Study On The Flotation Of Micro-grained Scheelite

China is abundant of scheelite resources which can be exploited potentially.Meanwhile most scheelite is fine dissemination particle size and brittle, and is intimately associated with gangue mineral,resulting in easy overgrinding and hard to be separated in flotation. As a result, loss of fine-grained scheelite is very serious.Aiming at the problem, the flotation behavior of fine-grained scheelitethe, calcite and fluorite in different reagent systems was studied in this paper. Fine particle scheelite was separated from micro-grained calcite and fluorite with mixed inhibitor.Mechanism of reagents and collectors and mineral was disscussed by calculation of solution chemistry, Zeta potential measurements,turbidity test and IR spectroscopy and study of interactions between particles.The collection ability of anionic collectors and amine cationic collectors on fine-grained scheelite, calcite and fluorite was relatively strong,while the selectivity was weak,as a result,fine scheelite was difficult to recovered. There is no remarkable selective inhibiting ability of single depressant on the three kinds of micro fine minerals.Based on synergistic effect theory,a new composite depressor was developed,which composed by oxalate and water glass.The fine-grained fluorite and calcite were inhibited strongly by composite depressor in the neutral and weak alkaline condition, while the fine scheelite were inhibited weakly.Results of artificial mixed minerals showed that, the combined depressant of oxalic acid and water glass has good selectivity on the separation of fine-grained scheelite from calcite and fluorite.In the scheelite floatation system, the effective component of water glass and oxalic acid was activated silicic acid colloids and C2O42-respectively. While oxalic acid combined with water glass,on the one hand, the generation and aggregation of silicic acid moleculesare were strengthened and more fine silicic acid particles formed, on the other hand,more C2O42- were dissociated from oxalic acid. Synergistic effect happened between water glass and oxalic acid, and the inhibiting ability on minerals was strengthened.Fine-grained scheelite, fluorite and calcite formed agglomeration in the sodium oleate aqueous, while dispersed in the water glass and oxalic acid aqueous.In the neutral and weak alkaline condition, under the combined action of mixed depressants and sodium oleate, fine scheelite particles formed stronger agglomeration;fine calcite particles and fluorite particles dispersed; high potential barrier existed in fine scheelite particles and fluorite, as well as in fine scheelite particls and calcite, which resulted in dispersion condition.Water glass, oxalic acid and sodium oleate respectively adsorbed on the surface of minerals, the latter two were mainly chemical adsorption, and adsorption was strengthened when the first two mixed. In the neutral condition, under the combined action of mixed depressants and sodium oleate, the chemical adsorption happened on the surface of scheelite acting with sodium oleate and on the surface of calcite and fluorite acting with mixed depressant respectively.