| Zhijin phosphate deposits bearing rare earths, which had been found in 1950s—1970s, are 10 kilometers far from Zhijin town center. The reserves of phosphate rock are 1.3 billion tons, which more than a half of that of Guizhou. The rocks contain rare earths which are 1. 44 million tons, the large number of rare earths is second in our country. For the whole phosphate deposits, the average P2O<sub>5 is 17% and Re2O<sub>3 is 0.05-0.1%. However, the phosphate ores are sedimentary phosphate deposit that is very difficult to deal with .So far, there is no way to use P2O<sub>5 and recovery rare earths ultimately. Therefore, we study the reverse flotation technology and wet process phosphoric acid (WPA) technology on the phosphate rocks according to the natures of phosphate ores. The single factor and orthogonal test have been used to find the optimum conditions in the experimentsThe results are following:1. For the reverse flotation technology, the optimum conditions are that: WF—01 consumption is 0.8Kg/t, phosphoric acid consumption is 15Kg/t, pulp density is 30% , time consumption is 10mins. In the conditions, the concentrate of P2O<sub>5 32. 27%, Re2O3 0. 1370%, MgO 1.16% had been obtained from phosphate ore containing P2O5 23. 01 % , Re2O3 0.0937%, MgO 5.17 % respectively. The recoveries of 93.67 % P2O5 and Re2O3 94.17% could be reached.2. In reverse flotation technology, the movements of grade, recovery and loss about P2O5 and Re2O3 are concurrent.3. For wet process phosphoric acid (WPA) technology, the optimum conditions are that: Temperature is 75±3℃, the excess coefficient of sulfuric acid is 1.05, liquid to solid ratio 2.5:1, time consumption is 3 hours. Under the conditions, the conversion of P2O5 is 97. 75% and the concentration of phosphoric acid is 19.19%. The leaching rates of Re2O3 and Y2O3 are 50. 98% and 58. 94%. The calculations of thermodynamics show the leaching can go completely. In the view of dynamics angle, the leaching of phosphoric concentrates bearing rare earths are controlled by the... |
