Purification of Cassiterite Mineral Bangka Indonesia by Pyrometallurgy and Hydrometallurgy Methods

Abstract

The cassiterite mineral is producing mineral of tin. It is widely used in the manufacture of catalysts such as FTO (Fluorine Tin Oxide) glass coatings or as a SnO2 pigment. Tin is usually used in energy and electronics sector. Cassiterite can be found on the islands of Bangka, Belitung, Kundur, Singkep, Karimun and Kampar. In Indonesia, cassiterite mixed with other minerals such as ilmenite, quartz sand, zircon, rutile, pyrite, calcite, lanthanum and monazite. Those mixtures able to give rise of problems if used as raw chemical materials in tin production. The purifying process of cassiterite is done by pyrometallurgy and hydrometallurgy methods. The XRF and XRD analysis of raw cassiterite show that the main components are Sn and O. The decomposition process is done by mixing cassiterite and kalium sulfate (K2SO4) with a ratio of 2:3. The leaching process is performed using KOH to dissolve SnO2 because the compound is soluble in a strong base. The optimum result is obtained at decomposition temperature 800 and time of 4 hours. The intermediate product kalium stannate (K2SnO3) is not formed because cassiterite has a structure which may cause some difficulties to react with the salt kalium sulfate (K2SO4).