Separation of particles of different surface energies through control of humidity

•Glass beads and substrates were treated to change their hydrophilic/hydrophobic balance.•Interfacial energy between particles and substrates was measured with impact tests.•Relative air humidity influences the interfacial energy of different surface types.•Relative air humidity was controlled to ac...

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Bibliographic Details
Published in:Minerals engineering 2021-01, Vol.160, p.106680, Article 106680
Main Authors: Moreno Baqueiro Sansao, Bernardo, Kellar, Jon J., Cross, William M., Romkes, Albert
Format: Article
Language:English
Subjects:
Adhesion forces
Physical separation
Relative humidity
Sustainability
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Summary:•Glass beads and substrates were treated to change their hydrophilic/hydrophobic balance.•Interfacial energy between particles and substrates was measured with impact tests.•Relative air humidity influences the interfacial energy of different surface types.•Relative air humidity was controlled to achieve separation of different particles.•Higher recovery of hydrophilic particles was achieved at RH levels between 50% and 55%. Many of the methods to classify and concentrate minerals and the subsequent extraction of metals takes place in water-based environments (aqueous solutions). Sustainable processing through the reduction of water consumption will become a key factor to make mining operations viable in the long term. In humid environments, capillary condensation of water can occur between the particle and substrate. The objective herein is to identify separation windows in which control of relative air humidity (RH) yields different substrate adhesion for hydrophilic and hydrophobic particles of different values of interfacial energy. Plasma cleaned glass beads, and trichloro(octadecyl)silane (TCOD) treated beads were poured on a plasma cleaned glass disk and an impact caused the detachment of particles. Impact tests performed under a range of RH showed that separation of plasma cleaned and TCOD treated particles can be achieved in 80% of the tests at humidity levels between 45% and 55%. The recovery of plasma cleaned particles was five times greater than TCOD treated particles at humidity levels between 50% and 55%.
ISSN:0892-6875
1872-9444
DOI:10.1016/j.mineng.2020.106680