Utilization of water glass as a dispersant to improve the separation performance of fluorite from barite slimes

Fluorite is easily affected by the slime coating of fine barite during the froth flotation separation. In this work, the water glass (WG) was utilized as a dispersant to improve the flotation separation performance between fluorite and barite slimes. The single minerals flotation results revealed that barite slimes could be selectively depressed by gelatinized starch (GS), while WG had little effect on the floatability of barite and fluorite using sodium oleate (NaOl) as a collector. The flotation results of artificially mixed minerals showed that the separation efficiency of fluorite from barite was significantly reduced when barite existed as slimes. However, the presence of WG could eliminate the negative effect of barite slimes on the flotation fluorite by using the reagents scheme of GS/NaOl. Zeta potential results indicated that the fluorite surface charge turned from positive to negative with the addition of WG, then the barite slimes coating was detached from the fluorite surface because of the electrostatic repulsion, allowing the cleaning fluorite surface to once again interact with NaOl. The DLVO calculation was also conducted to reveal the agglomerate and disperse of different particles in the flotation system of fluorite-barite slimes. • Fluorite flotation is easily affected by the barite slimes because of the hetero-coagulation. • WG makes the interaction between fluorite and barite slimes turn to electrostatic repulsion. • WG can act as a dispersant to strip barite slimes from fluorite surfaces. • WG can improve the flotation separation of fluorite from barite slimes.