A novel depressor useful for flotation separation of diaspore and kaolinite

The floatation of the minerals diaspore and kaolinite was investigated using dodecylamine as the collector. Separating diaspore and kaolinite in a neutral pH pulp is difficult since they then have similar floatability. A depressor consisting of an AlCl3/Na2SiO3 mixture is demonstrated to solve this problem. Diaspore sinking may be seen when the ratio of AlCl3 to Na2SiO3 is 3:1. We refer to this mixture as ATNO. The influence of Al/Si ratio in the feedstock and the grain size of fed minerals on separation was examined. An Al/Si ratio in the concentrate greater than 11 may be obtained when the Al/Si ratio of the feed is between 2.53 and 4.96. However, the grain size of the diaspore greatly influences the concentrate grade. Finer grain size of the diaspore (<40 μm) in pulp makes the flotation separation less than ideal, no matter what the kaolinite grain size.