How to extract potassium carbonate from plant ash? _Industrial additives

Properties

Potassium carbonate is in the form of monoclinic crystals, white powder, fine granular crystals or round pellets, with a relative density of 2.428 and a melting point of 891°C. Easily soluble in water, its aqueous solution is alkaline. It is insoluble in ethanol and ether, has strong hygroscopicity, and is easy to agglomerate. It can easily absorb carbon dioxide and form potassium bicarbonate when exposed to air for a long time.

Extraction of potassium carbonate from plant ash

The main components of plant ash are potassium carbonate, calcium oxide, and phosphorus pentoxide. Potassium carbonate is soluble, and the potassium salts in plant ash can be extracted through steps such as dissolution, filtration, evaporation, cooling and crystallization.
The steps are as follows:
(1) Put a certain amount of plant ash into the beaker, and add water to a point 1cm~2cm above the surface of the plant ash. Heat slightly while stirring with a glass rod to dissolve the potassium salt in the plant ash into the water.
(2) Prepare a filter and filter the arkema plant ash in the beaker together with the infusion liquid. Finally, a clear filtrate is obtained.
(3) Pour the filtrate into the evaporating dish, heat the evaporating dish, and use a glass rod to continuously stir the solution to prevent droplets from splashing. When only a small amount of liquid remains after evaporation, stop heating.
(4) Leave the evaporating dish to cool and the potassium salt crystals will slowly precipitate.
(5) Dissolve the potassium salt crystals and add hydrochloric acid to see if there is gas generated that will make the clear lime water mixed. If there is, it means that there are carbonate ions.

Purpose

Potassium carbonate is a raw material for the production of electron tubes, television picture tubes, and computer monitor glass bulbs. Used in the production of optical glasses to increase transparency, strength and refractive index. It is also used in the production of electric welding rods to prevent arc breakage during welding. It is the raw material for food additives potassium sorbate, potassium dihydrogen phosphate and other products. It can be used as foliar spray fertilizer and as raw material for compound fertilizer. It can also be used to produce vat dyes and whitening of ice dyeing. Used as an absorbent to remove hydrogen sulfide and carbon dioxide. Mixed with soda ash, it can be used as dry powder fire extinguishing agent. It can also be used as an auxiliary raw material for acetone and alcohol production and as an anti-aging agent in rubber production. The aqueous solution can be used for scouring cotton and degreasing wool. In addition, it is also used in the production of inks, photographic chemicals, polyester, explosives, electroplating, tanning, ceramics, building materials, crystal and medicine. It is used as a Tim Lomon-Haas additive in the production of instant noodles and carbonated beverages to play the role of leavening and preservative.