羧化壳聚糖对镍黄铁矿/蛇纹石浮选体系的作用机理

摘要

The aggregation/dispersion effect of carboxylation chitosan on flotation system of serpen-tine and pentlandite and its mechanism were studied by flotation experiments, sedimentation tests, zeta potential, and calculations of DLVO theory.The results show that the serpentine particles coat on the pentlandite surface by hetero-aggregation.It reduces the hydrophobicity of pentlandite sur-face and decreases the flotation recovery of pentlandite.The hetero-aggregation between pentland-ite and the particles of serpentine can be eliminated by adding carboxylation chitosan, which in-creases the pentlandite recovery in pentlandite/serpentine system.The results show that the effect of carboxylation chitosan on the particles mixture dispersion will be stronger than that of carboxym-ethyl cellulose at pH 8.5.The positively charged serpentine is absorbed on the negatively charged pentlandite surface by electrostatic interaction, and influences on flotation of pentlandite.The addi-tion of carboxylation chitosan significantly changes the surface electrical properties of serpentine, and makes electrostatic attraction convert into electrostatic repulsion between pentlandite and the particles of serpentine, thereby improving the flotation recovery of pentlandite.%通过矿物浮选试验、沉降试验、动电位和DLVO理论计算,考察了羧化壳聚糖在蛇纹石/镍黄铁矿浮选体系中的聚集/分散作用,研究了羧化壳聚糖对颗粒间的分散作用机理.研究结果表明:蛇纹石颗粒通过异相凝聚罩盖于镍黄铁矿表面上,降低镍黄铁矿表面疏水性能,影响其可浮性;羧化壳聚糖消除了镍黄铁矿与蛇纹石颗粒间异相凝聚,提高镍黄铁矿/蛇纹石体系中镍黄铁矿的浮选回收率.在pH为8.5时,羧化壳聚糖对镍黄铁矿/蛇纹石颗粒间的分散作用显著,并且强于羧甲基纤维素;荷正电的蛇纹石通过静电作用吸附在荷负电镍黄铁矿表面影响其浮选,羧化壳聚糖加入显著改变蛇纹石表面电性,使镍黄铁矿与蛇纹石颗粒间由静电吸引变为静电排斥,表现为异相分散,从而提高镍黄铁矿的浮选回收率.