Selective flotation separation of fluorite and barite with carboxylated chitosan as depressant

Abstract

Fluorite and barite share similar physicochemical properties, making them challenging to separate efficiently using flotation. To address this problem, sodium oleate (NaOL) was used as a collector to study the separation effect of carboxylated chitosan (CCS) as a depressant for fluorite and barite. Infrared Spectroscopy (FTIR) test, X-ray photoelectron spectroscopy (XPS), Zeta potential test, contact angle test and adsorption test were investigate the selective depression mechanism of CCS. The test results showed that CCS, acting as the depressant, effectively depressed fluorite and separated fluorite and barite. According to mechanistic analysis, CCS developed stable chemisorption by bonding the carboxyl group (–COOH) in its molecule and the calcium sites of fluorite. In contrast, CCS adsorption on barite was a hydrogen bonding interaction, making CCS easily fall off the barite surface. As a result, NaOL can be stably adsorbed on the barite surface, whereas CCS present on the fluorite surface consumes a high number of Ca sites and reduces Ca sites available for NaOL adsorption, resulting in distinct hydrophobicity and floatability differences between fluorite and barite. Consequently, barite and fluorite were successfully separated.