Abstract: China has rich pyrite resource, which is not only a sulfur resource but also an important iron resource. Therefore, compared with other materials for acid making, acid-making with pyrite has a congenital favorable condition. We have found through the study on the mineral properties of pyrite cinder that the iron minerals in the pyrite cinder are mostly of honerycomb-like, dissemination and residual structure, especially of dissemination structure. Therefore, the iron grade and recovery will not be high when conventional methods are used in its separation. It is proposed to use the waste heat from the acid-making process to recover the iron in the acid-making tailing by a countercurrent process. Under the conditions of a grinding pulp density of 65%, 1 000 A/m magnetic intensity of half-countercurrent wet permanent magnetic separator, 8% CaCO₃, 5% 2# reagent, 40min treatment time and 8% C dosage, an iron concentrate containing 63.55% iron and 0.19% sulfur can be achieved, with a recovery reaching 83.11%.

Key words: Pyrite cinder, Countercurrent process, Low intensity magnetic separation