Fine particle high gradient magnetic entrapment

The entrapment of fine colloidal paramagnetic (and diamagnetic) particles at magnetic capture centers in the colloid is reviewed. The effect of thermal diffusion on the entrapment from a static colloid is examined in the 1-D and 2-D cases. The latter case allows prediction of captured volumes of colloidal particles. The interparticle effects due to the Helmholtz double-layer electrical interaction and the magnetic dipole-dipole interaction are introduced, and their effect on the 1-D theory is calculated and shown to be of importance. A theory that incorporates the double-layer effect into the 2-D case is presented, and its predicted effects upon the volume of captured particles is examined. The flow of the colloid is introduced, and a framework that allows fine particle capture to be included as a special case of normal size particle entrapment theory is suggested. A diagrammatic means of assessing the effects of thermal diffusion and interparticle effects on entrapment is described.