It is known that oxidation is one of the most common ways for penlandite to be introducted into tailing during traditional coarse-particle sulfide flotation. However, it could become much more complicated and challenging problems for the low-grade, fine-disseminated Cu-Ni sulfides containing Pt and Pd in Yunnan Mine, accompanied with more than 75% of the content of MgO in the ore sample is. Direct flotation tests had been conducted to extract the metallic values as much as possible by adding traditional depressants and collectors, such as carboxylmethyl cellulose, starch, sodium silicate, butyl xanthate, (BX), butyl ammonium dithophosphate (BA) and etc., the relatively satisfied recoveries of Cu, Ni, Pt and Pd in the concentrate from bench flotation tests were obtained, however, more than 30% of metallic values still lost in the slime. In this study, bench flotation tests for the ore sample fromYunnan Mine, micro-flotation tests of serpentines and pentlandite from Jinchuan Mine and their settling rate tests were conducted to figure out how the oxidation influence the recovery of the ultra-fine nickel sulfide. All the tests results pointed to the presence of over-oxidation on the ultra-fine nickel sulfide surface and lead to the loss of Ni containing Pt and Pd in the slime tailing. Some methods which tried to slow the speed of oxidation on mineral surface during grinding and flotation were introduced in order to recover the values before over-oxidation of sulfides; however, the slime coating of serpentines also may play an important role in disturbing the floatability of ultra-fine sulfide.
Correction: The sensitive detection of single-cell secreted lactic acid for glycolytic inhibitor screening with a microdroplet biosensor
