A Study On The Processing Technology Of Duobaoshan's Refractory Porphyry Copper Ores

The copper minerals of great importance are short in China. Development new processing technology for refractory copper ores are meaningful. A large-scale refractory porphyryr deposit, named as Duobaoshan Copper Mine in Heilongjiang Province, were researched detailedly in the separation of the copper and molybdenum in the ores. Previous study has shown that the ores are difficult to make qualified molybdenum concentrates from. This study achieved a good recovery of Cu and Mo through a new process.Process mineralogy study investigated the ore's mineral composition, texture and structure, researched the inlay feature and intergrowth of Cu- and Mo-beariing minerals. It is drawn that fine sizes of valurable minerals as chalcopyrites, bornite and molybdenite etc, and that complex relations among them are the true reason accounting for the difficult processing of the ores.Batch tests in lab led to the following novel process: raw ores-grinding-bulk flotation of Cu- and Mo-bearing minerals-regringding of rougher-flotation of Cu-bearing minerals. Its advantage is the rejection of most tailings at coarser size and separation of Cu and Mo at reasonable level. When the ores of 0.45% Cu and 0.028 %Mo are grinded to 61.2% minus 200 meshes, by one-step rough flotation, two- step cleaning and two-step scavenging flotation, copper concentrate with a yield of 0.92% and recovery of 44.87% in Cu contains 24.30%Cu and 0.43% Mo; the Cu-Mo concentrate with a yield of 0.0.67% contains 27.67% Cu, 5.27% Mo, the recoveries of Cu and Mo are 37.22% and83.33% respectively.Mentioned process has been tested in pilot plant. Produced Cu concentrate, with the yield of 1.35% and the recovery of 69.47% in Cu, contains 23.16%Cu and 033%Mo. Produced Cu-Mo concentrate containing 24.5%cu, 6.55%Mo recovers 16.32% Cu and 70.18%Mo , stands for a yield of 0.30%. The total recovery of Cu is 85.79%. This result reaches the expected target.Separation of copper and molybdenum in Cu-Mo concentrate by metallurgical process is conducted. Roasting-leaching by Na₂CO₃ is tested and adopted. It is proved that pre-Ieaching of CuSO₄ by water can reduce the consumption and cost of Na₂CO₃. Optimum conditions were determined. By roasting for 30-60 min at 650C, then water leaching for 30-60 min at room temperature with liquid/solids ratio of 2, and then Na₂CO₃ leaching for 30-60min at 80C with liquid/solids ratio of 2, Mo and Cu leaching rates reach 94.62% and 99% respectively. Slag after leaching Mo contains Cu 25%, Aul3.8g/t, Ag/114g/t, ideal material for Cu pyrometailurgy. Pilot plot test on Roasting-Leaching confirmed the separation of Cu-Mu feasible.The pregnant from Mo leaching experienced cleaning, evaporation and crystallization process. Through that, (NH4)2MoO2 meeting the requirements of National standard were obtained.