Study On The Effect Of Combined Inhibitors Of Zn²⁺?Fe³⁺ And Sodium Silicate On The Flotation Separation Of Fluorite And Calcite

Fluorite is the main raw material for producing anhydrous hydrofluoric acid,aluminum fluoride and many other important fluorides.It is a kind of non-metallic mineral resource with strategic significance.Flotation is the most commonly used method to enrich fluorite.Because both fluorite and calcite contain Ca²⁺active sites on their surfaces,their floatiability is similar,and they have good hydrophobicity in the presence of fatty acid collector,and there is mutual conversion on the mineral surface,it is difficult to achieve effective separation of the two minerals by sodium silicate.Therefore,this paper takes fluorite and calcite as the research objects and introduces two metal ions,Zn²⁺and Fe³⁺,combined with sodium silicate as inhibitors to discuss the effect and its mechanism of combined inhibitors on flotation separation of fluorite and calcite.The main research contents and conclusions of this paper are as follows:When sodium silicate is used as inhibitor,two minerals are well inhibited.The inhibition effect of sodium silicate on fluorite is slightly greater than that of calcite,and the effective separation of fluorite and calcite cannot be achieved by the use of sodium silicate.When Zn²⁺and sodium silicate group are used as inhibitors,the flotation recovery of fluorite is much higher than that of calcite in the two combinations of adding Zn²⁺before sodium silicate and pre-mixing of Zn²⁺and sodium silicate under the best conditions.The inhibition effect of Zn²⁺combined with sodium silicate on fluorite is not obvious,but the inhibition effect on calcite is stronger than that of sodium silicate alone,indicating that the combined Zn²⁺combined with sodium silicate inhibitor is better than that of sodium silicate in selective separation of fluorite and calcite.When Fe³⁺and sodium silicate group are used as inhibitors,the flotation recovery of fluorite is much higher than that of calcite in the two combinations of adding Fe³⁺before sodium silicate and pre-mixing of Fe³⁺and sodium silicate under the best conditions.Compared with sodium silicate,the inhibition effect of Fe³⁺combined with sodium silicate can selectively inhibit calcite,but have little effect on fluorite flotation,thus achieving effective separation of fluorite and calcite.The flotation test results of artificial mixed ore show that,when Zn²⁺,Fe³⁺and sodium silicate are respectively used as cooperative inhibitors,the four combination inhibitors have certain selectivity for flotation separation of fluorite and calcite mixed ore,and the Zn²⁺-sodium silicate combination inhibitor has the best flotation separation effect.The results of adsorption measurement,Zeta potential measurement,chemical calculation of flotation solution and XPS analysis show that,sodium silicate generates calcium silicate by combining with the active site Ca²⁺ion on the surface of calcium-containing minerals,which hinders the adsorption of sodium oleate on its surface,and then inhibits the flotation of calcium-containing minerals.With the combination of Zn²⁺,Fe³⁺and sodium silicate inhibitors,a large number of active components such as Zn²⁺-sodium silicate polymer,Fe³⁺-sodium silicate polymer,hydroxyl Fe³⁺and Si(OH)₄ can be formed in the solution,while the content of active components such as SiO(OH)₃^-and SiO₂(OH)₂^2-which inhibit fluorite flotation can be reduced.Zn²⁺-sodium silicate polymer,Fe³⁺-sodium silicate polymer,hydroxyl Fe³⁺and Si(OH)₄ have strong adsorption on the surface of calcite,which hinders the further adsorption of sodium oleate on the surface of calcite.Therefore,compared with sodium silicate,the inhibition effect of Zn²⁺,Fe³⁺and sodium silicate combined inhibitors on calcite flotation is enhanced,and the inhibition effect on fluorite flotation is weakened,and the flotation separation of fluorite and calcite is achieved.