Updated Characterization of Dorowa Phosphate Rock Mined in Zimbabwe

Abstract

The physical and chemical characteristics of mined phosphate rock will vary temporally as the location and nature of the ore body changes and as the type of equipment used in the beneficiation processes change over time. For the Dorowa phosphate rock (DPR) in Zimbabwe where economic challenges have affected the viability of phosphate rock mining and led to the closure of the mine twice, there is a need to evaluate if there have been any significant changes in its quality. The current DPR concentrate contained 11% more apatite and about 50% less calcite and other gangue minerals compared to mineralogical modal concentrations earlier reported for the DPR. Total P was found to have increased by 2% from previously reported figures to 16.5% by weight. Previously unreported, the cadmium content was found to be 0.16 mg kg−1. The reactivity of the DPR was similar to previously reported values of 2.1%, 1.8% and 0.88% (w/w) in 2% citric acid, 2% formic acid and neutral ammonium citrate, respectively. Because of this, the DPR has low potential for direct application without modification. We conclude, therefore, that the apatite mineralogy of the ore being currently mined has not significantly changed in the past 25 years, while the beneficiation process has improved.