The effect of the particle parameters of morphology and wettability in ultrafine particle flotation and froth fractionation

Froth flotation is well-established and efficient in the selective separation of valuable particles from unwanted material with sizes ranging from 10 µm to 200 µm. However, when it comes to the separation of ultrafine particles (< 10 µm) there are still some challenges, or rather opportunities. This research is part of the German research foundation priority programme DFG-SPP 2045 “MehrDimPart” aiming at developing a method for the separation of ultrafine particles based on multiple particle properties. Amongst such properties are wettability, morphology (shape or roughness) and size with applications not only in mineral processing but in general chemical engineering.
In order to study the effect of particle morphology on ultrafine particle flotation, three differently shaped fractions are used for testing, e.g. spherical particles, elongated particles and irregularly shaped particle fragments. Said particles are analysed for their wettability, which is varied by esterification using alcohols with differing alkyl chain lengths, through contact angle measurements. The particle size and shape properties are assessed by a combination of scanning electron microscopy, laser diffraction and optical microscopy.
Flotation tests are carried out using a novel flotation device that was designed especially for the flotation of ultrafine particles, combining advantages from machine-type froth flotation and column flotation.
Besides introducing a new concept of ultrafine particle flotation and froth fractionation, the study is contributing to the common understanding of flotation and the impact of different complex particle properties.