A process route for preparing high purity strontium or barium compounds

Abstract

The application discloses a process route for preparing high-purity strontium or barium compounds and belongs to the technical field of material utilization. A strontium or barium carbonate containing multiple impurities and an oxide and the like are added into a high-molecular-weight organic acid under stirring to prepare an organic acid salt solution containing strontium and impurity elements. The organic acid salt solution is washed by using an inorganic acid or a small-molecular-weight organic acid solution, and strontium or barium dissolved in the organic acid is washed into an aqueous solution. According to the purity of strontium or barium and the content of impurities, the number of washing is adjusted until the purity of the obtained strontium solution or barium solution meets the quality requirement. The strontium solution or barium solution meeting the quality requirement is concentrated and crystallized to obtain corresponding salts. The qualified strontium solution or barium solution is used as raw material, and a carbonate, oxalic acid or an oxalate is added to obtain strontium carbonate or barium carbonate and strontium oxalate or barium oxalate products. The organic acid salt solution after washing strontium or barium is regenerated by using a high-concentration acid and is recycled.

Description

Technical Field

[0001] This invention relates to the field of materials utilization technology, and in particular to a process route for preparing high-purity strontium or barium compounds. Background Technology

[0002] High-purity strontium and barium salts have important applications in high-end fields such as electronic ceramics, optical glass, high-temperature superconductors, and high-temperature resistant materials. Their preparation methods require strict control of impurity content to ensure the products meet purity requirements. Celestite (SrSO4), barite, and abamite are the main natural mineral resources for strontium and barium, with abundant reserves and low prices. The preparation of high-purity strontium and barium salts using celestite, barite, and abamite is a major source for industrial production. Currently, the main method for producing the corresponding strontium or barium salts from these minerals is the high-temperature calcination method, which converts celestite ore into sulfides and barite and abamite into oxides under carbon reduction conditions. Then, strontium or barium salts are obtained through water leaching, concentration crystallization, and recrystallization. Since calcium, magnesium, strontium, and barium are all Group II elements, they occur together in strontium and barium ores. Therefore, existing methods mainly rely on the differences in the solubility of the soluble salts of each element, separating them through crystallization. Due to the limitations of this method, the purity and yield of strontium and barium products are restricted. Therefore, developing efficient and environmentally friendly new element separation technologies using minerals such as celestite, barite, and barite as raw materials to form a new method for preparing high-purity strontium and barium compounds is the main way to solve the existing problems.

[0003] The main methods for preparing strontium salts from celestite include carbothermic reduction and precipitation conversion, which convert sparingly soluble strontium sulfate into soluble strontium salts. Examples include CN102345678A, CN1050531A, CN104192882B, CN106586975A, CN115215362B, CN114853045B, CN116924447A, CN112093815A, etc., as well as CN115432728B describing the hydrogen reduction method for preparing strontium sulfide, CN110042231A proposing a calcium-fixing method, CN106115760B describing the preparation of nano-strontium carbonate from urea through microbial decomposition, and CN105836780A proposing a process to improve the conversion rate of strontium sulfate to strontium carbonate through cavitation effect. In other related patents, the above two methods are also used to convert sparingly soluble strontium sulfate into soluble salts, and then strontium salts are prepared based on the solubility product of the sparingly soluble compound and the difference in solubility of the soluble salt. No other patent applications for separating calcium, magnesium, strontium, and barium have been found.

[0004] CN104567890A discloses a method for preparing high-purity strontium carbonate using celestite and CO2. The method involves reacting celestite with water and CO2 under high pressure to produce strontium carbonate and sulfuric acid. The strontium carbonate precipitate is washed and dried to obtain high-purity strontium carbonate. The crystal morphology of strontium carbonate is optimized by controlling the CO2 pressure and reaction time. The byproduct sulfuric acid can be further processed or recovered. The process is environmentally friendly and suitable for the preparation of high-purity products. However, it requires high-pressure equipment, resulting in high investment costs.

[0005] Currently, the main method for producing strontium carbonate is the reduction method. This method involves reacting celestite with a reducing agent (such as pulverized coal or coke) at high temperatures to produce strontium sulfide (SrS). The strontium sulfide is then dissolved in water, and the filtrate, after filtration to remove insoluble substances, reacts with a carbonation reagent to produce strontium carbonate. For example, CN105678901A discloses a method for preparing high-purity strontium carbonate using the celestite reduction method. Celestite is mixed with pulverized coal and calcined at high temperatures (1000-1200℃) to produce strontium sulfide. The strontium sulfide dissolves in water, and the insoluble substances are removed by filtration. CO2 is bubbled into the strontium sulfide solution or a sodium carbonate solution is added to precipitate strontium carbonate. The strontium carbonate precipitate is washed and dried to obtain high-purity strontium carbonate. High-temperature reduction improves reaction efficiency. Multiple washing and filtration processes are used to remove impurities. This method is suitable for processing high-grade celestite ore. However, high-temperature calcination consumes a lot of energy, and the byproduct hydrogen sulfide needs to be properly handled.

[0006] The chlorination process involves reacting celestite with hydrochloric acid to produce strontium chloride (SrCl2), which then reacts with sodium carbonate to produce strontium carbonate. For example, CN106789012A discloses a method for preparing high-purity strontium carbonate using the chlorination process of celestite. Celestite reacts with hydrochloric acid to produce a strontium chloride solution. Impurities (such as Ca) are removed using an ion exchange resin. 2+ Ba 2+ A sodium carbonate solution is added to a strontium chloride solution to form a strontium carbonate precipitate. The precipitate is then washed and dried to obtain high-purity strontium carbonate. This method uses ion exchange technology to improve product purity. The byproducts, sulfuric acid and sodium chloride, can be recycled. This method is suitable for the preparation of high-purity strontium carbonate. However, it consumes a large amount of hydrochloric acid, resulting in high costs.

[0007] Similar to the methods used for processing celestite, barite can be processed into a series of barium compounds through chemical processing methods such as carbon reduction roasting, calcium chloride roasting, and raw ore refining. The most common method is carbon reduction roasting, which involves mixing barite powder with excess coal powder and roasting it at a high temperature of 1050-1150°C to reduce barium sulfate to barium sulfide melt (commonly known as "black ash"). The soluble barium sulfide is then separated by water leaching, serving as an intermediate product for the production of various barium salts. The method for producing high-purity barium carbonate involves first preparing a barium chloride solution, then purifying it through recrystallization before converting it to barium carbonate. Compared to barite, barite is easier to prepare into barium chloride, which is then used to prepare barium salts through recrystallization and precipitation. For example, CN114956147B describes a process for co-producing caustic soda, soda ash, and barium sulfate using a salt carrier and barite. CN112591781A discloses a process for producing electronic-grade barium chloride using low-grade barite ore; CN104891549B discloses a process for producing barium chloride using barite as raw material; and CN101559967 discloses a method for preparing barium nitrate, calcium nitrate, calcium sulfate, and sodium nitrate using medium- to low-grade barium carbonate ore. Most of these methods convert carbonates into soluble salts, followed by concentration and crystallization or recrystallization to separate barium from calcium, magnesium, and other minerals. The method disclosed in CN119263329A first involves ore beneficiation, then high-temperature calcination to decompose barium sulfate into barium oxide, followed by water leaching, the addition of zinc oxide, stirring to remove sulfur, heating and evaporating the filtrate for concentration, and cooling and recrystallization to obtain barium hydroxide octahydrate. The method provided in CN118771433A uses a microwave calcination process; other steps are similar to other methods.

[0008] With the continuous depletion of resources and increasing cost pressures, the use of low-grade minerals containing strontium and barium is becoming increasingly unavoidable. These minerals contain increasingly higher levels of various impurities such as calcium, magnesium, iron, aluminum, and related elements, making the development and production of methods for purifying strontium and barium increasingly important. Summary of the Invention

[0009] The purpose of this invention is to provide a process route for preparing high-purity strontium or barium compounds, solving the aforementioned problems. This method involves converting strontium or barium-containing raw materials through precipitation of insoluble substances, forming a mixture of carbonates or oxides containing various impurities such as calcium, magnesium, iron, and aluminum. Using these carbonates or oxides as raw materials, a novel method is proposed to separate strontium and barium from other impurities, and to prepare high-purity strontium and barium compounds, such as strontium chloride, barium chloride, strontium nitrate, barium nitrate, strontium formate, barium formate, strontium acetate, barium acetate, strontium carbonate, barium titanate, and strontium oxalate and barium oxalate. This invention prepares the aforementioned high-purity strontium or barium compounds by dissolving strontium or barium-containing carbonates and oxides in different solvents and washing them with different detergents, forming a new method suitable for industrial purification and large-scale preparation of high-purity strontium or barium products, meeting the needs of high-tech fields such as electronics and optics.

[0010] To achieve the above objectives, the present invention provides a process route for preparing high-purity strontium or barium compounds, comprising the following steps:

[0011] (1) Celestite and barite are calcined at high temperature to convert them into oxides, or the oxides obtained by calcination are leached with acid to obtain a chloride solution. Soluble carbonates are added to the solution to obtain carbonate precipitates; or the chloride solution is concentrated to obtain chloride crystals, which are then dissolved and precipitated with soluble carbonates before use; or the sulfate of ground celestite is converted into carbonate in a soluble carbonate solution before use; barite can be used directly without conversion.

[0012] (2) Dissolve the above-mentioned carbonates or oxides or barite with high molecular weight organic acids to form an organic acid salt solution containing strontium or barium and impurity elements;

[0013] (3) The organic acid salt solution obtained in step (2) is thoroughly mixed with an aqueous solution of inorganic acid or low molecular weight organic acid of a certain concentration and volume. The strontium or barium dissolved in the organic acid is washed into the aqueous solution. Then, the solution is allowed to stand and separate into layers to complete the washing process and obtain an aqueous solution containing strontium or barium. In this step, the washing with inorganic acid or low molecular weight organic acid is based on the different binding abilities of strontium, calcium, magnesium, barium and iron (III) ions with organic acid. The barium ions or barium ions can be washed off the organic solution by inorganic acid or low molecular weight organic acid.

[0014] The strontium or barium aqueous solution obtained in step (3) is concentrated or precipitated to form any of the following products: strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, strontium acetate or barium acetate, strontium carbonate or barium carbonate, or strontium oxalate or barium oxalate.

[0015] (4) The organic acid salt solution after washing strontium or barium in step (3) is regenerated with a high concentration of acid to remove impurities dissolved in the high molecular weight organic acid. The regenerated high molecular weight organic acid is then recycled.

[0016] Preferably, in step (2), the purity of strontium or barium in the organic acid salt solution is in the range of 45-99%.

[0017] Preferably, in step (2), the high molecular weight organic acid is an organic acid with a solubility of less than 1 g / L in water, and the high molecular weight organic acid is any one of organic phosphonic acid, organic sulfuric acid, organic sulfonic acid, organic sulfonamide and organic carboxylic acid.

[0018] Preferably, the organophosphonic acid is either a monophosphonic acid or a diphosphonic acid; the alkyl group in the phosphonic acid is a straight-chain or branched alkyl group, or a saturated or unsaturated alkyl group, and the total number of carbon atoms is 4 to 30.

[0019] Preferably, the alkyl group in the organic sulfuric acid is a straight-chain or branched alkyl group, or a saturated and unsaturated alkyl group, with a total number of carbon atoms of 16 to 30; the alkyl group in the organic carboxylic acid is a straight-chain or branched alkyl group, or a saturated and unsaturated alkyl group, with a total number of carbon atoms of 12 to 30; and the organic sulfonamide is a monosulfonamide or a disulfonamide, with the alkyl group in the organic sulfonamide being a straight-chain or branched alkyl group, or a saturated and unsaturated alkyl group, with a total number of carbon atoms of 16 to 30.

[0020] Preferably, in step (2), the alkyl group in the high molecular weight organic acid is a chlorinated alkyl group.

[0021] Preferably, in step (2), the dissolution conditions of strontium or barium carbonate and oxide in high molecular weight organic acid are as follows: under stirring conditions, the dissolution temperature is 20 to 80°C, the dissolution time is 5 min to 600 min, and the solid-liquid mass-volume ratio of strontium or barium carbonate and oxide and high molecular weight organic acid is 1 g: (1-1000) ml.

[0022] Preferably, in step (3), the inorganic acid or low molecular weight organic acid used for washing the organic acid salt solution containing strontium or barium and impurity elements is any one of high-purity hydrochloric acid, nitric acid, formic acid, or acetic acid. After washing, strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, and strontium acetate or barium acetate are obtained. Using the strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, and strontium acetate or barium acetate solution as raw material, soluble carbonates or oxalic acid and oxalates are added to form strontium carbonate or barium carbonate or strontium oxalate or barium oxalate and the corresponding soluble salts. The precipitate is filtered and washed to obtain strontium carbonate or barium carbonate or strontium oxalate or barium oxalate products.

[0023] Preferably, in step (3), the washing conditions for the organic acid salt solution containing strontium or barium and impurity elements are as follows: washing temperature 20 to 80°C, washing time 1 min to 100 min, mass-volume ratio of organic acid salt solution to inorganic acid or low molecular weight organic acid 1 g: 0.01-1000 ml, washing times 1 to 50 times, acidity of inorganic acid or low molecular weight organic acid 0.1 to 10 mol / L, and purity of the product obtained by concentration or precipitation greater than 98%.

[0024] Therefore, the present invention has the following beneficial effects:

[0025] The raw materials used in this invention have a wide range of strontium or barium content, and the invention method is highly adaptable, suitable for raw materials with different contents. Under normal temperature and pressure conditions, it can selectively separate strontium or barium from other impurities. The operating conditions are mild, with no exhaust gas or waste acid / alkali emissions, low energy consumption, high purity and yield of strontium or barium products, and easy to automate continuous operation.

[0026] The technical solution of the present invention will be further described in detail below through embodiments. Detailed Implementation

[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0028] The technical solution of the present invention will be further described below through embodiments.

[0029] Example 1

[0030] This embodiment provides a process route for producing a high-purity strontium compound, as follows: Celestite and barite are calcined at high temperature to convert them into oxides. These oxides are then leached with hydrochloric acid to obtain a chloride solution. The resulting chloride solid is then concentrated and crystallized. This solid is dissolved and added to sodium carbonate to obtain industrial-grade strontium carbonate, with a composition of 97.28% strontium carbonate, 0.48% calcium carbonate, 1.43% barium carbonate, 0.008% iron(III), and 0.37% sulfate. At room temperature, 20g of this strontium carbonate composition is thoroughly mixed with 220ml of an organic solvent containing 60% bis(dodecyl)phosphonic acid and 40% isomeric tetradecyl and hexadecyl alcohols. After the solid is completely dissolved, an organic solution containing strontium, calcium, magnesium, barium, and iron(III) is obtained. Based on the different binding abilities of strontium, calcium, magnesium, barium, and iron(III) ions to organic acids, barium ions can be washed away from this organic solution using a low concentration of hydrochloric acid. The number of washing cycles depends on the concentration of barium ions and the required purity of the strontium product. Following the principle of small, frequent washes to ensure product quality, the organic solution was washed three times with 100 mL of 0.01 mol / L hydrochloric acid solution. After the final wash, the barium ion concentration in the aqueous solution was 0.021 g / L, meeting the requirement of a strontium chloride purity greater than 99.9%. Then, the strontium-containing organic solution was washed with 100 mL of 2.5 mol / L hydrochloric acid to obtain a 109.52 g / L strontium chloride solution; the barium ion concentration was 0.008 g / L, the calcium ion concentration was less than 0.031 g / L, the iron ion concentration was 0.0005 g / L, and the sulfate concentration was trace; the strontium chloride purity was greater than 99.9%. Using this solution as a raw material, strontium carbonate or strontium oxalate precipitates with a purity greater than 99.9% can be prepared. After thorough washing, the strontium carbonate or strontium oxalate product is obtained. When the hydrochloric acid washing solution is replaced with a nitric acid solution of the same concentration, a strontium nitrate solution with a purity greater than 99.9% can be obtained.

[0031] Example 2

[0032] This embodiment provides a process route for producing high-purity strontium carbonate, as follows:

[0033] At room temperature, 20 g of the above-mentioned industrial-grade strontium carbonate was thoroughly mixed with 200 ml of an organic solvent containing 50% octadecyl sulfuric acid and 50% isomeric tetradecyl and hexadecyl alcohols. After the solid was completely dissolved, it was washed three times with 100 ml of pure water. Then, the organic solvent containing strontium was washed with 100 ml of 2.5 mol / L hydrochloric acid to obtain a 110.63 g / L strontium chloride solution; wherein the concentration of barium ions was 0.005 g / L, the concentration of calcium ions was 0.053 g / L, the concentration of iron ions was 0.0003 g / L, and the concentration of sulfate ions was trace; the purity of strontium chloride was greater than 99.9%. When the hydrochloric acid washing solution was replaced with a nitric acid solution of the same concentration, a strontium nitrate solution with a purity greater than 99.9% could be obtained. Using strontium nitrate as raw material, and precipitating agents such as sodium carbonate, sodium bicarbonate or ammonium carbonate or ammonium bicarbonate, urea, ammonia and carbon dioxide, strontium carbonate precipitate with a purity greater than 99.9% can be prepared. After thorough washing to remove sodium nitrate or ammonium nitrate, strontium carbonate product is obtained.

[0034] Example 3

[0035] This embodiment provides a process route for high-purity strontium formate, as follows:

[0036] Using celestite ore as raw material, the process involves reduction calcination, hydrochloric acid leaching, and filtration. Sodium carbonate is added to the filtrate to convert strontium, calcium, and magnesium in the leachate into carbonate or hydroxide precipitates. The precipitate contains 57.28% strontium carbonate, 26.17% calcium carbonate, 9.46% magnesium carbonate, and the remainder consists of 2.36% ferric oxide, 2.85% aluminum oxide, and small amounts of potassium and sodium carbonates. 20g of this mixture is dissolved in 250ml of an organic solution of 40% n-octadecyl sulfonic acid and 60% isocetyl alcohol at 60°C, and the insoluble matter is removed by centrifugation. The organic solvent was washed three times with 100 ml of pure water, and then washed with 70 ml of 2.5 mol / L formic acid solution to obtain a strontium formate solution with a strontium concentration of 90.86 g / L; wherein the magnesium ion concentration was 0.018 g / L, the calcium ion concentration was less than 0.082 g / L, the iron ion concentration was 0.0016 g / L, and the aluminum ion concentration was 0.0042 g / L. The purity of strontium formate was greater than 99.5%.

[0037] Example 4

[0038] This embodiment provides a process route for high-purity strontium chloride, as follows:

[0039] Using celestite ore as raw material, the process involves reduction calcination, hydrochloric acid leaching, and filtration. Sodium carbonate is added to the filtrate to convert strontium, calcium, and magnesium in the leachate into carbonate or hydroxide precipitates. The precipitate contains 45.47% strontium carbonate, 25.39% calcium carbonate, 24.53% magnesium carbonate, and the remainder consists of 1.52% ferric oxide, 1.33% aluminum oxide, and small amounts of potassium and sodium carbonates. 20g of this mixture is dissolved in 350ml of an organic solution of 40% di-p-octadecylbenzenesulfonamide and 60% hexadecane at 80°C, and the insoluble matter is removed by centrifugation. The organic solvent was washed three times with 100 ml of pure water, and then washed with 80 ml of 1.50 mol / L hydrochloric acid solution to obtain a strontium chloride solution with a concentration of 64.69 g / L; the concentration of magnesium ions was 0.1953 g / L, the concentration of calcium ions was less than 0.0832 g / L, the concentration of iron ions was 0.0014 g / L, and the concentration of aluminum ions was 0.0022 g / L. The purity of strontium chloride was greater than 99%.

[0040] Example 5

[0041] This embodiment provides a process route for high-purity strontium chloride, as follows:

[0042] Using barite ore as raw material, barite powder was obtained through crushing and grinding. This raw material contains 72.16% strontium carbonate, 10.54% calcium carbonate, 9.563% magnesium carbonate, and the remaining components are 1.52% ferric oxide, 1.33% aluminum oxide, and small amounts of potassium and sodium carbonates. 20g of this mixture was dissolved in 200ml of an organic solvent containing 50% octadecyl palmitic acid and 50% isooctadecyl alcohol at 80°C, and the insoluble matter was removed by centrifugation. The organic solvent was washed three times with 200ml of pure water, and then washed with 74ml of 2.5mol / L hydrochloric acid solution to obtain a strontium chloride solution with a concentration of 108.84 g / L; wherein the magnesium ion concentration is 0.3345g / L, the calcium ion concentration is less than 0.1263g / L, the iron ion concentration is 0.0012g / L, and the aluminum ion concentration is 0.0024g / L. The purity of the strontium chloride is greater than 99%.

[0043] Example 6

[0044] This embodiment provides a process route for barium compounds, as follows:

[0045] Using barite ore as raw material, the process involves reduction calcination, hydrochloric acid leaching, and filtration. The filtrate is concentrated to obtain crystals. After dissolving these crystals, sodium carbonate is added, causing barium, calcium, and magnesium to convert into carbonate or hydroxide precipitates. The precipitate contains 92.35% barium carbonate, 2.78% calcium carbonate, 1.84% magnesium carbonate, and the remaining components are 0.33% ferric oxide, 0.23% aluminum oxide, and small amounts of potassium and sodium carbonates. 20g of this mixture is dissolved in 110ml of an organic solution of 50% octadecyl palmitic acid and 50% isooctadecyl alcohol at 80°C, and the insoluble matter is removed by centrifugation. The organic solvent was washed three times with 200 ml of pure water, followed by washing with 80 ml of 2.5 mol / L hydrochloric acid solution to obtain a barium chloride solution with a barium concentration of 154.45 g / L; the concentration of magnesium ions was 0.6316 g / L, the concentration of calcium ions was less than 0.2295 g / L, the concentration of iron ions was 0.0022 g / L, and the concentration of aluminum ions was 0.0014 g / L. The purity of barium chloride was greater than 99%. Using this barium chloride as raw material, barium carbonate precipitate with a purity greater than 99% can be prepared by precipitation with sodium carbonate, sodium bicarbonate or ammonium carbonate or ammonium bicarbonate, urea, and precipitants such as ammonia and carbon dioxide. After thorough washing to remove sodium chloride or ammonium chloride, the barium carbonate product is obtained.

[0046] Example 7

[0047] This embodiment provides a process route for barium chloride, as follows:

[0048] Using barite ore as raw material, the process involves reduction calcination, hydrochloric acid leaching, and filtration. Sodium carbonate is added to the filtrate to convert barium, calcium, and magnesium in the leachate into carbonate or hydroxide precipitates. The resulting precipitate contains 62.44% barium carbonate, 4.93% calcium carbonate, 2.52% magnesium carbonate, and the remaining components are 0.15% ferric oxide, 0.21% aluminum oxide, 19.91% silicon dioxide, and other impurities. At room temperature, 20g of this mixed oxide component is thoroughly mixed with 80ml of an organic solvent containing 60% bis(dodecyl)phosphonic acid and 40% isomeric tetradecyl and hexadecyl alcohols. After complete dissolution of the solid, the mixture is washed four times with 80ml of pure water, followed by washing with 80ml of 0.5mol / L hydrochloric acid solution, yielding a barium chloride solution with a barium ion concentration of 129.43 g / L; a calcium ion concentration of 0.121 g / L; an iron ion concentration of 0.0015 g / L; and a trace sulfate concentration. The purity of barium chloride is greater than 99.9%.

[0049] Example 8

[0050] The organic solution after washing barium ions in Example 7 was washed with 40 ml of 6 mol / L hydrochloric acid. The residual impurities such as calcium, magnesium, iron, and aluminum in the organic solvent were replaced by hydrogen ions. 99.5%, 99.8%, 98.2%, and 98.5% of calcium, magnesium, iron, and aluminum ions were transferred from the organic solvent to the aqueous solution. After standing and separation, the chloride aqueous solution containing these elements was separated from the organic solution. The organic solution was restored to its original properties and could be recycled.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process route for preparing high-purity strontium or barium compounds, characterized in that, Includes the following steps: (1) Celestite and barite are converted into oxides or carbonates, while barite can be used directly without conversion; (2) Dissolve the above-mentioned carbonates or oxides or barite with high molecular weight organic acids to form an organic acid salt solution containing strontium or barium and impurity elements; In step (2), the high molecular weight organic acid is an organic acid with a solubility of less than 1 g / L in water, and the high molecular weight organic acid is any one of organic phosphonic acid, organic sulfuric acid, organic sulfonic acid, organic sulfonamide and organic carboxylic acid; The organophosphonic acid is either a monophosphonic acid or a diphosphonic acid; the alkyl group in the phosphonic acid is a straight-chain or branched alkyl group, or a saturated and unsaturated alkyl group, and the total number of carbon atoms is 4 to 30. The alkyl groups in organic sulfuric acid are straight-chain or branched alkyl groups, or saturated and unsaturated alkyl groups, with a total number of carbon atoms ranging from 16 to 30. The alkyl groups in organic carboxylic acids are straight-chain or branched alkyl groups, or saturated and unsaturated alkyl groups, with a total number of carbon atoms ranging from 12 to 30. The organic sulfonamide is a monosulfonamide or a disulfonamide, and the alkyl group in the organic sulfonamide is a straight-chain or branched alkyl group, or a saturated and unsaturated alkyl group, with a total number of carbon atoms of 16 to 30. (3) Mix the organic acid salt solution obtained in step (2) thoroughly with the aqueous solution of inorganic acid or low molecular weight organic acid, wash the dissolved strontium or barium into the aqueous solution, and then separate the layers to complete the washing process and obtain an aqueous solution containing strontium or barium. The strontium or barium aqueous solution obtained in step (3) is concentrated or precipitated to form any of the following products: strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, strontium acetate or barium acetate, strontium carbonate or barium carbonate, or strontium oxalate or barium oxalate. (4) The organic acid salt solution after washing strontium or barium in step (3) is regenerated with a high concentration of acid to remove impurities dissolved in the high molecular weight organic acid. The regenerated high molecular weight organic acid is then recycled.

2. The process route for preparing high-purity strontium or barium compounds according to claim 1, characterized in that, In step (2), the purity of strontium or barium in the organic acid salt solution ranges from 45% to 99%.

3. The process route for preparing high-purity strontium or barium compounds according to claim 1, characterized in that, In step (2), the alkyl group in the high molecular weight organic acid is a chlorinated alkyl group.

4. The process route for preparing high-purity strontium or barium compounds according to claim 3, characterized in that, In step (2), the dissolution conditions of strontium or barium carbonate and oxide in high molecular weight organic acid are as follows: under stirring conditions, the dissolution temperature is 20 to 80°C, the dissolution time is 5 min to 600 min, and the solid-liquid mass-volume ratio of strontium or barium carbonate and oxide and high molecular weight organic acid is 1 g: (1-1000) ml.

5. The process route for preparing high-purity strontium or barium compounds according to claim 1, characterized in that, In step (3), the inorganic acid or low molecular weight organic acid used to wash the organic acid salt solution containing strontium or barium and impurity elements is any one of high-purity hydrochloric acid, nitric acid, formic acid or acetic acid. After washing, an aqueous solution of strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, strontium acetate or barium acetate is obtained. Using the aqueous solution of strontium chloride or barium chloride, strontium nitrate or barium nitrate, strontium formate or barium formate, strontium acetate or barium acetate as raw material, carbonate or oxalate is added to produce strontium carbonate, barium carbonate or strontium oxalate, barium oxalate.

6. The process route for preparing high-purity strontium or barium compounds according to claim 1, characterized in that, In step (3), the washing conditions for the organic acid salt solution containing strontium or barium and impurity elements are as follows: washing temperature 0 to 100℃, washing time 1 min to 100 min, mass-volume ratio of organic acid salt solution to inorganic acid or low molecular weight organic acid 1 g: 0.01-1000 ml, washing times 1 to 50 times, acidity of inorganic acid or low molecular weight organic acid 0.1 to 10 mol / L, and purity of the product obtained by concentration or precipitation greater than 98%.