Lithium hydroxide is an inorganic white crystalline solid which is soluble in water to make a highly basic solution as it is a hygroscopic substance. It is commercially available in its anhydrous form (LiOH) or in its monohydrate form (LiOH.H2O). Although lithium hydroxide is strongly alkalic and reacts with acids to produce lithium salts, it is the weakest known alkali metal hydroxide.
Lithium hydroxide is produced from the reaction between lithium carbonate and calcium hydroxide, both in solution form, due to its low cost and abundance of calcium hydroxide. This reaction produces dissolved lithium hydroxide and precipitates of calcium carbonate. The lithium carbonate itself is obtained from treating brines or spodumene deposits in upstream processes. The chemical equation is as follows:
Li2CO3 + Ca(OH)2 → 2 LiOH + CaCO3
Next, once the reaction occurs, calcium carbonate is separated by means of mechanical separation such as filtration to be able to obtain crude lithium hydroxide solution. To increase the purity, the solution is passed through several evaporators or crystallizers to concentrate the solution before drying takes place. Fluid bed dryers are utilized to be able to effectively dehydrate the lithium hydroxide, as it has low electrical consumption as well as high thermal efficiency. Crystallizers and spray dryers are also commonly used in the industry.
Alternatively, lithium oxide can be dissolved in water as shown in the chemical equation below. Likewise, this process follows the same steps for the separation and drying to obtain high purity crystals of lithium hydroxide.
Li2O + H2O → 2LiOH
Once lithium hydroxide crystals are made, their particle size is reduced to be able to ensure uniformity of product before being packaged and delivered to a wide variety of industries.
- Electronics Industry
Lithium hydroxide is used as an electrolyte in battery production, such as in lithium ion, nickel-cadmium and nickel hydrogen batteries, and many more. These batteries are then used for various purposes like in digital cameras, smartphones, pacemakers, etc.
- Soap Industry
In the soap industry, lithium hydroxide is used to manufacture lithium soaps by saponification, which are salts of stearic acid or other fatty acids. It is then applied as lithium based grease thickeners, improving its stability, water resistance, heat resistance and other mechanical properties.
- Textile Industry
Moreover, lithium hydroxide is used as a cation for an anionic dye to improve the light-fastness of dyes and enhance the brilliance of some pigments. This product also serves as a fluxing agent in inorganic glazes and pigments. In inkjet technology, lithium hydroxide alters the viscosity of inks as well as altering the internal components of printers, allowing to maintain the pH conditions during storage.
- Chemical Industry
Lithium hydroxide is useful in exhaust-gas treatment systems in industrial plants to reduce specific gas emissions. It is also valuable to be used in carbon dioxide scrubber inside spacecraft and submarines, as it reacts with carbon dioxide in the surroundings to make lithium carbonate hence preventing people from suffocating.