The effect of morphology of microparticles hydrophobized via esterification with alcohols on the specific surface energies distributions

Froth flotation is a well-established and efficient particle processing technique especially for the selective separation of mineral particles from unwanted material within sizes ranging from 10 µm to 200 µm. However, there are still some challenges and unexplored opportunities when it comes to the separation of ultrafine particles (< 10 µm). Within the German research foundation priority programme DFG-SPP 2045 “MehrDimPart” we aim to develop a novel multidimensional separation device for such ultrafine particles based on the particle parameters of wettability, morphology (shape or roughness) and size.
One important aspect of our investigations in this new flotation device lies in the modification of the materials surface, which is achieved via esterification with alcohols. To study the effect of the particle morphology/shape on the hydrophobization of glass microparticles, three differently shaped but same sieve sized fractions are used for applying esterification, among them spherical particles, elongated particles and particle fragments with varying shapes. The characterisation of the particle wettability is realised using the inverse gas chromatography method with additional information on the surface energy components distributions. The wettability is varied using alcohols with different chain length and the resulting surface energy components distributions are put in context with flotabilities of the particles in two flotability characterisation set-ups, i.e. tube microflotation and particle adhesion to hydrocarbons.