Magnetization Roasting–Weak Magnetic Separation: The Key to High-Grade Siderite Concentrates

 Magnetization roasting followed by weak magnetic separation is regarded as one of the most effective methods for upgrading refractory siderite ores. During roasting, siderite decomposes into magnetite, enhancing its magnetic properties. This transformation fundamentally changes the ore’s beneficiation behavior.

The roasting process typically involves heating siderite in a reducing atmosphere. As carbon dioxide is released, iron carbonate transforms into magnetite. The magnetic contrast between transformed magnetite and gangue minerals enables efficient weak magnetic separation.

Weak magnetic separators can then recover magnetite with high efficiency, producing iron concentrates with significantly improved grade and recovery rates.

This method is especially suitable for finely intergrown or complex siderite ores that do not respond well to flotation or gravity separation.

In many beneficiation plants, magnetization roasting is integrated with grinding, classification, and staged magnetic separation to maximize performance.

While the energy cost of roasting is considerable, the dramatic improvement in concentrate quality often justifies the investment. As global iron ore resources decline in quality, magnetization roasting continues to gain prominence as a key technology for siderite beneficiation.