Dissolution of wollastonite and its flotation and surface interactions with tallow-1,3-diaminopropane (duomeen T)

Abstract

Wollastonite finds an important place among industrial minerals due to its high chemical and thermal resistance and also as a substitute for asbestos. With the depletion of high-grade ores and increased demand, it becomes inevitable to process low-grade ores. Flotation can be employed effectively for processing these ores. Flotation behavior of wollastonite was studied using tallow-1,3-diaminopropane as collector in the Hallimond micro-flotation cell. The flotation recoveries obtained were correlated with contact angle measurements. Dissolution studies clearly bring out the incongruent dissolution of wollastonite, resulting in a silica rich layer on the surface of the mineral. The release rates of calcium and silicon decrease with the particle size. Maximum flotation obtained at 1 · 105 M diamine concentration. DRIFT studies indicate that the intensity of alkyl chain bands increases with increasing diamine concentration, thus corroborating increased presence of diamine on wollastonite resulting in maximum contact angle and flotation recovery. Surface free energy values of wollastonite were determined by different approaches using contact angle data of well-defined components of polar and apolar liquids. An attempt has been made to correlate between the flotation response and the surface free energy values of wollastonite in the presence diamine.