Flotation of lignite pretreated by sorbitan monooleate

In this study, sorbitan monooleate was used to pretreat lignite prior to flotation tests. First, the lignite sample and water were mixed with 0%, 0.5%, 1%, 1.5% and 2% (on the basis of the weight of the coal) of sorbitan monooleate to produce five types of flotation slurries. FTIR, XPS and SEM were used to analyze the surface properties of the lignite sample. The flotation tests were used to indicate the improvements in flotation of lignite after the sorbitan monooleate pre-treatment. FTIR and XPS results showed that there are many oxygenated functional groups in lignite such as carboxyl group and hydroxyl groups. Furthermore, SEM results showed that there are many holes on the lignite surface. These holes will be filled with water in the flotation pulp. The flotation results indicated that sorbitan monooleate can improve the lignite flotation at low concentrations of sorbitan monooleate. However, the flotation behavior of lignite deteriorated at higher concentrations of sorbitan monooleate.