A COMPARATIVE STUDY OF RECOVERING FINE SCHEELITE IN TAILINGS BY FLOTATION CELL AND FLOTATION COLUMN

摘要

There are nearly 2000 tons of cleaner circuit tailings containing about 0.32～0.78% WO_3 at the tailings dam in Xiang'an Tungsten mine, China, which results in a great resource loss. In order to recover fine scheelite from the tailings, conventional mechanical cell and modified flotation column were investigated. With a flotation cell, different kinds of collectors and depressants as well as their dosages were tested. The results show that flotation cell did not recover fine scheelite because of a very low enrichment ratio. The first flotation column with the height of 2,800 mm and diameter of 140 mm was designed and manufactured for pilot scale test. The important operating parameters such as the superficial velocity of the feed and air, the addition of wash water were studied. The optimum operation parameters were: the superficial velocity of the feed 0.27 cm/s, the superficial velocity of air 1.57 cm/s. The second flotation column with the height of 7,000 mm and diameter of 600 mm was designed and manufactured for full scale column flotation experiments, which were carried out in the flotation plant of Xiang'an Tungsten mine. The average recovery of WO_3 reached 43.41% with an average grade of 24.52%, resulting in an enrichment ratio of 35.03. The recoveries of the particles between +5～-1μm and +10 -19μm were 67.23% and 70.81%, respectively. The results indicate that it is feasible to use modified flotation column to recover fine scheelite from the flotation tailings. Application of such flotation column will make full use of the resource and bring great economic profits to the enterprise.