In this work, the effect of intensive milling on the conversion of microcline (KAlSi3O8) to potassium chloride (KCl) during chlorination roasting was investigated. A feldspar ore with 10.89 percent potassium oxide (K2O), containing mainly microcline and a small amount of albite (NaAlSi3O8) was milled for mechanical activation. The ore was mixed with calcium chloride and then roasted to 1,000 °C to obtain KCl, which was dissolved by water leaching. Potassium recovery from unmilled ore increased rapidly up to 800 °C but then drastically decreased at higher temperatures due to the removal of KCl from the furnace by evaporation. Potassium recovery was 31.95 percent from the unmilled ore and 88.43 percent from ore that was milled for 15 min and roasted at 750 °C. It is concluded that intensive milling caused mechanical activation of microcline to reduce the chlorination roasting temperature.
Full-text paper:
Mining, Metallurgy & Exploration, https://doi.org/10.1007/s42461-023-00785-3
