Effect of water-in-oil and oil-in-water with Span 80 on coal flotation

Fine particles can be concentrated by flotation, and collector emulsification can improve flotation performance. However, the difference between the effect of oil-in-water and water-in-oil with the same emulsifier on flotation performance is little known. In this study, oil-in-water and water-in-oil emulsions with the same amount of Span 80 were prepared, and the flotation rate tests were compared. The particle size composition and the recovered water of concentrates were compared for kerosene, water-in-oil, and oil-in-water emulsions as collectors. The amount of kerosene adsorbed in the concentrates was analyzed by FTIR measurements. The results showed that oil-in-water with 0.5 g Span 80 had the largest concentrate yield and combustible recovery, while water-in-oil had had larger ash content, flotation rate constant, and recovered water. The reasons for these are that the differences in oil droplet composition of both emulsions lead to variations in coarse particle yields in the concentrates, further causing the change of recovery water which influences the variation of fine particles.