阅读说明：本技术 一种试剂级硫酸钾的制备方法 (Preparation method of reagent-grade potassium sulfate ) 是由 冯冬娅 陈浩 颜学伦 方静 于 2020-07-24 设计创作，主要内容包括：本发明公开了一种试剂级硫酸钾的制备方法,包括如下步骤：(1)将硫酸水溶液和氢氧化钾水溶液混合,用量为H<Sub>2</Sub>SO<Sub>4</Sub>：KOH的摩尔比为1:1.2～1.8,静置沉降；(2)将步骤(1)的清液与氢氧化钾或氢氧化钾水溶液混合。本发明方法耗能低、工艺步骤简单、生产效率高,制得的试剂级硫酸钾纯度高。(The invention discloses a preparation method of reagent-grade potassium sulfate, which comprises the following steps: (1) mixing the sulfuric acid aqueous solution and the potassium hydroxide aqueous solution in the amount of H 2 SO 4 : the molar ratio of KOH is 1: 1.2-1.8, and standing and settling are carried out; (2) mixing the clear liquid in the step (1) with potassium hydroxide or a potassium hydroxide aqueous solution. The method has the advantages of low energy consumption, simple process steps, high production efficiency and high purity of the prepared reagent-grade potassium sulfate.)

1. The preparation method of reagent-grade potassium sulfate is characterized by comprising the following steps of:

(1) mixing the sulfuric acid aqueous solution and the potassium hydroxide aqueous solution in the amount of H₂SO₄: the molar ratio of KOH is 1: 1.2-1.8, and standing and settling are carried out;

(2) mixing the clear liquid in the step (1) with potassium hydroxide or a potassium hydroxide aqueous solution.

2. The preparation method according to claim 1, wherein the mass fraction of sulfuric acid in the aqueous sulfuric acid solution is 55% to 80%;

the mass fraction of the potassium hydroxide in the potassium hydroxide aqueous solution obtained in the steps (1) and (2) is 20-60%.

3. The method according to claim 2, wherein the mass fraction of sulfuric acid in the aqueous sulfuric acid solution is 60% to 75%.

4. The method according to claim 2, wherein the mass fraction of potassium hydroxide in the aqueous potassium hydroxide solution in steps (1) and (2) is 30 to 48%.

5. The method of claim 1, wherein the step of(1) In (H)₂SO₄: the molar ratio of KOH is 1: 1.4-1.6.

6. The method according to any one of claims 1 to 5, wherein the step (2) is to add potassium hydroxide or an aqueous solution of potassium hydroxide to the clear solution separated in the step (1).

7. The method according to claim 6, wherein the step (2) uses an aqueous solution of potassium hydroxide.

8. The preparation method according to claim 1, wherein the amount of the potassium hydroxide or the aqueous solution of potassium hydroxide used in the step (2) is such that the pH of the system is 6.5 to 7.

9. The method according to claim 6, wherein the potassium hydroxide or the aqueous solution of potassium hydroxide is fed in a batch manner.

10. The preparation method according to claim 1, wherein the materials in the step (2) are mixed to obtain a crystal slurry, and the crystal slurry is subjected to solid-liquid separation to obtain wet solids and then dried.

Technical Field

The invention belongs to the field of chemical production, and particularly relates to a preparation method of reagent-grade potassium sulfate.

Background

Potassium sulfate is colorless rhombic or hexagonal crystal or powder, but industrial products are mostly grey white, bitter and salty in taste, and have the chemical formula of K₂SO₄. Potassium sulfate is widely used in various fields such as environment, medicine, food, agriculture, chemical industry, etc., and can be used as chemical neutral and physiological acidic fertilizer, as laxative in medicine, and also used for preparing alum, glass, potassium carbonate, etc. The potassium sulfate has wide application range in the industrial field, is used for preparing intermediates in the dye industry field and is used for clarification in the glass industry fieldThe cleaning agent is used as an auxiliary agent in the field of spice industry, is used as a general additive in food industry, and can also be used for serum protein life examination.

Disclosure of Invention

The invention aims to provide a preparation method of reagent-grade potassium sulfate, which has the advantages of high product purity, high yield, less impurities, simple process steps, low energy consumption and high production efficiency.

The invention provides a preparation method of reagent-grade potassium sulfate, which comprises the following steps:

(1) mixing the sulfuric acid aqueous solution and the potassium hydroxide aqueous solution in the amount of H₂SO₄: the molar ratio of KOH is 1: 1.2-1.8, and standing and settling are carried out;

(2) mixing the clear liquid in the step (1) with potassium hydroxide or a potassium hydroxide aqueous solution.

In order to solve a plurality of process problems in the prior art, the inventor unexpectedly finds that the mixed solution of potassium bisulfate and potassium sulfate can reduce metal compounds in the solution in the crystallization and sedimentation process, and potassium hydroxide is further added into the mixed solution, so that potassium sulfate with higher purity can be obtained, and the energy consumption and the production efficiency are obviously improved.

The reagent-grade potassium sulfate is of analytical purity grade, and meets the standard established in potassium sulfate chemical reagent (GB/T16496-1996).

Further, the mass fraction of the sulfuric acid in the sulfuric acid aqueous solution is 55-80%;

the mass fraction of the potassium hydroxide in the potassium hydroxide aqueous solution obtained in the steps (1) and (2) is 20-60%.

It should be understood that the mass fractions of the aqueous solutions of potassium hydroxide in steps (1) and (2) are independently selected from 20% to 60%, i.e., the mass fractions of the aqueous solutions of potassium hydroxide used in steps (1) and (2) may be the same or different, and the same applies to the rest of the similar cases.

Further, the mass fraction of the sulfuric acid in the sulfuric acid aqueous solution is 60-75%.

Furthermore, the mass fraction of the potassium hydroxide in the potassium hydroxide aqueous solution in the steps (1) and (2) is 30-48%.

Further, in the step (1), H₂SO₄: the molar ratio of KOH is 1: 1.4-1.6.

The concentration and the dosage of the sulfuric acid are too high, so that the reaction is violent and easy to explode, the molar ratio and the concentration of the sulfuric acid and the potassium hydroxide are too low, the reaction is incomplete, and crystals cannot be completely precipitated, and the inventor finds that when the concentration range of the sulfuric acid is controlled to be 55-80 percent, the concentration of the potassium hydroxide is 20-60 percent, and the H content is controlled to be H content₂SO₄: when the molar ratio of KOH is 1: 1.2-1.8, crystals can be completely precipitated, and the purity of subsequent products can be better ensured.

According to the above preparation method, the step (2) is to add potassium hydroxide or an aqueous solution of potassium hydroxide to the clear liquid separated in the step (1).

Further, in the step (2), an aqueous solution of potassium hydroxide is used.

And (3) reacting the potassium hydroxide aqueous solution instead of the potassium hydroxide solid powder with the clear liquid obtained in the step (1), so that the potassium hydroxide solid is prevented from being coated when the potassium sulfate is separated out, and the purity of the product is better ensured.

Further, the amount of the potassium hydroxide or the potassium hydroxide aqueous solution in the step (2) is such that the pH of the system is 6.5-7.

Further, the potassium hydroxide or the aqueous solution of potassium hydroxide is added in a batch manner.

The batch addition refers to non-one-time addition, and can be realized by adding the raw materials at a certain or different feeding speed within a period of time, or by dividing the raw materials to be added into a plurality of parts and adding the parts for a plurality of times within a certain period of time.

Further, mixing the materials in the step (2) to obtain crystal mush, carrying out solid-liquid separation on the crystal mush to obtain wet solid, and drying.

The invention has the following beneficial effects:

(1) the product prepared by the process has the advantages of less impurities, high purity and yield and good quality.

(2) The method has the advantages of simple process flow, no need of energy and time consuming processes such as precise filtration and the like, low energy consumption and low production cost, and is suitable for industrial production.

Detailed Description

The technical solutions of the present invention are described clearly and completely below, and it is obvious that the described embodiments are some, not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.