摘要
研究了极弱磁场存在时微细粒赤铁矿水基悬浮体中矿粒间的相互作用．研究结果揭示．极弱磁场存在时反铁磁性的赤铁矿颗粒由于本身具有瞬时磁偶极．在pH10．9的悬浮体中，形成了一种较为松散的链状聚团体；外磁场中赤铁矿粒间磁相互作用能的作用距离远大于其它三种表面力，达1μm以远；极弱磁场中，赤铁矿颗粒间虽然存在较高能垒，达110～120×10-19J，但是次能谷的深度达|-9×10-19|J相当于-220KT左右）以上，而且其数值随当点磁感应强度的升高而加大；与热稳定性相比，赤铁矿悬浮体的次能谷剪切稳定性对次能谷聚团具支配作用；在本研究所用的剪切流场（G平均值为30s－1）及0．004T～0．01T的极弱磁场中赤铁矿粒间可以在次能谷形成快速聚团（Ws＝1）；提高剪切强度．如70～120s－1以上，次能谷聚团将被破坏．计算结果与沉降试验所观察到的现象一致．
The interaction among particles of aqueous fine hematite suspension in an exceedinglyweak magnetic field is studied. Some interesting results are revealed. Certain porouschain-like aggregates were formed in the fine hematite suspension of pH 10.9 due tohematite is a kind of canted amiferromagnetism, in which there exist dipole moments.The action depth of magnetic interaction potential, that reaches more than 1 μm, wasmuch deeper than that of other three interaction potentials in the magnetic field. Althoughthere exists a .energy barrier of 110 ~120 ×10-19J between fine hematite particles, thereexists a secondary depth of |-9 × 10-19|J (about-220KT), and the depth will be increased with the enlargement of magnetizing induction intensity of that point in theexceedingly weak magnetic field. comparing with Browning stability, the shear stability is the dominant factor of an aggregation happened in the secondary depth. A fast secondary depth aggregation (Ws=1) between fine helnatite particlcs could be achieved in a combined field of a shear flow field of 30s-1 (average G) and an exceedingly weak magnetic field of 0.004T^0.01T. The aggregation will be damaged if the average G of the fluid field is increased to more than 70~120s-1. Theory deduction results are in keeping with what sedimation tests show.
出处
《有色金属》
CSCD
1998年第4期26-33,共8页
Nonferrous Metals
基金
国家自然科学基金!59704005
关键词
极弱磁场
微细粒赤铁矿
次能谷聚团
选矿
exceedingly weak magnetic field
fine hematite particle
secondary depth aggregation
