Study on Process Mineralogy and Separation Technology of a Fine−grained Carbonate−type Collophane from Yunnan

To facilitate the better utilization of a carbonate−type collophane from Yunnan, its process mineralogy characteristics—including mineral composition, structure and texture, dissemination characteristics of major minerals, and degree of liberation—were systematically investigated using techniques such as an Automated Mineralogy Identification and Characterization System (AMICS) combined with chemical analysis. The results indicate that the valuable mineral in the ore is single, identified as apatite, while the gangue minerals are complex, primarily consisting of dolomite and quartz. Iron is mainly distributed in limonite and pyrite, and aluminum is primarily found in minerals such as diopside, K−feldspar, and muscovite. The mineral intergrowth relationships are predominantly two−phase and multiphase. Apatite crystallizes in relatively coarse particles, whereas the gangue minerals exhibit fine crystal particles and are further enriched in the finer size fractions, significantly increasing the difficulty of flotation. The presence of aluminum in quartz and diopside is attributed to certain elemental doping or mineral intergrowth. Through a reverse flotation process to remove silicon and magnesium gangue minerals, a phosphate concentrate product with a grade of 31.52% P₂O₅ and a recovery of 67.54% was obtained, while the MgO−removal tailings product assayed 4.11% P₂O₅. The final concentrate product, with its high grade, can be used as a raw material for producing feed−grade calcium phosphate. The middling product, with a grade of 27.48% P₂O₅, can serve as a raw material for fertilizer production, thus enabling the classified and high−value utilization of the phosphate ore. This study provides a theoretical basis for separating magnesium, silicon, iron, and aluminum minerals from phosphate ore and offers guidance for the rational development and utilization of phosphate resources in this mining area.