Behavioral Differences of Apatite Flotation from Surface and Depth Zones of Urmia Qare-Aghaj Polymetallic Deposit

Floatation behavior of apatite mineral from the surface and deep samples of polymetallic ores from Gharah-Aghaj Urmia was studied. Floatation experiments were performed in the form of an experimental design considering the pH, solid percentage, and collector consumption amount as variables, for two samples of mentioned surface and deep ores. Results of the experiments approved the feasibility of obtaining concentrate from both samples, but the qualities of concentrates are completely different and floatation behavior of apatite of deep sample is weaker compared with the surface sample. Analyzing the effect of variables on the resultant grade and recovery revealed that pH, solid percentage and collector amount have a negative effect on surface sample grade. However, in the deep sample, pH and solid content don’t have a significant effect on grade and the effect of collector amount on deep sample grade is positive. After optimization of floatation conditions for both samples, at optimized conditions, for the surface sample after a rougher stage and 5 cleaner stages, a concentrate with a grade of 33.23%% P2O5 and a recovery of 74.80%, and for the deep sample after 6 cleaner stages, a concentrate with a grade of 28.81% P2O5 and a recovery of 55.01% were obtained. Characterization revealed that deep concentrate has calcite and Magnesio-Hornblende which floats along with apatite and prevents the increase of the final concentrate grade. On the other hand, results of elemental analysis by EDX showed that the amount of fluorine element in the deep sample is lower in comparison to the surface sample, which is a reason for the low floatation strength of deep sample apatite. Finally, it has been concluded that in the Urmia Gharah-Aghaj ore deposit, as the depth increases the floatation efficiency of apatite decreases.