低品位难选磷矿微晶化加工及磷元素释放机理研究

Common phosphate mineral powder has been used as a kind of fertilizer, which has green and environment friendly eco effect. However, this application was limited because of the lower releasing efficiency of phosphate element. On the other hand, since the high grade phosphate mineral is getting less and less, the cost of chemical phosphate fertilizer is growing rapidly. The chemical phosphate fertilizer contaminating the fresh water after added to the soil, the agriculture could not be sustainable. In this research work, the low grade phosphate rocks（Yunnan,P2O5＜20%）and phosphate tailings (Guizhou,P2O5≈9～11%)）are taken as the raw material to prepare high reactivity microcrystalline phosphate mineral powder, and the horizontal stirring mill will be used as it has a higher energy density method to enhance the mechanochemical phenomena on the phosphate mineral. Kinds of modern analysis methods will be used to measure the crystal structure in micro-scale, the phosphorus-releasing efficiency and other physical-chemical characteristics to clarify the microcrystallizing process and phosphorus releasing rule. Based upon the analytic hierarchy process（AHP）， a comprehensive evaluation index model assessing microcrystalline degree will be created. The microcrystalline process will be optimized, by taking the phosphate releasing rate as primary targets. By this research, to solve the technical problems for non-acidification application of phosphorus mineral of low-grade and difficult separation, discover the theoretical basis for microcrystalline processing technique which is feasible proved by practical application, and lay the theoretical foundation for the application of mechanochemistry in mineral processing.

普通磷矿粉直接用作磷肥具有加工流程短、环境友好的特点，但由于磷元素释放率低，这种矿粉加工技术一直没能推广。随着高品位优质磷矿资源的日益短缺、磷化肥生产成本的攀升、水溶性磷肥流失造成的地表水富营养化，农业生产的可持续性和水资源的保护均受到一定程度的影响。本项目将以低品位难选胶磷矿（云南，P2O5＜20%）及浮选磷尾矿(贵州，P2O5约9～11%)为研究对象，采用高强度机械能量输入方式对其进行微晶化加工，制备高活性磷矿粉；借助先进测试技术对这种磷矿粉的理化性能与机械力化学现象进行研究并建立相应的定量表征体系，确定微晶化过程与磷释放等因素之间的关系。基于层次分析法建立微晶化程度综合评价模型，以磷释放率为主要目标，实现微晶化加工工艺的最优化。本项目研究可望解决低品位难选磷矿的非酸化利用及磷尾矿难以再利用的技术难题，为已经被证明可行的矿物粉体的微晶化加工技术的工业化应用奠定坚实的理论基础。

优质磷矿短缺使含磷化肥成本逐年攀升、施用后流失又造成湖泊富营养化，严重影响到农业可持续发展。本项目以云南低品位难选胶磷矿、贵州浮选磷尾矿、湖北碳氟磷灰石为主成分的磷矿、河南含铁的低品位磷矿、河南云母、安徽钾长石等为研究对象，采用高强度机械能量输入方式对其进行微晶化加工，制备高活性磷矿粉，利用XRD、粒度、表面积、红外等分析手段，表明了各种微晶化磷矿粉X-衍射主峰高度逐渐降低，内部晶格发生畸变，结晶度下降，紊乱和无定型化程度升高，无定形物含量增加；不同磷钾矿粉的机械力化学效应显著不同，证明了其理化性能与机械力化学效应具有显著相关性，并建立了相应的定量表征体系和综合评价模型。微晶化过程使有效元素含量提高一倍以上，并表现出良好的缓释性。本项目研究已经有效的解决了磷钾矿的非酸化利用及产生大量尾矿废物的技术难题，提高了中低品位磷钾矿的资源利用率，为已经被证明可行的机械力化学作用在矿物加工方面的应用奠定坚实的理论基础。