CHALLENGING THE 'CRAGO' DOUBLE FLOAT PROCESS AMINE-FATTY ACID FLOTATION OF SILICEOUS PHOSPHATES

摘要

In the conventional phosphate flotation (Crago) process, 30-40 percent by weight of the silica present in the feed are floated twice, first by fatty acid, and then by amine. The Crago process is therefore inefficient in terms of collector efficiency. Also, the phosphate mining industry is faced with higher fatty acid prices, lower feed grade, and stricter environmental regulations. For these reasons, the Florida Institute of Phosphate Research has developed an amine-fatty acid flotation flowsheet, the reverse "Crago". In this process, fine sands are first floated with a minimum dosage of amine condensate added stepwise. The concentrate from prefloat is then floated with a blend of surfactant/fatty acid/fuel oil The technical and economic feasibility of this process were evaluated on seven feeds of varying characteristics, producing concentrates analyzing 30~32percent P_2O_5 and 4-10 percent Insol with P_2O_5 recoveries of over 93percent, at total reagent costs below