Wang Jingyi, Xie Lei, Lu Qingye, Wang Xiaogang, Wang Jianmei, Zeng Hongbo
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2V4, Canada.
Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 2V4, Canada.
J Colloid Interface Sci. 2020 Jun 15;570:350-361. doi: 10.1016/j.jcis.2020.03.007. Epub 2020 Mar 6.
Molybdenite (MoS) has attracted great attention in the field of advanced materials. MoS is normally separated from other minerals by selective flotation, and chemical reagents (so-called depressants) are required to lower the surface hydrophobicity of MoS. Previous studies had controversial arguments on the adsorption of organic and inorganic depressants, i.e., carboxymethyl cellulose (CMC), Ca and Mg on the anisotropic MoS surfaces. Therefore, in this work, the interactions of these depressants on MoS basal and edge surfaces in alkaline solutions were investigated using electrochemical techniques. The MoS edge surface had higher electrochemical reactivity than the basal surface, and the electrochemical reactivity of both the surfaces reduced after treatment in CMC, Ca and Mg solutions, which suggested that the depressants adsorbed on both basal and edge surfaces. The cyclic voltammetry and scanning electrochemical microscopy results indicated that the coverage of adsorbed inorganic species, i.e., Ca(OH), CaCO and Mg(OH) particles, on MoS basal and edge surfaces was lower than that of CMC. The randomly distributed hydrophilic Ca(OH), CaCO and Mg(OH) particles on MoS basal surface reduced the possibility of bubble attachment, which was the main reason for the depressed MoS floatability reported in the literature.
辉钼矿（MoS）在先进材料领域引起了极大关注。辉钼矿通常通过选择性浮选与其他矿物分离，并且需要化学试剂（所谓的抑制剂）来降低辉钼矿的表面疏水性。先前的研究对于有机和无机抑制剂，即羧甲基纤维素（CMC）、钙和镁在各向异性辉钼矿表面的吸附存在争议。因此，在本工作中，使用电化学技术研究了这些抑制剂在碱性溶液中与辉钼矿基面和边缘表面的相互作用。辉钼矿边缘表面比基面具有更高的电化学反应活性，并且在CMC、钙和镁溶液中处理后，两个表面的电化学反应活性均降低，这表明抑制剂吸附在基面和边缘表面上。循环伏安法和扫描电化学显微镜结果表明，吸附在辉钼矿基面和边缘表面上的无机物种，即Ca(OH)、CaCO和Mg(OH)颗粒的覆盖度低于CMC。辉钼矿基面上随机分布的亲水性Ca(OH)、CaCO和Mg(OH)颗粒降低了气泡附着的可能性，这是文献中报道的辉钼矿可浮性降低的主要原因。
