Study on the flotation selectivity of a problem phosphate ore

Three types of mineralisation are present in the phosphate ore mined by Ser rana in Araxa, Brazil: oxidised, micaceous and silicate-carbonate. The mica ceous and silicate-carbonate are considered problem ores. This investigatio n deals with characterisation and fundamental studies performed on fraction s resulting from the purification of five samples from the silicate-carbona te type collected in the mine, representing portions with visually differen t aspects, designated as: barite, carbonatite, green micaceous, brown-green micaceous and brown clay. Each type was purified in the laboratory and the n submitted to mineralogical characterisation, zeta potential determination s, and microflotation experiments with anionic and cationic collectors. The samples, with the exception of the barite, are mineralogically complex and the selectivity between apatite and the gangue minerals is poor. The only feasible route for processing the silicate-carbonate ore is blending it wit h the standard oxidised ore. (C) 2001 Elsevier Science Ltd. All rights rese rved.