Revealing the role of dithiocarbamate ester group in hydroxamic acid flotation of cassiterite with in situ AFM, DFT and XPS
Revealing the role of dithiocarbamate ester group in hydroxamic acid flotation of cassiterite with in situ AFM, DFT and XPS
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DOI：
10.1016/j.apsusc.2022.154521
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发表时间：
2022-08
影响因子：
6.7
通讯作者：
Jing Qi;Sheng Liu;Yan Dong;Guangyi Liu
中科院分区：
文献类型：
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作者：
Jing Qi;Sheng Liu;Yan Dong;Guangyi Liu
为探讨二硫代氨基甲酸酯在锡石羟肟酸浮选中的作用，设计了一种特殊表面活性剂-[（3-羟氨基）-丙氧基]- n -辛基二硫代氨基甲酸酯（DTCHA）。以二硫化碳、辛胺、丙烯酸甲酯和羟胺为原料，采用“一锅法”简便地合成了DTCHA。在这种情况下，原子力显微镜（afm）清楚地捕获了自组装在锡石上的DTCHA聚集体，这显著提高了其表面疏水性。DFT（密度泛函理论）计算预测二硫代氨基甲酸酯基具有给电子和静电相互作用的能力，可能是DTCHA的第二反应中心。XPS （x射线光电子能谱）和FTIR（傅里叶变换红外光谱）可以推断DTCHA在水溶液中与Sn（Ⅳ）离子反应时，二硫代氨基甲酸盐与Sn之间存在成键作用，而与锡石表面Sn（Ⅳ）原子的成键作用尚未得到结论。二硫代氨基甲酸酯的加入几乎没有削弱DTCHA对方解石的浮选选择性，但对锡石的疏水性却明显增强。因此，DTCHA对锡石和方解石的浮选分离具有较强的捕收力和选择性。揭示DTCHA的二硫代氨基甲酸酯作为疏水性基团在锡石浮选中的作用，为设计氧化矿物捕收剂提供了新的策略。也就是说，除了烷基基团外，硫化物矿物的一些亲矿巯基可以作为氧化矿物浮选的首选疏水基团。
To explore the role of dithiocarbamate ester group in hydroxamic acid flotation of cassiterite, a special surfactantS-[(3-hydroxyamino)-propoxy]-N-octyl dithiocarbamate (DTCHA) was designed. With carbon disulfide, octylamine, methyl acrylate and hydroxylamine as raw materials, DTCHA was facilely synthesized by a “one-pot” approach.In situAFM (atomic force microscopy) clearly captured DTCHA aggregates self-assembled on cassiterite, which significantly increased its surface hydrophobicity. DFT (density functional theory) calculation predicted that the dithiocarbamate ester group possessed the ability of electron-donating and electrostatic interaction, and might be the second reactive center of DTCHA. XPS (X-ray photoelectron spectroscopy) and FTIR (Fourier transform infrared spectra) allowed to infer a bonding interaction between DTCHA’s dithiocarbamate with Sn during DTCHA reaction with Sn(Ⅳ) ions in aqueous solutions, while that with surface Sn(Ⅳ) atoms of cassiterite wasn’t concluded. The attendance of the dithiocarbamate hardly weakened the flotation selectivity of DTCHA against calcite, while its hydrophobization towards cassiterite became much stronger. Thus, DTCHA possessed the stronger collecting power and better selectivity for flotation separation of cassiterite from calcite than octyl hydroxamic acid. Revealing the role of DTCHA’s dithiocarbamate as a hydrophobic group in cassiterite flotation offered a new strategy for designing oxide minerals collector. That was, besides alkyl groups, some sulfhydryl minerophilic groups for sulfide minerals could be designed as preferable hydrophobic groups for oxide minerals flotation.