Xinhai 4000,000 t/a Iron Ore Tailings Reprocessing Project

Yunnan 4000,000 t/a iron ore dressing plant was built in 2007 and put into operation in 2008. The original processing capacity was 500,000 t/a, the annual iron concentrate was 264,300 tons, and the grade of iron concentrate was 64.00%, the recovery rate was 82.80%. In 2006, the processing capacity of this plant was expanded to 4000,000 t/a.

Iron Ore Dressing Process

This plant adopted three stage closed-circuit grinding, including one-stage semi-autogenous grinding, two and three stage grinding (four 4. 8m x 7m large ball mills). And the separation operation adopted low intensity magnetic separation-strong magnetic separation-direct flotation this joint process. The autogenous mill in one stage grinding mill formed a closed circuit with linear vibration screen, and the granularity of undersize material was -6mm. Then, the material entered into hydrocyclone that formed closed-circuit with two-stage grinding. After the one and two stage continuous grinding, -200 mesh discharge of hydrocyclone overflow was up to 60%. Through the low-intensity magnetic separation and strong magnetic separation, the rough concentrate was sent to the hydrocyclone that formed closed-circuit with three stage grinding, and – 325 mesh discharge accounted for 80%.

Purpose of Tailings Reprocessing

Although the iron concentrate reached the target design of 1.864 million tons, the grade of raw ore was dropped to 35%, which was much lower than the original design. Therefore, the mine owner entrusted Xinhai to finish the later iron ore dressing process, and achieve the initially expected effect. By analyzing the original production line, Xinhai finally decided to choose tailing reprocessing.

After analyzing the tailing composition several times, Xinhai decided to adopt one roughing and one cleaning strong magnetic separation process, which guaranteed that each index achieved the expected effect.

When the iron grade of second strong magnetic tailings was 20. 00% ~ 30. 00%, the grade of iron concentrate reached 52. 00%, the grade of tailings was 13.00% ~ 18. 00%, and the grade of total tailings was reduced to 14. 00%. Finally, the daily concentrate of this plant was up to 600 ~ 800 t, and the annual amount of iron concentrate reached 150 ~ 200 thousand tons.