claim 1, characterized in that: The oxygen concentration of the pyrolysis is less than 5%, and the temperature is 300°C to 800°C.

9. The method for producing alumina using aluminum-rich coal gangue according to claim 1, characterized in that: The aluminum content of the aluminum-rich coal gangue raw material is greater than or equal to 40%, and the particle size of the aluminum-rich coal gangue powder ranges from 0 mm to 3 mm.

10. A system for producing alumina using aluminum-rich coal gangue, characterized in that: It includes a pretreatment mechanism, a pyrolysis mechanism, a first separation mechanism, a thermal activation mechanism, a second separation mechanism, a heat exchange mechanism, a desiliconization mechanism and an aluminum extraction mechanism; The pretreatment mechanism is used to crush and screen the aluminum-rich coal gangue raw material to obtain aluminum-rich coal gangue powder; The pyrolysis mechanism is connected to the pretreatment mechanism, and the aluminum-rich coal gangue powder output by the pretreatment mechanism is input into the pyrolysis mechanism under the influence of hot air for pyrolysis to obtain pyrolysis material; The first separation mechanism is connected to the pyrolysis mechanism, and the pyrolysis material output by the pyrolysis mechanism is input to the first separation mechanism for primary separation to obtain a high-temperature oil-gas mixture and a solid product, wherein the oil-gas mixture includes high-temperature coal gas and high-temperature tar; The thermal activation mechanism is connected to the first separation mechanism, and the solid product output by the first separation mechanism is input into the thermal activation mechanism under the carrying gas for activation reaction to obtain calcined aluminum-rich coal gangue; The second separation mechanism is connected to the thermal activation mechanism, and the calcined aluminum-rich coal gangue output by the thermal activation mechanism is input into the second separation mechanism for secondary separation to obtain reaction tail gas and high-temperature active silicon aluminum oxide; The heat exchange mechanism is connected to the second separation mechanism, and the high-temperature active silicon-aluminum oxide output by the second separation mechanism is input into the heat exchange mechanism for heat exchange cooling to obtain the temperature-reduced active silicon-aluminum oxide; The desiliconization mechanism is connected to the heat exchange mechanism, and the cooling active silicon-aluminum oxide output by the heat exchange mechanism is input into the desiliconization mechanism for pre-desiliconization treatment to obtain a treated product; The aluminum extraction mechanism is connected to the desiliconization mechanism, and the treated product output by the desiliconization mechanism is input into the aluminum extraction mechanism to extract aluminum to obtain aluminum oxide.

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