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Importance in Agriculture

Potassium sulfate is a crucial fertilizer in agriculture. It contains potassium and sulfur, essential elements for crop growth and development.Potassium promotes photosynthesis, while sulfur enhances crop quality.
Benefits of potassium sulfate in agriculture include increasing soil potassium content, improving crop yield and quality, promoting fruit development, enhancing plant resistance, and preventing soil salinization. It is particularly important for crops sensitive to chloride ions, such as tobacco, flax, cotton, watermelon, and tea.

Other Uses

Glass industry: Used as a precipitant.
Dye industry: Functions as an intermediate.
Spice industry: Acts as an auxiliary.
Pharmaceutical industry: Employed as a laxative.

Production Methods

Extraction from Sea and Lake Salt Brine:
1. High-Temperature Salt Method: Involves using high-temperature salt as a raw material in the production of potassium chloride. The process includes conversion of high-temperature salt and potassium chloride, flotation separation to obtain soft potassium alum and industrial salts, and subsequent transformation and separation to obtain potassium sulfate.
2. Bitter Brine Evaporation-Flotation Method: Further improvement of the high-temperature salt method. In this method, bitter brine and self-produced carnallite are blended, followed by evaporation and concentration until the solid phase is obtained. This phase includes a mixture of salts such as hydrated magnesium sulfate and potassium chloride. After separation, potassium sulfate is obtained.
3. Ion Exchange Method: Involves passing seawater through an exchange column equipped with natural adsorbent to adsorb potassium ions. The circulating fluid is then used to elute potassium ions in the exchange column, resulting in a potassium-rich eluent that is further processed to obtain potassium sulfate.
Production from Potassium Salt Ores: Utilization of potassium sulfate-containing ores, such as polyhalite and alunite, to produce potassium sulfate through various physical and chemical processes. However, this method faces challenges such as difficulty in separation and processing, poor product quality, and low yield.
Conversion Methods:
1. Mannheim Method: Involves the reaction between potassium chloride and sulfuric acid to produce potassium sulfate. This method is characterized by high-grade product output but faces challenges such as equipment corrosion, high investment costs, and production of hydrochloric acid as a by-product.
2. Establishment Law: Developed in China, this method utilizes potassium chloride, sulfuric acid, and ammonia to produce potassium sulfate through association, displacement, and dissociation reactions. Despite its advantages, challenges such as equipment corrosion and scale-up limitations exist.
3. Metathesis Method: Involves the reaction between various soluble salts containing potassium sulfate and potassium chloride to produce potassium sulfate. Different types of soluble sulfates can be used in this method.
New Process: Utilizes zeolite as an ion exchanger to extract potassium ions from seawater. This process involves continuous circulation and conversion, collecting potassium-rich solution for further processing. It offers advantages such as technical applicability, simplicity, minimal waste discharge, and cost savings through by-product utilization.

General Description

Potassium sulfate (VI), also known as dipotassium sulfate, is a chemical compound with the formula K2SO4. It is a colorless or white crystalline solid that is highly soluble in water. Potassium sulfate is commonly used as a fertilizer because of its high potassium content, which is essential for plant growth and development. It is also used in the manufacturing of glass, ceramics, and cement, as well as in the synthesis of other chemicals. In addition, potassium sulfate has a variety of industrial applications, including in the production of potassium alum and as a component in fire extinguishing powders. Overall, potassium sulfate is a versatile compound with numerous uses in agriculture, industry, and everyday products.