CN115626647A - Method for preparing potassium fluosilicate from fluorine-containing liquid - Google Patents
Method for preparing potassium fluosilicate from fluorine-containing liquid Download PDFInfo
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- CN115626647A CN115626647A CN202211275261.5A CN202211275261A CN115626647A CN 115626647 A CN115626647 A CN 115626647A CN 202211275261 A CN202211275261 A CN 202211275261A CN 115626647 A CN115626647 A CN 115626647A
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- fluorine
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/08—Compounds containing halogen
- C01B33/10—Compounds containing silicon, fluorine, and other elements
- C01B33/103—Fluosilicic acid; Salts thereof
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
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Abstract
The invention discloses a method for preparing high-purity potassium fluosilicate by fluorine-containing liquid, which comprises the steps of mixing silicon slag with a certain mass fraction of acid, reacting at a certain temperature under stirring, carrying out suction filtration on the mixture of the silicon slag and the acid, washing with deionized water until the washing water is neutral, putting the washed silicon slag into a drying oven at 100-300 ℃, and grinding the dried silicon slag into superfine silicon slag powder; concentrating the fluorine-containing liquid at a certain vacuum degree and temperature, heating a certain amount of concentrated solution to 40-50 ℃ after reaching the end point of concentration, adding a certain amount of superfine silicon powder, stirring for reaction, filtering after the reaction is finished, adding a proper amount of sylvite into the supernatant, slowly cooling to normal temperature, reacting under the condition of normal temperature stirring, filtering, washing and drying to obtain the high-purity potassium fluosilicate. The method is simple to operate, the raw materials are all cheap medicaments and industrial byproducts, the preparation conditions are mild, and the method is an effective and feasible method for preparing the high-purity potassium fluosilicate.
Description
Technical Field
The invention belongs to the field of phosphorus chemical production, and particularly relates to a method for preparing high-purity potassium fluosilicate from fluorine-containing liquid.
Background
The potassium fluosilicate is used as an auxiliary agent for smelting magnesium and aluminum in the metallurgical industry, is used for manufacturing potassium glass, optical glass and opaque glass in the glass industry, is used for manufacturing pesticides in the pesticide industry, is used for manufacturing intermediates in the chemical industry, is used as an analytical reagent in analytical chemistry, and can also be used for the aspects of ceramic synthetic mica and the like.
The fluorine resource amount in the phosphorite accounts for about 90 percent of the world fluorine resource accumulation amount, about 70 percent of the fluorine resource in the phosphorite enters the phosphoric acid in the wet processing process, about 50 to 60 percent of the fluorine resource in the phosphoric acid escapes in the form of fluorine-containing gas in the concentration process and is recovered in the form of fluosilicic acid, and the recovery of the fluorine resource from the phosphoric acid is a main way for recovering the fluorine in the phosphorite, but the recovery of the fluorine in a gas phase is very limited, only about one fourth of the fluorine escapes from the gas phase, and about three quarters of the fluorine does not escape in the form of gas but mainly exists in the liquid phase of the wet phosphoric acid and the acid water in the form of hydrofluoric acid and fluosilicic acid, so that the fluorine impurity can be removed by recovering the part of the fluorine, and the social and economic benefits are created.
Aiming at the problem that most of fluorine in a wet-process phosphoric acid liquid phase is focused on how to effectively remove fluorine, for example, sodium salt is used as a defluorinating agent, the main purpose is to improve the quality of the wet-process phosphoric acid and reduce the content of impurities in the wet-process phosphoric acid, documents report that fluorine in the wet-process phosphoric acid liquid phase is prepared into primary products such as sodium fluosilicate or potassium fluosilicate, and other documents report that the sodium fluosilicate or potassium fluosilicate is further processed into sodium fluoride or potassium fluoride through the steps of primary alkalization, primary filtration, primary concentration and the like. The invention aims to prepare a high-purity potassium fluosilicate product by taking fluorine-containing liquid in wet-process phosphoric acid production as a fluorine source.
Disclosure of Invention
In order to achieve the purpose, the technical scheme of the invention is as follows: a method for preparing high-purity potassium fluosilicate by fluorine-containing liquid comprises (1) mixing silicon slag with acid, reacting under stirring, suction filtering the obtained mixture, washing to neutrality, drying, and grinding into silicon slag powder;
(2) Adding fluorine-containing liquid into the superfine silicon powder, stirring for reaction, filtering after the reaction is finished, taking supernate, adding potassium salt into the supernate, and filtering, washing and drying after the stirring reaction is finished to obtain the potassium fluosilicate.
The silicon slag comprises 70-80% of silicon dioxide, 5-10% of fluorine ions, 3-5% of water and inevitable metal ion impurities.
The acid is nitric acid or hydrochloric acid or the mixture of the nitric acid and the hydrochloric acid, and the mass fraction of the acid is 20-40%.
Mixing the silicon slag with acid, and reacting for 2-5h at 55-75 ℃.
Putting the silicon slag washed to be neutral into a drying oven at the temperature of 100-300 ℃ for 3-5 hours, and grinding the dried silicon slag into silicon slag powder; the fineness of the silicon slag powder is more than 400 meshes and accounts for 80-100 percent.
The fineness of the silicon slag powder is more than 600 meshes and accounts for 70-80 percent.
The fluorine-containing liquid is wet-process phosphoric acid tail gas washing circulating liquid and comprises fluorine and phosphorus, wherein the fluorine content is 5% -12%, and the phosphorus
The content of (A) is 0.5-1.0%. The fluorine-containing liquid is concentrated to 20-40% of the original volume fraction at the temperature of 70-80 ℃ and the vacuum degree of-60-80 kpa before reaction.
Adding the fluorine-containing liquid into the superfine silicon powder, and stirring and reacting for 1-3h at 40-60 ℃; adding potassium salt, and reacting at room temperature for 1-3h under stirring.
The mass ratio of the fluorine-containing liquid to the silicon slag powder to the potassium salt is 1:1-1.5:0.5-1.1; the potassium salt comprises any one of potassium nitrate, potassium carbonate and potassium chloride.
According to the invention, fluorine elements in the silicon slag and the liquid are recycled, soluble impurities contained in the silicon slag can be removed through acid leaching, and relatively pure silicon slag is completely dehydrated after being baked at high temperature, so that the purity of the silicon slag reaches a relatively ideal level, and a silicon oxygen group is formed on a main chain of a silicon dioxide structure in the dehydration process and has higher activity than that of the main chain structure; the silicon slag after grinding has larger specific surface area and is amorphous silicon dioxide fine particles, the activity is further improved due to a space tetrahedral mesh structure formed by silicon and oxygen, the high-activity silicon slag is utilized to react with fluorine in liquid, the degree of the bonding reaction of the fluorine and silicon micro particles is greatly increased, fluorine elements in the liquid are all converted into fluorine silicate, and the fluorine can be solidified by adding sylvite to obtain a pure potassium fluosilicate product.
Has the advantages that: the main raw materials for preparing the fluosilicic acid are byproduct waste residues and fluorine-containing liquid generated in wet-process phosphoric acid, and the two byproducts are used for preparing the high-purity potassium fluosilicate through a series of steps, so that the waste is changed into valuable, and the method has great reference significance for reducing the waste residues and the waste water generated in the chemical production.
Detailed Description
The invention is further described below with reference to specific examples.
Example 1
Adding a proper amount of silicon slag into a hydrochloric acid solution with the mass fraction of 20%, reacting for 2 hours under constant-temperature stirring at the temperature of 55 ℃, filtering, washing the silicon slag to be neutral (the pH value is 6.8-7.2), placing the silicon slag in a drying oven at the temperature of 150 ℃, continuously baking for 2 hours after complete drying, cooling, grinding until the proportion of the silicon slag with more than 400 meshes reaches 90%, wherein the content of the silicon slag with more than 600 meshes is 60%, the content of the silicon slag with more than 500 meshes is 80%, and hermetically storing the silicon slag for later use. Vacuum concentrating fluorine-containing liquid to 30% of the mass, heating to 40 deg.C, adding the above silicon slag 1.1 times of the mass of the fluorine-containing liquid, reacting for 2 hr, filtering, adding potassium nitrate 0.9 times of the mass of the fluorine-containing liquid, reacting for 2 hr, filtering, washing, and drying to obtain potassium fluosilicate with yield of 90.8% and purity of 98.1%.
Examples 1 to 1
The method and the steps are the same as the example 1, and only the conditions are changed: the proportion of the silicon slag ground to more than 300 meshes reaches 100 percent, wherein the content of the silicon slag passing through 500 meshes is 40 percent, and the content of the silicon slag passing through 400 meshes is 80 percent. The yield of the potassium fluosilicate is 83.5 percent and the purity is 90.2 percent.
Examples 1 to 2
The method and the steps are the same as the example 1, and only the conditions are changed: the silicon slag is ground to the proportion of more than 400 meshes reaching 100 percent, wherein the content of the silicon slag passing through 600 meshes is 40 percent, and the content of the silicon slag passing through 500 meshes is 80 percent. The yield of the potassium fluosilicate is measured to be 90.6 percent, and the purity is measured to be 96.2 percent.
Example 2
Adding a proper amount of silicon slag into a hydrochloric acid solution with the mass fraction of 30%, reacting for 2 hours under constant-temperature stirring at 55 ℃, filtering, washing the silicon slag to be neutral (the pH is 6.8-7.2), placing the silicon slag in an oven at 300 ℃, continuously baking for 3 hours after completely drying, cooling, grinding until the proportion of the silicon slag with more than 400 meshes reaches 100%, wherein the content of the silicon slag with 600 meshes is 70%, the content of the silicon slag with 500 meshes is 90%, and hermetically storing the silicon slag for later use. Concentrating fluorine-containing liquid in vacuum to 20% of the mass, heating to 40 ℃, adding the silicon slag, wherein the mass of the silicon slag is equal to that of the fluorine-containing liquid, reacting for 2 hours, filtering, taking clear liquid, adding potassium carbonate, the mass of the potassium carbonate is 0.9 times that of the fluorine-containing liquid, reacting for 2 hours, filtering, washing and drying to obtain potassium fluosilicate, and determining that the yield of the potassium fluosilicate is 91.3% and the purity of the potassium fluosilicate is 98.5%.
Example 2-1
The method and the steps are the same as the example 2, and only the conditions are changed: washing the silicon slag to be neutral (the pH value is 6.8-7.2), then placing the silicon slag in an oven at 100 ℃ for baking for 1 hour, cooling and grinding. The yield of the potassium fluosilicate is measured to be 82.4 percent, and the purity is measured to be 86.2 percent.
Examples 2 to 2
The method and the steps are the same as the example 2, and only the conditions are changed: after the silicon slag is reacted by acid, the silicon slag is washed to be weakly acidic, and the pH value is 4.5-5.2. The yield of the potassium fluosilicate is 85.3 percent and the purity is 91.5 percent.
Example 3
Adding a proper amount of silicon slag into a nitric acid solution with the mass fraction of 30%, reacting for 2 hours under constant-temperature stirring at 55 ℃, filtering, washing the silicon slag to be neutral (the pH value is 6.8-7.2), placing the silicon slag into an oven with the temperature of 200 ℃, continuously baking for 3 hours after completely drying, cooling, grinding until the proportion of the silicon slag with more than 400 meshes reaches 80%, wherein the content of the silicon slag with more than 600 meshes is 40%, the content of the silicon slag with more than 500 meshes is 60%, and hermetically storing the silicon slag for later use. Vacuum concentrating fluorine-containing liquid to 20% of the mass, heating to 40 deg.C, adding the above silicon slag 1.1 times of the fluorine-containing liquid, reacting for 2 hr, filtering, adding potassium nitrate 0.9 times of the fluorine-containing liquid, reacting for 2 hr, filtering, washing, and drying to obtain potassium fluosilicate with yield of 88.3% and purity of 94.6%.
Example 4
Adding a proper amount of silicon slag into a hydrochloric acid solution with the mass fraction of 20%, reacting for 2 hours under constant-temperature stirring at 55 ℃, filtering, washing the silicon slag to be neutral (the pH is 6.8-7.2), placing the silicon slag into a drying oven with the temperature of 100 ℃, continuously baking for 3 hours after complete drying, grinding after cooling until the proportion of the silicon slag with more than 400 meshes reaches 100%, wherein the content of the silicon slag with more than 600 meshes is 30%, and the content of the silicon slag with more than 500 meshes is 90%, and sealing and storing the silicon slag for later use. Concentrating fluorine-containing liquid in vacuum to 20% of the mass, heating to 40 ℃, adding the silicon slag, wherein the mass of the silicon slag is 0.9 times of that of the fluorine-containing liquid, reacting for 2 hours, filtering, taking clear liquid, adding potassium nitrate, the mass of the potassium nitrate is equal to that of the fluorine-containing liquid, reacting for 2 hours, filtering, washing and drying to obtain potassium fluosilicate, and detecting that the yield of the potassium fluosilicate is 89.5% and the purity is 93.2%.
Claims (10)
1. The method for preparing potassium fluosilicate by using fluorine-containing liquid is characterized by comprising the following steps of:
(1) Mixing the silicon slag with acid, reacting while stirring, performing suction filtration on the obtained mixture, washing to be neutral, drying and grinding into silicon slag powder;
(2) Adding fluorine-containing liquid into the superfine silicon powder, stirring for reaction, filtering after the reaction is finished, taking supernate, adding potassium salt into the supernate, and filtering, washing and drying after the stirring reaction is finished to obtain the potassium fluosilicate.
2. The method for preparing potassium fluosilicate from fluorine-containing liquid according to claim 1, wherein the silicon slag comprises 70-80% of silicon dioxide, 5-10% of fluorine ions, 3-5% of water and inevitable metal ion impurities.
3. The method for preparing potassium fluosilicate by using fluorine-containing liquid as claimed in claim 2, wherein the acid is nitric acid or hydrochloric acid or a mixture of the nitric acid and the hydrochloric acid, and the mass fraction of the nitric acid and the hydrochloric acid is 20-40%.
4. The method for preparing potassium fluosilicate by using fluorine-containing liquid as claimed in claim 3, wherein the silicon slag is mixed with the acid and then reacted for 2-5h at 55-75 ℃.
5. The method for preparing potassium fluosilicate from fluorine-containing liquid according to claim 1, wherein the silicon slag washed to be neutral is put into an oven at 100-300 ℃ for 3-5 hours, and the dried silicon slag is ground into silicon slag powder; the fineness of the silicon slag powder is more than 400 meshes and accounts for 80-100 percent.
6. The method for preparing potassium fluosilicate by using fluorine-containing liquid as claimed in claim 1, wherein the fineness of the silicon slag powder is more than 600 meshes and 70-80% of the ratio.
7. The method for preparing potassium fluosilicate by using fluorine-containing liquid as claimed in claim 1, wherein the fluorine-containing liquid is wet-process phosphoric acid tail gas washing circulating liquid, wherein the fluorine content is 5-12%, and the phosphorus content is 0.5-1.0%.
8. The method for preparing potassium fluosilicate from fluorine-containing liquid according to claim 1, wherein the fluorine-containing liquid is concentrated to 20-40% of original volume fraction at 70-80 ℃ and vacuum degree of-60 kpa-80 kpa before reaction.
9. The method for preparing potassium fluosilicate by using fluorine-containing liquid as claimed in claim 8, wherein the fluorine-containing liquid is added with the ultrafine silicon powder and then stirred for reaction at 40-60 ℃ for 1-3h; adding potassium salt, and reacting at room temperature for 1-3h under stirring.
10. The method for preparing potassium fluosilicate from fluorine-containing liquid according to claim 9, wherein the mass ratio of the fluorine-containing liquid to the silicon slag powder to the potassium salt is 1:1-1.5:0.5-1.1; the potassium salt comprises any one of potassium nitrate, potassium carbonate and potassium chloride.
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| CN202211275261.5A CN115626647A (en) | 2022-10-18 | 2022-10-18 | Method for preparing potassium fluosilicate from fluorine-containing liquid |
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| CN202211275261.5A CN115626647A (en) | 2022-10-18 | 2022-10-18 | Method for preparing potassium fluosilicate from fluorine-containing liquid |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1207366A (en) * | 1998-08-22 | 1999-02-10 | 杨显庆 | Process for producing calcium hydrogen phosphate by once-through defluorination |
| CN203754432U (en) * | 2013-12-26 | 2014-08-06 | 青海稼诚硅业有限公司 | Remelting device for producing high-purity silicon by using silicon residues |
| CN103991882A (en) * | 2014-03-14 | 2014-08-20 | 武汉工程大学 | Method for preparing potassium fluoride by using fluoride in liquid phase of wet process phosphoric acid |
| CN106698478A (en) * | 2015-11-16 | 2017-05-24 | 贵州省化工技术研发中心 | Recycling method of fluorine from wet-process phosphoric acid |
| CN112320803A (en) * | 2020-10-27 | 2021-02-05 | 贵州省化工研究院 | Method for producing solid ammonium fluosilicate by using fluosilicic acid in phosphoric acid |
-
2022
- 2022-10-18 CN CN202211275261.5A patent/CN115626647A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1207366A (en) * | 1998-08-22 | 1999-02-10 | 杨显庆 | Process for producing calcium hydrogen phosphate by once-through defluorination |
| CN203754432U (en) * | 2013-12-26 | 2014-08-06 | 青海稼诚硅业有限公司 | Remelting device for producing high-purity silicon by using silicon residues |
| CN103991882A (en) * | 2014-03-14 | 2014-08-20 | 武汉工程大学 | Method for preparing potassium fluoride by using fluoride in liquid phase of wet process phosphoric acid |
| CN106698478A (en) * | 2015-11-16 | 2017-05-24 | 贵州省化工技术研发中心 | Recycling method of fluorine from wet-process phosphoric acid |
| CN112320803A (en) * | 2020-10-27 | 2021-02-05 | 贵州省化工研究院 | Method for producing solid ammonium fluosilicate by using fluosilicic acid in phosphoric acid |
Non-Patent Citations (1)
| Title |
|---|
| 戴永年: "《戴永年文集》", 冶金工业出版社, pages: 214 - 215 * |
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