Screening Organic Molecules for Activation of Medium- and Low-Grade Dolomite Phosphate Rocks.

With depletion of high grade phosphate rock (PR) for phosphoric acid production, increasing interest is attracted to explore low- and medium-grade PR resources. In this study, several organic compounds and their combinations were tested for their potential in activating dolomite phosphate rock (DPR) from central Florida. Three DPR samples representing high- (DPR5), medium- (DPR1), and low-grade DPR (DPR7) were selected for this experiment. The DPR samples were ground to < 100 mesh and blended with each of the pre-screened organic agents at 5% by manual grinding for 15 min with 15% moisture. The activating efficacy was determined by the increase in water soluble phosphorus (WSP) release from the activated as compared to the original DPRs. The results indicated that grinding with and without addition of water did not significantly increase WSP, whereas addition of activating agent substantially enhanced WSP release from the DPRs. However, the activating efficacy varied largely among the organic agents and their combinations and between the types of DPR materials.

Keywords: Wastes reuse; High efficient activators; Environment friendly products; Water soluble phosphate