Production of a Phosphate Concentrate from the Tailings of a Niobium Ore Concentrator

Apatite is the main source of phosphorous for the making of chemical fertilizers. While apatite is usually recovered from phosphate orebodies as the primary product of a mining exploitation, this paper documents the approach taken to produce a phosphate concentrate as a secondary product from the tailings of a niobium ore concentrator. The conventional desliming/flotation scheme used to process phosphate ores was tested and adapted to process one of the reject streams of a niobium concentrator in order to produce a salable phosphate concentrate. For that particular material, it was found that the reverse flotation of apatite yielded better results than the commonly used direct flotation of apatite. The recommended approach to produce the phosphate concentrate is desliming followed by reverse flotation of apatite and an acid leaching of the apatite concentrate to lower the MgO content below the specification for a phosphate concentrate. The obtained phosphate concentrate assays more than 32% P2O5 at a P2O5 recovery of 41%, which although low is found to be economic for the case of processing plant reject tailings.