Effect and mechanisms of sodium carbonate on the auto-carrier flotation of scheelite

Because of the low recovery of -10 μm fine scheelite particles in scheelite flotation, some amount of fine scheelite is lost in the tailing, resulting in the wasting of scheelite resources. It is urgently needed to solve the problems inherent in fine scheelite flotation and explore new processes of fine ores to effectively recover fine scheelite. The carrier flotation has proven to be an effective method of improving the recovery of scheelite by promoting the recovery of fine particles. Based on studies of the effect of particle size and particle fraction on scheelite flotation, the application of auto-carrier flotation in the recovery of -10 μm scheelite using sodium carbonate in both the presence and absence of sodium carbonate were studied. The effect of percentage carrier, particle size of carrier, and sodium carbonate on the auto-carrier flotation of scheelite were also studied through flotation tests, theoretical calculation, and instrument testing. The results indicate that the contents and particle size of coarse particles exert significant influence on auto-carrier flotation. The recovery of fine scheelite with a size of -10 μm is increased by using auto-carrier flotation with the proper carrier percentage and size. The addition of sodium carbonate strengthens the carrier flotation of scheelite and therefore improves the scheelite recovery. Furthermore, the addition of sodium carbonate can also expand the percentage and particle size range of carrier mineral. The results of mechanism studies indicate that there exists interaction among scheelite particles, which results in the adhesion of fine particle to carrier. The hydrophobic force is the main reason that the scheelite particles attracted each other, and the addition of sodium carbonate increases the adsorption of sodium oleate onto the scheelite surface, thereby improving the hydrophobicity of scheelite and the hydrophobic force among scheelite particles. It can be concluded that the auto-carrier flotation of scheelite can be improved by adding sodium carbonate.