PROCESS FOR THE BENEFIT OF PHOSPHATE MINES

摘要

Beneficiation of phosphate minerals (A) comprises first controlled attrition for at least 5 min. to produce fine particles, then removal of fines such that less than 1% of the treated material is in the form of particles of below 100 microns. The treated ore is then subjected to at least one anionic phosphate flotation stage. Pref. the attrition is carried out on a pulp contg. 60-80 wt.% (A) with agitation so that the relative velocity of particles of (A) in the pulp is below 5m. per sec., and pulp residence time in the treatment vat is 5-60 min. Pref. during this stage the ratio d80 to d20 increases by at least 1.5 (d80 and d20 are the smallest mesh sizes through which 80% and 20% of the particles will pass). Flotation is pref. in 3 stages (a) sepn. of phosphate particles with gangue; (b) removal of silica and (c) removal of carbonates. The method is esp. used to treat Florida phosphate rock which contains dolomite and-or calcite as well as silica. It gives a prod. of low MgO content without requiring expensive reagents.