Enhancing flotation separation of fine-grained cassiterite and calcite with cetylpyridine bromide as a dispersant

Calcite is a common gangue mineral in tin ore, which seriously affects the flotation of fine-grained cassiterite. The enhanced flotation separation of fine-grained cassiterite and calcite with cetylpyridine bromide (CPB) as a dispersant were investigated in the study. The CPB significantly improved the flotation separation efficiency of fine-grained cassiterite and calcite, and it exhibited an excellent dispersion effect and relieved the coating phenomenon of calcite particles on the surface of cassiterite particles. The CPB changed the surface potential of cassiterite from negative value to positive value when the pH was in the range of 3.4–11.5. However, regardless of treatment with CPB, the surface potential of calcite was positive when the pH was below 11.5. The O on the surface of cassiterite reacted with CPB, promoting the chemical adsorption of CPB on the surface of cassiterite. There was weak physical adsorption between CPB and calcite. The covering between cassiterite and calcite without CPB was mainly dependent on van der Waals interaction energy and electrostatic interaction energy. When CPB was in the presence, cassiterite and calcite were repelled by the hydrophobic interaction energy and electrostatic interaction energy.