Abstract The concentrations of P and K in leaching solution are relatively low and the consumption of acid is relatively large, which are the existing problems in the leaching of… Click to show full abstract
Abstract The concentrations of P and K in leaching solution are relatively low and the consumption of acid is relatively large, which are the existing problems in the leaching of P and K from P-K associated ore by using the low-temperature acid leaching process. In this work, a sequential leaching process with leachate recycling was developed, in which P and K were sequentially leached out from P-K associated ore and the obtained P- and K-containing leachates were recycled into the next leaching process. In this sequential process with leachate recycled two times the concentrations of K and P2O5 in leachate were increased from 20.18 and 15.79 g/L to 53.26 and 45.97 g/L, respectively. In comparison, in the simultaneous leaching process with leachate recycling both the leaching efficiencies of K and P and the concentrations of K and P2O5 were significantly lower than those in the sequential leaching process, which can be mainly attributed to the fact that Ca in the ore, which could react with PO43− to generate Ca-containing sediments, was precipitated first in the sequential leaching process. The sequential leaching process with leachate recycling will provide an efficient method for leaching and concentrating P and K from P-K associated ore.
               
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