Song S., Lopez-Valdivieso A., Ojeda-Escamilla M. C.
Instituto de Metalurgia, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona 550, Lomas 2a Sección, C.P. 78210, San Luis Potosí, Son Luis Potosí, Mexico
J Colloid Interface Sci. 2001 May 1;237(1):70-75. doi: 10.1006/jcis.2001.7422.
The adsorption of ethyl and amyl xanthate ions on galena and sphalerite fines has been studied using electrophoretic light-scattering (ELS) measurements. It was performed on galena and sphalerite (<2&mgr;m) in aqueous solution at different potassium ethyl xanthate (PEX) and potassium amyl xanthate (PAX) concentrations. It has been observed that the presence of PEX or PAX caused the isoelectric points (IEP) of galena and sphalerite fines to shift and the electrophoretic mobility to reverse in sign, indicating that the xanthate ions chemisorbed on galena and sphalerite surfaces. This adsorption markedly broadened the electrophoretic mobility distribution of the mineral fines, suggesting that the populations of the particles have quite different adsorption densities of xanthate ions, and therefore the particle hydrophobicity was different. This phenomenon might be attributable to the effect of the hemimicelle adsorption of the xanthate ions on the minerals, the nonuniform distribution of active sites and their degree of activity, the effect of particle size and shape, etc. The nonuniform adsorption has been found to increase with increasing PEX or PAX concentration, reaching a maximum at a medium concentration followed by a decline. Also, experimental results have demonstrated that the nonuniform adsorption of the xanthate ions is much stronger on sphalerite than on galena, which may explain why sphalerite has a worse flotation response than galena when alkyl xanthates are used as collectors in flotation systems. Copyright 2001 Academic Press.
采用电泳光散射（ELS）测量法研究了乙基黄药离子和戊基黄药离子在方铅矿和闪锌矿细粒上的吸附情况。实验在不同浓度的乙基黄原酸钾（PEX）和戊基黄原酸钾（PAX）的水溶液中对方铅矿和闪锌矿（<2μm）进行。观察到PEX或PAX的存在会导致方铅矿和闪锌矿细粒的等电点（IEP）发生移动，且电泳迁移率的符号发生反转，这表明黄药离子化学吸附在了方铅矿和闪锌矿表面。这种吸附显著拓宽了矿物细粒的电泳迁移率分布，表明颗粒群体具有相当不同的黄药离子吸附密度，因此颗粒的疏水性也不同。这种现象可能归因于黄药离子在矿物上的半胶束吸附作用、活性位点的不均匀分布及其活性程度、颗粒大小和形状的影响等。已发现不均匀吸附随PEX或PAX浓度的增加而增加，在中等浓度时达到最大值，随后下降。此外，实验结果表明，黄药离子在闪锌矿上的不均匀吸附比方铅矿上要强得多，这可能解释了在浮选体系中使用烷基黄药作为捕收剂时，闪锌矿的浮选响应比方铅矿差的原因。版权所有2001年学术出版社。
