The effect of pretreatments on the dissolutions of impurities from Indonesian cassiterite mineral

The purpose of this research was to purify cassiterite from associated minerals (impurities) and to investigate the effects of pretreatment on the dissolution of impurities from Indonesian cassiterite mineral. The steps of this research are as follows: characterization, pretreatment and leaching processes by dilute hydrochloric acid (HCl) solution. Firstly, cassiterite was characterized by X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) techniques, and then pretreatments were carried out including washing, roasting at 700 °C and both combinations of washing and roasting at 700°C. Cassiterite obtained from the processes of pretreatment and without pretreatment was then leached using 10% HCl solution with temperature variations of 35 °C – 150 °C for 2 hours in atmospheric condition. The results showed that the chemistry composition of cassiterite was as follows: 57.82% Sn, 0.45% Si, 1.45% Ti, 1.79% Fe, 3.43% La, 3.37% Ce and 31.69 % others. The best condition for purification of cassiterite was leaching without pretreatment that has the highest dissolution of associated mineral from cassiterite than other processes (pretreatment) for leaching at 110 °C for 2 hours. This research was able to purify cassiterite with a chemical composition as follows: 66.14% Sn, 0.27% Si, 1.38% Ti, 1.18% Fe, 2.12% La, 2.03% Ce and 26.88% others. These results are quite satisfactory because this technology is quite simple and economical.