Abstract
Colemanite, Datolite, and kurnakovite are some of important industrial borate minerals, which have chemical compositions as Ca2B6O11•5H2O, CaBSi4(OH), and Mg2B6O11•5H2O. They are commonly used as the source of glass or glass fiber. However, they have a limitation because of cations in the composition. The colemanite ore has been processed to separate out boron component in the form of boric acid. The effect of process parameters, such as concentration of sulfuric acid, heating temperature, recrystallization and drying condition on the boric acid crystal phase, purity, and shape of particle was studied. Boron and calcium in colemanite have been dissolved in sulfuric acid solution and calcium has been separated out as a calcium sulfate solid, which has very small solubility in hot water, while boric acid has been fully dissolved. Finally the boric acid has been crystallized using solubility difference by lowering temperature.
