铁离子和亚铁离子对滑石浮选的影响及作用机理

Influence and mechanism of ferric and ferrous ions on flotation of talc

通过对滑石纯矿物的浮选实验和动电位的测试,结合水解金属离子溶液化学计算,研究铁离子和亚铁离子对滑石浮选的影响,并探讨其吸附机理。实验结果表明:在没有金属氢氧化物沉淀时溶液中存在的水解金属离子在滑石表面的吸附对滑石的非极性表面和极性端面产生不同的影响,使滑石ξ电位的符号由负变正,但滑石的天然可浮性不变;在金属氢氧化物沉淀的pH值与它的零电点之间,滑石的非极性表面变得亲水,导致滑石的浮选受到抑制。其疏水性的改变是由于在氢氧化物沉淀的pH值与它的零电点之间,在滑石的极性和非极性表面产生了氢氧化物沉淀的多相凝聚。

Flotation of talc and the mechanism of adsorption of ferric and ferrous ions on surface of talc were investigated through the flotation experiments of pure talc, measurements of zeta potentials and the calculation of solution chemistry. The results show that without the precipitate of the metal hydroxide on the nonpolar （face） and polar （edge）surfaces of talc are affected differently by the adsorption of the hydrolyzed metal cations in the aqueous solution. The natural hydrophobicity of talc is unaltered by the presence of the hydroxyl compound of Fe（Ⅲ） and Fe（Ⅱ）, whereas the zeta potential of talc changes sign from negative to positive through the adsorption of these complex species onto the polar surfaces. Upon the precipitation of the cations of metal hydroxides on the nonpolar surfaces are rendered hydrophilic and lead to the depression of talc between the precipitation pH and the point-of-zero charge of the metal hydroxides, probably due to heterocoagulation of the metal precipitate on both the nonpolar and polar surfaces.