Leaching and the residue flotation of a low-grade Ni-Cu-PGM sulfide ore

摘要

According to the mineralogy of a low-grade Ni-Cu-PGM sulfide ore, a leaching-flotation process was introduced to process the ore. The leaching tests were focused on temperature, acid concentration, and grinding fineness under normal pressure. Results show that most of Mg and Fe can be effectively leached by 25% H_2SO_4 with a small amount of copper and nickel loss in leaching solution. Through separating Fe and Mg in the leaching solution, iron oxide red assaying 75%Fe_2O_3 and light magnesium oxide assaying 95%MgO were obtained. Residue flotation shows that a bulk concentrate assaying 2.72%MgO with a higher PGM recovery can be obtained. The most important fact is that the grade of PGM in the residue gets doubled relative to the raw ore, which enlarges the available low-grade PGM resource in China.