阅读说明：本技术 一种氟化钾的生产工艺 (Production process of potassium fluoride ) 是由 张军航 郭兰兰 胡进华 邓卫国 厉皖成 洪志林 于 2019-11-21 设计创作，主要内容包括：本发明公开了一种氟化钾的生产工艺,将氢氧化钙桨液缓慢抽入到氟硅酸钾浆液中,充分反应；反应液进行固液分离,固体为氟化钙和二氧化硅混合物,固体进行打浆进入氟硅酸钾合成工序；将清液静置,待沉降沉淀后进入浓缩釜进行浓缩,得到氟化钾母液；将浓缩后的氟化钾母液结晶干燥即得无水氟化钾；将水投入反应釜中,开动搅拌,投入氟化钙和二氧化硅混合物,补充氯化钾和盐酸,充分反应,反应完毕进行固液分离,所得固体即为氟硅酸钾湿料成品,用于钾脱硅工序。本发明以氟化钙、二氧化硅、氯化钾、盐酸为原料,无需使用氢氟酸,氟化钙是含氟废水处理副产品,实现了废水资源回收。(The invention discloses a production process of potassium fluoride, which comprises the steps of slowly pumping calcium hydroxide slurry into potassium fluosilicate slurry for full reaction; carrying out solid-liquid separation on the reaction liquid, wherein the solid is a mixture of calcium fluoride and silicon dioxide, and pulping the solid to enter a potassium fluosilicate synthesis process; standing the clear liquid, and after settling and precipitation, feeding the clear liquid into a concentration kettle for concentration to obtain a potassium fluoride mother liquid; crystallizing and drying the concentrated potassium fluoride mother liquor to obtain anhydrous potassium fluoride; putting water into a reaction kettle, starting stirring, putting a mixture of calcium fluoride and silicon dioxide, supplementing potassium chloride and hydrochloric acid, fully reacting, and carrying out solid-liquid separation after the reaction is finished to obtain a solid, namely a finished product of the wet potassium fluosilicate material, which is used for a potassium desiliconization process. The invention takes calcium fluoride, silicon dioxide, potassium chloride and hydrochloric acid as raw materials, hydrofluoric acid is not needed, the calcium fluoride is a fluorine-containing wastewater treatment byproduct, and the wastewater resource recovery is realized.)

1. A production process of potassium fluoride is characterized by comprising the following steps:

s1, adding calcium hydroxide into water to prepare calcium hydroxide slurry;

s2, putting potassium fluosilicate into water to be beaten into potassium fluosilicate slurry; slowly pumping the calcium hydroxide slurry into the potassium fluosilicate slurry for full reaction;

s3, after the reaction in the reaction kettle is completed, carrying out solid-liquid separation on the reaction liquid, wherein the solid is a mixture of calcium fluoride and silicon dioxide, pulping the solid, and entering a potassium fluosilicate synthesis process;

s4, standing the clear liquid, and after settling and precipitating, feeding the clear liquid into a concentration kettle for concentration to obtain a potassium fluoride mother liquid;

s5, crystallizing and drying the concentrated potassium fluoride mother liquor to obtain anhydrous potassium fluoride;

and S6, adding water into the reaction kettle, starting stirring, adding the mixture solid of calcium fluoride and silicon dioxide obtained in the step S3, supplementing potassium chloride and hydrochloric acid, fully reacting, performing solid-liquid separation after the reaction is finished, wherein the obtained solid is a finished product of the wet potassium fluosilicate material, and sending the finished product to the step S2 to perform a potassium fluoride desiliconization step.

2. The process for producing potassium fluoride according to claim 1, wherein: in step S2, the molar ratio of potassium fluosilicate to calcium hydroxide is 1: 2.

3. the process for producing potassium fluoride according to claim 1, wherein: in step S5, the potassium fluoride mother liquor is injected into the tank to be sprayed, and then injected into the spray drying tower from the tank to be sprayed for spray drying.

4. The process for producing potassium fluoride according to claim 1, wherein: in step S2, the pH at the end of the reaction is controlled to 8.5-9.

5. The process for producing potassium fluoride according to claim 1, wherein: in step S6, the molar ratio of calcium fluoride to silica in the solid obtained in step S3 is 2: 1, and the molar ratio of calcium fluoride to silicon dioxide in step S6 is 3: 1, so calcium fluoride should also be supplemented.

Technical Field

The invention relates to the technical field of fluorine chemical industry, in particular to a production process of potassium fluoride.

Background

In the field of chemicals, salts are a common chemical. Salts play a very important role both in industrial production and in scientific research in the laboratory. The potassium salt is a common salt, and plays an important role in actual industrial production and scientific research.

Among them, potassium fluoride is a common potassium salt, and may be referred to as potassium fluoride salt. It has the corresponding chemical formula of KF and molecular weight of 58.10. Is normally white monoclinic crystal or crystalline powder, is salty in taste, and is easy to absorb moisture. Meanwhile, potassium fluoride is very soluble in water and insoluble in ethanol. The water solution is alkaline and can corrode glass and porcelain, the relative density is 2.454, and the melting point is 858 ℃. In practical applications, it is often used in the glass engraving, food preservation and electroplating industries. Further, the solder flux, the insecticide, the fluorinating agent for organic compounds, the catalyst, and the absorbent (absorbing HF and moisture) can be used. Due to the importance of potassium fluoride in practical production applications, the demand for it has also increased year by year.

At present, anhydrous hydrogen fluoride is generally selected as a production raw material when potassium fluoride is prepared. However, anhydrous hydrogen fluoride is expensive, and if the anhydrous hydrogen fluoride is industrially produced in a large scale, the raw material cost is high, which is not favorable for large-scale production and application. The applicant's prior application patent CN 107973321 a discloses a preparation method of potassium fluoride, which adopts fluosilicic acid and potassium fluosilicate as production raw materials to replace hydrogen fluoride as production raw materials, thereby reducing production cost.

Disclosure of Invention

The invention aims to provide a production process of potassium fluoride, which takes calcium fluoride, silicon dioxide, potassium chloride and hydrochloric acid as raw materials, does not need to use hydrofluoric acid, and realizes the recovery of wastewater resources because the calcium fluoride is a fluorine-containing wastewater treatment byproduct.

In order to achieve the purpose, the invention adopts the following technical scheme: a production process of potassium fluoride is characterized by comprising the following steps:

s1, adding calcium hydroxide into water to prepare calcium hydroxide slurry;

s2, putting potassium fluosilicate into water to be beaten into potassium fluosilicate slurry; slowly pumping the calcium hydroxide slurry into the potassium fluosilicate slurry for full reaction;

s3, after the reaction in the reaction kettle is completed, carrying out solid-liquid separation on the reaction liquid, wherein the solid is a mixture of calcium fluoride and silicon dioxide, pulping the solid, and entering a potassium fluosilicate synthesis process;

s4, standing the clear liquid, and after settling and precipitating, feeding the clear liquid into a concentration kettle for concentration to obtain a potassium fluoride mother liquid;

s5, crystallizing and drying the concentrated potassium fluoride mother liquor to obtain anhydrous potassium fluoride;

and S6, adding water into the reaction kettle, starting stirring, adding the mixture solid of calcium fluoride and silicon dioxide obtained in the step S3, supplementing potassium chloride and hydrochloric acid, fully reacting, performing solid-liquid separation after the reaction is finished, wherein the obtained solid is a finished product of the wet potassium fluosilicate material, and sending the finished product to the step S2 to perform a potassium fluoride desiliconization step.

Further preferably, in step S2, the molar ratio of potassium fluorosilicate to calcium hydroxide is 1: 2

Preferably, in step S5, the potassium fluoride mother liquor is injected into the tank to be sprayed, and then injected into the spray drying tower from the tank to be sprayed for spray drying, and the crystal drying is performed by a spray drying method, so that the speed is high and the product particles are uniform.

Further preferably, in step S2, the pH at the end of the reaction is controlled to 8.5 to 9.

More preferably, in step S6, the molar ratio of calcium fluoride to silica in the solid obtained in step S3 is 2: 1, and the molar ratio of calcium fluoride to silicon dioxide in step S6 is 3: 1, so calcium fluoride should also be supplemented.

The invention has the beneficial effects that: potassium fluosilicate and calcium hydroxide are used as raw materials to produce potassium fluoride, byproducts of calcium fluoride and silicon dioxide do not need to be separated, potassium chloride and hydrochloric acid are directly added to produce potassium fluosilicate, the silicon dioxide can be recycled, calcium fluoride is a raw material for synthesizing potassium fluosilicate and a byproduct for producing potassium fluoride, the calcium fluoride can be partially recycled, final calcium forms a final product in a calcium chloride mode, the raw materials required to be consumed in actual production are calcium fluoride, potassium chloride, hydrochloric acid and calcium hydroxide, the final product is potassium fluoride and calcium chloride, and recycling of part of the raw materials is achieved.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

The reaction equation of the production process of potassium fluoride of the invention is as follows:

1、K₂SiF₆+2Ca(OH₎₂→2CaF₂+SiO₂+2KF

2、3CaF₂+SiO₂+2KCl+4HCl→K₂SiF₆+3CaCl₂+2H₂O

the specific process steps are as follows:

s1, adding water into the reaction kettle, starting stirring, adding calcium hydroxide, and beating into calcium hydroxide slurry;

s2, adding water into the reaction kettle, starting stirring, adding potassium fluosilicate, and beating into potassium fluosilicate slurry; and slowly pumping the calcium hydroxide slurry into the potassium fluosilicate slurry for full reaction, wherein the pH value of the reaction end point is 8.5-9.

S3, after the reaction in the reaction kettle is completed, carrying out solid-liquid separation on the reaction liquid, pulping the solid, and entering a potassium fluosilicate synthesis process;

and S4, standing the clear liquid for 12-24h, and then feeding the clear liquid into a concentration kettle.

And S5, pumping the concentrated potassium fluoride mother liquor into a to-be-sprayed groove, and pumping the to-be-sprayed groove into a spray drying tower for spray drying to obtain the finished product, namely the anhydrous potassium fluoride.

And S6, adding water into the reaction kettle, starting stirring, adding the solid in the step S3, supplementing potassium chloride and hydrochloric acid, fully reacting, performing solid-liquid separation after the reaction is finished to obtain the solid, namely the finished product of the wet potassium fluosilicate material, and sending the solid to the step S2 to perform the potassium fluoride desilication step.