Process for converting soluble sulphate into other acid salts and new use of amantadine and its salts

Abstract

The application provides a method and application of converting soluble sulfate into other acid salt and a new use of adamantylamine and its salt. The original soluble sulfate is converted into other acid salt of corresponding cation by using adamantylamine and its salt as a medium, and the sulfate is converted into the sulfate of corresponding cation of (hydro) carbonate, thereby providing a new path for disposal of the sulfate (especially sodium sulfate). By selecting appropriate acid and base, the original soluble sulfate can be recycled and value-added. The method has low energy consumption, is green and environmentally friendly, consumes little adamantylamine and its salt, and can effectively alleviate the environmental protection problems of excess by-product sodium sulfate and difficult resource treatment. In particular, the application provides a new method for the lithium battery industry and other industries with by-product sodium sulfate and resource treatment of solid waste sodium sulfate, which can effectively solve the problem of hindered production caused by the inability to dispose of by-product sodium sulfate and alleviate the problem of excess sodium sulfate that cannot be effectively disposed of.

Description

Technical Field

[0001] This invention relates to the chemical reaction transformation of salts, specifically using adamantane salts as a medium to convert soluble sulfates into other anions, and also relates to new application scenarios for adamantane and its salts. Background Technology

[0002] Sulfates, especially inorganic sulfates, are widely available. Besides natural minerals, the main industrial source is a byproduct of sulfuric acid use. Sulfuric acid is widely used in metallurgical and metal processing industries. Particularly in non-ferrous metal production, sulfuric acid is widely used as an excellent leaching agent for the recovery of resources such as uranium ore, laterite nickel ore, spent lithium battery cathode materials, and copper slag. The leaching and refining processes of various metals, including lithium, copper, nickel, cobalt, manganese, and uranium, all require the use of sulfuric acid to dissolve and generate metal sulfates. These metal sulfates undergo a series of reaction transformations, typically ultimately converting into inexpensive sulfates—sodium sulfate and calcium sulfate—which are produced in large quantities and are difficult to process.

[0003] Calcium sulfate, commonly known as gypsum, is slightly soluble in water. High-quality gypsum has a wide range of applications, but gypsum produced as a byproduct of neutralizing waste sulfuric acid is of low quality and difficult to treat, becoming one of the solid wastes that are stockpiled in large quantities. Sodium sulfate, on the other hand, is highly soluble in water, and its solid form easily absorbs moisture and deliquesces when exposed to air, making it unsuitable for large-scale stockpiling like calcium sulfate.

[0004] Sodium sulfate is also an important industrial raw material with a wide range of applications, mainly used in the manufacture of water glass, glass, porcelain enamel, pulp, refrigerant mixtures, detergents, desiccants, dye diluents, analytical chemical reagents, pharmaceuticals, and animal feed. High-purity, fine-particle anhydrous sodium sulfate is called Glauber's salt (sodium sulfate decahydrate), which absorbs water to form sodium sulfate decahydrate, also known as mirabilite. Glauber's salt can also be prepared by cooling and crystallizing a supersaturated sodium sulfate solution. Heating Glauber's salt dissolves the sodium sulfate in its own water of crystallization to form a solution. High-temperature crystallization of sodium sulfate solution can also yield low-water-of-crystallization crystals or anhydrous sodium sulfate.

[0005] In recent years, the rise of the battery industry has led to a significant increase in the production capacity of sodium sulfate as a byproduct. For example, in the production of lithium carbonate, lithium iron phosphate, and precursors for lithium-ion battery cathode materials, the conversion of high-value metal sulfates almost entirely results in the conversion of them into inexpensive sodium sulfate. The only way to treat this sodium sulfate-containing wastewater is through distillation concentration and high-temperature crystallization to produce sodium sulfate as a byproduct, which can then be sold. Sodium sulfate decahydrate (Glauber's salt) obtained through low-temperature crystallization has no market. Because decrystallization requires a large amount of energy, it is less energy-efficient than the high-temperature crystallization during distillation concentration to directly obtain monohydrate or anhydrous sodium sulfate crystals; even if given away for free, no one would buy it. To achieve energy savings in distillation concentration, multi-effect evaporation is required, typically using triple-effect or quadruple-effect evaporation equipment combined with secondary steam compression equipment to form an MVR distillation system, which consumes even less steam energy. However, this increases equipment investment, and high-temperature crystallization requires high operational control; slight errors can cause pipe blockages, making operation difficult. Furthermore, in recent years, with the expansion of the battery industry, the production capacity of sodium sulfate, a by-product, has become excessive, leading to market saturation. In addition, it contains heavy metals such as nickel, cobalt, and manganese, as well as other impurities, resulting in low quality and low price, which increases the production cost of the battery industry.

[0006] Compared to calcium sulfate and sodium sulfate, other sulfates have far better applications. Potassium sulfate is an important fertilizer, with a higher value than potassium chloride. Other sodium salts, such as sodium chloride, have better resource utilization than sodium sulfate. Industrial sodium chloride can be electrolyzed to produce sodium hydroxide, chlorine, hydrochloric acid, and other byproducts. It can also be used in the combined alkali production process to produce soda ash, achieving recycling. Sodium sulfate has no industrial electrolytic applications. Processing it into sodium sulfate powder for sale is currently the most common technical route for treating sodium sulfate wastewater. However, sodium sulfate itself has low value, and the high transportation costs limit its sales area. Although new technologies such as membrane separation and electrodialysis have emerged in recent years, they have failed to be widely adopted due to high investment costs and low added value. As waste, sodium sulfate lacks the economic benefits of resource utilization, is difficult to separate, and its good water solubility limits its storage path, leaving landfill as the only option. As the cheapest and most abundant byproduct of sulfuric acid consumption, sodium sulfate lacks a resource recycling pathway like sodium chloride. Summary of the Invention

[0007] To address the challenges in sulfate processing, this invention provides a method for converting soluble sulfates into other anions and a novel application of adamantane salt. Specifically, it utilizes adamantane salt as a medium to achieve the chemical conversion of soluble sulfates with other salts.

[0008] One of the inventors previously developed a method for preparing adamantane carbonate (also called adamantane carbonate) precipitate by adding adamantane salt to carbonate (bicarbonate). Adamantane sulfate (also called adamantane sulfate) is also a precipitate, and it can also react with carbonate (bicarbonate) to form adamantane carbonate. The solubility of adamantane carbonate is lower than that of adamantane sulfate, while adamantane carbonate can react with acids to form the corresponding adamantane salt and carbon dioxide. Following a suggestion from another inventor, a solution of soluble adamantaneamine salt is reacted with soluble sulfate to form adamantaneamine sulfate precipitate. The cations of the soluble sulfate combine with the corresponding anions of the soluble adamantaneamine salt to form a soluble salt, which can then be separated into solid and liquid components. The liquid is concentrated to obtain a salt in which the corresponding cations of the soluble sulfate combine with the anions of the acid molecules in the soluble adamantaneamine salt. The adamantaneamine sulfate precipitate is then reacted with a soluble carbonate (hydrocarbonate) solution to form adamantaneamine carbonate precipitate and a new soluble sulfate. This process is repeated, and the liquid is concentrated to obtain the new sulfate. The adamantaneamine carbonate precipitate reacts with an acid to form soluble adamantaneamine salt and carbon dioxide. The carbon dioxide is absorbed by an alkaline solution and converted back into carbonate (hydrocarbonate). The resulting soluble adamantaneamine salt then reacts with the soluble sulfate, and this cyclical reaction converts the soluble sulfate into other soluble anions. In this way, carbon dioxide emissions are not increased, and the recycling of adamantane salt is formed. Using adamantane salt as a medium, the original dissolved sulfate is converted into other acid anions of the corresponding cation (the salt in which the corresponding cation of the dissolved sulfate combines with the acid anion of the acid molecule in the dissolved adamantane salt). The sulfate is converted into the sulfate of the corresponding cation of carbonate (hydrogen) salt, thus realizing the conversion of the original dissolved sulfate.

[0009] In conversion reactions, selecting appropriate acids and bases can generate value. In the conversion of inorganic salts that are difficult to interconvert, direct neutralization products of the added acid or base can be avoided, thus achieving high-value conversion and utilization of low-value sulfates. The carbonates (bicarbonates) mentioned include carbonates, bicarbonates, and carbonates produced by the decomposition of percarbonates, with ammonium carbonate (bicarbonate) being preferred. The alkali solutions preferably include ammonia, sodium hydroxide solution, or potassium hydroxide solution. The acids preferably include common acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, phosphoric acid, and hydrobromic acid. The reaction of bicarbonate with adamantane sulfate produces carbon dioxide, which can be absorbed and reused. To reduce bicarbonate consumption, an alkali solution can be used to react with bicarbonate to prepare a normal carbonate, which is then reacted with adamantane sulfate. For example, ammonium bicarbonate can be mixed with ammonia to prepare an ammonium carbonate solution.

[0010] The reusable soluble adamantaneamine salts are preferably adamantaneamine hydrochloride, adamantaneamine nitrate, adamantaneamine formate, adamantaneamine acetate, adamantaneamine phosphate, adamantaneamine hydrobromide, etc. The initially introduced soluble adamantaneamine salts, adamantaneamine sulfates, and adamantaneamine carbonates can be used directly or converted through reaction. For example, soluble sulfates can be introduced by reacting an acid with adamantaneamine carbonate or adamantaneamine; adamantaneamine sulfates can be introduced by reacting adamantaneamine or adamantaneamine carbonate with sulfuric acid, or by reacting soluble adamantaneamine salts with sulfate ions; adamantaneamine carbonates can be introduced using adamantaneamine, adamantaneamine sulfate, or soluble adamantaneamine salts as raw materials. As long as adamantaneamine sulfate, adamantaneamine carbonate, or soluble adamantaneamine salt is used to convert soluble sulfates, regardless of the method of introduction, it falls within the scope of protection of this invention. The methods for converting soluble sulfates into other anions, including adamantaneamine, adamantaneamine sulfate, adamantaneamine carbonate, and soluble adamantaneamine salts, as described in this invention, represent novel uses for these substances that have not been previously reported.

[0011] This invention can be widely applied to the conversion of sulfates, especially metal sulfates. Using this method, the previous economical but environmentally unfriendly single-process method of converting sulfuric acid into inexpensive metal sulfates after consumption can be changed. Instead, it can be adapted to local conditions to convert sulfuric acid into other anions, reducing waste generation. The following application scenarios illustrate the application of this invention in various industries; these application scenarios are merely illustrative and do not limit the scope of application of this invention.

[0012] This invention can be used to convert sodium sulfate. Sodium sulfate is a widely produced byproduct of industrial production. The process involves reacting sodium sulfate in solution with a soluble adamantaneamine salt solution, such as adamantaneamine hydrochloride solution, to produce sodium chloride and adamantaneamine sulfate precipitate. After solid-liquid separation, the filtrate is a sodium chloride solution, which can be concentrated to obtain solid sodium chloride. The adamantaneamine sulfate reacts with ammonium carbonate (bicarbonate) solution to produce ammonium sulfate and adamantaneamine carbonate. After solid-liquid separation, the filtrate is an ammonium sulfate solution, which can be concentrated to obtain solid ammonium sulfate. The adamantaneamine carbonate reacts with hydrochloric acid to produce adamantaneamine hydrochloride and carbon dioxide. Ammonia is used to absorb the carbon dioxide, producing an ammonium carbonate (bicarbonate) solution. Repeating these steps allows the conversion of sodium sulfate into sodium chloride and ammonium sulfate by adding inexpensive hydrochloric acid and ammonia. Sodium chloride is used in the chlor-alkali industry to produce sodium hydroxide and hydrochloric acid, enabling recycling. Ammonium sulfate is a widely used fertilizer with a higher added value than sodium sulfate.

[0013] The same method can be used to treat sodium sulfate wastewater or waste salt. Common acids such as acetic acid, formic acid, and hydrobromic acid can also be used to obtain the corresponding sodium salts such as sodium acetate, sodium formate, and sodium bromide. Before treatment, wastewater can be treated using methods such as stripping, precipitation, adsorption, and membrane treatment to separate impurities such as ammonia, nickel, cobalt, manganese, and lithium, thereby improving the quality of the salt. After concentrating the mother liquor to enrich nickel, cobalt, manganese, and lithium, appropriate treatment can also be carried out to improve the quality of the salt. In the specific implementation process, when sodium sulfate reacts with soluble adamantane sulfate, a slight excess of sodium sulfate is used for the reaction, and the final pH of the reaction solution is adjusted to 2-7 to ensure more complete precipitation of adamantane sulfate and reduce the consumption of adamantane sulfate. When the sodium chloride concentrate has a high sodium sulfate content, it is returned to react with adamantane sulfate again to reduce the amount of sodium sulfate entrained in the sodium chloride. When carbonate (bicarbonate) reacts with adamantane sulfate, a slight excess of carbonate (bicarbonate) is used for the reaction, and the final pH of the reaction solution is adjusted to 6-10 to ensure more complete precipitation of adamantane carbonate and reduce the consumption of adamantane sulfate. When concentrating ammonium sulfate solution, sulfuric acid is added to adjust the pH to 5-6 to increase the purity of the ammonium sulfate byproduct. Washing adamantane sulfate and adamantane carbonate and reusing the wash water can achieve more thorough separation of inorganic salts. When adamantane carbonate reacts with acid, it should be dissolved completely; excessive acid should not be added. When reacting with sulfate, the weaker the acidity of the reaction solution, the lower the solubility of adamantane sulfate. Increasing the sedimentation time allows the precipitate to grow larger crystals, and the aggregation of small crystals facilitates solid-liquid separation. The same applies to the reaction with carbonate (bicarbonate) solutions; a moderate pH and extended sedimentation time ensure more complete precipitate conversion. During solid-liquid separation, the reaction solution temperature should not be too high; below room temperature is better to reduce solubility. The smaller the pore size of the filter media used for solid-liquid separation, the less permeate, and the less adamantane carbonate is lost. With proper condition control, the loss of adamantane carbonate is minimal, less than 0.2% per cycle. To further recover adamantane salt, when reacting the concentrated soluble sulfate solution with the soluble adamantane salt to obtain a salt solution where the corresponding cation of the soluble sulfate is combined with the acid anion of the acid molecule in the soluble adamantane salt, sodium hydroxide can be added to adjust the pH to alkaline. This allows for the initial stripping of any potentially introduced ammonium salts to generate ammonia, followed by distillation of a small portion of the liquid to recover adamantane. Because adamantane is sublimable, it can be distilled out and placed in distilled water. Extraction using a non-water-soluble solvent, followed by oil-water separation, and further recovery of adamantane salt from the organic phase containing adamantane by adding acid, can also be achieved. Adding a small amount of alkali solution before extraction improves the extraction effect. The preferred non-water-soluble solvents used are benzene, toluene, xylene, heptane, octane, trimethylpentane, methylhexane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, methyl tert-butyl ether, P204 (diisooctyl phosphate), P507 (2-ethylhexyl phosphate mono-2-ethylhexyl ester), etc., one or more of these solvents can be used in any proportion. These are standard practices in the industry and will not be elaborated upon further.

[0014] Valuable metal sulfates are generally converted into inexpensive sodium sulfate. Furthermore, soluble valuable metal sulfates can be directly converted using this invention, without needing to react with sodium hydroxide or sodium carbonate (bicarbonate) to generate sodium sulfate before conversion. This is applicable in scenarios where zinc, nickel, cobalt, manganese, copper, and other metals are used to produce other salts by preparing sulfate solutions with sulfuric acid. In lithium extraction processes, lithium sulfate solutions obtained from sulfuric acid leaching are typically precipitated with sodium carbonate to obtain lithium carbonate. Using this invention, lithium sulfate solution can be reacted with a soluble adamantaneamine salt solution, such as adamantaneamine acetate solution, to produce lithium acetate and adamantaneamine sulfate precipitate; after solid-liquid separation, the filtrate is a lithium acetate solution, which is then reacted with sodium carbonate to obtain lithium carbonate product, with sodium acetate as a by-product salt; adamantaneamine sulfate can be reacted with ammonium carbonate (hydrogen carbonate) solution to produce ammonium sulfate and adamantaneamine carbonate; after solid-liquid separation, the filtrate is an ammonium sulfate solution, which can be concentrated to obtain solid ammonium sulfate; adamantaneamine carbonate can be reacted with acetic acid to produce adamantaneamine hydrochloride and carbon dioxide; ammonia water is used to absorb the carbon dioxide to produce ammonium carbonate (hydrogen carbonate) solution. For example, in the reaction of zinc sulfate with sodium hydroxide or sodium carbonate for precipitation, the zinc sulfate solution can be reacted with a soluble adamantaneamine salt solution, such as adamantaneamine acetate solution, to produce zinc acetate and adamantaneamine sulfate precipitate; after solid-liquid separation, the filtrate is a zinc acetate solution, and sodium carbonate is added to react to obtain (basic) zinc carbonate, with sodium acetate as a by-product salt; adamantaneamine sulfate reacts with ammonium carbonate (hydrogen carbonate) solution to produce ammonium sulfate and adamantaneamine carbonate; after solid-liquid separation, the filtrate is an ammonium sulfate solution, which can be concentrated to obtain solid ammonium sulfate; adamantaneamine carbonate reacts with acetic acid to produce adamantaneamine hydrochloride and carbon dioxide; ammonia water is used to absorb carbon dioxide to produce ammonium carbonate (hydrogen carbonate) solution.

[0015] Valuable metal sulfates are generally converted into inexpensive sodium sulfate after use, while waste sulfuric acid is generally converted into inexpensive calcium sulfate, such as titanium gypsum. Waste sulfuric acid can be distilled, concentrated, and desalted for reuse. However, if the concentration is too low, the energy consumption is huge, and an economical but environmentally unfriendly method is generally used: neutralization into gypsum for solid waste treatment. Low-concentration waste sulfuric acid can also be treated using this invention. When treating low-concentration waste sulfuric acid, it is not necessary to use soluble adamantane salts. The waste sulfuric acid solution can be reacted with adamantane or adamantane carbonate to generate adamantane sulfate precipitate. Other acids contained in the waste sulfuric acid, such as phosphoric acid, remain in the acid solution. Solid-liquid separation is performed, and the filtrate and adamantane sulfate precipitate are obtained. The adamantane sulfate reacts with ammonium carbonate (bicarbonate) solution to generate ammonium sulfate and adamantane carbonate. The adamantane carbonate then reacts with the waste acid for recycling. This method can also be used to purify mixed acid solutions with low sulfuric acid content. In this application scenario, the generated adamantane carbonate can further react with alkaline solutions such as sodium hydroxide or potassium hydroxide. The adamantane is collected by steam distillation for reaction with waste acid, while the sodium hydroxide or potassium hydroxide is converted into sodium carbonate or potassium carbonate. Although the alkalinity weakens, it does not affect its neutralization effect and can be used for neutralization reactions. Similarly, in addition to ammonium carbonate (bicarbonate), other carbonates can also be used.

[0016] Similar methods can be used to treat electroplating wastewater and metal pickling wastewater. For example, electroplating wastewater containing copper, nickel, chromium, zinc, and manganese, as well as stainless steel pickling wastewater, typically contains sulfates and residual sulfuric acid. In this case, soluble adamantaneamine salt can be reacted with adamantaneamine or adamantaneamine carbonate to convert the sulfuric acid and sulfate ions into adamantaneamine sulfate. For example, adamantane is reacted with sulfuric acid until it reaches a weakly acidic or neutral state. Then, an adamantane acetate solution is added to react with sulfate, producing corresponding acetate and adamantane sulfate precipitates. After solid-liquid separation, the filtrate is an acetate solution. Sodium hydroxide is then added to react with the filtrate, precipitating valuable metals such as copper, nickel, chromium, zinc, and manganese. The byproduct is sodium acetate. Alternatively, adamantane sulfate reacts with ammonium carbonate (or ammonium bicarbonate) solution to produce ammonium sulfate and adamantane carbonate. After solid-liquid separation, the filtrate is an ammonium sulfate solution, which can be concentrated to obtain solid ammonium sulfate. Part of the adamantane carbonate reacts with acetic acid to produce adamantane hydrochloride and carbon dioxide; a portion is returned for recycling with waste sulfuric acid. Ammonia is used to absorb carbon dioxide, producing an ammonium carbonate (or ammonium bicarbonate) solution. This method can be extended to treat mixtures of sulfate and dilute sulfuric acid. Similarly, besides ammonia, other alkaline solutions such as sodium hydroxide and potassium hydroxide can also be used.

[0017] To reiterate, the carbonates (bicarbonates) used in the examples above can be replaced with other carbonates (bicarbonates), the alkali solutions used in the examples can be replaced with other alkali solutions, the acids used in the examples can be replaced with other acids, and the soluble adamantaneamine salts used in the examples can be replaced with other soluble adamantaneamine salts; the carbonates (bicarbonates) include carbonates, bicarbonates, and carbonates produced by the decomposition of percarbonates, preferably ammonium carbonate (bicarbonate); the alkali solutions are preferably ammonia water, sodium hydroxide solution, or potassium hydroxide solution; the acids are preferably common acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, phosphoric acid, and hydrobromic acid; and the soluble adamantaneamine salts are preferably adamantaneamine hydrochloride, adamantaneamine nitrate, adamantaneamine formate, adamantaneamine acetate, adamantaneamine phosphate, or adamantaneamine hydrobromide.

[0018] This invention, besides its application in sulfate treatment, can also be applied to the conversion of other difficult-to-prepare salts, such as ammonium halides. Taking ammonium bromide production as an example, the traditional process involves neutralizing ammonium bromide with ammonia water and hydrobromic acid or bromine vapor. The resulting ammonium bromide is in the form of fine particles suspended in the air, making it difficult to absorb. Instead, ammonium sulfate reacts with adamantane hydrobromide to form adamantane sulfate precipitate. Ammonium bromide dissolves in water, and solid-liquid separation and concentration of the filtrate yield solid ammonium bromide. Adamantane sulfate reacts with ammonium carbonate (bicarbonate) solution to form ammonium sulfate and adamantane carbonate. Solid-liquid separation again yields an ammonium sulfate solution, which can be used as a raw material. Adamantane carbonate reacts with hydrobromic acid to form adamantane hydrobromide and carbon dioxide. Ammonia water is used to absorb the carbon dioxide, generating an ammonium carbonate (bicarbonate) solution. Repeating these steps allows for the batch production of ammonium bromide. Compared to directly reacting ammonia water with hydrobromic acid or bromine vapor, this process reduces equipment investment and the use and generation of odorous gases.

[0019] The above application descriptions only list some application scenarios. While conventional methods or steps may be modified or supplemented based on the technical features of this invention, the overall technical solution originates from the technical solution of this invention. Technical solutions relying on adamantane and its salts for conversion are all within the protection scope of this invention.

[0020] The beneficial effects of this invention are as follows: It provides a novel method for converting soluble sulfates into other anion salts. The original soluble sulfate is converted into other anion salts corresponding to the cations, and the sulfate ions are converted into sulfates of the corresponding cations of carbonates (bicarbonates), providing a new pathway for the disposal of sulfates (especially sodium sulfate). By selecting appropriate acids and bases, the cyclical value-added conversion of the original soluble sulfate can be achieved. This method has low energy consumption, is environmentally friendly, and consumes little adamantane and its salts, effectively alleviating the environmental problem of excess and difficult-to-recycle by-product sodium sulfate. In particular, it provides a new method for the lithium battery industry and other industries that produce by-product sodium sulfate, as well as for the resource-based treatment of sodium sulfate from solid waste, effectively solving the production obstacles caused by the inability to dispose of by-product sodium sulfate and alleviating the problem of ineffective disposal of excess sodium sulfate. Detailed Implementation

[0021] To better explain the present invention, the following examples illustrate specific implementations of the invention.

[0022] Example 1: Weigh 90.0 g of adamantane carbonate and add 595 g of 5% white vinegar. The reaction is allowed to completely dissolve, yielding an adamantane acetate solution. Weigh 85 g of commercially available sodium sulfate and add 10 g of water. Heat until completely dissolved, then add the adamantane acetate solution and stir to react. Cool to room temperature and age for 1 hour. Filter to separate the adamantane sulfate precipitate. Add 100 g of water to wash the precipitate and filter again. Combine the two filtrates, concentrate, and dry to obtain 40.8 g of 99.0% sodium acetate. Add 39.5 g of ammonium bicarbonate and 100 g of water to the adamantane sulfate solid. Stir to react for 1 hour, age for half an hour, filter to separate the adamantane carbonate precipitate, add 100 g of water to wash the precipitate and filter again. Combine the two filtrates, concentrate, and dry to obtain 33.0 g of 98.8% ammonium sulfate. Dry the filtrate to recover 89.8 g of adamantane carbonate.

[0023] Example 2: Weigh 92.5 g of adamantane hydrochloride and dissolve it completely in 150 g of water. Weigh 85 g of commercially available sodium sulfate, add 10 g of water and heat until completely dissolved. Add the adamantane hydrochloride solution and stir to react. Cool to room temperature and age for 1 h. Filter to separate the adamantane sulfate precipitate. Add 100 g of water to wash the precipitate and filter again. Combine the two filtrates, concentrate, and dry to obtain 29.1 g of 99.0% sodium chloride. Add 39.5 g of ammonium bicarbonate and 100 g of water to the adamantane sulfate solid, stir to react for 1 h, age for half an hour, filter to separate the adamantane carbonate precipitate, add 100 g of water to wash the precipitate and filter again. Combine the two filtrates, concentrate, and dry to obtain 32.9 g of 99.0% ammonium sulfate. Dry the filtrate to recover 89.8 g of adamantane carbonate.

[0024] Example 3: 89.8 g of adamantane carbonate obtained in Example 2 was added to 595 g of 5% white vinegar, and the reaction was allowed to completely dissolve to obtain an adamantane acetate solution. 84 g of commercially available sodium sulfate was weighed, added to 10 g of water, and heated until completely dissolved. The adamantane acetate solution was then added and the mixture was stirred to react. The mixture was cooled to room temperature and aged for 1 h. The adamantane sulfate precipitate was separated by filtration. The precipitate was washed with 100 g of water and filtered again. The two filtrates were combined, concentrated, and dried to obtain 40.8 g of 99.0% sodium acetate. The adamantane sulfate solid was added to 39.5 g of ammonium bicarbonate and 100 g of water, stirred for 1 h, and aged for half an hour. The adamantane carbonate precipitate was separated by filtration. The precipitate was washed with 100 g of water and filtered again. The two filtrates were combined, concentrated, and dried to obtain 33.0 g of 98.8% ammonium sulfate. 89.7 g of adamantane carbonate was recovered from the dried filtrate.

[0025] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the content of the invention, the implementation methods and the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing implementation methods and embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the implementation methods and technical solutions of the present invention.

Claims

1. A method for converting a soluble sulfate into other anions, characterized in that: A soluble sulfate solution is reacted with a soluble adamantane sulfate to form an adamantane sulfate precipitate. The solid and liquid phases are separated, and the liquid is concentrated to obtain a salt in which the corresponding cation of the soluble sulfate is combined with the anion of the acid molecule in the soluble adamantane sulfate. The adamantane sulfate then reacts with a soluble carbonate to form a new sulfate that dissolves in water. The resulting adamantane carbonate precipitate is then separated from the solid phase. The separated adamantane carbonate reacts with an acid to form a soluble adamantane sulfate and carbon dioxide. The carbon dioxide is absorbed by an alkaline solution to form carbonate. The resulting soluble adamantane sulfate then reacts with a soluble sulfate to convert the soluble sulfate into other soluble anions.

2. The method for converting soluble sulfates into other anions according to claim 1 is applied to the conversion of sodium sulfate.

3. The method for converting soluble sulfates into other anions according to claim 1 is applied to the conversion of other soluble metal sulfates besides sodium sulfate.

4. The method for converting soluble sulfates into other anions according to claim 1 is applied to the preparation of ammonium halides.

5. A method for treating dilute sulfuric acid solution, characterized in that: A liquid containing sulfuric acid reacts with adamantane or adamantane carbonate to form adamantane sulfate precipitate. Solid-liquid separation is performed to obtain the filtrate and the adamantane sulfate precipitate. Adamantane sulfate reacts with ammonium carbonate (bicarbonate) solution to form ammonium sulfate and adamantane carbonate. The adamantane carbonate, either directly or after being converted into adamantane, is recycled for reaction with the liquid containing sulfuric acid.

6. A method for treating a mixture of sulfate and dilute sulfuric acid, characterized in that: Dissolved adamantaneamine salt is reacted with adamantaneamine or adamantaneamine carbonate with a liquid containing dilute sulfuric acid and sulfate to form adamantaneamine sulfate precipitate. Solid-liquid separation is performed to obtain the filtrate and adamantaneamine sulfate precipitate. Adamantaneamine sulfate reacts with carbonate (hydrocarbonate) solution to form the corresponding sulfate and adamantaneamine carbonate. Part of the adamantaneamine carbonate reacts with acid to form soluble adamantaneamine salt, and part is returned for recycling with sulfuric acid. The generated carbon dioxide is absorbed by alkaline solution to form carbonate.

7. The method according to claims 1, 5, and 6, characterized in that: The carbonates include carbonates, bicarbonates and percarbonates, with ammonium carbonate (bicarbonate) being preferred; the alkaline solution is preferably ammonia water, sodium hydroxide solution or potassium hydroxide solution.

8. The method according to claims 1, 5, and 6, characterized in that: The acid is preferably a common acid such as hydrochloric acid, nitric acid, formic acid, acetic acid, phosphoric acid, or hydrobromic acid; the soluble adamantaneamine salt is preferably adamantaneamine hydrochloride, adamantaneamine nitrate, adamantaneamine formate, adamantaneamine acetate, adamantaneamine phosphate, or adamantaneamine hydrobromide.

9. A novel use of adamantane, adamantane sulfate, adamantane carbonate, and soluble adamantane salt, characterized in that: The adamantane, adamantane sulfate, adamantane carbonate, and soluble adamantane salt are used in any one of claims 1-6.