阅读说明：本技术 一种电子级氢氧化钾的制备工艺 (Preparation process of electronic-grade potassium hydroxide ) 是由 戈烨铭 何珂 汤晓春 于 2021-06-25 设计创作，主要内容包括：本发明涉及一种电子级氢氧化钾的制备工艺,包括依次且连续进行的如下步骤：将氯化钾水溶液以恒定流速依次通过第一螯合树脂、第二螯合树脂进行吸附得到氯化钾高纯溶液,后浓缩得氯化钾晶体,将氯化钾晶体中加入纯水溶解,溶解后经双极膜电渗析系统处理后得到低浓度氢氧化钾溶液,最后加热浓缩得到电子级氢氧化钾。本发明的电子级氢氧化钾的制备工艺可使金属阳离子Fe～(2+),Ca～(2+),Mg～(2+),Ni～(2+),Zn～(2+)≤100ppb,Na～(+)≤50ppm,且该制备工艺简单易操作,可连续大规模生产高浓度高纯度电子级氢氧化钾。(The invention relates to a preparation process of electronic-grade potassium hydroxide, which comprises the following steps of sequentially and continuously: and (2) sequentially passing a potassium chloride aqueous solution through the first chelating resin and the second chelating resin at a constant flow rate for adsorption to obtain a potassium chloride high-purity solution, concentrating to obtain potassium chloride crystals, adding pure water into the potassium chloride crystals for dissolution, treating by a bipolar membrane electrodialysis system after dissolution to obtain a low-concentration potassium hydroxide solution, and finally heating and concentrating to obtain the electronic-grade potassium hydroxide. The preparation process of the electronic-grade potassium hydroxide can lead the metal cation Fe to be 2+ ,Ca 2+ ,Mg 2+ ,Ni 2+ ,Zn 2+ ≤100ppb,Na + Less than or equal to 50ppm, and the preparation process is simple and easy to operate, and can continuously produce high-concentration high-purity electronic-grade potassium hydroxide on a large scale.)

1. A preparation process of electronic-grade potassium hydroxide is characterized by comprising the following steps: the preparation process comprises the following steps which are sequentially and continuously carried out:

(1) sequentially passing a potassium chloride aqueous solution through a first chelating resin and a second chelating resin at a constant flow rate for adsorption to obtain a high-purity potassium chloride solution;

(2) concentrating the high-purity potassium chloride solution obtained in the step (1) to obtain potassium chloride crystals;

(3) adding high-purity water to the potassium chloride crystal obtained in the step (2) for dissolving, and treating the dissolved potassium chloride aqueous solution by a bipolar membrane electrodialysis system to obtain a low-concentration potassium hydroxide solution;

(4) heating and concentrating the low-concentration potassium hydroxide solution obtained in the step (3) to obtain electronic-grade potassium hydroxide;

wherein the first chelating resin is aminocarboxylic acid chelating resin or aminophosphoric acid chelating resin, and the second chelating resin is iminodiacetic acid type chelating resin or fluorinated modified iminodiacetic acid type chelating resin.

2. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: the potassium chloride aqueous solution in the step (1) is prepared by dissolving industrial-grade potassium chloride or food-grade potassium chloride in high-purity water.

3. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: the concentrations of the potassium chloride aqueous solution in the step (1) and the potassium chloride aqueous solution in the step (3) are both 300-400 g/L.

4. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: in the step (1): and (3) allowing the potassium chloride aqueous solution to pass through the first chelating resin and the second chelating resin in sequence at a constant flow rate for adsorption and then pass through the extraction resin to obtain the high-purity potassium chloride solution.

5. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: in the step (1), the first chelating resin and the second chelating resin are both pretreated, and the method specifically comprises the following steps: firstly, immersing chelate resin in ethanol, stirring for 2h at room temperature, then washing the ethanol with deionized water, immersing the chelate resin in acid liquor, stirring for 2h at room temperature, then washing with deionized water to be neutral, and repeating the process for 3 times; and immersing the chelate resin in alkali liquor, stirring for 2h at room temperature, washing to be neutral by using deionized water, repeating the process for 3 times, and finally drying.

6. The process of claim 5, wherein the reaction is carried out in the presence of a solvent selected from the group consisting of: the acid solution is a hydrochloric acid aqueous solution or an acetic acid aqueous solution, and the content of the acid solution is 3-5%; the alkali liquor is potassium hydroxide aqueous solution or ammonia water, and the content of the alkali liquor is 3-5%.

7. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: and (3) mother liquor generated in the concentration process in the step (2) is used for preparing the potassium chloride aqueous solution in the step (1).

8. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: in the step (4), the electronic-grade potassium hydroxide is a solution or a solid.

9. The process for preparing electronic grade potassium hydroxide according to claim 1, wherein: the concentration of the electronic-grade potassium hydroxide solution is 35-45%; fe²⁺,Ca²⁺,Mg²⁺,Ni²⁺,Zn²⁺≤100ppb，Na⁺≤50ppm。

10. An electronic grade potassium hydroxide, characterized by: the electronic grade potassium hydroxide according to any one of claims 1-9.

Technical Field

The invention belongs to the technical field of chemical preparations, and particularly relates to a preparation process of electronic-grade potassium hydroxide.

Background

The potassium hydroxide is a main raw material of stripping liquid and developer in the electronic industries of photovoltaics, panels, semiconductors and the like, the purity of the potassium hydroxide has great influence on the quality of rear-stage products, and industrial-grade potassium hydroxide cannot meet the requirements. Therefore, it is necessary to purify industrial-grade potassium hydroxide to improve the quality.

At present, electronic-grade potassium hydroxide is generally prepared into a potassium hydroxide solution, and then heavy metal and sodium ions are removed by methods such as ion exchange or cooling, freezing and crystallization, but the method has the disadvantages of slow production efficiency, low energy efficiency and unsatisfactory purification effect, and the concentration of the obtained potassium hydroxide heavy metal ions is still high.

Chinese patent CN106904637A discloses a purification process of high-activity potassium hydroxide, which comprises dissolving with ionic water, dropping acetone at 5 deg.C for crystallization, centrifuging under the protection of nitrogen, filtering to obtain filter cake, and drying under reduced pressure under the protection of nitrogen to obtain high-purity potassium hydroxide suitable for ITO development.

Chinese patent CN 111910204a discloses an electronic grade potassium hydroxide purification process, which specifically comprises: adding pure water into food-grade potassium chloride for dissolving at high temperature, filtering, introducing hydrogen chloride gas or hydrogen chloride water solution into the solution, carrying out salt crystallization on the solution to obtain an acid salt mixed solution, carrying out centrifugal treatment on the acid salt mixture, separating to obtain wet-based high-purity potassium chloride crystals, adding pure water for dissolving to obtain saline water with a certain concentration, carrying out electrolytic treatment on the saline water through a bipolar membrane, and concentrating and evaporating to obtain electronic-grade potassium hydroxide. The potassium chloride crystal prepared by the method has low crystal efficiency, has high requirement on the purity of introduced hydrogen chloride gas or hydrogen chloride aqueous solution, otherwise more impurity ions are introduced, which is not beneficial to purification, and further influences the purity of subsequent potassium hydroxide.

Disclosure of Invention

The invention aims to provide a preparation process of electronic-grade potassium hydroxide, which can lead metal cation Fe to be generated²⁺, Ca²⁺,Mg²⁺,Ni²⁺,Zn²⁺≤100ppb，Na⁺Less than or equal to 50ppm, and the preparation process is simple and easy to operate, and can continuously produce high-concentration high-purity electronic-grade potassium hydroxide on a large scale.

The technical scheme adopted by the invention for solving the problems is as follows: a preparation process of electronic-grade potassium hydroxide comprises the following steps which are sequentially and continuously carried out:

(1) sequentially passing a potassium chloride aqueous solution through a first chelating resin and a second chelating resin at a constant flow rate for adsorption to obtain a high-purity potassium chloride solution;

(2) concentrating the high-purity potassium chloride solution obtained in the step (1) to obtain potassium chloride crystals;

(3) adding high-purity water to the potassium chloride crystal obtained in the step (2) for dissolving, and treating the dissolved potassium chloride aqueous solution by a bipolar membrane electrodialysis system to obtain a low-concentration potassium hydroxide solution;

(4) heating and concentrating the low-concentration potassium hydroxide solution obtained in the step (3) to obtain electronic-grade potassium hydroxide;

wherein the first chelating resin is aminocarboxylic acid chelating resin or aminophosphoric acid chelating resin, and the second chelating resin is iminodiacetic acid type chelating resin or fluorinated modified iminodiacetic acid type chelating resin.

Preferably, the potassium chloride aqueous solution in the step (1) is prepared by dissolving industrial-grade potassium chloride or food-grade potassium chloride in high-purity water.

Preferably, the concentration of the potassium chloride aqueous solution in the step (1) and the concentration of the potassium chloride aqueous solution in the step (3) are both 300-400 g/L.

Preferably, in the step (1): and (3) allowing the potassium chloride aqueous solution to pass through the first chelating resin and the second chelating resin in sequence at a constant flow rate for adsorption and then pass through the extraction resin to obtain the high-purity potassium chloride solution.

Preferably, in the step (1), both the first chelating resin and the second chelating resin are pretreated, specifically: firstly, immersing chelate resin in ethanol, stirring for 2h at room temperature, then washing the ethanol with deionized water, immersing the chelate resin in acid liquor, stirring for 2h at room temperature, then washing with deionized water to be neutral, and repeating the process for 3 times; and immersing the chelate resin in alkali liquor, stirring for 2h at room temperature, washing to be neutral by using deionized water, repeating the process for 3 times, and finally drying.

More preferably, the acid solution is a hydrochloric acid aqueous solution or an acetic acid aqueous solution, and the content of the acid solution is 3-5%; the alkali liquor is potassium hydroxide aqueous solution or ammonia water, and the content of the alkali liquor is 3-5%.

Preferably, the mother liquor produced during the concentration in step (2) is used for preparing the aqueous solution of potassium chloride in step (1).

Preferably, the electronic grade potassium hydroxide in step (4) is a solution or a solid.

Preferably, the concentration of the electronic-grade potassium hydroxide solution is 35-45%; fe²⁺,Ca²⁺,Mg²⁺,Ni²⁺,Zn²⁺≤100ppb，Na⁺≤50ppm。

The invention also provides electronic-grade potassium hydroxide prepared according to the preparation process of the electronic-grade potassium hydroxide.

Compared with the prior art, the invention has the advantages that:

(1) the potassium chloride solution is adsorbed by chelating resin to obtain a high-purity potassium chloride solution, the recovery rate can reach more than 90%, the chelating resin and metal ions in the potassium chloride solution perform a coordination reaction to form a stable structure similar to a small-molecule chelate, and compared with the ion exchange resin adsorbed by electrostatic action, the high-purity potassium chloride solution has stronger associativity and higher selectivity; the chelate resin can be regenerated and reused; the invention selects two chelating resins and carries out pretreatment, thereby greatly improving the adsorption capacity and the adsorption range.

(2) The potassium chloride solution is adsorbed by chelating resin, purified by extraction resin, and concentrated and crystallized to further reduce the contents of heavy metal ions and sodium ions.

Drawings

FIG. 1 is a flow chart of the preparation process of electronic grade potassium hydroxide of the present invention.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 1, a flow chart of the preparation process of the electronic grade potassium hydroxide in this embodiment is shown.

Example 1

A preparation process of electronic-grade potassium hydroxide comprises the following steps which are sequentially and continuously carried out:

(1) dissolving food grade potassium chloride to obtain 300g/L aqueous solution (60 deg.C), sequentially filling with aminocarboxylic acidAdsorption column for acid chelate resin, adsorption column packed with iminodiacetic acid type chelate resin (D751) and adsorption column flow rate of 15m³And h, replacing for 0.5h, purifying by using P507 extraction resin for 0.5h to obtain the high-purity potassium chloride solution.

(2) Concentrating and crystallizing the high-purity potassium chloride solution at 110 ℃ to obtain potassium chloride crystals.

(3) Dissolving potassium chloride crystals with high-purity water to prepare 300g/L potassium chloride solution, and electrolyzing by a bipolar membrane electrodialysis system consisting of a bipolar membrane and a cation exchange resin membrane to obtain low-concentration potassium hydroxide solution.

(4) Heating and concentrating the low-concentration potassium hydroxide solution to obtain 35% concentration electronic-grade potassium hydroxide solution, wherein Ca²⁺7ppb，Mg²⁺5.5ppb，Ni²⁺3.6ppb，Fe²⁺26ppb，Na⁺5.8ppm。

Wherein, the amino carboxylic acid chelating resin and the iminodiacetic acid chelating resin (D751) are pretreated, and the pretreatment comprises the following specific steps: firstly, immersing chelate resin in ethanol, stirring for 2 hours at room temperature, and then washing the ethanol with deionized water; then immersing the chelate resin into hydrochloric acid aqueous solution with the mass content of 3%, stirring for 2h at room temperature, washing to be neutral by deionized water, and repeating the process for 3 times; and immersing the chelate resin into a potassium hydroxide aqueous solution with the mass content of 3%, stirring for 2h at room temperature, washing to be neutral by using deionized water, repeating the process for 3 times, and finally drying.

Example 2

A preparation process of electronic-grade potassium hydroxide comprises the following steps which are sequentially and continuously carried out:

(1) dissolving food-grade potassium chloride to prepare 350g/L aqueous solution (70 ℃), sequentially adsorbing with an adsorption tower filled with aminocarboxylic acid chelate resin and an adsorption tower filled with fluorinated modified iminodiacetic acid chelate resin, wherein the flow rate of the adsorption tower is 15m³And h, replacing for 0.5h, purifying by using P507 extraction resin for 0.5h to obtain the high-purity potassium chloride solution.

(2) Concentrating and crystallizing the potassium chloride high-purity solution at 110 ℃ to obtain potassium chloride crystals.

(3) Dissolving potassium chloride crystals with high-purity water to prepare 300g/L potassium chloride solution, and electrolyzing by using a bipolar membrane electrodialysis system to obtain low-concentration potassium hydroxide solution.

(4) Heating and concentrating the low-concentration potassium hydroxide solution to obtain 35% concentration electronic-grade potassium hydroxide solution, wherein Ca²⁺7.1ppb，Mg²⁺5.4ppb，Ni²⁺3.5ppb，Fe²⁺29ppb，Na⁺6.3ppm。

Wherein, the amino carboxylic acid chelating resin and the fluorinated modified iminodiacetic acid chelating resin are pretreated, and the method specifically comprises the following steps: firstly, immersing chelate resin in ethanol, stirring for 2 hours at room temperature, and then washing the ethanol with deionized water; then immersing the chelate resin into a hydrochloric acid aqueous solution with the mass content of 4%, stirring for 2h at room temperature, washing to be neutral by deionized water, and repeating the process for 3 times; and immersing the chelate resin into a potassium hydroxide aqueous solution with the mass content of 4%, stirring for 2h at room temperature, washing to be neutral by using deionized water, repeating the process for 3 times, and finally drying.

Example 3

A preparation process of electronic-grade potassium hydroxide comprises the following steps which are sequentially and continuously carried out:

(1) dissolving food-grade potassium chloride to prepare 350g/L aqueous solution (65 ℃), sequentially adsorbing with an adsorption tower filled with aminocarboxylic acid chelate resin and an adsorption tower filled with fluorinated modified iminodiacetic acid chelate resin, wherein the flow rate of the adsorption tower is 15m³And h, replacing for 0.5h, purifying by using P507 extraction resin for 0.5h to obtain the high-purity potassium chloride solution.

(2) The absorbed potassium chloride solution is concentrated and crystallized at 110 ℃ to obtain potassium chloride crystals.

(3) Dissolving potassium chloride crystals with high-purity water to prepare 400g/L potassium chloride solution, and electrolyzing by using a bipolar membrane electrodialysis system to obtain low-concentration potassium hydroxide solution.

(4) Heating and concentrating the low-concentration potassium hydroxide solution to obtain 45% concentration electronic-grade potassium hydroxide solution, wherein Ca²⁺7.7ppb，Mg²⁺6.3ppb，Ni²⁺4.6ppb，Fe²⁺33ppb，Na⁺6.6ppm。

Wherein, the amino carboxylic acid chelating resin and the fluorinated modified iminodiacetic acid chelating resin are pretreated, and the method specifically comprises the following steps: firstly, immersing chelate resin in ethanol, stirring for 2 hours at room temperature, and then washing the ethanol with deionized water; then immersing the chelate resin into a hydrochloric acid aqueous solution with the mass content of 4%, stirring for 2h at room temperature, washing to be neutral by deionized water, and repeating the process for 3 times; and immersing the chelate resin into a potassium hydroxide aqueous solution with the mass content of 4%, stirring for 2h at room temperature, washing to be neutral by using deionized water, repeating the process for 3 times, and finally drying.

Comparative example 1

The only difference from example 1 is: the chelating resin was not pretreated.

Ca in the obtained electronic grade potassium hydroxide solution²⁺77.8ppb，Mg²⁺50.8ppb，Ni²⁺63.5ppb，Fe²⁺119ppb，Na⁺55.0ppm。

Comparative example 2

The only difference from example 1 is: without extraction resin purification.

Ca in the obtained electronic grade potassium hydroxide solution²⁺56.7ppb，Mg²⁺45.8ppb，Ni²⁺35.9ppb，Fe²⁺102ppb，Na⁺51.5ppm。

Comparative example 3

The only difference from example 1 is: without adsorption by aminocarboxylic acid chelate resin.

Ca in the obtained electronic grade potassium hydroxide solution²⁺78.7ppb，Mg²⁺60.5ppb，Ni²⁺55.8ppb，Fe²⁺126ppb，Na⁺60.4ppm。

Comparative example 4

The only difference from example 1 is: without adsorption by iminodiacetic acid-based chelating resins.

Ca in the obtained electronic grade potassium hydroxide solution²⁺89.9ppb，Mg²⁺70.5ppb，Ni²⁺63.5ppb，Fe²⁺131ppb，Na⁺65.9ppm。

In addition to the above embodiments, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of the claims of the present invention.