Improvement of Hematite Dephosphorization by Flotation Method in Chador-Malu Iron Ore Processing Plants

摘要

Chador-Malu iron ore mine is located at 180 km north-east of Yazd in central desert of Iran. Its mineable reserve is 320 Mt of iron ore containing 55.2 % Fe and 0.94 % P in average. The production has begun on 1999. The ore processes at four parallel lines; each line has 400 t/h capacity. The processing line includes grinding to d80=30 ?m and magnetite separation by low intensity magnetic separators, hematite separation by high gradient magnetic separator, and finally, upgrading of iron as well as separation of apatite using flotation method. At the beginning, the efficiency of flotation was not satisfactory and the recovery of iron was often less than 70 %. The reagents of flotation were caustic soda to adjust pH=10.5, corn starch as hematite depressant and an amphoteric collector as the collector of apatite. A research program is carried out to modify the flotation conditions. The caustic soda and corn starch are replaced by soda ash and water glass. As the consequence the recovery of iron is increased to about 90 %.