Table of Contents
Magnetic and Electrical Separation
Volume 10 (1999), Issue 1, Pages 1-19

Magnetic Separation of Calcite Using Selective Magnetite Coating

1Regional Research Laboratory (CSIR), Bhubaneswar 751 013, India
2Indian School of Mines, Dhanbad 826004, India

Received 30 September 1998; Accepted 22 December 1998

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Magnetic separation of naturally occurring calcite (98.2% CaCO3) using selective coating of synthetic colloidal magnetite with sodium oleate has been investigated as a function of pH, concentration of colloidal magnetite, magnetic intensity and particle size. Colloidal magnetite treated with sodium oleate (oleate magnetite) is found to be a better coating agent than the natural magnetite. The mechanism of oleate magnetite coating has been investigated through adsorption and electrokinetics measurements. FTIR studies indicate that there is a possible chemical interaction between calcite and magnetite surfaces on which sodium oleate is adsorbed. Magnetic susceptibility measurement shows a finite susceptibility of calcite by the addition of colloidal magnetite. In the investigation with calcite, calcite recoveries of > 94% have been achieved at a colloidal magnetite concentration of 0.25 ml/g and 7.1 kG of magnetic intensity. In case of synthetic mixture of calcite and quartz > 90% calcite recovery at a grade of 80.9% CaCO3 has been achieved at the optimum pH of 11.