GB1057213A - Processing of phosphate rock - Google Patents

Abstract

1,057,213. Concentrating ores. AMERICAN AGRICULTURAL CHEMICAL CO. April 21, 1965 [May 6, 1964], No. 16846/65. Heading B2H. Phosphate rock is beneficiated by subjecting feed phosphate rock contaminated with siliceous material to a wet grinding operation to yield a ground phosphate rock leaving a particle size smaller than about 14 mesh (Tyler scale), selecting a fraction of the ground phosphate having a particle size greater than 325 mesh and subjecting it to a cationic flotation operation whereby the siliceous contaminant material is floated off and a concentrate having a phosphate content higher than that of the feed phosphate rock is recovered. The flotation operation is a froth flotation one carried out in the presence of a cationic amine flotation agent. Additional reagents employed in the flotation operation are caustic soda and kerosene. In one embodiment, the various steps of which are illustrated in the flow chart of Fig. I, deslimed phosphate rock is wet ground in a rod mill to pass through a 28 mesh, or preferably 35 mesh, screen. The ground rock is classified to remove the - 150 mesh fraction. The remaining - 28 to +150 major fraction is subjected to amine-flotation for the separation of siliceous materials which may be discarded as tailings or waste. The resulting concentrate having an increased phosphate content is recovered as product. The - 150 mesh ground fraction is thickened, filtered and subjected to chemical treatment such as by reaction with sulphuric or phosphoric acid to yield a phosphate fertilizer material. In another embodiment, Fig. 2, (not shown), phosphate pebble is treated and the - 150 mesh fraction is either acidulated to yield fertilizer material or pelletized to yield a phosphorous furnace burden. In a further embodiment, Fig. 3 (not shown), in which also phosphate pebble is treated, a -14 mesh fraction is passed through a 35 mesh screen. The -14 +35 mesh fraction is subjected to amine flotation. The -35 mesh fraction is passed through a 150 mesh screen. The -35 +150 mesh fraction is subjected to amine flotation and the -150 mesh fraction is filtered and recovered as furnace burden after pelletization or as fertilizer material after drying or acidulation. The -150 mesh fraction in any of the above embodiments may be further segregated into higher -mesh fractions and each fraction subjected to amine flotation. Quantitative examples are given.