Recovery of apatite from flotation tailings

Apatite is the most common phosphate mineral and a vital nonrenewable resource which is the only economically feasible source of phosphorus for phosphate fertilizers and chemicals. The progressive depletion of ore deposits, allied to the growing demand for food in the world, makes it imperative to use phosphate deposits rationally and to develop recycling processes for accumulated mineral processing wastes. The work reported here involved an evaluation of the possible reuse of phosphate flotation tailings from a Brazilian fertilizer manufacturer. A special flotation apparatus was used in operations in order to examine the effect of the mixture of two different collectors, as well as operating variables (air flow rate, recycle flow rate, and conditioning time) and reagent dosages. The results indicate that the use of a mixture of the synthetic reagent and rice bran oil soap increased the selectivity of the concentrate considerably. A grade of 29.4% P2O5 and a recovery of 46.2% were obtained under selected operating conditions.

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► The reuse of phosphate flotation tailings from a Brazilian fertilizer manufacturer has been evaluated.
► The use of a mixture of collectors synthetic (KE) and conventional increased the flotation selectivity.
► The flotation performance as a function of operating variables has been quantified.
► A grade of 29.4 wt.% P2O5 and a recovery of 46.2 wt.% were obtained under selected operating conditions.
► The results shown that a reject from a phosphate industry is potentially reusable through the flotation.