Formation of surface protective coatings on arsenopyrite using Al-catecholate complex and its mode of inhibition of arsenopyrite oxidation
Formation of surface protective coatings on arsenopyrite using Al-catecholate complex and its mode of inhibition of arsenopyrite oxidation
复制标题
儿茶酚铝配合物在毒砂表面形成保护层及其抑制毒砂氧化的方式
DOI：
10.1051/matecconf/201926806015
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发表时间：
2019
影响因子：
--
通讯作者：
Hiroyoshi Naoki
中科院分区：
文献类型：
--
作者：
Park Ilhwan;Tabelin Carlito;Inano Hiroyuki;Seno Kensuke;Higuchi Kazuki;Ito Mayumi;Hiroyoshi Naoki
毒砂是自然界中最常见的含砷硫化物矿物。当暴露在大气条件下时，它很容易被氧化，并通过采矿、选矿、提取冶金和地下空间开发等人为活动向环境中释放有毒的砷(As)。载体微胶囊(CME)是一种利用金属有机络合物在硫化物矿物表面选择性地形成保护膜的技术。在这项研究中，研究了铝儿茶酸盐络合物(即铝基CME)对毒砂氧化的抑制作用。铝(III)和邻苯二酚在不同pH条件下形成三种络合物，其中[Al(CAT)]+对毒砂氧化的抑制作用最强。其抑制效果随着[Al(CAT)]+浓度的增加而提高，这主要是由于在较高浓度下形成了更广泛的表面保护层。用扫描电子显微镜、X射线能谱和X射线光电子能谱对浸出渣进行了表面表征，结果表明，化学机械浸出处理后的毒砂表面覆盖了贝叶石(γ-Al(OH)3)。电化学研究结果表明，表面保护膜对毒砂氧化的阳极和阴极半电池反应均有抑制作用。
Arsenopyrite is the most common arsenic-bearing sulfide mineral in nature. It is readily oxidized and releases toxic arsenic (As) into the environment when exposed to atmospheric conditions via anthropogenic activities like mining, mineral processing, extractive metallurgy, and underground space developments. Carrier-microencapsulation (CME) is a technique that uses metal(loid)-organic complexes to selectively form protective coatings on the surfaces of sulfide minerals. In this study, CME using Al-catecholate complexes (i.e., Al-based CME) was investigated to suppress the oxidation of arsenopyrite. Aluminum(III) and catechol form three complex species depending on the pH and among them, [Al(cat)]+was the most effective in suppressing arsenopyrite oxidation. Its suppressive effect was improved as [Al(cat)]+concentration increased due most likely to the formation of a more extensive surface protective coating at higher concentrations. Surface characterization of leaching residues using SEM-EDX and XPS indicates that CME-treated arsenopyrite was covered with bayerite (γ-Al(OH)3). The results of electrochemical studies showed that the surface protective coatings suppressed both anodic and cathodic half-cell reactions of arsenopyrite oxidation.