Mineralogical studies of bauxite (I)

Bauxites from several localities were studied mineralogically by means of optical and X-ray methods. The materials studied are from the following localities: Haiphong, French Indo-China; Bintan I., Dutch East Indies; Palau I., Caroline Archiperago; Montpellier, France; unknown localities in South America, Malaya, India, Greece and Yugoslavia. Bauxite from Haiphong is the only one which consists essentially of diaspore. That from Montpellier is essentially composed of böhmite, while those from Bintan, Palau, S. America and Malaya are essentially of gibbsite. Greek bauxite is a mixture of diaspore and gibbsite, while Yugoslavian and Indian ones are of böhmite and gibbsite. Their refractive indices determined by immersion method are shown in Tab. 4, and their X-ray powder photographs are shown in Figs. 3, 7 and 9. The thermal properties of diaspore, bohmite and gibbsite were preliminarily examined and the dehydrated products were determined by X-ray method. The results are shown in Tab. 5. The present studies were carried out under the guidance of Prof. S. Közu, to whom author's hearty thanks are due.