A method for forced conversion of valuable components in white ash by wet grinding

Abstract

A method for forced conversion of valuable components in white gangue through wet grinding and pulping is disclosed. The method involves intelligent gangue selection, crushing the gangue, and then forcibly reacting it with a multi-component complex acid (hydrochloric acid, sulfuric acid, and nitric acid) in a rotary ball mill under crushing and penetrating conditions. The aqua regia effect of the multi-component acid easily breaks the chemical bonds of silicates in the gangue under gravity crushing, allowing the aluminum and iron metal components in the material to be dissolved by acid. The reaction product, aluminum ferrite, is washed and dissolved in water and subjected to an ammonia displacement reaction to obtain a mixture of aluminum hydroxide and iron hydroxide. The mixture is then subjected to alkali dissolution to extract aluminum hydroxide, achieving precise separation of aluminum and iron components and purification of alumina. Sodium silicate is produced by alkaline conversion of silica. Sodium silicate is then used to absorb carbon dioxide to displace silicic acid, which is then dried by high-pressure atomization to form molecular sieve hollow granules. In this invention, aluminum is extracted by acid extraction and silicon by alkali extraction, enabling resource utilization of solid waste while optimizing the process and maximizing the value of the products.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, and in particular to a method for the forced conversion of valuable components in white gangue through wet milling and pulping in the comprehensive utilization of industrial solid waste. Background Technology

[0002] Coal gangue is one of the largest industrial solid wastes generated and accumulated in my country, accounting for approximately 10%-20% of raw coal production. These gangue piles not only occupy vast amounts of land but also release SO2, CO, and dust through spontaneous combustion, polluting the atmosphere. Rainwater leaching from these piles also produces acidic wastewater containing heavy metals and salts, severely polluting the soil and groundwater. Some loose gangue piles also pose risks of landslides and mudslides. The traditional "piling-compacting-covering" disposal method is no longer sustainable.

[0003] In recent years, the national government has issued a series of policies to drive a fundamental shift in coal gangue treatment methods. Documents such as the "Solid Waste Pollution Prevention and Control Law" explicitly list coal gangue as a key area for research and development, requiring adherence to the principles of "reduction, resource recovery, and harmless disposal," and setting specific targets for comprehensive utilization rates. Local policies and environmental inspections in major coal-producing areas have directly linked coal gangue issues to the survival and development of enterprises, forcing industrial upgrading.

[0004] Early utilization of coal gangue was mainly limited to low-tech backfilling and road construction. With the advancement of materials science, chemical processes, and the concept of a circular economy, its utilization has expanded to diverse fields such as building material production, energy recovery, chemical raw material extraction, and ecological restoration. The core logic of technological development is rapidly shifting from "reduction and disposal" to "resource-based value enhancement," striving to solve environmental problems while simultaneously unlocking its inherent mineral, energy, and material value.

[0005] Currently, the comprehensive utilization of coal gangue has formed four major technological directions, constituting tiered utilization.

[0006] 1. Utilization as building materials: Producing building materials, preparing new cementitious materials, and extracting high-value-added minerals.

[0007] 2. Energy utilization: The calorific value is recycled for power generation, heating, and the preparation of clean fuels.

[0008] 3. Chemical Utilization (Extraction of Valuable Elements)

[0009] Aluminum, silicon, titanium, gallium and other elements are extracted from coal gangue through hydrometallurgical processes such as acid and alkali leaching or high-temperature activation techniques to prepare aluminum-based products and synthesize porous materials.

[0010] 4. Ecological and engineering applications: underground filling and open-pit mine backfilling, land reclamation and ecological restoration, road construction and foundation materials.

[0011] Despite the diverse technological pathways, large-scale and efficient utilization still faces multiple constraints, primarily manifested in the following aspects: 1) Compositional complexity and volatility: The composition of coal gangue varies greatly due to differences in mining areas and coal seams, and fluctuates drastically, resulting in poor adaptability of single technologies and difficulties in standardization and large-scale production. 2) Some high-value technologies (such as efficient aluminum extraction and the preparation of high-end materials) still suffer from high energy consumption, long processes, poor product stability, and difficulties in controlling secondary pollution. 3) Apart from a few pathways such as power generation and brick making, many high-value technologies lack cost competitiveness, heavily rely on government subsidies or policy mandates, and have weak market-driven forces. 4) Market acceptance of coal gangue building materials products needs to be improved; relevant national and industry standards are still incomplete, affecting product quality certification and large-scale promotion. 5) Coal-producing areas often do not overlap with areas densely populated with building materials and chemical industries, resulting in high long-distance transportation costs, necessitating the development of regional integrated utilization industries.

[0012] In conclusion, there are still many shortcomings in the treatment of solid waste coal gangue: Although land reclamation and soil improvement have absorbed a huge amount of solid waste, the complex composition of coal gangue can lead to the leaching of acidic wastewater containing heavy metals and salts by rainwater, which can seriously pollute the soil and groundwater.

[0013] Because coal gangue is prone to spontaneous combustion, using it for mine backfilling and roadbed construction only takes into account the function of replacing sand and gravel, but buries uncertain hidden dangers.

[0014] The main components of coal gangue are alumina and silicon dioxide. Alumina is an important strategic resource and currently occupies an important position in international resource reserves. Using it for low-value applications such as building materials, mine backfilling, land reclamation, and manufacturing improved soil not only poses a risk of secondary pollution, but also represents a waste of resources and a short-sighted behavior that does not pay the price for high-value use.

[0015] Although the current state of chemical waste utilization is worrying, with high energy consumption and serious secondary pollution, continuous improvement and innovation, along with ongoing technological advancements, will inevitably lead to the maximization of value, the minimization of cost, and the maximization of processing energy. This is because chemical utilization is an essential step in the utilization of any industrial solid waste. Only through chemical conversion methods can valuable components be extracted, converted, separated, and purified, thus maximizing their value. However, white gangue in coal gangue, due to its different formation mechanism and structure dominated by aluminum silicate with very little fixed carbon and volatile matter, is difficult to decompose and activate through combustion. Therefore, extracting alumina and silica using chemical methods is challenging, and it remains a difficult-to-treat and utilize solid waste. Only through technological innovation can large-scale solid wastes such as coal gangue be truly utilized as resources. Summary of the Invention

[0016] The purpose of this invention is to provide a method for forcibly converting valuable components in white gangue through wet milling pulping to solve the above-mentioned technical problems.

[0017] To achieve the above-mentioned objectives, the present invention provides the following technical solution: Technical solution: 1. White gangue and black gangue are separated by intelligent gangue sorting equipment. White gangue is crushed into small particles with a particle size of less than 5mm by a crusher.

[0018] 2. Based on the alumina content in the white gangue, prepare a polyacid solvent by the relative atomic mass ratio of the chemical reaction formula. Then, put hydrochloric acid, sulfuric acid and nitric acid into high-level acid storage tanks respectively. Acid tank (1) stores hydrochloric acid, acid tank (2) stores sulfuric acid and acid tank (3) stores nitric acid.

[0019] 3. The crushed raw material (1) is sent to the feed port of the drum ball mill through a screw conveyor or belt conveyor and discharged into the drum ball mill from the feed hopper, so that the material rises and falls along the wall as the drum rotates.

[0020] 4. First, open the discharge valve of the acid (1) storage tank in sequence, allowing the metered hydrochloric acid to slowly flow into the drum and mix with the raw materials as it rotates. Then, open the discharge valve of the acid (2) storage tank and slowly inject sulfuric acid into the material that has been mixed with hydrochloric acid solvent in the drum. Then, open the discharge valve of the acid (3) storage tank and slowly inject nitric acid into the material that has been mixed with both hydrochloric acid and sulfuric acid solvents, so that the raw material (1) becomes a paste-like raw material (2) after being mixed with the three solvents.

[0021] 5. Under the rotation of the drum, the raw material (2) and the grinding media are lifted to a certain height along with the drum body. Due to gravity, they detach from the drum wall and slide down in a parabolic path. The grinding media and the material rotate and tumble at a uniform speed in the grinding tank, which generates strong cutting, impact and crushing on the material, so that the solvent achieves the purpose of wetting, grinding, dispersing and emulsifying the material. The strong acid component in the solvent continues to penetrate the material during the crushing process, which enhances the chemical oxidation ability and achieves the forced conversion effect. When the raw material (2) is ground into an emulsified paste and the pH value rises to 4-5, the forced conversion between the material and the solvent is completed.

[0022] 6. After the reaction in the drum is basically complete, slowly introduce an appropriate amount of clean water (greater than or equal to 3 times the amount of material) into the drum through the water pipe to rinse and dilute the material, and then discharge the diluted material intermittently.

[0023] 7. The discharged diluted material is introduced into the washing and dissolving system, and the soluble salt generated by the reaction is dissolved in water by continuous counter-rotating stirring to form the product liquid (1). The product liquid (1) is filtered through a multi-stage filter to filter out the clear liquid (1) and the retained solids (1).

[0024] The generated liquid (1) is an unfiltered mixed solution; the clear liquid (1) is an aluminate and ferrate solution after filtering out impurities; the solid (1) is the slag material with silicon dioxide as the main component after aluminum and iron extraction.

[0025] 8. Introduce the clear liquid (1) into the ammonia replacement system and add ammonia water or ammonia gas to carry out the replacement reaction, displacing aluminum hydroxide and iron hydroxide.

[0026] 9. The mixture after displacement is subjected to sedimentation for solid-liquid separation, and the precipitate is mixed with sodium hydroxide in proportion. Because aluminum hydroxide in the precipitate is an amphoteric oxide that can be dissolved in both acid and alkali, while iron hydroxide is a unipolar oxide that can only be dissolved in acid but not in alkali, sodium hydroxide dissolves aluminum hydroxide in the mixture to form sodium tetrahydroxyaluminate solution, which is then filtered with undissolved iron hydroxide through a plate and frame filter press to separate the product liquid (2) and solid (2).

[0027] The solid (2) is the ferric hydroxide solid after the sodium tetrahydroxyaluminate liquid has been separated; The generated solution (2) is a sodium tetrahydroxyaluminate solution; 10. Carbon dioxide is bubbled into a sodium tetrahydroxyaluminate solution to carry out an ion exchange reaction, displacing aluminum hydroxide.

[0028] 11. Analyze the content of silicon dioxide in solid (1), prepare solid sodium hydroxide according to the ratio of relative molecular mass in the chemical reaction formula, and after uniform mixing, put it into the drum of the ball mill and add an appropriate amount of water so that the ratio of material to water is greater than 1:1 and forms a paste; repeat the acid dissolution process to force the conversion of silicon dioxide with sodium hydroxide in grinding and rolling.

[0029] 12. When the alkaline dissolution reaction proceeds to a point where the pH of the material is less than or equal to 9, the reaction is complete. An appropriate amount of clean water (greater than or equal to 3 times the amount of the material) is introduced into the tank to rinse and dilute the material, and then the diluted material is discharged intermittently. The discharged diluted material is introduced into the washing and dissolving system, and the soluble salts generated by the reaction are dissolved in the water to become the product liquid (3) through continuous counter-rotating stirring.

[0030] The generated liquid (3) is a sodium silicate solution mixed with unreacted impurity particles. The generated liquid (3) is filtered through a multi-stage filter to remove the clear liquid (2) and the retained solids (3).

[0031] The clear liquid (2) is a sodium silicate solution; The solid (3) is an impurity component that is difficult to convert.

[0032] 13. The clear liquid (2) is introduced into the carbon dioxide ion exchange system and the tail gas generated by the drying process is introduced, so that the clear liquid (2) absorbs the carbon dioxide in the tail gas and produces an ion exchange reaction, displacing silicic acid and sodium carbonate. The mixture of silicic acid and sodium carbonate is then filtered through a plate and frame filter press. The silicic acid is retained and becomes a filter cake, while the sodium carbonate is filtered out with the solution.

[0033] 14. The silica filter cake is stirred at high speed to form a thick slurry, which is then dried by high-pressure atomization to produce foamed hollow granular molecular sieves. Sodium carbonate solution is reacted with calcium hydroxide to produce sodium hydroxide and calcium carbonate, which are then separated by centrifugation and dehydration. The calcium carbonate is then dried to produce nano-calcium carbonate, and the sodium hydroxide is recycled for alkaline silica dissolution. Detailed Implementation

[0034] White gangue forms in the roof and floor of coal seams, where alumina and silica exist in the form of aluminum silicate, which is difficult to oxidize and decompose under normal conditions. If coal gangue is to be processed and utilized chemically, the stable chemical structure of aluminum silicate makes conversion and extraction difficult. Furthermore, the resulting components lack fixed carbon and volatile organic matter, making combustion an ineffective method for decomposing aluminum silicate. Therefore, valuable components must be extracted and utilized through specialized chemical methods.

[0035] Based on the physical and chemical characteristics of white gangue, this invention creates a wet milling and forced conversion method. During wet milling, the acid radicals in the solvent and the metal ions of the reactants are targeted and locked together under strong pressure to achieve forced conversion through crushing and penetration. This objective is achieved through the following method.

[0036] 1. White gangue and black gangue are separated by intelligent gangue sorting equipment, and the white gangue is extracted.

[0037] The intelligent gangue sorting machine is a sorting device that uses X-ray + AI high-speed camera intelligent recognition method for sorting. White gangue and black gangue are significantly different in color, so an AI high-speed camera is used for identification. A recognition model is established based on the color difference for analysis. The material is located and tracked through big data sorting, and finally sorted through an intelligent jetting system. The selected white gangue is crushed into small particles with a particle size of less than 5mm by a crusher to make raw materials (1).

[0038] 2. Solvent and gangue are pressed and penetrated together through a horizontal wet ball mill to achieve forced conversion.

[0039] The raw material (1) is conveyed to the storage hopper above the feed inlet of the drum ball mill by a screw conveyor or belt conveyor. The storage hopper is a storage container with a meter. The stored material is quantified according to the material capacity and conversion speed in the ball mill. The amount in each hopper is sufficient for one cycle of the ball mill.

[0040] The described rotary ball mill is a horizontal device composed of a rotary drum, an electric drive unit, grinding media balls of different specifications, a protective jacket, a support frame, an automatic unloading device, an exhaust channel, and a gaseous pollutant adsorption and purification device. The rotary drum is made of acid and alkali resistant 321 stainless steel and lined with high wear-resistant polyurethane. The grinding media balls are made of 316 stainless steel and come in various sizes from large to small. The grinding media accounts for 1 / 3 of the rotary drum's capacity.

[0041] After the raw material (1) is added from the storage container to the feed funnel, it is discharged into the ball mill drum. The material rises and falls along the wall as the drum rotates. Open the discharge valve of the acid (1) storage tank to allow the metered hydrochloric acid to slowly flow into the drum and mix with the raw material (1) under rotation. Then open the discharge valve of the acid (2) storage tank to slowly inject sulfuric acid into the material that has been mixed with hydrochloric acid solvent in the drum. Then open the discharge valve of the acid (3) storage tank to slowly inject nitric acid into the material that has been mixed with hydrochloric acid and sulfuric acid solvents, so that the solvent forms a multi-component composite acid. The multi-component composite acid, which is made up of three strong acids, greatly enhances the oxidizing ability of the solvent, so that it produces the aqua regia effect, which rapidly corrodes and oxidizes the reactants, so that the raw material (1) becomes a paste-like raw material (2) under strong corrosion and oxidation.

[0042] The raw material (2) is lifted to a certain height by the rotation of the drum and the grinding media. Due to gravity, it falls off the drum wall along a parabolic line. The grinding media and the material roll at high speed in the grinding tank, which produces strong cutting, impact and crushing on the material. Due to the strong oxidation ability of the three acids, coupled with the crushing force of the grinding media, the kinetic potential and divergence force of the acid radical ions in the solvent are excited, which target and bite the aluminum ions in the alumina, so that it achieves forced conversion.

[0043] When the pH value of the reactants in the drum rises to greater than 4, the reaction is basically completed. Then, an appropriate amount of clean water (greater than or equal to 3 times the amount of material) is introduced into the drum to rinse and dilute the material, and then the diluted material is discharged in batches intermittently.

[0044] The discharged diluted material is introduced into the washing and dissolving system, and the soluble salt generated by the reaction is dissolved in water to form the product liquid (1).

[0045] The generated liquid (1) is filtered through a multi-stage filter to filter out the clear liquid (1) and the retained solids (1).

[0046] When the clear liquid (1) is introduced into the ammonia replacement system, ammonia water or ammonia gas is added, and the aluminum and iron components in the clear liquid (1) are replaced in the form of aluminum hydroxide and iron hydroxide.

[0047] The replaced mixture was filtered by a plate and frame filter press to separate the clear liquid (2) and solids (2).

[0048] The generated solution (1) is a mixed solution of alumina and iron oxide dissolved in a polybasic acid; The clear liquid (1) is a mixed solution containing various aluminates after the unreacted silica has been separated; The solid (1) mentioned above is the silica solid after the aluminate liquid has been separated; The clear liquid (2) mentioned above is a polyacid ammonium solution generated after ammonia replacement; The solid (2) is a mixture of aluminum hydroxide and iron hydroxide.

[0049] The solid (1) was analyzed for its silica content. A sodium hydroxide solution with a mass concentration of 30-42% was prepared according to the ratio of relative molecular mass in the chemical reaction formula and loaded into a drum ball mill. The acid dissolution process was repeated to force the silica to be converted with sodium hydroxide during grinding and rolling.

[0050] When the alkaline dissolution reaction proceeds to a pH of less than or equal to 9, the reaction is complete. Then, an appropriate amount of clean water (greater than or equal to 3 times the amount of the material) is introduced into the tank to rinse and dilute the material, and the diluted material is then discharged intermittently at intervals.

[0051] The discharged diluted material is introduced into the washing and dissolving system, and the soluble salt generated by the reaction is dissolved in water by continuous counter-rotating stirring to become the product liquid (3).

[0052] By analyzing the content of aluminum hydroxide in solid (2), the amount of sodium hydroxide required to dissolve aluminum hydroxide is prepared according to the ratio of relative molecular mass in the chemical reaction formula. The measured sodium hydroxide is mixed with solid (2) and loaded into a roller ball mill for grinding to complete the permeation conversion. The converted product is washed, dissolved, and filtered. After filtering out iron hydroxide, the filtrate is reacted with carbon dioxide to replace aluminum hydroxide. Aluminum hydroxide is then processed into aluminum hydroxide or aluminum oxide products. Iron hydroxide is processed into finished products.

[0053] The generated liquid (3) is a sodium silicate solution mixed with unreacted impurity particles. The generated liquid (3) is filtered through a multi-stage filter to remove the sodium silicate solution and residue. The sodium silicate solution is introduced into a carbon dioxide ion exchange system and the tail gas generated in the drying process is introduced, so that the sodium silicate solution absorbs the carbon dioxide in the tail gas to produce an ion exchange reaction, displacing silicic acid and sodium carbonate.

[0054] A mixture of silicic acid and sodium carbonate is filtered through a plate and frame filter press. The silicic acid is retained and becomes a filter cake, while the sodium carbonate is filtered out with the solution.

[0055] The silica filter cake is stirred at high speed to make a thick slurry, and then dried by high pressure atomization to make a foam hollow particle molecular sieve. The sodium carbonate solution is reacted with calcium hydroxide to produce sodium hydroxide and calcium carbonate, and then the two substances are separated by centrifugation and dehydration.

[0056] Calcium carbonate is dried to produce nano-calcium carbonate, and sodium hydroxide is recycled for alkaline silicon dissolution.

[0057] Example: A pilot project for the comprehensive utilization of 50,000 tons / year of coal gangue, jointly developed by Gaotouyao Coal Mine of Inner Mongolia Beilian Electric Energy Development Co., Ltd. and Longyuan (Beijing) Environmental Protection Technology Co., Ltd.

[0058] Project Implementer: Gaotouyao Coal Mine, Inner Mongolia Beilian Electric Energy Development Co., Ltd. Partner: Longyuan (Beijing) Environmental Protection Technology Co., Ltd.

[0059] Inner Mongolia Beilian Electric Energy Development Co., Ltd.'s Gaotouyao Coal Mine and Longyuan (Beijing) Environmental Protection Technology Co., Ltd. have reached a cooperation agreement on the comprehensive utilization of coal gangue from the mine. The agreement outlines a method for the comprehensive treatment of coal gangue produced by the mine, involving "forced conversion of valuable components in white gangue through wet grinding and pulping." The coal gangue composition is as follows: Fe2O3: 2.45%, SiO2: 55.68%, Al2O3: 31%, CaO: 0.49%, SO3: 0.18%, fixed carbon and volatile matter 11%, calorific value 200 kcal. Based on the composition analysis, this coal gangue is a high-alumina coal gangue with low calorific value, making it unusable for combustion and rendering its calorific value untapped. To reduce coal mine solid waste emissions, this project employs "a method for forced conversion of valuable components in white gangue through wet grinding and pulping." This method uses a chemical approach to treat and utilize coal gangue through forced conversion. By alternating alkali and acid extraction to extract aluminum and silicon from the coal gangue in stages and steps, the project also removes carbon dioxide from the drying process flue gas. This creates a synergistic effect between flue gas decarbonization and coal gangue aluminum and silicon extraction in the treatment process, integrating coal gangue treatment with flue gas purification. The extracted usable components are greater than 95%.

[0060] Construction content and scale

[0061] (I) Construction Content

[0062] 1. Construct two wet ball mills with a capacity of 3.5t / h each, and force-convert 7t / h of white gangue.

[0063] 2. Matching acid (1 sulfuric acid) storage tank 50t 3 units, with matching acid (2) nitric acid storage tanks of 50t. 3 units, with matching acid (3) hydrochloric acid storage tanks totaling 50t. 10 units. Two blending units, two 50m³ composting tanks, and two 10m³ / unit washing and dissolving tanks. 10 units: two ammonia exchangers (5 m³ / unit); two carbon dioxide ion exchangers (5 m³ / unit); 9 Two 250 / 6 row-type multi-stage filters and two plate and frame filter presses, each with a capacity of 120 m² and a capacity of 5 t / h.

[0064] One precast concrete mixing machine; (10kW-3.5) 16) One bipolar brush-spreading dryer and granulator; (5kw-3.5) 22) One high-pressure atomizing dryer; two 20m² pulse bag dust collectors.

[0065] (I) Construction Scale

[0066] 50,000 tons / year, 6.25 t / h.

[0067] Process Flow

[0068] 1. White gangue and black gangue are separated by intelligent gangue sorting equipment, and the white gangue is extracted.

[0069] The intelligent gangue sorting machine is a gangue sorting device that uses X-ray + AI high-speed camera intelligent recognition method for sorting. White gangue and black gangue have a large color difference, so AI high-speed camera is used for identification. The recognition model is established based on the color difference for analysis. The material is located and tracked through big data sorting, and finally sorted by intelligent jet blowing system. The sorted white gangue is crushed into small particles with a particle size of less than 5mm by crusher to make raw material (1).

[0070] The crusher mentioned is either a hammer crusher or a disc crusher, with a disc crusher being preferred.

[0071] 2. Solvent and gangue are pressed and penetrated together through a horizontal wet ball mill to achieve forced conversion.

[0072] The raw material (1) is conveyed to the storage hopper above the feed inlet of the drum ball mill by a screw conveyor or belt conveyor. The storage hopper is a storage container with a meter. The stored material is quantified according to the material capacity and conversion speed in the ball mill. The amount in each hopper is sufficient for one cycle of the ball mill.

[0073] The described roller ball mill is a horizontal device composed of rollers, electric drive unit, grinding media balls of different specifications, protective jacket, support, automatic unloading device, exhaust channel, gaseous pollutant adsorption and purification device, etc. The roller is made of acid and alkali resistant 321 stainless steel and lined with high wear resistant polyurethane. The grinding media balls are made of 316 stainless steel and the grinding media accounts for 1 / 3 of the roller capacity.

[0074] After the raw material (1) is added from the storage container to the feed funnel, it is discharged into the ball mill drum and rises and falls along the wall as the drum rotates. The discharge valve of the acid (1) storage tank is slowly opened, so that the metered hydrochloric acid slowly flows into the drum and mixes with the raw material (1) under rotation; then the discharge valve of the acid (2) storage tank is opened, so that the sulfuric acid is slowly injected into the material that has been mixed with hydrochloric acid solvent in the drum; then the discharge valve of the acid (3) storage tank is opened, so that the nitric acid is slowly injected into the material that has been mixed with hydrochloric acid and sulfuric acid solvents, so that the solvent forms a multi-component complex acid, which greatly enhances the oxidizing ability of the solvent, so that it produces the aqua regia effect, rapidly corroding and oxidizing the reactants, so that the raw material (1) becomes a paste-like raw material (2) under strong corrosion and oxidation.

[0075] The raw material (2) is lifted to a certain height by the rotation of the drum and the grinding media. Due to gravity, it falls off the drum wall along a parabola. The grinding media and the material roll at high speed in the grinding tank, which produces strong cutting, impact and crushing on the material. Due to the super strong oxidation ability of the three acids, coupled with the crushing force of the grinding media, the motion potential and divergence force of the acid radical ions in the solvent are excited, which targets and bites the aluminum ions in the alumina, so that it achieves forced conversion.

[0076] When the pH value of the reactants in the drum rises to greater than 4, the reaction is basically complete. Then, an appropriate amount of clean water (greater than or equal to 3 times the amount of material) is introduced into the drum to rinse and dilute the material, and then the diluted material is discharged intermittently at intervals.

[0077] The discharged diluted material is introduced into the washing and dissolving system, and the existing technology of counter-rotating stirring is used to dissolve the soluble salt generated in the reaction into the water to form the product liquid (1).

[0078] The generated liquid (1) is filtered through a multi-stage filter to filter out the clear liquid (1) and the retained solids (1).

[0079] When the clear liquid (1) is introduced into the ammonia replacement system, ammonia water or ammonia gas is added, and the aluminum and iron components in the clear liquid (1) are replaced in the form of aluminum hydroxide and iron hydroxide.

[0080] The replaced mixture is filtered by a plate and frame filter press to separate the product liquid (2) and solids (2).

[0081] The generated solution (1) is a mixed solution of alumina and iron oxide dissolved in a polybasic acid; The clear liquid (1) is a mixed solution containing various aluminates after the unreacted silica has been separated; The solid (1) is the silica solid after separating the aluminate and ferrate liquids; The generated liquid (2) is a polyacid ammonium solution generated after ammonia replacement; The solid (2) is a solid material containing aluminum hydroxide and iron hydroxide.

[0082] The solid (2) is mixed with sodium hydroxide in a certain proportion. Because aluminum hydroxide in the precipitate is an amphoteric oxide that can be dissolved in both acid and alkali, while iron hydroxide is a unipolar oxide that can only be dissolved in acid but not in alkali, sodium hydroxide dissolves the aluminum hydroxide in the mixture to form sodium tetrahydroxyaluminate solution. The sodium tetrahydroxyaluminate solution and iron hydroxide are then separated by filtration through a plate and frame filter press with the undissolved iron hydroxide.

[0083] Carbon dioxide is bubbled into a sodium tetrahydroxyaluminate solution to carry out an ion exchange reaction, displacing aluminum hydroxide.

[0084] The silica content of the solid (1) was analyzed, and solid sodium hydroxide was prepared according to the ratio of relative molecular mass in the chemical reaction formula. Then, 1.5 times the mass of sodium hydroxide was added to water and mixed evenly. The mixture was then loaded into a roller ball mill and the acid dissolution process was repeated to force the silica to transform with sodium hydroxide during grinding and rolling.

[0085] When the alkaline dissolution reaction proceeds to a pH less than or equal to 9, the reaction is complete. Then, an appropriate amount of clean water (greater than or equal to 3 times the amount of the material) is introduced into the tank to rinse and dilute the material, and then the diluted material is discharged intermittently.

[0086] The discharged diluted material is introduced into the washing and dissolving system, and the soluble salt generated by the reaction is dissolved in water by continuous counter-rotating stirring to become the product liquid (3).

[0087] The generated liquid (3) is a sodium silicate solution mixed with unreacted impurity particles.

[0088] The generated liquid (3) is filtered through a multi-stage filter to filter out the clear liquid (2) and the retained solids (2).

[0089] The clear liquid (2) is a sodium silicate solution; The solid (2) is an impurity component that is difficult to convert.

[0090] The clear liquid (2) is introduced into the carbon dioxide ion exchange system and the tail gas generated by the drying process is introduced, so that the clear liquid (2) absorbs the carbon dioxide in the tail gas to produce an ion exchange reaction and replaces silicic acid and sodium carbonate.

[0091] A mixture of silicic acid and sodium carbonate is filtered through a plate and frame filter press. The silicic acid is retained and becomes a filter cake, while the sodium carbonate is filtered out with the solution.

[0092] The silica filter cake is stirred at high speed to make a thick slurry, which is then atomized under high pressure to make a foam hollow particle molecular sieve. Sodium carbonate solution is reacted with calcium hydroxide to produce sodium hydroxide and calcium carbonate, and then the two substances are separated by centrifugation and dehydration.

[0093] Calcium carbonate is dried to produce nano-calcium carbonate, and sodium hydroxide is recycled for alkaline silicon dissolution.

[0094] Benefit analysis: According to the chemical reaction formula: 3H₂SO₄ (74.6%) + Al₂O (25.4%) = Al₂(SO₄)₃ (86.4%) + 3H₂O (13.6%); 6HNO3 (78.75%) + Al2O3 (21.25%) = Al(NO3)3 (88.9%) + 3H2O (11.1%); 6HCl (68.23%) + Al2O3 (31.77%) = 2AlCl3 (83.16%) + 6H2O (16.84%); Composition of coal gangue: Fe2O3: 2.45%, SiO2: 55%, AL2O3: 31%, CaO: 0.49%, SO3: 0.18%, fixed carbon and volatile matter 11%, calorific value 200kcal.

[0095] AL2O3: 30% 50000 95% = 14,250 tons. Based on the chemical reaction 3H₂SO₄ (74.6%) + Al₂O (25.4%) = Al₂(SO₄)₃ (86.4%) + 3H₂O (13.6%), the acid method extracts 95% of alumina, which is 50,000 tons. 0.3 0.95 = 14,250 tons. Calculated based on relative molecular mass: 10% sulfuric acid from the polybasic acid is consumed: 0.485 million tons (converted to 100% content), producing 0.56 million tons of aluminum sulfate; according to the chemical reaction formula: 6HNO3 (78.75%) + Al2O3 (21.25%) = Al(NO3)3 (88.9%) + 3H2O (11.1%);

[0096] Consuming 10% of nitric acid (99% purity): 0.53 million tons, producing 0.598 million tons of aluminum nitrate; Based on the chemical reaction formula: 6HCl (68.23%) + Al2O3 (31.77%) = 2AlCl3 (83.16%) + 6H2O (16.84%), we can conclude that 60% of the hydrochloric acid (content 33%) was consumed, totaling 30,600 tons, and 37,300 tons of aluminum chloride were generated. 2. Ammonia replacement: 3. According to the chemical reaction formula: Al2(SO4)3 (62.05%) + 6NH3H2O ​​(37.95%) = 2Al(OH)3 (28.3%) + 3(NH4)2SO4 (71.7%); Al(NO3)3 (66.98%) + 3NH3H2O ​​(33.02%) = Al(OH)3 (24.5%) + 3NH4NO3 (75.5%); AlCl3 (55.93%) + 3NH3H2O ​​(44.07%) = Al(OH)3 (32.7%) + 3NH4Cl (67.3%); The result is that 0.56 million tons of aluminum sulfate are generated in the acid dissolution reaction, 0.255 million tons of aluminum hydroxide are replaced by reacting with ammonia, 0.34 million tons of ammonia are consumed, and 0.647 million tons of ammonium sulfate are generated.

[0097] In the acid dissolution reaction, 0.598 million tons of aluminum nitrate are generated, and 0.218 million tons of aluminum hydroxide are replaced by reacting with ammonia. 0.295 million tons of ammonia are consumed, and 0.67 million tons of ammonium nitrate are generated.

[0098] In the acid dissolution reaction, 33,700 tons of aluminum chloride are generated, 19,700 tons of aluminum hydroxide are replaced by reacting with ammonia, 26,550 tons of ammonia are consumed, and 40,500 tons of ammonium chloride are generated.

[0099] 4. Alkali dissolution of silicon dioxide: 95% of silica, or 50,000 tons, can be extracted from coal gangue using an alkaline method. 0.55 0.95 = 26,100 tons.

[0100] According to the chemical reaction formula SiO2(42.85%)+2NaOH(57.15%)=Na2SiO3(87.14%)+H2O(12.86%), the conversion of 26,100 tons of silicon dioxide requires the consumption of 34,800 tons of sodium hydroxide and the generation of 53,000 tons of sodium silicate.

[0101] 5. Carbon dioxide replacement

[0102] According to the chemical reaction formula: Na2SiO3 (66.3%) + CO2 (23.9%) + H2O (9.7%) = H2SiO3 (42.4%) + Na2CO (57.6%).

[0103] H2SiO3→SiO2(76.9%)+H2O(23.1%). The reaction of sodium silicate and carbon dioxide consumes 19,000 tons of carbon dioxide, displacing 33,900 tons of silicic acid and producing 46,100 tons of sodium carbonate; the silicic acid is dried to produce 27,800 tons of silicon dioxide.

[0104] According to the chemical reaction formula: Na2CO3 (58.9%) + Ca(OH)2 (41.1%) = 2NaOH (44.4%) + CaCO3 (55.6%), sodium carbonate and calcium hydroxide react to produce 34,800 tons of sodium hydroxide and 43,500 tons of calcium carbonate.

[0105] It has an easy effect: 1. In terms of the chemical reaction method, wet grinding and forced conversion are adopted to improve the conversion capacity of the chemical reaction under crushing and penetration.

[0106] 2. In terms of solvent selection, the mixture of three strong acids—hydrochloric acid, sulfuric acid, and nitric acid—forms a multi-component complex acid, which greatly enhances the solvent's oxidizing power, causing it to produce an aqua regia effect. This rapidly corrodes and oxidizes the reactants, turning the raw materials into soluble salts under strong corrosive and oxidizing action.

[0107] 3. The solvent and raw materials are forcefully cut, impacted and crushed by the grinding media inside the drum. Due to the strong oxidizing power of the three acids, coupled with the gravity crushing of the grinding media, the kinetic potential and divergence force of the acid radical ions in the solvent are exceptionally stimulated, targeting and binding the aluminum ions in the alumina, thus achieving forced conversion.

[0108] 4. Special methods and special solvents are used to enable the resource utilization of white gangue.

Claims

1. A method for forced conversion of valuable components in white gangue through wet milling and pulping, characterized in that: 1) Sorting and extracting white gangue and making it into small particles; 2) Preparing a multi-component compound acid in a roller ball mill to dissolve the aluminum and iron metal components in the material under crushing and penetrating conditions to produce a forced conversion effect; 3) Washing the reaction products aluminates and ferrates with water, and separating the clear liquid from the retained solids (1) by filtration; 4) Introducing the clear liquid into an ammonia replacement system for replacement reaction to replace aluminum hydroxide and iron hydroxide; 5) Separating the aluminum and iron hydroxide from the replacement mixture by alkali dissolution; 6) Reacting the solids (1) with sodium hydroxide to produce sodium silicate; 7) Producing silica molecular sieve hollow granule balls by post-processing sodium silicate; 8) Producing sodium hydroxide and nano calcium carbonate by causticizing sodium carbonate generated in the post-processing of sodium silicate.

2. The method for forced conversion of valuable components in white gangue through wet grinding and pulping as described in claim 1, wherein the sorting and extraction of white gangue and its preparation into small particles is carried out by using intelligent gangue sorting equipment to sort white gangue and black gangue, and crushing the white gangue into small particles with a particle size of less than 5mm by a crusher.

3. A method for forced conversion of valuable components in white gangue through wet grinding and pulping as described in claim 1, wherein the preparation of a multi-component composite acid in a drum ball mill to dissolve aluminum and iron metal components in the material is based on the alumina content in the white gangue according to the relative atomic mass ratio of the chemical reaction formula. Hydrochloric acid, sulfuric acid, and nitric acid are sequentially introduced into the drum ball mill, so that after the three solvents are mixed, the crushed gangue is ground by the grinding media balls under the rotation of the drum, allowing the solvent to penetrate the material under high pressure to form a forced conversion. Its characteristic is: After the crushed gangue material is lifted to a certain height by the rotation of the cylinder, it falls off the cylinder wall along a parabolic line due to gravity. The grinding media and materials rotate and tumble at a uniform speed in the grinding tank, which produces strong cutting, impact and crushing on the materials, so that the solvent can achieve the purpose of wetting, grinding, dispersing and emulsifying the materials.

4. The method for forced conversion of valuable components in white gangue through wet grinding and pulping according to claim 1, wherein the forced conversion effect is achieved by dissolving aluminum and iron metal components in the material under the condition of acid crushing and penetration in a drum ball mill, is characterized by: The strong acid components in the solvent penetrate the material forcefully during the rolling process, thereby enhancing the chemical oxidation capacity and achieving forced conversion.

5. The method for forced conversion of valuable components in white gangue through wet milling and pulping according to claim 1, wherein the product of water washing and dissolving is obtained by continuously stirring in a counter-rotating stirring system with water at a volume of 3 times or more of the material to dissolve the soluble salts generated in the reaction into aluminate and ferrate solutions.

6. The method for forced conversion of valuable components in white gangue by wet milling pulping according to claim 1, wherein the ammonia replacement is performed by filtering and clarifying a mixed solution of aluminate and ferrate and then introducing it into an ammonia replacement system, through which ammonia water or ammonia gas is introduced to generate a replacement reaction to displace aluminum hydroxide, ferric hydroxide, ammonium sulfate, ammonium nitrate, and ammonium chloride.

7. The method for forced conversion of valuable components in white gangue through wet milling and pulping as described in claim 1, wherein the extraction of aluminum components by reacting a mixture of aluminum hydroxide and ferric hydroxide solids with an alkali involves separating the aluminum hydroxide and ferric hydroxide mixture after the displacement reaction by sedimentation solid-liquid separation, and mixing the precipitate with sodium hydroxide in a certain proportion; characterized in that... Because aluminum hydroxide in the precipitate is an amphoteric oxide, it can dissolve in both acids and alkalis, while iron hydroxide is a unipolar oxide, it can only dissolve in acids but not alkalis. Therefore, sodium hydroxide dissolves the aluminum hydroxide in the mixture to form sodium tetrahydroxyaluminate solution, which is then filtered with the undissolved iron hydroxide using a plate and frame filter press to separate the aluminum and iron components.

8. The method for forced conversion of valuable components in white gangue by wet milling and pulping according to claim 1, wherein the solid (1) is reacted with sodium hydroxide to generate sodium silicate, The method involves analyzing the content of silicon dioxide in the solid (1), preparing solid sodium hydroxide according to the ratio of relative molecular mass in the chemical reaction formula, mixing it evenly, loading it into the drum of a ball mill, adding an appropriate amount of water, so that the ratio of material to water is greater than 1:1 and forming a paste-like state; repeating the acid dissolution process to force the conversion of silicon dioxide with sodium hydroxide during grinding and crushing.

9. The method for forced conversion of valuable components in white gangue through wet grinding and pulping according to claim 1, wherein the production of silica molecular sieve hollow granule balls by post-processing sodium silicate is achieved by high-pressure atomization drying. The high-pressure atomization is a method in which the silica filter cake pressed by the plate and frame filter press is stirred at high speed to form a thick slurry, and then sprayed by a high-pressure spray gun in the drying tower to achieve drying through convection heat exchange with hot air. Due to the high-pressure spraying, the dried product is a hollow particle. Since the silica crystals have a particle size of less than 0.5 nanometers during formation, close to the molecular size, the sphere walls stack into a molecular sieve shape under the expansion effect during drying, hence the name molecular sieve hollow granule balls.

10. The method for forced conversion of valuable components in white gangue by wet milling pulping according to claim 1, wherein the sodium carbonate generated in the post-treatment of sodium silicate is subjected to a causticization reaction to produce sodium hydroxide and nano-calcium carbonate, wherein sodium carbonate and calcium hydroxide are subjected to a causticization reaction, and in the reaction, since the reactivity of calcium ions is greater than that of sodium ions, the carbonate ions in sodium carbonate are stripped to generate calcium carbonate, and the sodium ions combine with hydroxide ions to generate sodium hydroxide.