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New Mobile Pre-Processing Equipment for Florida Phosphate Mining



In Florida phosphate mining, slurry pumping accounts for one third of the energy consumption of the mining process. Various studies have shown that the optimum solid-water ratio for slurry pumping is at approximately 60 Cw%. Today the slurry density is between 25-35 Cw%. With an increase of the slurry density to 60 Cw% energy savings of up to 50 % can be achieved.

This research project dealt with the problem of deagglomeration and slurrying of the phosphate matrix. After a profound analysis of the raw materials, a wide range of tests was performed using high-pressure water jets up to 200 bars (2900 psi) for disaggregation. Disaggregation with this technology is possible, but the necessary throughput cannot be reached due to the long retention time required. Therefore selective crushing tests with a wet hammer mill were executed. Using this technology it has been possible to achieve a solids content of 60 Cw%. The advantages obtained by the new technology can be summarized as follows:

Reduction of water demand
Reduction of energy consumption
Reduction of phosphate loss through higher degree of disaggregation
Uniformity of the mass flow, no overloading of washer units
Reduction of washer steps at processing plant is possible