菱镁矿、白云石和方解石的浮选第一性原理研究

First-principles Study on Flotation of Magnesite,Dolomite and Calcite

为了更好地实现菱镁矿的浮选脱钙,基于密度泛函理论,通过Materials Studio(MS)软件模拟优化了菱镁矿、白云石和方解石的晶体结构、解理面、与常见浮选药剂的作用模型,计算了这3种矿物的能带结构、态密度、表面能、与常见浮选药剂的前线轨道以及相互作用能等参数,从微观角度研究了钙镁碳酸盐矿物的浮选机理。理论研究表明:菱镁矿、白云石和方解石均为绝缘体,六偏磷酸钠和水玻璃比油酸钠和十二胺更容易与这3种矿物结合;菱镁矿{104}、白云石{110}、方解石{104}是这3种矿物的完全解理面;这3种矿物的钙镁离子与油酸钠的羰基氧发生了化学吸附,与十二胺是物理吸附,N—H…O氢键起了重要作用;推测出十二胺对钙镁碳酸盐矿物浮选有一定的选择性。第一性原理的推测结果基本得到了纯矿物浮选试验的验证,因此,第一性原理对浮选分离药剂的选择和机理研究有一定的指导意义。

In order to better achieve the flotation decalcification of magnesite,the crystal structure,cleavage surface, minerals and the interaction model with common flotation reagents of magnesite,dolomite and calcite were simulated by Materials Studio(MS)software based on density functional theory.The energy band structure,density of states,surface energy of the three minerals,the frontier orbital ,as well as interaction energy between the minerals and common flotation reagents were calculated,which helps to study flotation mechanism of calcium-magnesium carbonate minerals from microscopic view.Theoretical studies indicated that magnesite,dolomite and calcite are all insulators.Sodium hexametaphosphate and water glass are interacted with these three minerals easily,compared with sodium oleate and dodecylamine.The complete cleavage surface of magnesite,dolomite and calcite are {104}plane,{110}plane and {104}plane respectively.The calcium ions and magnesium ions of these three minerals are chemically adsorbed with the carbonyl oxygen of sodium oleate,and the interaction with dodecylamine is the physical adsorption accompanied with the formation of N-H…O hydrogen bonds,indicating a selectivity interaction between dodecylamine and calcium magnesium carbonate minerals in flotation.The speculative results of the first principles are basically verified by the pure minerals flotation experiments,which indicates that the first-principles has guiding significance for the selection of flotation separation agents and its mechanism research.