菱镁矿石中碳酸盐矿物的溶解特性及对浮选影响的调控

Flotation is the most effective method for removing impurity from magnesite ore. The flotation separation of carbonate minerals including magnesite and dolomiteis influenced by their similar floatability.Due to the dissolution of magnesite and dolomite in water, their surface properties and floatability are inevitably changed. The difference of dissolving properties and components between magnesite and dolomite could extend the floatability difference between them. With the aid of Materials Studio simulation software,solid-liquid equilibrium properties of magnesite and dolomite and their solubility could be calculated and analyzed.The dissolved components of minerals in the process of flotation separation could be determined by the methods of solution chemistry, AAS, ICP, IOIO, and so on. According to the explicated effect of dissolving properties and components on floatability, the controlling measurements about magnesite ore flotation could be constructed, which could promote the effective separation of magnesite and dolomite. Based on the above study, the interaction mechanisms of minerasl and flotation reagents, dissolved components would be investigated by Gaussian，XPS, AFM, Zeta potential,IR and so on. The prospective results could enrich and complete the separation theory and practice of magnesite ore, and establish the foundation for improving utilization levels of magnesite resources.

菱镁矿石除杂的最有效手段是浮选，因其中的碳酸盐矿物菱镁矿和白云石可浮性相近而影响二者的浮选分离效果。菱镁矿和白云石均具有溶解特性，矿物溶解势必改变其表面性质及可浮性。菱镁矿和白云石的溶解特性及溶解组分不同使扩大二者可浮性差异成为可能。本项目利用Materials Studio模拟软件，计算分析菱镁矿和白云石的固液平衡特性及在介质中溶解度，结合原子吸收分光光度计、电感耦合等离子体质谱和负离子色谱等检测手段及溶液化学基本原理，确定浮选分离过程中矿物的溶解组分，明确矿物的溶解特性及溶解组分对其可浮性的影响，建立菱镁矿石浮选体系的调控机制，实现菱镁矿与白云石的有效分离；在此基础上，采用Gaussian软件计算及X射线光电子能谱、原子力显微镜、Zeta电位、红外光谱等检测分析手段，研究矿物与浮选药剂、溶解组分的作用机理。研究结果可丰富和完善菱镁矿石分选理论与实践，为提高菱镁矿资源利用水平奠定基础。

菱镁矿石中主要目的矿物菱镁矿和含钙脉石白云石均为碳酸盐矿物，二者可浮性相近，进行浮选分离难度较大。菱镁矿和白云石具有溶解特性，溶解后表面性质发生变化，研究二者的溶解特性及溶解、溶解组分对可浮性的影响有意义。.菱镁矿、白云石单矿物溶解试验结果表明，随着矿浆浓度、搅拌转速和搅拌时间的增大，溶出钙镁离子增多；随pH值增大，溶出钙镁离子降低；随六偏磷酸钠（6P）用量增多，溶出钙镁离子先降后增；随捕收剂LKD用量的增多，溶出钙镁离子先增后降；随着温度升高，溶出钙镁离子先增后降；在相同条件下，白云石的溶解能力大于菱镁矿；SEM-EDS结果表明，菱镁矿、白云石溶解后部分钙镁离子吸附到矿物表面；AFM结果表明，在相同条件下，白云石的溶解深度和宽度大于菱镁矿。.构建菱镁矿、白云石在电中性、酸性、中性、碱性条件下的溶剂化模型。结果表明，菱镁矿、白云石表面吸附H2O；H2O中H原子会跟菱镁矿、白云石表面暴露的 O形成氢键；菱镁矿、白云石表面在吸附H2O的同时有部分镁钙离子溶出，在酸性溶剂化模型的矿物表面钙镁离子基本都溶出。.研究菱镁矿和白云石溶解及Mg2+、Ca2+、Fe3+存在时矿物的浮选行为。菱镁矿、白云石在加酸溶解后可浮性均下降；在蒸馏水中溶解后浮选，菱镁矿的可浮性下降，白云石可浮性升高，当不含药剂时，菱镁矿和白云石的回收率差最大，分别由45.04%降至37.26%、68.40%升至71.60%。加Mg2+、Ca2+后，菱镁矿、白云石溶解后浮选的回收率比不溶解时低。添加Fe3+后，菱镁矿的回收率比不溶解时高、白云石的回收率比不溶解时低；溶解率较大时，菱镁矿的回收率高于白云石。随着Mg2+用量的增大，菱镁矿、白云石溶解后的回收率下降。随着Ca2+、Fe3+用量的增大，菱镁矿的回收率升高，白云石的回收率下降。人工混合矿试验表明， LKD体系下矿物溶解后浮选可提高菱镁矿除钙效果。.菱镁矿、白云石溶解后与LKD作用的红外光谱、SEM-EDS、Zeta和XPS分析结果表明，菱镁矿、白云石与LKD主要靠静电和氢键作用发生吸附。计算模拟结果表明，LKD在白云石表面的作用较强。