A realistic description of influence of the magnetic field strength on high gradient magnetic separation
A realistic description of influence of the magnetic field strength on high gradient magnetic separation
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DOI：
10.1016/j.mineng.2015.06.004
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发表时间：
2015-08
影响因子：
4.8
通讯作者：
Xiayu Zheng;Yu-hua Wang;Dongfang Lu
中科院分区：
文献类型：
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作者：
Xiayu Zheng;Yu-hua Wang;Dongfang Lu
在高梯度磁选中，磁场强度是一个非常重要的参数。通常认为，磁场强度的增加会导致矿物磁化率的降低和可供磁性颗粒聚集的基质表面积的降低，这是导致强磁场下矿物回收率降低的原因。但磁场强度对不同性质颗粒在HGMS中行为的具体影响还不清楚。在HGMS过程中，一个非常重要的因素通常被忽略，即低等级共生体的行为。本文利用粒子聚集模型和粒子俘获模型研究了磁场强度对HGMS中磁性单体和共生体行为的影响。尽管矿物的磁化率降低，但磁性单体的堆积分布随磁场强度的增加而增大。在低磁场下，低品位共晶几乎不能在基体上堆积，而在强磁场下，可以在基体上大量堆积。在强磁场下，低品位共生单体与细小单体之间存在竞争堆积。与细粒单体相比，粗粒共生长物具有更大的堆积轮廓和更短的捕获时间，并将优先在基质上积累。在某些情况下，粒子的竞争积累会导致在强磁场中的回收率降低。中等强度的磁场可以保证较高的回收率。对于品位高、回收率高的磁性产品，要求单体解离度高，避免矿物的过度研磨，也可考虑对矿物进行粗细分开处理。
The magnetic field strength is a very important parameter in high gradient magnetic separation (HGMS). It was usually thought that the increase of magnetic field strength will lead to the decrease of the minerals’ susceptibility and the matrices’ surface area available for the buildup of the magnetic particles, which was responsible for the decrease of the mineral recovery in high magnetic field. But the detailed influence of the magnetic field strength on the behavior of the particles of different characteristics in HGMS is still not clear. A very important factor was usually ignored in the process of HGMS, namely the behavior of the low grade intergrowths. In this article, the influence of magnetic field strength on the behavior of the magnetic monomers and intergrowths in HGMS was investigated with the particle buildup model and the particle capture model. The buildup profile of the magnetic monomers increases with the increase of the magnetic field strength despite the decrease of the minerals’ susceptibility. The low grade intergrowths can hardly accumulate on the matrices in a low magnetic field but can largely accumulate on the matrices in a high magnetic field. In a high magnetic field, there exists the competitive accumulation between the low grade intergrowths and the fine monomers. Coarse intergrowths may have larger buildup profile and shorter capture time than the fine monomers and will accumulate preferentially on the matrices. In some circumstances, the competitive accumulation of the particles will lead to the decrease of the recovery in a high magnetic field. A moderate high magnetic field can ensure a high recovery. For a magnetic product of high grade and recovery, high monomer dissociation degree is necessary and the over grinding of the minerals should be avoided, and classifying the minerals to handle the coarse fraction and the fine fraction separately can also be considered.