Magnetic Concentration of Hematite at Wabush Mines Plant-Scale Application of Rare Earth Permanent Magnetic Separators

摘要

The Wabush Mines concentrator has been in production since 1965 producing a hematite concentrate. The concentration process incorporates gravity separation to concentrate the hematite followed by electrostatic separation to reject the residual silica. Over the years, high levels of manganese in the ore have resulted in higher than acceptable levels of manganese in the hematite concentrate. This has resulted in a more selective mine plan that has significantly reduced the life of the deposit. A high intensity magnetic separation process has been developed that replaces the electrostatic separation process. This process magnetically collects the hematite while rejecting both the silica and manganese. A 120 LTPH production line incorporating a three stage magnetic separation process was implemented in the Concentrator in March 2010. This project is termed the "Manganese Removal Project." The metallurgical results from the magnetic separation production line indicate: 1. A feed rate of 120 LTPH is sustainable with acceptable rejection levels of SiO_2 and Mn. 2. The manganese rejection is approximately 50 percent with the higher manganese levels in the feed range responding with higher rejection rates. 3. The cut-off grade for the manganese in the mine plan can be significantly increased. The installed production line represents the first of a total of eight conceptual lines. The development, installation, and testing of the magnetic separation production line are addressed.