The production practice of the Xinyu Concentrator has shown that the dry pre-selection and stage grinding process for ultra-poor magnetite with easy-to-grind and easy-to-grind ore content of 13.0% or less can achieve the best beneficiary results. The iron ore grade can be stabilized at 63.0%-65.0%, and the metal recovery rate is over 83.00%. Qian'an Iron Ore is rich in resources and has been developed and used very early. After many years of exploration and practice, the production capacity of medium and small concentrators, which are in line with mining, has become more stable. The production process is becoming more and more reasonable, and a certain selection of Anshan-style poor magnetite has been accumulated. The successful experience.
(1) 15 ~ 250,000 t/a scale concentrator. The crushing process generally uses two sections of open-circuit crushing, one section uses a 400 mm x 600 mm jaw crusher, and the second section uses a crusher jaw crusher, a medium cone crusher or a hammer crusher. In recent years, a new type of small-scale concentrator two-stage crushing almost all use hammer crusher. For iron ore with more than 8% ore of fine ore and more than 8% of water, the second-stage crusher chooses the vertical axis type hammer crusher; for the iron ore with more lump or less water, the second-stage crushing uses the flat axis type. Hammer crusher. The difference between the two is that the vertical axis hammer crusher is not easy to clog in crushing ore with more fine or large water content. The disadvantage is that the size of the crushing product is not easy to control, and the coarse-grained particles are more in the product; the flat-shaft hammer type The product size of the crusher is controlled by the lining grid and the particle size is easy to adjust. The disadvantage is that the ore with large crushing fines and large water content is easy to clog.
(2) 25 to 1 million t/a concentrators. 25 to 100 million Ua-scale concentrators have more than 30 in Qian’an. The crushing process of these concentrators generally uses a three-stage closed circuit crushing process. Raw ore feed uses mechanical vibration plate feeder, coarse crusher uses jaw crusher, middle crusher adopts standard cone crusher or fine crusher jaw crusher, fine crusher adopts short head cone or hammer crusher, and screening equipment adopts Inertia shaker. Before the ore screening, a magnetic pulley with a magnetic field strength of 291-320 kA/m was used to classify the tailings with a yield of 1% to 25% and a particle size of -120 mm. The broken end products are sorted by a magnetic pulley with a magnetic field strength of 120_160 kA/m, and the tailings yield is 15% to 25%. The final product size of the crushing operation is -15 mm, and the crushing process is shown in Figure 2.6 -12. The hammer crusher has been widely used in the second and third stage crushing operations. Compared with other types of crushers, it has a large crushing ratio, high efficiency, low power consumption, and can be selectively broken. The equipment is small in size, light in weight, simple in structure, and manufactured. Easy and easy maintenance and other advantages.