Reagents used in the flotation of phosphate ores: a critical review

Phosphate rock needs processing to reduce the content of gangue minerals such as silicates, carbonates, and clays to meet the requirements of the phosphate industry. Froth flotation method has been an important part of the concentration process since the 1920s and today, more than half of the world's marketable phosphate is produced by froth flotation. The literature on the processing of phosphate rocks by flotation is critically reviewed. Commonly used collectors, depressants, auxiliary reagents, and their mixtures in the flotation of the phosphate ores were tabulated. The advantages and disadvantages of the reagent type and structure (e.g., ionic and nonionic) on flotation were criticized. Based on the literature it was concluded that using surfactant mixtures has certain advantages over single surfactant as synergistic effect between surfactant mixtures were observed at different experiments such as surface tension, contact angle, adsorption, and flotation. (C) 2003 Elsevier Science Ltd. All rights reserved.