Fe(Ⅲ)-XG配合物选择性絮凝微细粒赤铁矿与石英及其机理研究

Fe(Ⅲ)-XG Complex Selective Flocculation of Fine-grained Hematite and Quartz and Its Mechanism

基于金属离子配位理论,将FeCl_(3)·6H_(2)O与黄原胶(XG)按一定比例混合制备Fe(Ⅲ)-XG配合物,用于改善微细粒赤铁矿难沉降、回收效果差的问题。采用沉降实验研究了不同条件下Fe(Ⅲ)-XG对微细粒赤铁矿和石英的选择性絮凝行为,结合动电位、红外光谱和显微镜分析,揭示Fe(Ⅲ)-XG对赤铁矿的絮凝作用机理。矿物絮凝沉降试验结果表明:以黄原胶和Fe(Ⅲ)为絮凝剂,无法实现赤铁矿与石英的选择性絮凝,而黄原胶与FeCl_(3)·6H_(2)O质量比为1︰9时生成的Fe(Ⅲ)-XG配位絮凝剂,对赤铁矿和石英表现出较强的选择性絮凝作用,pH值为6时两者沉降率差异最大,分别为91.50%和39.96%。显微镜观察结果证实,Fe(Ⅲ)-XG作用下,赤铁矿颗粒形成块状絮体,且絮体密实程度更大,而石英颗粒间未发生团聚作用,处于相对分散的状态。Zeta电位、溶液化学计算、吸附量实验与红外光谱分析结果表明:黄原胶主要通过羧酸基团的羰基C=O与Fe^(3+)发生配位作用形成Fe(Ⅲ)-XG配合物,Fe(Ⅲ)-XG在石英和赤铁矿表面吸附方式不同,因而在两种矿物表面吸附量不同。Fe(Ⅲ)-XG中的羟基氧和赤铁矿表面的铁元素发生化学键合特异性吸附在赤铁矿表面,而在石英表面只有微弱的氢键吸附。通过FeCl_(3)·6H_(2)O与黄原胶配位组装可显著提升微细粒赤铁矿选择性絮凝分离效果,为赤铁矿选择性絮凝分选提供新的策略和理论指导。

Based on the coordination theory of metal ions,Fe(Ⅲ)-XG complexes were prepared by mixing FeCl_(3)·6H_(2)O with xanthan gum(XG)in a certain proportion,which was used to improve the problems of difficulties in sedimentation and recycling.The selective flocculation behavior of Fe(Ⅲ)-XG on fine-grained hematite and quartz under different conditions was studied by sedimentation experiment.The mechanism of Fe(Ⅲ)-XG flocculation on hematite was revealed by potentiodynamic,infrared spectrum and microscope analysis.The results of mineral flocculation and sedimentation test show that the selective flocculation of hematite and quartz can not be realized with xanthan gum and Fe(Ⅲ)as flocculants.When the mass ratio of xanthan gum to FeCl_(3)·6H_(2)O was 1:9,the Fe(Ⅲ)-XG complex flocculant showed strong selective flocculation on hematite and quartz.When pH value was 6,the precipitation rates of the two flocculants were 91.50%and 39.96%,respectively.The microscopic observation results confirmed that under the action of Fe(Ⅲ)-XG,hematite particles formed massive floccule,and the massive floccule was more dense,while quartz particles did not agglomerate and were in a relatively dispersed state.The results of Zeta potential,solution chemistry calculation,adsorption capacity experiment and infrared spectrum analysis showed that xanthan gum formed Fe(Ⅲ)-XG complex mainly through the coordination between carbonyl C=O of carboxylic acid group and Fe^(3+),The adsorption modes of Fe(Ⅲ)-XG on the surface of quartz and hematite were different,so the adsorption capacity of the two minerals was different.The hydroxyl oxygen in Fe(Ⅲ)-XG and the iron on the surface of hematite are chemically bonded and adsorbed specifically on the surface of hematite,while there is only weak hydrogen bonding adsorption on the surface of quartz.Through the coordination assembly of FeCls·6H,O and xanthan gum,the selective flocculation separation effect of micro-fine hematite can be significantly improved,and a new strategy and theoretical guidance for the selective flocculation separation of hematite can be provided.