自 2 0世纪 5 0年代后期对磁铁矿脱磁过程大量的研究以来 ,对细颗粒物料磁性的物理基础的认识愈加深入。基于这些新的认识 ,对脱磁过程 ,特别是对细磨天然磁铁矿脱磁过程进行了重新研究。磁力仪测量显示 ,当颗粒尺寸减小至 10 μm以下时 ,矫顽力和剩磁显著增加。虽然工业标准的 6 0 Hz脱磁线圈能很大程度上减少这些颗粒的剩磁 ,但它们仍处于强烈磁化状态 ,在静止条件下形成 10 0个或者更多颗粒的团聚体。虽然在以前高矫顽力的人造磁铁矿研究工作中 ,已经发现增加施加磁场的强度和频率能改善脱磁效果 ,但是 ,将同样的条件应用于细磨天然磁铁矿没有取得有意义的结果。细磨磁铁矿颗粒经过脱磁后的大量剩磁是其基本的属性 ,它与每个颗粒中有限的磁畴值有关。这些颗粒在任何特定的单元操作条件下 ,是表现为单个颗粒行为还是表现为更大的团聚体行为取决于颗粒所受的剪切应力的大小 Since the late 1950s, a great deal of research has been conducted on the demagnetization process of magnetite, which has deepened the understanding of the physical basis of magnetism of fine-grained materials. Based on these new understandings, the demagnetization process, especially the demagnetization process of finely ground natural magnetite, has been re-studied. Magnetometer measurements show a significant increase in coercivity and remanence when the particle size is reduced below 10 μm. Although industry standard 60 Hz demagnetization coils can greatly reduce the remanence of these particles, they remain strongly magnetized and form agglomerates of 10 0 or more particles under static conditions. Although it has been found that increasing the strength and frequency of the applied magnetic field can improve the demagnetization effect in the previous research work on high coercivity artificial magnetite, applying the same conditions to the fine grinding of natural magnetite did not make any meaningful result. Finely ground magnetite particles after demagnetization of a large number of remanence is its basic property, it is limited with each particle magnetic domain value. The behavior of these particles to behave as a single particle or into a larger aggregate under any particular unitary operating condition depends on the magnitude of the shear stress to which the particles are exposed