Stepwise conversion of phosphate ore flotation tailings into high value-added products of calcium carbonate whiskers and nano-magnesium oxide

Abstract

With the exploitation and utilization of phosphorus resources, the accumulation of phosphate ore flotation tailings (POFTs) has become a major ecological concern. In this study, POFTs were utilized to prepare high value-added products of aragonite-type calcium carbonate whiskers through ammonium salt leaching and nano-magnesium oxide via step conversion. The effects of crystal control agents and reaction conditions on the calcium carbonate whisker, as well as the influence of dispersants on nano MgO, were explored. Under optimum conditions, calcium carbonate whiskers with length of 10-15 μm (aspect ratio of approximately 10-20) and 15-20 μm (aspect ratio of approximately 15-25) were prepared. In addition, nano-magnesium oxide with tunable particle size was obtained by regulating the dispersants polyethylene glycol (PEG)-2000 and EDTA-2Na. This work provides a viable approach for the resource utilization of POFTs and the preparation of high value-added products.