Selective Flotation Between Apatite And Siliceous Gangue

The surface dissolution of apatite in pulp will change its surface properties and the solution chemistry environment. Silicon-calcium phosphate rock contains mainly siliceous gangue (quartz as the representative) and calcareous gangue (represented by dolomite). Since in alkaline conditions (pH> 10), quartz is easy to be activated by Ca2+, and Ca2+ dissolved in apatite solution has a negative impact on the separation of apatite and quartz. The thesis studied the basic flotation behavior of apatite and quartz, and the influence by Ca2+ and various inhibitors on the separation of apatite and quartz. And investigate the types of pH regulator, and the mechanism of the impact on the flotation behavior by Ca2+ and the water glass. And by potentiodynamic tests, X-ray photoelectron spectrometric and flotation solution chemistry, reveals the substances on apatite surface and the principle of the activation of quartz in the sodium carbonate system. Get the following results:1. The floatability of apatite is superior to quartz. Using Na2CO3 as the pH regulator can improve the floatability of apatite, and increase the floatability difference between apatite and quartz. In alkaline medium, the active substance on apatite surface is CaHPO4. When adding Na2CO3 solution, the content of HPO42-component increases in the apatite saturated solution, in other words, the active substance increased on surface, therefore the recovery increased.2. Adding Ca2+ in flotation process at pH>10 (Na2CO3 or NaOH), the recovery of quartz increases rapidly. The mechanism of activation is that the new generation of CaCO3 deposites on the quartz surface. In the system of Na2CO3 as pH regulator, the recovery of apatite has dropped after adding Ca2+, while in the system of NaOH as pH regulator system, the floatability of apatite almost have not been affected.3. In the study of the impact of inhibitor species on flotation separation of apatite and quartz, water glass was found to be superior to guar gum, lignin sulfonate, dextrin, and sodium hexametaphosphate. Even as to quartz activated by Ca2+, water glass still has a strong inhibitory effect on its, but almost no effect on the apatite.Thus, under alkaline conditions, we can select Na2CO3 as the pH regulator, water glass as inhibitor in the flotation separation of apatite and quartz, and the results are satisfactory.