Abstract:Solution chemistry and ？otation of cassiterite in the presence of alkyl hydroxamic acid collector were investigated. Results show that the alkyl hydroxamic acid is able to float fine cassiterite very well at relatively alkaline conditions, and the pH range of better flotability broadens with the increase of chain length of the collector. Moreover, the metal cations influence the flotation mostly depending on the pH of the medium and to some extent on the concentration of metal cations. Theoretical calculation on the group electronegativity indicates that the alkyl chain length of about seven is of great superiority in the synthetization of hydroxamic acid collector for cassiterite flotation. A co-adsorption between molecules and ions onto cassiterite surface is considered according to the lg c—pH diagram analysis. In terms of zeta potential and infrared spectra, the main interaction involves electric charge interaction, hydrogen bonding interaction and complexation, with the proposed formation of an O, O-five membered rings chelate compound .

Key words: fine cassiterite; flotation; alkyl hydroxamic acid; chelate