| Phosphorus is an essential element in the growth of plants and animals, and it is the key to increase food production,and it is the indispensable material in national defense, industry and top science.Phosphate resources in human survival and development has the characteristics of irreplaceability.Therefore,to achieve the sustainable development and utilization of phosphorus resource has important significance for food security, human survival, technology development, and national security.Object of this study was a low grade collophane in Yongshan district,Zhaoton city, Yunnan province.Process mineralogy studies have shown that the main component of the sample ore is P2O516.84%, MgO1.17%, SiO231.82%, CaO35.43%, and it is high silicon low magnesium phosphate type. The main phosphate is colloidal fluorapatite (collophanite), and a small amount of microcrystalline apatite. The main gangue mineral is siliceous minerals (chalcedony) and quartz. Secondary gangue mineral is calcite, dolomite and a small amount of Iron argillaceous and carbonaceous etc.With the depth study of the main mineral composition and disseminated, and combining with related data of domestic and international, we has carried on the exploration experiment to the ore. In experiment process, we adopt two methods to processing the ore which are flotation and roasting-slaking-desliming. When in the experiment of roasting-slaking-desliming,condition experiments and the best condition test have been carried out respectively to the roasting time and roasting temperature, feed size, slaking temperature and water temperature. Experimental results show that the ore contain high silicon and low magnesium, and the granule of value mineral is so tiny, so the method of roasting-slaking-desliming cannot make effective enrichment of phosphate. When in the experiment of flotation, we respectively compared the straight floatation, the reverse flotation and positive-reverse flotation. Eventually the test proved, for the ore, the straight floatation process can get relatively good indicator which float phosphate directly.After the straight floatation test is determined,we investigate the influence of factors on the flotation indexes such as flotation temperature, grinding fineness, roughing reagent condition, scavenging and concentration reagent condition, tailings scavenging. On the basis to determine the optimum conditions for the mineral, we compared the four different schemes. The experimental results showed that:When we used the pulp waste liquid as collector, sodium hexametaphosphate as gangue inhibitors, and the flotation flow was one roughing, two scavengings and three cleanings, obtaining a flotation target that content of P205was27.03%, recovery of P205was70.18%in the closed circuit experiment. And the contents of MgO was1.09%in the concentrate; when the flotation flow was one roughing, one scavengings and five cleanings, obtaining a flotation target that contents of P2O5was30.12%, recovery of P2O5was46.96%in the closed circuit experiment. And the content of MgO was1.0%in the concentrate; Because this is a very difficult election ore, when we obtained the first-grade concentrate (ω(P2O5)%>30.0), the recovery P2O5was less than50%. Concentrate grade increased by1%, recovery rate will decline by7.5%. The main reason is that the structure of ore is complicated, and the relationship of collophane and gangue minerals is very close. Siliceous minerals in collophane are inclusions, and the monomer solution is difficult. The main of concentrate is the rich locked-particles, to improve the concentrate grade we should remove a part of the locked-particles, but it will lead to lower recoveries, recoveries and concentrate grade cannot be taken into account at the same time.The results of this paper show that, for high silicon low magnesium phosphate rock type, using the method of the straight floatation to recover the phosphate material is feasible. And the flotation agents derive from a wealth of sources in the test program, and the process operability is strong. This paper provides references for production practices and similar exploitation of phosphate.And this paper has important significance to achieve the comprehensive development of the use of low-grade phosphate. |
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