What are the introduction and preparation methods of lithium hydroxide?
Lithium hydroxide is a white monoclinic fine crystal. Lithium hydroxide has a spicy odour and is strongly alkaline. When lithium hydroxide is placed in air, it absorbs carbon dioxide and water. It is a chemical substance soluble in water, lithium hydroxide slightly soluble in ethanol, insoluble in ether, is a corrosive substance.
1.The use of lithium hydroxide
Lithium hydroxide can be used as unfolding agent for spectral analysis, lubricating oil. Alkaline battery electrolyte additives, can increase the battery capacity of 12% to 15%, to improve the service life of 2 to 3 times.
Can be used as a carbon dioxide absorber, can purify the air in the submarine, the chemical equation is: 2LiOH (s) + CO2 (g) = Li2CO3 (s) + H2O (l).
Used in the production of lithium salt and lithium grease, alkaline battery electrolyte, lithium bromide refrigeration machine absorption liquid, lithium soap (lithium soap), lithium salt, developer, etc., or as an analytical reagent, etc.; petroleum, chemical, light industry, the nuclear industry and other uses. Used in alkaline storage battery, aluminium content is not more than 0.06%, lead content is not more than 0.01%. Used as an analytical reagent, photographic developer, also used in the manufacture of lithium; to be used as a raw material for the production of lithium compounds. Can also be used in metallurgy, petroleum, glass, ceramics and other industries.
2. Preparation method of lithium hydroxide
1, complex decomposition method
Lithium hydroxide is usually by the lithium carbonate and lime milk into a slurry, heated with 100 ℃ water vapour, filtered calcium carbonate method to prepare. The method is more commonly used. Li2CO3(s)+Ca(OH)2=2LiOH(s)+CaCO3↓
2、Oxidation reduction method
Lithium metal and water action system. The raw material is more expensive, less used.
2Li+2H2O=2LiOH+H2↑
3, lime sintering method
(1) lithium pyroxene concentrate (generally containing 6% lithium oxide), mixed with limestone and ground fine, sintered at 1150 ~ 1250 ℃ to generate lithium aluminate and calcium silicate, crushed by wet milling, leaching lithium hydroxide with the wash solution, filtered by settling, the leach solution was evaporated and concentrated, crystalline lithium hydroxide monohydrate finished product is produced, and its chemical equation is:
Li2O-AI2O3-4SiO2+8CaO→Li2O-Al2O3+4[2CaO-SiO2]
Li2O-AI2O3+Ca(OH)2→2LiOH+CaO-AI2O3
(2) Industrial lithium hydroxide was dissolved in cold water under stirring, the insoluble matter was filtered off, the filtrate was heated and evaporated until crystals appeared, cooled and shaken dry, i.e., lithium hydroxide monohydrate reagent was produced.
(3) with lithium hydroxide monohydrate as raw material, in the phosphorus pentoxide fitted with the dryer drying for several days, anhydrous lithium hydroxide can be obtained. Can also be produced by slowly heating lithium hydroxide monohydrate to 140 ℃ dehydration in a stream of hydrogen.