Ca(Ⅱ)-XG配合物选择性絮凝赤铁矿与石英的作用机理

Mechanism of Selective Flocculation of Hematite and Quartz with Ca(Ⅱ)-XG Complexes

Ca(Ⅱ)为凝聚剂、黄原胶为絮凝剂的赤铁矿与石英选择性絮凝分选体系中,Ca(Ⅱ)不可避免会与黄原胶形成配合物(Ca(Ⅱ)-XG),研究Ca(Ⅱ)-XG选择性絮凝分离赤铁矿与石英对赤铁矿石选择性絮凝提质具有重要意义。通过矿物沉降试验并结合显微镜观察、Zeta电位、溶液化学计算与红外光谱分析对Ca(Ⅱ)-XG选择性絮凝分离赤铁矿与石英行为规律及作用机理进行了研究。矿物絮凝沉降试验结果表明:以黄原胶为絮凝剂,赤铁矿与石英沉降差异随矿浆p H值增加逐渐减弱,Ca(Ⅱ)对赤铁矿与石英凝聚沉降差异不大;黄原胶与CaCl2质量比为1∶9时生成的配合物对赤铁矿和石英表现出较强的选择性絮凝作用,pH值为2时两者沉降率差异最大,分别为85%和30%。显微镜观察结果证实,配合物絮凝赤铁矿颗粒可形成较大絮体,石英颗粒基本不发生团聚。Zeta电位、溶液化学计算与红外光谱分析结果表明:配合物与赤铁矿、石英间均存在静电引力与化学吸附作用,且配合物与赤铁矿间的化学作用较配合物与石英的作用强。基于试验结果与分析,绘制了配合物选择性絮凝赤铁矿与石英模型图。因此,通过调整配合物中黄原胶与Ca(Ⅱ)配比及矿浆pH值,可实现赤铁矿和石英矿物颗粒选择性絮凝分离,为赤铁矿选择性絮凝分选提供新的策略和理论指导。

Ca(Ⅱ)being the coagulant and xanthan gum being the flocculant were used in the system of selective flocculation separation of hematite from quartz,but Ca(Ⅱ)-XG complex was formed by calcium ion and xanthan gum inevitably.The study,Ca(Ⅱ)-XG selective flocculation separation hematite from quartz,is significance for the hematite ore quality improvement.Flocculation settling tests combined with microscopic observation,Zeta potential,solution chemical calculation,and infrared spectra analysis were used to study the behavior and mechanism of Ca(Ⅱ)-XG selective flocculation separation hematite from quartz.The results of flocculation settling tests showed that the gap in settling between hematite and quartz decreased with increasing of the pH value of pulp,and the effect of Ca(Ⅱ)on the gap in settling between hematite and quartz was insignificancy.Furthermore,the complexes made by combining xanthan gum with calcium chloride at a mass ratio of 1∶9 demonstrated strong selective flocculation of hematite and quartz.At pH=2,the gap in settling rates between the two minrals was the greatest,reaching 85%and 30%,respectively.The results of microscopic observation indicated that quartz particles essentially nonflocculation whereas the hematite particles flocculated by complexes tend to form larger flocs.Zeta potential,solution chemical calculation and infrared spectra analysis showed that there was chemisorption and the electrostatic gravitational force between the complexes and hematite and quartz,in which the chemical interaction with hematite being stronger than the interaction with quartz.Based on the experimental data and analytical,a model schematic for the complexes′selective flocculation of hematite with quartz was created.So,the selective flocculation separation of hematite from quartz can be made by changing the ratio of xanthan gum and Ca(Ⅱ)in Ca(Ⅱ)-XG complex and the pH value of pulp,which could provide new strategy and theoretical basis for selective flocculation separation of hematite ore.