A method for recovering high-purity potassium chloride from fluorination reaction by-products

A technology of fluorination reaction and potassium chloride, which is applied in the chemical field, can solve the problems of small calcium fluoride precipitate particle size filtration, inability to recycle potassium fluoride, high cost and environmental protection issues, etc., to improve solid form and improve utilization The effect of low value and cost

Active Publication Date: 2018-02-13
RONGCHENG QINGMU CHEM MATERIALS
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] ①Patent CN102730710B reacts potassium fluoride with acetonitrile solution of boron trifluoride to make potassium tetrafluoroborate, obtains crude potassium chloride and filters it out; High, there are large cost and environmental protection problems in industrialization
[0005] ② Add appropriate amount of water to the by-product to dissolve most of potassium fluoride and part of potassium chloride, filter out undissolved potassium chloride, add magnesium chloride to the filtrate to obtain magnesium fluoride, filter, apply mechanically to the filtrate, and dry the solid magnesium fluoride. The potassium chloride obtained by the method is easy to introduce magnesium ions, and the content of fluoride ions is also higher, and the product purity is not high
This method cannot recycle potassium fluoride, and the obtained potassium chloride may introduce calcium ion impurities, so that the purity is not high, and the calcium fluoride precipitate has a small particle size and is difficult to filter out by ordinary methods

Method used

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  • A method for recovering high-purity potassium chloride from fluorination reaction by-products

Examples

Experimental program
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Effect test

Embodiment 1

[0035] Add 1000g of KCl-KF mixed salt (the mass fraction of potassium fluoride is 20%), which has been dried at 500°C for 2 hours, into the autoclave, and dissolve 1200g of liquid ammonia at 20°C and a pressure of 1.3Mpa. Then filter, the filtrate is the liquid ammonia solution of potassium fluoride, and gasification obtains 196g of pure potassium fluoride powder, purity 99%, yield 98%, filter cake is potassium chloride crude product, and filter cake is used 11g water and 69g The mixed solution of ethanol is rinsed, then add about 1560g of water to dissolve the solid, then slowly heat up to about 80 ° C, until the solid is just completely dissolved, then cool to room temperature, and add 3120g of isopropanol for recrystallization to obtain potassium chloride crystals , and then washed with an appropriate amount of isopropanol and dried to obtain 750 g of pure white potassium chloride with a purity of 99.92% and a yield of 93.8%.

Embodiment 2

[0037] Add 1000g of KCl-KF mixed salt (the mass fraction of potassium fluoride is 10%), which has been dried at 500°C for 2 hours, into the autoclave, and add 600g of liquid ammonia to dissolve it at 20°C and a pressure of 1.3Mpa. Then filter, the filtrate is the liquid ammonia solution of potassium fluoride, and gasification obtains 97g of pure potassium fluoride powder, purity 99%, yield 97%, filter cake is potassium chloride crude product, and filter cake is mixed with 13g water and 77g The mixed solution of ethanol is rinsed, then add about 1760g of water to dissolve, then slowly heat up to about 80 ° C, until the solid is just completely dissolved, then cool to room temperature, and add 3520g of isopropanol for recrystallization to obtain potassium chloride crystals, Then wash with an appropriate amount of isopropanol and dry to obtain 850 g of pure white potassium chloride with a purity of 99.95% and a yield of 94.4%.

Embodiment 3

[0039] Add 1000g of KCl-KF mixed salt (the mass fraction of potassium fluoride is 30%), which has been dried at 500°C for 2 hours, into the autoclave, and dissolve 1800g of liquid ammonia at 20°C under a pressure of 1.3Mpa. Then filter, the filtrate is the liquid ammonia solution of potassium fluoride, and gasification obtains 294g of pure potassium fluoride powder, the purity is 99%, and the yield is 98%. The filter cake is the potassium chloride crude product. The mixed solution of ethanol is rinsed, then add about 1370g of water to dissolve, then slowly heat up to about 80 ° C, until the solid is just completely dissolved, then cool down to room temperature, and add 2740g of isopropanol for recrystallization to obtain potassium chloride crystals, Then wash with an appropriate amount of isopropanol and dry to obtain 656 g of pure white potassium chloride with a purity of 99.92% and a yield of 93.7%.

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Abstract

The invention provides a method for recovering highly pure potassium chloride from a fluorination reaction byproduct. The method comprises the following steps: 1, preprocessing: carrying out heat treatment on the fluorination reaction byproduct to remove adhered organic matter wastes; 2, dissolving and separating: placing a preprocessed solid mixture in a separation device, introducing liquid ammonia to dissolve potassium fluoride in the preprocessed solid mixture to form a mixed solution, filtering the mixed solution to obtain a filter cake which is crude primary potassium chloride and a filtrate which is a liquid ammonia solution of potassium chloride, squeezing the filtrate, introducing the squeezed filtrate to a pressure reducing chamber, and reducing the pressure to normal pressure to gasify the liquid ammonia in the filtrate in order to obtain a pure potassium fluoride solid; 3, washing: adding a mixed solvent A to the crude primary potassium chloride, washing the crude primary potassium chloride to remove residual trace impurities, and filtering the washed crude primary potassium chloride to obtain crude secondary potassium chloride; and 4, purifying: adding deionized water to the crude secondary potassium chloride, heating the deionized water to dissolve the crude secondary potassium chloride in order to prepare a saturated solution, cooling the saturated solution to room temperature, adding a solvent B to carry out re-crystallization, filtering the obtained solution, washing obtained crystals with the solvent b, and drying the washed crystals to obtain highly pure potassium chloride.

Description

technical field [0001] The invention relates to a method for recovering by-products in the chemical field, in particular to a method for recovering high-purity potassium chloride from potassium fluoride reaction by-products. technical background [0002] Potassium chloride has a wide range of uses. It is the basic raw material for the manufacture of various potassium salts or alkalis such as potassium hydroxide, potassium sulfate, potassium nitrate, potassium chlorate, potassium red alum, etc. It is also used as a diuretic and a drug for the prevention and treatment of potassium deficiency. use. And potassium chloride accounts for 70%-95% of the by-products of potassium fluoride reaction, which has huge economic value, but has been neglected for a long time, and potassium fluoride is widely used in organic fluorination reactions as a common fluorinating agent. , can also be used for glass carving, food preservation, electroplating, when used as a fluorinating agent in organ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01D3/18C01D3/14
CPCC01D3/14C01D3/18C01P2006/80
Inventor 孙燕超李晓明孙朋波
Owner RONGCHENG QINGMU CHEM MATERIALS
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