A method for producing magnesium aluminum silicate by utilizing potassium feldspar potassium extraction by-product

Abstract

The application discloses a method for producing magnesium aluminum silicate by using potassium feldspar potassium extraction by-products, and comprises the following steps: providing potassium feldspar potassium extraction by-products; mixing the potassium feldspar potassium extraction by-products with magnesium-containing compounds to form a reaction system and reacting, while controlling the pH value of the reaction system to be 6.5-10.0, the molar ratio of silicon and aluminum to be 7-13, and the molar ratio of magnesium and aluminum to be 0.5-1.4; and performing solid-liquid separation on the obtained product, and then performing washing, drying and crushing treatment to obtain the magnesium aluminum silicate. The method uses potassium feldspar potassium extraction tailings, tail liquid and various silicon and aluminum compounds as raw materials, introduces magnesium compounds, adjusts the proportions of silicon, aluminum, magnesium and sodium, and synthesizes the magnesium aluminum silicate, so that the tailings, tail liquid and by-products can be recycled and used in a high value way.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization technology of potassium feldspar extraction by-products, specifically relating to a method for producing magnesium aluminum silicate using potassium feldspar extraction by-products. Background Technology

[0002] Currently, my country imports one-third of its potash fertilizer demand. my country is rich in potassium feldspar resources, with reserves far exceeding those of soluble potassium salts, providing favorable conditions for potash fertilizer extraction.

[0003] However, producing one ton of potash fertilizer from potassium feldspar generates over ten tons of tailings and liquid as byproducts. The high costs of treating these byproducts significantly increase the production cost of potash fertilizer. Furthermore, the limited variety of byproducts from comprehensive utilization, coupled with a small market capacity and low cost-effectiveness, severely restricts the industrial application of potash fertilizer production processes using potassium feldspar. With my country's increasing emphasis on environmental protection, the comprehensive utilization of potassium feldspar resources is essential during potash extraction. Utilizing potassium feldspar to co-produce bulk commodities while producing potash fertilizer is a growing trend in process development.

[0004] Magnesium aluminum silicate is a synthetically produced hydrated aluminum silicate layered compound. Its chemical composition is highly tunable, with exchangeable cations distributed between the layers, primarily Na. + Ca 2+ Mg 2+ And so on, followed by K. + Li + Its crystal has a TOT structure, consisting of two layers of silicon-oxygen tetrahedra sandwiching a layer of aluminum-oxygen octahedra. Some of the silicon and aluminum are replaced by aluminum and magnesium, respectively, forming a fixed negatively charged layer. The exchangeable cations that maintain the charge neutrality between the layers have a great influence on it.

[0005] Industrial magnesium aluminum silicate is widely used in foundry sand binders, drilling mud, sewage treatment, cat litter, soil improvement and remediation, catalyst carriers, and moisture-proof building materials. Global annual consumption exceeds 10 million tons, and domestic demand continues to grow with the rapid development of environmental governance, ecological restoration, oil and gas extraction, and emerging industries.

[0006] Existing comprehensive utilization processes for potassium feldspar mainly include: overall preparation of potassium-silicon multi-element fertilizers, decomposition followed by stepwise extraction, and preparation of composite materials. The stepwise extraction process primarily utilizes acids or alkalis to decompose potassium feldspar, then separates and extracts the decomposition products step by step. This method can yield multiple products, but the process is complex. The method for preparing composite materials involves using the waste liquid and residue from potassium extraction from potassium-rich rocks to produce molecular sieves, cement, and other products, thus achieving comprehensive utilization of potassium-rich rocks. However, limited market capacity and compatibility issues between tailings and waste liquids and other industries restrict the application of this route.

[0007] Existing technologies for potassium extraction from potassium feldspar yield products with either small market capacity or weak competitiveness compared to existing market products, making it difficult to achieve large-scale utilization and disposal of potassium feldspar tailings, liquids, and byproducts. The composition of potassium feldspar ore is highly variable, and existing comprehensive utilization processes for tailings, liquids, and byproducts from potassium feldspar extraction are ill-suited to these variations. Furthermore, existing processes cannot achieve in-situ solidification of harmful elements in potassium feldspar tailings and liquids, posing environmental risks and raising concerns about the reprocessing of waste residue and wastewater generated during comprehensive utilization. Summary of the Invention

[0008] The main objective of this invention is to provide a method for producing magnesium aluminum silicate using potassium feldspar as a byproduct of potassium extraction, thereby overcoming the shortcomings of the prior art.

[0009] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: This invention provides a method for producing magnesium aluminum silicate from potassium feldspar byproducts, comprising: Provides potassium extraction byproducts from potassium feldspar; The potassium feldspar potassium extraction byproduct is mixed with a magnesium-containing compound to form a reaction system and reacted. At the same time, the pH value of the reaction system is controlled to be 6.5~10.0, the molar ratio of silicon to aluminum is 7~13, and the molar ratio of magnesium to aluminum is 0.5~1.4. The molar ratio of silicon to aluminum is calculated as the SiO2 / Al2O3 molar ratio, and the molar ratio of magnesium to aluminum is calculated as the MgO / Al2O3 molar ratio. Furthermore, the product obtained from the reaction is subjected to solid-liquid separation, followed by washing, drying, and pulverizing to obtain magnesium aluminum silicate.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention uses potassium feldspar tailings, tail liquid and various silicon and aluminum compounds produced by the extraction of potassium as raw materials, which are rich in elements such as silicon, aluminum and sodium. By introducing magnesium compounds and adjusting the proportions of silicon, aluminum, magnesium and sodium, magnesium aluminum silicate is synthesized, realizing the resource utilization and high-value utilization of tailings, tail liquid and by-products. (2) The current global consumption of magnesium aluminum silicate obtained by this invention is as high as 10 million tons. With the increasing demand from domestic environmental governance, ecological restoration, oil and gas extraction and emerging industries, the consumption and value of magnesium aluminum silicate will continue to rise, thus providing support for the industrialization of potassium extraction process from potassium feldspar. (3) The content of silicon, aluminum, magnesium, sodium and trace elements in magnesium aluminum silicate of the present invention can be adjusted within a large range to obtain different properties and adapt to different uses. This can be matched with the potassium extraction tailings and tailings corresponding to potassium feldspar of various purities. This process is perfectly matched with the potassium extraction process of potassium feldspar. (3) The magnesium aluminum silicate generated by the present invention can solidify the toxic elements released during the activation process of potassium feldspar in situ, which greatly reduces the environmental risk of potassium extraction process of potassium feldspar. Detailed Implementation

[0011] In view of the deficiencies of the prior art, the applicant, through long-term research and extensive practice, has proposed the technical solution of this invention. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0012] Specifically, as one aspect of the technical solution of this invention, a method for producing magnesium aluminum silicate using potassium feldspar as a byproduct includes: Provides potassium extraction byproducts from potassium feldspar; The potassium feldspar potassium extraction byproduct is mixed with a magnesium-containing compound to form a reaction system and reacted. At the same time, the pH value of the reaction system is controlled to be 6.5~10.0, the molar ratio of silicon to aluminum is 7~13, and the molar ratio of magnesium to aluminum is 0.5~1.4. The molar ratio of silicon to aluminum is calculated as the SiO2 / Al2O3 molar ratio, and the molar ratio of magnesium to aluminum is calculated as the MgO / Al2O3 molar ratio. Furthermore, the product obtained from the reaction is subjected to solid-liquid separation, followed by washing, drying, and pulverizing to obtain magnesium aluminum silicate.

[0013] In some preferred embodiments, the potassium feldspar potassium extraction byproducts include potassium feldspar potassium extraction tailings, tailings liquid, and byproduct silicon and aluminum compounds.

[0014] In some preferred embodiments, the potassium feldspar extraction byproduct includes any one or more combinations of unreacted mineral raw materials, hydrated silica, sodium silicate, aluminum hydroxide, aluminosilicate hydrate, sodium aluminate, sodium hydroxide, sodium carbonate, and impurities, and is not limited thereto.

[0015] In some preferred embodiments, the magnesium-containing compound includes any one or more combinations of magnesium carbonate, magnesium silicate, magnesium hydroxide, magnesium oxide, magnesite, hydromagnesite, hydrocellulose magnesite, magnesium carbonate hydrate, water-soluble magnesium salt, and basic magnesium salt, and is not limited thereto.

[0016] In some preferred embodiments, the method includes: mixing the potassium feldspar extraction byproduct, the magnesium-containing compound, and water to form a reaction system and reacting it at room temperature to 200°C for 12 hours to 60 days, wherein the solid-liquid mass ratio in the reaction system is 1:5 to 1:100. Here, the solid in the solid-liquid mass ratio refers to the solids in the potassium feldspar extraction byproduct, the magnesium-containing compound, etc., and the liquid refers to the water in the byproduct and any added water.

[0017] Furthermore, when the reaction temperature is 100~200℃ and the reaction time is greater than 7 days, the concentration of potassium ions in the reaction system is controlled to be ≤0.1 mol / L. When the concentration of potassium ions in the reaction system is greater than 0.1 mol / L, mineral types such as illite and illite-saturated mixed layers will appear in the system.

[0018] In some preferred embodiments, the types of reactions include closed pressureless reactions or closed hydrothermal self-generated pressure reactions.

[0019] In some preferred embodiments, when unreacted residue remains after the reaction is completed, the magnesium aluminum silicate gel product in the upper layer of the reaction apparatus is extracted, and then washed to obtain an aqueous solution of magnesium aluminum silicate colloidal precipitate and soluble salts.

[0020] In some preferred embodiments, after the reaction is completed and there is no reaction residue, the obtained product is centrifuged and washed to obtain an aqueous solution of magnesium aluminum silicate colloidal precipitate and soluble salts.

[0021] Furthermore, the aqueous solution of the soluble salts serves as a source of sodium and magnesium raw materials for regulating the reaction system.

[0022] Furthermore, when the potassium ion concentration in the aqueous solution of the soluble salt is higher than the sum of the sodium and magnesium ion concentrations, the potassium ions need to be removed.

[0023] Furthermore, the aqueous solution of the soluble salt is mainly composed of a near-neutral and weakly alkaline solution.

[0024] In some preferred embodiments, the drying temperature is 50~200°C.

[0025] This invention uses potassium feldspar tailings, tailings liquid, and various silicon and aluminum compounds produced by-products, which are rich in elements such as silicon, aluminum, and sodium, as raw materials. By introducing magnesium compounds and adjusting the proportions of silicon, aluminum, magnesium, and sodium, magnesium aluminum silicate is synthesized, realizing the resource-based and high-value utilization of tailings, tailings liquid, and by-products, which is in line with the spirit of the "Comprehensive Solid Waste Management Action Plan" (State Council Document No. 14

[2025] ).

[0026] The by-product tailings from the production of magnesium aluminum silicate in this invention can be returned to the hydrothermal system control stage or the potassium feldspar extraction process. The content of silicon, aluminum, magnesium, sodium and trace elements in magnesium aluminum silicate can be adjusted within a wide range to obtain different properties and adapt to different uses. This can be matched with the potassium extraction tailings and residues corresponding to potassium feldspar of various purities. This process is perfectly compatible with the potassium feldspar extraction process.

[0027] The present invention has a simple process, the product is synthesized in one step in a reaction vessel, the product separation and post-processing are simple, and there is no need for cumbersome neutralization, acid leaching or metathesis reactions. It is easy to operate in industrial scale and facilitates control of the quality and production cost of magnesium aluminum silicate products.

[0028] This invention features a green and environmentally friendly process, effectively utilizing all materials and achieving a closed-loop cycle with zero emissions of waste. More importantly, the generated magnesium aluminum silicate can solidify harmful elements released during the activation of potassium feldspar in situ, greatly reducing the environmental risks of the potassium extraction process from potassium feldspar.

[0029] The magnesium aluminum silicate product obtained by this invention currently has a global consumption of over 10 million tons. With the increasing demand from domestic environmental governance, ecological restoration, oil and gas extraction, and emerging industries, the consumption and value of magnesium aluminum silicate will continue to rise, thus contributing to the industrialization of potassium extraction technology from potassium feldspar.

[0030] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments. These embodiments are implemented on the premise of the technical solution of the invention, and provide detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0031] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0032] Example 1 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0033] The system after the reaction was directly centrifuged to separate the solid phase, which was magnesium aluminum silicate, and the aqueous phase was a soluble salt solution.

[0034] The magnesium aluminum silicate precipitate was washed multiple times with pure water, dried at 200℃ and then powdered to obtain sodium-type magnesium aluminum silicate with high silicon, low magnesium and high adsorption capacity, which was used for the preparation of drilling mud.

[0035] The soluble salt solution obtained from the separation and the potassium extraction tailings are mixed, and after adjusting the silicon-to-aluminum ratio, magnesium-to-aluminum ratio and pH value, they are used again for the hydrothermal synthesis of magnesium aluminum silicate.

[0036] Comparative Example 1 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 5.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0037] The reaction system was directly centrifuged, and the resulting solid phase was mainly sodium aluminosilicate hydrate, while the aqueous phase was a soluble salt solution. Magnesium aluminum silicate gel was difficult to obtain.

[0038] Comparative Example 2 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 11.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0039] The system after the reaction was directly centrifuged. The resulting solid phase was mainly a mixture of magnesium aluminum hydrotalcite and zeolite, while the aqueous phase was a soluble salt solution.

[0040] Comparative Example 3 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by the addition of dilute acid solution to adjust the pH to 10.0. The silica-to-alumina ratio is set to 6, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0041] The system after the reaction was directly centrifuged to separate the solid phase, which was mainly a mixture of magnesium aluminum hydrotalcite and magnesium aluminum silicate, while the aqueous phase was a soluble salt solution.

[0042] Comparative Example 4 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 14, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0043] The system after the reaction was directly centrifuged. The resulting solid phase was mainly a mixture of zeolite and magnesium aluminum silicate, while the aqueous phase was a soluble salt solution.

[0044] Comparative Example 5 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.2, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0045] The system after the reaction was directly centrifuged to separate the solid phase, which was mainly a mixture of aluminosilicate gel and magnesium aluminum silicate, and the aqueous phase was a soluble salt solution.

[0046] Comparative Example 6 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 2.0, and the solid-liquid ratio to approximately 1:5. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0047] The system after the reaction was directly centrifuged to separate the solid phase, which was mainly a mixture of magnesium hydroxide and magnesium aluminum silicate, and the aqueous phase was a soluble salt solution.

[0048] Comparative Example 7 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:3. The reaction is carried out at 200℃ in a sealed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0049] The system after the reaction was directly centrifuged. The resulting solid phase mainly consisted of unreacted raw materials, intermediate products, and a mixture of magnesium aluminum silicate, while the aqueous phase was a soluble salt solution.

[0050] Comparative Example 8 Using pure-phase potassium feldspar as raw material, potassium is extracted hydrothermally from sodium hydroxide aqueous solution. After potassium salt extraction, the by-product, the potassium extraction tailings, is a strongly alkaline aqueous solution containing sodium silicate, hydrated silica, sodium aluminate, sodium hydroxide, and a small amount of impurity ions. Pure water, magnesium chloride, and hydrated silica are added to the aqueous solution, followed by dilute acid solution to adjust the pH to 10.0, the silica-to-alumina ratio to 13, the magnesium-to-alumina ratio to 0.5, and the solid-liquid ratio to approximately 1:150. The reaction is carried out at 200℃ in a closed hydrothermal reactor for 12 hours, followed by cooling to room temperature.

[0051] The system after the reaction was directly centrifuged. The resulting solid phase was mainly magnesium aluminum silicate, but the yield was extremely low. The aqueous phase was a soluble salt solution.

[0052] Example 2 Microcline was used as raw material, containing minerals such as potassium feldspar, sodium feldspar, and quartz. The microcline was mixed with sodium carbonate, calcined and activated, and then potassium was extracted by water leaching. The main components of the potassium extraction tailings included unreacted potassium feldspar, hydrated silica, sodium silicate, aluminum hydroxide, and trace amounts of iron and arsenic impurities. Pure water, magnesium silicate, and activated magnesium oxide were added to the potassium extraction tailings to adjust the system to a silica-to-alumina ratio of 10, a magnesium-to-alumina ratio of 1.4, a solid-liquid ratio of 1:100, and a pH of 6.5. The reaction was carried out in a closed hydrothermal reactor at 180℃ for 24 hours, and then cooled to room temperature.

[0053] The reaction system was first subjected to low-speed centrifugation to obtain reaction residue, the main component of which was unreacted potassium feldspar. The aqueous sol phase obtained from the first step was then subjected to high-speed centrifugation to obtain a solid phase of magnesium aluminum silicate and an aqueous solution of soluble salts. The arsenic content in the soluble salt aqueous solution was less than 10 μg / L, and arsenic, iron, etc., were solidified in the magnesium aluminum silicate.

[0054] Magnesium aluminum silicate precipitate was washed multiple times with pure water, dried at 150℃ and then powdered to obtain high-magnesium magnesium aluminum silicate, which is suitable for low-expansion building waterproofing materials.

[0055] The reaction residue obtained from the first step is returned to the potassium feldspar extraction process. The soluble salt solution obtained from the second step is mixed with the potassium extraction tailings, and after adjusting the silicon-aluminum ratio, magnesium-aluminum ratio and pH value, it is used again for the hydrothermal synthesis of magnesium aluminum silicate.

[0056] When the concentration of potassium ions accumulated in the soluble salt solution obtained in the second step exceeds the concentration of sodium ions, the potassium ions must be removed before the solution can be used again for the hydrothermal synthesis of magnesium aluminum silicate.

[0057] Example 3 Using high-purity sanstinite as raw material, potassium hydroxide aqueous solution is hydrothermally converted into potassium nepheline. Potassium nepheline is then acidified to extract potassium. The tailings after potassium extraction are silica-alumina composite hydrates (containing sulfates). These are mixed with the tailings obtained after alkaline hydrothermal potassium extraction (mainly containing sodium silicate, sodium aluminate, and small amounts of zinc, cadmium, etc.). Pure water, magnesium carbonate, hydrated silica, etc. are added to adjust the pH to 8.0, the silica-alumina ratio to 9, the magnesium-alumina ratio to 0.8, and the volume ratio of the precipitate to the aqueous phase to approximately 1:10. The reaction temperature is 100℃, and the reaction is carried out in a closed hydrothermal reactor for 7 days, followed by cooling to room temperature.

[0058] The reaction system was directly separated by high-speed centrifugation. The resulting solid phase was magnesium aluminum silicate, and the aqueous phase was a soluble salt solution with a total zinc and cadmium content of less than 20 μg / L. The magnesium aluminum silicate precipitate was washed multiple times with pure water, dried at 100℃, and then powdered to obtain magnesium aluminum silicate suitable for organic wastewater treatment.

[0059] The soluble salt solution obtained from the separation is mixed with the potassium extraction tailings and residues. After adjusting the silicon-to-aluminum ratio, magnesium-to-aluminum ratio, and pH value, it is reused for the hydrothermal synthesis of magnesium aluminum silicate. The cumulative concentration of potassium ions in the recycled salt solution must not exceed 0.1 mol / L.

[0060] Example 4 Using orthoclase as raw material, which contains minerals such as potassium feldspar, sodium feldspar, quartz, and dolomite, the potassium extraction tailings are hydrothermally decomposed in an alkaline sodium hydroxide solution. The main components of the tailings include unreacted potassium feldspar, hydrated silica, aluminum hydroxide, magnesium hydroxide, and calcium carbonate. Pure water, hydrated silica, and magnesium carbonate are added to the tailings to adjust the silica-to-aluminum ratio to 7, the magnesium-to-aluminum ratio to 0.6, the solid-liquid ratio to 1:20, and the pH to 9.0. The reaction is carried out in a closed hydrothermal reactor at 80℃ for 60 days, followed by cooling to room temperature.

[0061] The reaction system was centrifuged in the first step to obtain the reaction residue, which mainly consisted of unreacted potassium feldspar. An equal volume of pure water was added to the aqueous sol phase obtained in the first step, and a second centrifugation was performed. The resulting solid phase was magnesium aluminum silicate, and the aqueous phase was a soluble salt solution.

[0062] Magnesium aluminum silicate was soaked in a high-concentration calcium chloride solution to perform sodium-calcium replacement, centrifuged and precipitated again, washed multiple times, dried at 50°C and then powdered to obtain high-calcium magnesium aluminum silicate, which was used for the improvement of alkaline soils in Northwest China.

[0063] The reaction residue obtained from the first step of separation, the soluble salt solution obtained from the second step of separation, and the potassium extraction tailings are mixed and then used again for the hydrothermal synthesis of magnesium aluminum silicate after adjusting the silicon-aluminum ratio, magnesium-aluminum ratio, and pH value.

[0064] When the concentration of potassium ions accumulated in the soluble salt solution obtained in the second step exceeds the concentration of sodium ions, the potassium ions must be removed before the solution can be used again for the hydrothermal synthesis of magnesium aluminum silicate.

[0065] Example 5 Using primary products such as hydrated silica, sodium silicate, and aluminum hydroxide, which are byproducts of potassium extraction from potassium feldspar, as raw materials, pure water, sodium carbonate, and magnesite were added. The silica-alumina ratio, magnesium-aluminum ratio, solid-liquid ratio, and pH of the system were adjusted to 12, 1.2, 1:50, and 7.0. The mixture was kept at room temperature (approximately 20-25℃), and carbon dioxide was continuously introduced into the mixture to maintain a relatively constant water level in the container. The reaction was carried out for 1 day.

[0066] The system after the reaction was directly separated by high-speed centrifugation. The resulting solid phase was magnesium aluminum silicate, and the aqueous phase was a soluble salt solution.

[0067] Magnesium aluminum silicate precipitate was washed multiple times with pure water, dried at 180°C, and then powdered to obtain magnesium aluminum silicate suitable as a binder for refractory and building materials.

[0068] The soluble salt solution obtained from the separation was mixed with the primary by-product of potassium extraction, and after adjusting the silicon-to-aluminum ratio, magnesium-to-aluminum ratio and pH value, it was used again for the room temperature synthesis of magnesium aluminum silicate.

[0069] In addition, the applicant also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0070] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for producing magnesium aluminum silicate from potassium feldspar byproducts, characterized in that, include: Provides potassium extraction byproducts from potassium feldspar; The potassium feldspar potassium extraction byproduct is mixed with a magnesium-containing compound to form a reaction system and reacted. At the same time, the pH value of the reaction system is controlled to be 6.5~10.0, the molar ratio of silicon to aluminum is 7~13, and the molar ratio of magnesium to aluminum is 0.5~1.

4. The molar ratio of silicon to aluminum is calculated as the SiO2 / Al2O3 molar ratio, and the molar ratio of magnesium to aluminum is calculated as the MgO / Al2O3 molar ratio. Furthermore, the product obtained from the reaction is subjected to solid-liquid separation, followed by washing, drying, and pulverizing to obtain magnesium aluminum silicate.

2. The method according to claim 1, characterized in that: The potassium feldspar extraction byproducts include potassium feldspar extraction tailings, tail liquid and byproduct silicon and aluminum compounds; And / or, the potassium feldspar potassium extraction byproducts include any one or more combinations of unreacted mineral raw materials, hydrated silica, sodium silicate, aluminum hydroxide, aluminosilicate hydrate, sodium aluminate, sodium hydroxide, sodium carbonate, and impurities.

3. The method according to claim 1, characterized in that: The magnesium-containing compounds include any one or more combinations of magnesium carbonate, magnesium silicate, magnesium hydroxide, magnesium oxide, magnesite, hydromagnesite, hydrocellulose magnesite, magnesium carbonate hydrate, water-soluble magnesium salts, and basic magnesium salts.

4. The method according to claim 1, characterized in that, include: The potassium feldspar potassium extraction byproduct, magnesium-containing compound and water are mixed to form a reaction system and reacted at room temperature to 200°C for 12 hours to 60 days, wherein the solid-liquid mass ratio in the reaction system is 1:5 to 1:

100.

5. The method according to claim 4, characterized in that: When the reaction temperature is 100~200℃ and the reaction time is greater than 7 days, the concentration of potassium ions in the reaction system is controlled to be ≤0.1 mol / L.

6. The method according to claim 1, characterized in that: The types of reactions include closed pressureless reactions or closed hydrothermal self-generated pressure reactions.

7. The method according to claim 1, characterized in that: After the reaction is completed, there is unreacted residue. The magnesium aluminum silicate gel product in the upper layer of the reaction device is extracted and then washed to obtain an aqueous solution of magnesium aluminum silicate colloidal precipitate and soluble salts.

8. The method according to claim 1, characterized in that: After the reaction is completed and there is no reaction residue, the obtained product is centrifuged and washed to obtain an aqueous solution of magnesium aluminum silicate colloidal precipitate and soluble salts.

9. The method according to claim 8, characterized in that: The aqueous solution of the soluble salts serves as a source of sodium and magnesium raw materials for regulating the reaction system; And / or, when the potassium ion concentration in the aqueous solution of the soluble salt is higher than the sum of the sodium and magnesium ion concentrations, the potassium ions need to be removed.

10. The method according to claim 1, characterized in that: The drying temperature is 50~200℃.