CTZ series middle field strong permanent magnet roller (divided into semi magnetic and full magnetic magnetic system structures) is mainly used for purification of powdery, granular and small pieces of materials, or for recycling of iron, which plays a reliable role in protecting against damage and wear of crushers, grinders and presses. The utility model has the advantages of convenient installation, strong suction, no energy consumption, continuous operation and simple operation. According to the standard design of TD-75 belt conveyor, it can meet the user's requirements for high field strength and deep iron removal.