Abstract

Collecting properties of a new amphoteric collector (α-benzol amino benzyl phosphoric acid, BABP) for calcium-containing minerals were studied by micro-flotation tests and measuring mineral electrokinetic potentials and collector adsorption. The collector adsorption was confirmed by infrared spectroscopic characterization and adsorption determination. The results were interpreted based on solution chemistry calculations. BABP collector exhibited selectivity for fluorite and calcite in a weak alkaline medium. The increasing collecting power of BABP is apatite≪scheelite<calcite∼fluorite. Fluorite and calcite were positively charged while apatite and scheelite were negatively charged over a wide pH range. The collector addition caused a significant change in the zeta potential of the minerals, which correlated well with the floatability of the minerals. The monovalent anionic species were identified as the active components of amino phosphoric acids for collecting calcium-containing minerals. The chemisorption appeared to be the driving force for collector adsorption on fluorite, calcite and scheelite, with the extend of adsorption being determined by the site density of calcium on the minerals. With BABP as a collector, the flotation separation of calcite from apatite and fluorite from scheelite can be accomplished by careful control of flotation pH.