Abstract
This study investigates various decomposition methods for tungsten-molybdenum ores-wet, dry, and autoclave-to identify optimal conditions for Mo and W extraction. Four ore samples were examined: two reference materials and two natural samples from Central Kazakhstan.Natural samples О-3 and O-4, classified as refractory silica-rich tungsten-molybdenum ores, have complex mineralogical compositions.Optimal decomposition conditions for these ores were established for the first time, considering their geochemical features.X-ray fluorescence (XRF) and X-ray diffraction (XRD) were used to determine the elemental and phase composition, while ICP-MS analyzed digested solutions.The efficiency of Mo and W extraction depend on both mineralogical form and matrix.Nine decomposition methods were tested.For standard molybdenum-tungsten ore samples (O-1 and O-2), the highest recoveries were achieved using acid-based techniques, particularly autoclave digestion with HNO₃-HF and wet digestion with HNO₃.In contrast, natural samples with complex silica-rich matrices containing Al, Fe, and Ca (O-3 and O-4) required stronger approaches such as autoclave treatment with HNO₃-HF or HCl and alkaline sintering with Na₂CO₃ followed by HNO₃ dissolution.All experiments were performed in triplicate, with a standard deviation of 3-5%.These findings demonstrate the importance of matching decomposition strategies to ore characteristics for effective Mo and W recovery.