A novel surfactant styryl phosphonate mono-iso-octyl ester with improved adsorption capacity and hydrophobicity for cassiterite flotation

Abstract

In this paper, a novel surfactant styryl phosphonate mono-iso-octyl ester (SPE108) was introduced as a collector for the flotation of cassiterite for the first time. Structure-reactivity relationship of SPE108 was predicted by density functional theory (DFT) calculation, which indicated that the reactive sites of SPE108 mainly located on the PO and OH groups. Meanwhile, DFT calculations also elucidated that SPE108 possess stronger electron-donating ability to minerals than traditional collectors styrene phosphonic acid (SPA) and benzohydroxamic acid (BHA). The micro-flotation tests showed that SPE108 exhibited better collecting ability in the flotation of cassiterite compared with SPA and BHA. Adsorption tests inferred that SPE108 could adsorb onto cassiterite surface more easily than SPA and BHA. Surface tension and contact angle measurements indicated that the hydrophobization intensity of these collectors toward cassiterite was in the order as SPE108 > SPA > BHA. FTIR and XPS analyses indicated that SPE108 interacted with cassiterite mainly through the breakage of POH bond with the formation of POSn bond. Finally, the bonding model of SPE108 with cassiterite was proposed.