Abstract
The scavenger flotation circuit design and successful insoluble mineral flotation research discussed in this paper provide a solution to break the historical conventional potash production 90% recovery barrier and address the issues of fine tailings management. The author proposed an alternate solution to using fresh water to dissolve the residual salts in the fine tailings by instead processing the fine tailings stream through a two-stage scavenger flotation circuit. The first stage utilizes the novel application of reverse flotation of insoluble minerals (insols) to separate the insols from the fine halite and sylvite and directs the insol concentrate to the fine tailings management area. The second flotation stage recovers the ultrafine potash from the reverse flotation tailings.
The feasibility of flocculation-flotation of insoluble minerals on this “unfloatable” tailings stream was evaluated at both pilot and industrial scale. Complete liberation of the insoluble minerals, a fundamental characteristic of the ultrafine stream, resulted in near-perfect separation efficiencies from sylvite at high insol rejection rates when sufficient power intensity was provided. The application of this circuit design would increase operational sustainability, not only by reducing fine tailing costs and environmental impact but also by providing an opportunity to recover the ultrafine potash lost to tails from the mechanical desliming process.