Investigation Of Jigging As A Method For Removing Dolomite From High-Mgo Phosphate Ores

Dolomite [CaMg(CO3)2] is an intolerable impurity in phosphate ores, due to its MgO content. The need to develop a cost-effective method for the removal of dolomite from high-MgO phosphate ores becomes increasingly important as high-grade reserves become depleted. The jigging process has been investigated as a method for the beneficiation of phosphate ores. A laboratory-scale jig was constructed and tested using a semicontinuous, ?through-the-screen? jigging process. Two types of sedimentary phosphate ore were used; a sample from Plant 1 in the 4.00 x 0.85-mm size range, containing 1.55% MgO, and a sample from Plant 2 in the 3.40 x 0.85-mm size range, containing 3.07% MgO. These were tested, using previously optimized jigging parameters, at high and low feed rates. For the Plant 1 phosphate ore, a phosphate concentrate that contained 0.89% MgO was achieved with a bone phosphate of lime (BPL) recovery of 32.0%. For the Plant 2 phosphate ore, a phosphate concentrate that contained 1.38% MgO was achieved, with a BPL recovery of 74.7%. Minimum achievable MgO grades were also determined by analyzing hand-separated phosphate samples.