Dewatering of slimes from phosphate ores

Claim 1

A process for dewatering an aqueous slime waste product of phosphate ore mining and beneficiation, said aqueous slime waste product containing from about 1 to 5 percent by weight of solid phosphate ore particles having a particle size of less than 150 mesh and the balance is essentially water, which consists essentially of the steps of: adding to said aqueous slime waste product (a) from 3 to 15 percent by weight, based on the weight of said solid particles in said aqueous slime waste product, of a hydrophobic organic bridging liquid which is immiscible with water, said hydrophobic organic bridging liquid being selected from the group consisting of liquid hydrocarbons, nitrobenzene and chlorinated liquid hydrocarbons, and (b) from 0.1 to 5 percent by weight, based on the weight of said solid particles in said aqueous slime waste product, of a liquid conditioning agent effective to render the surfaces of said solid particles hydrophobic to form a twophase liquid system, said liquid conditioning agent having a balanced hydrophilic-hydrophobic molecular structure and capable of being adsorbed by said solid particles with the hydrophobic portion oriented outwardly, said liquid conditioning agent being selected from the group consisting of tall oil, xanthates, alcohols having a large hydrocarbon nucleus and primary amines having the formula RNH 2 wherein R is alkyl having 8 to 15 carbon atoms; agitating the two-phase liquid system to effect repeated collisions of said solid particles and thereby forming in said system a dispersion of agglomerates in said liquid system, said agglomerates consisting essentially of agglomerates of said solid particles wherein said solid particles are bound together by said hydrophobic organic bridging liquid; discontinuing said agitating; and separating said agglomerates from water, said hydrophobic organic liquid and said liquid conditioning agent.