CN115385363A

CN115385363A - Method for separating potassium fluoride and potassium chloride by using mixed alcohol reagent

Info

Publication number: CN115385363A
Application number: CN202211111039.1A
Authority: CN
Inventors: 赖育河; 谢光明; 杨瑞甫; 周江聪; 孙志幕; 邓婕
Original assignee: Fujian Longde New Energy Co ltd; Longyan University
Current assignee: Fujian Longde New Energy Co ltd; Longyan University
Priority date: 2022-09-13
Filing date: 2022-09-13
Publication date: 2022-11-25

Abstract

The invention discloses a separation method of industrial mixed potassium salt. The separation method of the mixed potassium salt comprises the following steps: dissolving mixed potassium salt in water, methanol and ethanol according to a certain proportion to obtain potassium chloride and mother liquor A; and (2) concentrating the mother liquor A obtained in the step (1) to obtain mother liquor A ', and recrystallizing the obtained mother liquor A' in methanol and ethanol to obtain potassium fluoride. The potassium chloride and the potassium fluoride obtained by the separation method have high purity.

Description

Method for separating potassium fluoride and potassium chloride by using mixed alcohol reagent

Technical Field

The invention belongs to the field of chemical synthesis, and particularly belongs to the field of separation of industrial mixtures.

Technical Field

In general, waste residues (also referred to as "industrial mixed potassium salts") generated by organic fluorination reaction contain about 80% of potassium chloride, about 10% of potassium fluoride, and the balance of tar, sulfolane and the like. The application field of such industrial mixed potassium salt is very limited because the above-mentioned waste slag contains fluoride, which is a dangerous chemical.

For the above waste residues, it is a common practice for enterprises to sell the waste residues as solid chemical wastes, or to burn the waste residues directly and then enter a sewage system. Although the latter can reduce the production cost, the environment is easily polluted, and the waste of potassium resources is easily caused.

The potassium chloride and the potassium fluoride have wide application, wherein the potassium chloride is mainly used in the inorganic industry and is a basic raw material for preparing various potassium salts, such as potassium hydroxide, potassium sulfate, potassium nitrate, potassium chlorate, potassium bichromate and the like, and the potassium chloride and the potassium fluoride are used as potash fertilizers in agriculture; the potassium fluoride is mainly used as a fluorinating agent in organic synthesis, and can also be used as a glass carving agent, a catalyst, an insecticide and the like.

The methanol and the ethanol have wide application and are basic organic chemical raw materials and high-quality fuels. The fuel is mainly used in the fields of fine chemical engineering, plastics and the like, and the two can be used as a novel clean fuel after deep processing and also can be mixed with gasoline for use. Both the colorless liquids are volatile, can be mutually dissolved with water in any proportion, are good in chemical properties of organic solvents, have the universality of alcohol substances, and can be subjected to catalytic oxidation, esterification reaction and the like.

Chinese patent application CN106006679A discloses a method for recovering high purity potassium chloride from fluorination reactor by-products, which specifically operates as follows: firstly, heat treatment is carried out to remove attached organic matters, then potassium fluoride is leached out by liquid ammonia in a pressurizing mode to realize the separation of potassium chloride and potassium fluoride, liquid ammonia solution of potassium fluoride is leached out, and separation and recovery are realized through vaporization. The method needs two different solvent systems for separating the potassium fluoride and the potassium chloride respectively, and needs the conditions of high temperature and high pressure,

liquid ammonia is easy to have unfriendly influence on the environment, is difficult to recover and is difficult to popularize in industrial production. In the scheme, the recovery rate of KF is 98%, the purity is 99%, the recovery rate of KCl is 94.4%, and the purity is 99.95%.

Chinese patent CN102730710B also discloses a method for separating a mixture of potassium chloride and potassium fluoride, which comprises the following steps: firstly, treating a mixture of potassium chloride and potassium fluoride at 300-500 ℃ for 1-5 hours, removing organic wastes, introducing a boron trifluoride/acetonitrile system, utilizing the principle that potassium chloride is insoluble in the system and potassium fluoride can enter the system and be converted into potassium tetrafluoroborate, filtering and separating a filtrate of potassium chloride and potassium tetrafluoroborate, and further treating the filtrate to obtain the potassium tetrafluoroborate as a byproduct for sale. The scheme converts KF into medium KBF4, the recovery rate is 97.3%, and the purity is not mentioned; KCl purity and recovery are also not mentioned. The method has simple process, but needs high-temperature treatment on the byproduct mixed potassium salt, has larger consumption of acetonitrile solvent and higher cost, and has certain environmental pollution problem

Disclosure of Invention

The invention aims to solve the technical problems that two different solvent systems are needed, the conditions of high temperature and high pressure are needed, the environment is not friendly, the solvent is difficult to recover and the industrial production is difficult to apply in a process method for separating and treating industrial mixed potassium salt in the prior art, or the defects of large solvent consumption, large environmental pollution and high cost exist, so that the separation method of the industrial mixed potassium salt is provided. By the separation method, high-purity potassium chloride and potassium fluoride can be separated from industrial mixed potassium salt in a single solvent system; the separation method can be further combined with process equipment to recover the solvent for reuse, thereby realizing continuous production, and the method has the advantages of simple process, mild condition, low energy consumption, strong operability, no pollution, reduction of production cost, remarkable economic benefit and social benefit and suitability for industrial production.

The invention adopts the following technical scheme:

dissolving mixed potassium salt in water, methanol and ethanol according to a certain proportion to obtain potassium chloride and mother liquor A;

and (2) concentrating the mother liquor A obtained in the step (1) to obtain mother liquor A ', and recrystallizing the obtained mother liquor A' in methanol and ethanol to obtain potassium fluoride.

Preferably, the ratio of water, methanol and ethanol is 2:1:1.

The invention has the following beneficial results:

the prior art needs two different solvent systems in the process method for separating and treating the industrial mixed potassium salt, and has the problems of high temperature and high pressure, environmental unfriendliness, difficult solvent recovery and difficult application to industrial production, or has the defects of large solvent consumption, large environmental pollution and high cost. The invention has the advantages that only two solvents of the same kind are mixed with water according to a certain proportion, and separation of industrial mixed potassium salt can be realized at room temperature. The solvent belongs to an environment-friendly solvent, is environment-friendly and is easy to recover.

Detailed description of the invention

Example 1

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 11.5mL of deionized water at room temperature, stirring to dissolve, and adding the following components in percentage by weight according to the weight of the deionized water: methanol: ethanol =2:1:1, 6ml of ethanol and 6ml of methanol were added in this order. Stirring and filtering, drying filter residues and weighing to obtain 10.6168g of the product, wherein the recovery rate is 76.2%, the potassium chloride in the product is 99.7% according to national standard, and the recovery rate of the potassium chloride is 93.0%.

Example 2

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 10mL of deionized water at room temperature, stirring to dissolve, and adding deionized water according to the weight ratio of deionized water: methanol: ethanol =1:1:1, 10ml of ethanol and 10ml of methanol were added in this order. Stirring and filtering, drying filter residues and weighing to obtain 9.8753g of a product, wherein the recovery rate is 70.9%, the potassium chloride content of the obtained product is 99.2% according to the national standard, and the recovery rate of the potassium chloride is 88.1%.

Example 3

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 10mL of deionized water at room temperature, stirring to dissolve, and adding the following components in percentage by weight according to the weight of the deionized water: methanol: ethanol =5:1:1, 2ml of ethanol and 2ml of methanol are added in sequence. Stirring and filtering, drying filter residues and weighing to obtain 9.6213g of a product, wherein the recovery rate is 69.0%, the potassium chloride content of the obtained product is 99.3% according to the national standard, and the recovery rate of the potassium chloride is 85.8%.

Example 4

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 15mL of deionized water at room temperature, stirring to dissolve, and adding deionized water according to the weight ratio of deionized water: methanol =2:1, 6ml of methanol was added. Stirring and filtering, drying filter residues and weighing to obtain 9.0321g of product with the recovery rate of 64.8%, wherein the potassium chloride in the product accounts for 99.8% and the potassium chloride in the product accounts for 80.5% according to national standard.

Example 5

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 15mL of deionized water at room temperature, stirring to dissolve, and adding deionized water according to the weight ratio of deionized water: ethanol =2:1, 6ml of ethanol are added. Stirring and filtering, drying filter residues and weighing to obtain 9.0523g of the product, wherein the recovery rate is 65.0%, the potassium chloride in the product is 99.8% according to national standard, and the recovery rate of the potassium chloride is 80.7%.

Comparative example

Example 6

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 15mL of deionized water at room temperature, stirring for dissolving, stirring and filtering, drying filter residues, and weighing to obtain 8.6154g of a product with the recovery rate of 61.8%, wherein the potassium chloride in the product accounts for 99.9% and the potassium chloride in the product accounts for 76.8% according to national standards.

Example 7

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 6mL of methanol at room temperature, stirring for dissolving, stirring and filtering, drying filter residues, and weighing to obtain a product 10.6887 with the recovery rate of 76.7%, wherein the potassium chloride in the product accounts for 90.6% and the potassium chloride in the recovery rate of 86.3% according to national standards.

Example 8

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 6mL of ethanol at room temperature, stirring to dissolve, stirring, filtering, drying filter residues, weighing to obtain the product 11.3354 with the recovery rate of 81.3%.

Example 9

Adding 11.2152g of potassium chloride and 2.7188g of potassium fluoride into a 100mL beaker, adding 6mL of methanol and 6mL of ethanol at room temperature, stirring for dissolving, stirring for filtering, drying filter residues, weighing to obtain a product 10.6457 with a recovery rate of 76.4%, wherein the potassium chloride content in the product is 96.2% and the potassium chloride recovery rate is 91.3% according to national standards.

Example 10

Taking 100g of industrial waste residue, adding 70ml of deionized water at room temperature, stirring and dissolving, and mixing the following components in percentage by weight: methanol: ethanol =2:1:1, adding 35ml of industrial ethanol and 35ml of industrial methanol in sequence. Stirring and filtering, drying filter residues and weighing to obtain 76.5190g of the product, wherein the recovery rate is 76.5%, and the potassium chloride content of the obtained product is 99.7% according to national standard.

Claims

1. A method for separating potassium fluoride and potassium chloride by using a mixed alcohol reagent is characterized by comprising the following steps: dissolving the mixed potassium salt in water, methanol and ethanol according to a certain proportion to obtain potassium chloride and mother liquor A; and concentrating the mother liquor A to obtain mother liquor A ', and recrystallizing the obtained mother liquor A' in methanol and ethanol to obtain the potassium fluoride.

2. The method for separating potassium fluoride and potassium chloride by using the mixed alcohol reagent as claimed in claim 1, wherein the ratio of water, methanol and ethanol is 2.

3. Use of the method of claim 1 for the separation of industrial mixed potassium salts at ambient temperature.