Potassium carbonate brief introduction

Potassium carbonate(Chemical formula: K2CO3, English name: Potassium carbonate), appears as colorless crystals or white particles, can absorb moisture, and is soluble in water. Its solution is weakly alkaline. Insoluble in alcohols and ethers. It can be obtained by reacting potassium hydroxide with carbon dioxide. Common fertilizers include potassium carbonate in plant ash. Standardized Control GND: 4163061-0 NDL: 00572682

Potassium carbonate Basic information

Potassium carbonate Numbering system

Potassium carbonate Physical and Chemical Properties

Appearance and characteristics:

White powder or granules

Density:

2.43 g/mL at 25 °C

Boiling point:

333.6ºC at 760 mmHg

Melting point:

891 °C(lit.)

Flash point:

111ºC

Water solubility:

1120 g/L (20 ºC)

Stability:

Stable. Incompatible with moisture, acids, magnesium bromine trifluoride and magnesium bromine trichloride.

Storage conditions:

Store at RT.

security information

• RTECS：

• TS7750000

Safety instructions:

S26-S36-S37/39

WGK Germany：

one

Hazard category code:

R22; R36/37/38

Customs code:

two billion eight hundred and thirty-six million and four hundred thousand

Dangerous goods transportation code:

three thousand two hundred and sixty-two

Packaging grade:

III

Dangerous goods signs:

Xn

Danger signs:

GHS07

Hazard description:

H302; H315; H319; H335

Hazard prevention instructions:

P280; P301 + P312 + P330; P305 + P351 + P338; P337 + P313

Signal words:

Warning

Production method and purpose

Production method

1. Refined potassium chloride solution (250g/L) by ion exchange method and treated with cation resin

(732) Column adsorption, and wash with distilled water until no chloride ions flow out. Then wash with 200g/L ammonium bicarbonate until the potassium ion in the effluent is below 2g/L. Heat the eluent to 150 ℃, then concentrate the solution to a relative density of around 1.593, and introduce CO2 gas for carbonization to precipitate potassium bicarbonate crystals. After centrifugal separation, use hot air at around 400 ℃ to decompose potassium bicarbonate into potassium carbonate. The reaction equation is as follows:

2. Electrolytic method: Dissolve potassium chloride in water (280g/L), then add an appropriate amount of potassium carbonate and potassium hydroxide to the refining tank to remove Ca2+and Mg2+. After clarification, adjust the pH value to 8-10 with hydrochloric acid and send it to the diaphragm electrolysis tank for electrolysis. The slot voltage is 2.8-3.5V, and the slot temperature is 60-70 ℃. The KOH content in the electrolyte is 10% to 15%, evaporated and concentrated to 50%, cooled to 30~50 ℃ to precipitate KCL, and the solution separated from potassium chloride is subjected to pre carbonization. When the KOH concentration is below 30g/L, the Fe (OH) 3 precipitate is removed by filtration. Then continue to concentrate to 50%, undergo secondary carbonization, and precipitate potassium bicarbonate. After separation, potassium carbonate was obtained by hot air drying (decomposition) at 300 ℃. Food grade potassium carbonate requires dissolving the aforementioned industrial products in water and adding reducing agents to remove heavy metals and arsenic. After concentration, crystallization, centrifugation, drying, and crushing, food grade potassium carbonate is obtained. The reaction equation is as follows:

3. The plant ash method uses various plant shells (such as cotton seed shells, tea seed shells, sunflower seed shells, etc.) to calcine and produce plant ash, which is mainly composed of potassium carbonate, potassium sulfate, and potassium chloride. Firstly, dissolve and extract with warm water. Add a small amount of lime milk to the extract, filter and clarify it, then evaporate and concentrate it to a relative density of 1.318. After cooling and crystallization, filter to remove potassium sulfate. Concentrate the mother liquor to a relative density of 1.526, cool and crystallize, and filter to remove potassium chloride. Concentrate the mother liquor until crystals have just precipitated, cool and crystallize, and filter to obtain potassium carbonate. Alternatively, it can be completely dissolved in water and CO2 gas can be introduced to transform all potassium carbonate into potassium bicarbonate crystals, which can then be calcined to obtain potassium carbonate. The reaction equation is as follows:

4. The Loubulan method mixes potassium sulfate, coal powder, and limestone in a certain ratio and mixes them with water. Among them, potassium chloride is controlled at 6% to 8%, sodium salt is controlled at 8% to 10%, and then black ash is obtained by melting at a temperature of 900 to 1000 ℃. Crush the black ash, soak it in hot water, evaporate the soaking solution to precipitate some unconverted potassium sulfate, and send the clear solution to the carbonization tower for pre carbonization after separation. Adding potassium permanganate to the carbonation solution causes impurities such as aluminum, silicon, and iron to precipitate. The filtrate evaporates until potassium carbonate and sodium double salts enter the impurity precipitate. The clear solution undergoes secondary carbonation to obtain crude potassium carbonate crystals, which are then filtered, washed with water, and calcined in a calcination furnace at 500-600 ℃ to produce potassium carbonate products. The reaction equation is as follows.

5. Add an equal amount of distilled water to industrial potassium carbonate, stir, heat to dissolve, then add a small amount of activated carbon and stir. Add an appropriate amount of potassium oxalate (to generate calcium oxalate precipitate to remove Ca2+ions) according to the content of Ca2+ions in the raw material, stir, heat to boiling, filter while hot, evaporate and concentrate the clear filtrate obtained until a crystalline film appears on the surface, stop heating, cool the crystallization, centrifuge and spin dry after complete crystallization, obtain hydrated potassium carbonate, heat to 105-110 ℃ for dehydration and drying, and obtain anhydrous potassium carbonate.

6. Photographic grade anhydrous potassium carbonate refining: Industrial potassium carbonate is dissolved in distilled water for solution purification, filtered to remove impurities, and the filtrate is evaporated, concentrated, cooled, crystallized, centrifuged, and dried to obtain anhydrous potassium carbonate products.

use to

Application areas: Inorganic industry is used to manufacture potassium sodium tartrate, potassium aluminum fluoride, potassium thiocyanate, and titanium dioxide. The pharmaceutical industry is used to manufacture long-acting sulfonamides, progesterone, cortisone, acar, estradiol benzoate, and other drugs. Glass enamel industry is used for preparing enamel powder to enhance its leveling properties, add it to glass to aid melting, and improve glass transparency and refractive index. The dye industry is used to manufacture Yin Dan Tu Lin, Disperse Red 3B, Reduced Ash M, etc. The printing and dyeing industry is used for the dyeing of vat dyes and the whitening of ice dyeing. The rubber industry is used to manufacture 4010 anti-aging agents. The woolen cotton industry is used for boiling cotton fabrics and degreasing wool.