Abstract: Lilou Iron Concentrator is the first one in China to adopt a process consisting of high intensity magnetic separation for discarding tailings, high intensity magnetic separation for cleaning and flotation for middlings. Since the completion of its construction, pre-commissioning had been made for several times, resulting in the indexes that were far inferior to those designed. In view of this, technical transformation was made on the weak links in the original process found in the pre-commissioning. After the transformation, an iron concentrate having a yield of 38.47%, grade of 64.87% and recovery of 77.14%was obtained in the pre-commissioning, which reached the designed values.

Key words: Low grade specularite, Process consisting of HIMS for discarding tailings, HIMS for cleaning and flotation for middlings, Pre-commissioning, Technical transformation