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Study on polymer-bridging flocculation performance of ultrafine specular hematite ore and its high gradient magnetic separation behavior: Description of floc microstructure and flocculation mechanism
Separation and Purification Technology ( IF 8.6 ) Pub Date : 2021-07-19 , DOI: 10.1016/j.seppur.2021.119304
Libo Zhou 1 , Yuexin Han 1 , Wenbo Li 1 , Yimin Zhu 1
Affiliation  

Flocculation magnetic separation process is one of the efficient and economical methods to recover fine weakly magnetic iron ore. It is well known that the structural characteristics of mineral flocculants have a significant effect on the flocculation magnetic separation process. Therefore, it is of great practical significance to adjust the structural characteristics and particle size of iron flocs to suit the high-gradient magnetic separation process. In this study, the effect of molecular structure and dosage of the reagents, pulp pH and stirring intensity on the flocculation performance and magnetic separation behavior of ultrafine specular hematite ore were studied by optical microscope observations along with image analysis and floc-magnetic separation experiments, respectively. Besides, the relationship among agglomeration factors, flocculation structure and separation index was established. The interaction mechanism between different starches and minerals was studied by electron scanning microscope (SEM) observation, particle interaction energy calculation, Zeta potential and infrared spectrometric measurements. The results showed that the flocs size gradually increased with the increase of molecular weight, amylopectin content and dosage of the reagent. An appropriate agitation intensity will be helpful to the aggregation of mineral particles, and the new flocculation will be destroyed as the stirring intensity is excessive. Compared with no additives in the separation process, the flocculation-magnetic separation process could increase the recovery rate by 1.5–2.0 percentage points on average when the flocs size was about 23 μm. With the increase of amylopectin content and molecular weight, the separation index increased gradually. Compared with tapioca starch, using carboxymethyl tapioca starch as flocculent, the iron grade of concentrate was increased by 1–2 percentage points. The microscopic morphology of the mineral particles showed that the agglomeration of ultrafine specular hematite particles was formed by the polymer bridging of starch in the pulp. The calculation results of interaction energy between particles showed that there was repulsive force between specular hematite and quartz particles due to the existence of repulsive energy of hydration, so the specular hematite and quartz particles were dispersed in the pulp. Zeta potential and FTIR test results showed that these starches can be selectively adsorbed on the specular hematite surface through electrostatic interaction and hydrogen bonding, while there was no obvious adsorption existed between starches and quartz.



中文翻译:

超细镜面赤铁矿聚合物架桥絮凝性能及其高梯度磁选行为研究:絮体微观结构及絮凝机理描述

絮凝磁选工艺是回收细弱磁性铁矿的一种高效、经济的方法。众所周知,矿物絮凝剂的结构特性对絮凝磁选过程有显着影响。因此,调整铁絮体的结构特征和粒径以适应高梯度磁选工艺具有重要的现实意义。本研究通过光学显微镜观察、图像分析和絮-磁分离实验研究了分子结构和试剂用量、矿浆pH值和搅拌强度对超细镜面赤铁矿絮凝性能和磁选行为的影响。分别。此外,集聚因素之间的关系,絮凝结构和分离指标的建立。通过电子扫描显微镜(SEM)观察、粒子相互作用能计算、Zeta电位和红外光谱测量研究了不同淀粉与矿物质之间的相互作用机制。结果表明,絮体大小随着分子量、支链淀粉含量和试剂用量的增加而逐渐增大。适当的搅拌强度有利于矿物颗粒的聚集,搅拌强度过大会破坏新的絮凝体。与分离过程中不添加添加剂相比,絮凝-磁选工艺在絮体粒径为23 μm左右时平均可提高1.5-2.0个百分点的回收率。随着支链淀粉含量和分子量的增加,分离指数逐渐增加。与木薯淀粉相比,以羧甲基木薯淀粉为絮凝剂,精矿铁品位提高1-2个百分点。矿物颗粒的微观形貌表明,超细镜面赤铁矿颗粒的团聚是由浆中淀粉的聚合物架桥形成的。颗粒间相互作用能的计算结果表明,镜面赤铁矿和石英颗粒之间由于水化排斥能的存在而存在排斥力,因此镜面赤铁矿和石英颗粒分散在矿浆中。

更新日期:2021-08-02
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