中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 7 July 2025 |
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Key Laboratory of Hunan Province for Metallurgy and Material Processing of Rare Metals, Central South University, Changsha 410083, China）
Abstract:Potassium hydroxide (KOH) was introduced into the molybdenite roasting process to convert molybdenum (Mo) and sulfur (S) into water-soluble potassium molybdate (K2MoO4) and potassium sulfate (K2SO4). Roasting with a 1.8-fold excess of KOH at 400 °C for 3 h enabled the leaching of over 99% of Mo from the molybdenum calcine using water. A precipitation method involving potassium–magnesium (K-Mg) salts was proposed for impurity removal. Under the conditions of pH 11, 30 °C, excess coefficient of 1.7 for Mg salts, and a duration of 1 h, 98.37% of phosphorus (P) was removed from the K2MoO4 solution. With post-purification, over 99% of Mo crystallized upon adjustment of pH to 1. Subsequently, S and K were recovered as K2SO4 fertilizer from the crystalline mother liquor. An environmentally sustainable approach was proposed to conduct molybdenite production and ensure the efficient recovery of both Mo and S.
Key words: molybdenite; sulfur fixation roasting; magnesium potassium phosphate; potassium polymolybdate
