Bi-functional hydrogen and coordination bonding surfactant: A novel and promising collector for improving the separation of calcium minerals
Bi-functional hydrogen and coordination bonding surfactant: A novel and promising collector for improving the separation of calcium minerals
复制标题
双功能氢和配位键表面活性剂：一种新型且有前途的捕收剂，用于改善钙矿物的分离
DOI：
10.1016/j.jcis.2020.10.059
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发表时间：
2020
影响因子：
9.9
通讯作者：
Gao Zhiyong
中科院分区：
文献类型：
--
作者：
Zhang Wanjia;Feng Zhitao;Yang Yuhang;Sun Wei;Pooley Stephen;Cao Jian;Gao Zhiyong
单功能螯合捕收剂在矿物浮选中表现出有限的选择性。特别是，钙矿物的选择性分离提出了一个重大的挑战，因为单官能螯合捕收剂，如脂肪酸，通过与相同的金属阳离子（Ca2+）配位而不可阻挡地吸附在矿物表面上。因此，迫切需要开发新型功能性捕收剂来分离钙矿物，并需要了解潜在的化学选择性。考虑到阴离子与萤石、方解石和白钨矿表面氢键结合能力的差异，在捕收剂分子中引入额外的氢键官能团是提高选择性的一种新策略。本研究开发了一种氢键和配位（双功能）捕收剂2-氰基-N-乙基氨基甲酰基乙酰胺（CEA），它能与钙矿物表面的钙离子（通过羰基）形成配位键，与阴离子（通过氨基）形成氢键。浮选试验结果表明，在pH值为7时，CEA能选择性地将白钨矿中的萤石和方解石分离。CEA的选择性主要取决于其电性质和阴离子与三种钙矿物的氢键结合能力。带负电荷的白钨矿表面不利于与CEA的配位键合，而带正电荷的萤石和方解石表面有利于与CEA的配位键合。此外，萤石（F-）和方解石（CO32-）与CEA中脲基的氢键结合能力高于白钨矿（WO42-），这也起着至关重要的作用。这种基于配位和氢键的表面活性剂设计方案在开发用于其他氧化矿物分离的尾制捕收剂/抑制剂方面具有很大的潜力。
Mono-functional chelating collectors exhibit limited selectivity in the flotation of minerals. In particular, the selective separation of calcium minerals presents a significant challenge because mono-functional chelating collectors, such as fatty acid, indistinguishably adsorb onto mineral surfaces by coordinating with the same metal cation (Ca2+). Thus, there is an urgent need to develop new-mode-functional collectors to separate calcium minerals and a need to understand the underlying chemoselectivity. Given the difference of the hydrogen bonding ability of anions with fluorite, calcite and scheelite surfaces, the introduction of additional hydrogen bonding functional groups into collector molecules is a novel strategy to improve selectivity. In this study, a hydrogen and coordination bonding (bi-functional) collector, 2-cyano-N-ethylcarbamoyl acetamide (CEA) was developed, which could form coordination bonds with the Ca2+ions (by carbonyl groups) and hydrogen bonds with the anions (by amino groups) on calcium mineral surfaces. The results of flotation tests showed that CEA can selectively separate fluorite and calcite from scheelite at pH 7. The promising selectivity of CEA lies in both the electrical properties and the anions’ hydrogen bonding ability with the three calcium minerals. The negatively charged scheelite surfaces are not conducive to coordination bonding with CEA while the positively charged fluorite and calcite surfaces are. Besides, the hydrogen bonding ability of fluorite (F−) and calcite (CO32−) with carbamido in CEA is higher than that of scheelite (WO42−), and this also plays an essential role. This coordination and hydrogen bonding based surfactant design protocol has a great potential in the development of tail-made collectors/depressants for the separation of other oxidized minerals.