Extraction Technology Of Quenching Agent In Mineral Luminescent Materials And Spectral Property

Materials science, information technology and energy sources are the three pillars industry in the 21st century. The development of every department in national economy and high-tech field is unavoidable to be promoted and restricted by the development of materials science. With the development of the science and technology, luminescence materials have been already widely applied to every field of the national defence, space navigation, industry and agriculture. In the research and application of luminescence materials, rare-earth luminescence materials account for leading and most important status, which have been applied to light, display and information. It has attracted much interest. So developing rare-earth luminescence materials is an important means by which resource advantage translates into economic and technological advantage At present, luminescence materials are synthesized with vast chemicals, so its price is too high. The mineral luminescence materials have many advantages, such as abundant resources, low production cost, simple technological and extensive prospect and so on. Therefore investigating the new mineral phosphor has become the global hot subject. Although the study of the mineral luminescence materials has been reported, it has not been applied to manufacturing production so far. The reason is that the natural mineral mixed some quenching element, such as iron, cobalt, nickel, etc. and the quenching agent reduces the luminescence intensity or loses the luminescence ability thoroughly. It depresses the luminescence efficiency and the value of the natural mineral. Compared to the chemical material, natural mineral has its own shortcoming with impurity or harmful element, which need mineral separation process, machinery and chemistry separating to leaching out in order to sweeping manufacture. So technological process of getting rid of quenching is the key to preparing mineral luminescence materials. The content of science and technology will increase by selling the mineral, it will blaze a way for nonmetallic minerals utilization, and promote the development of the application of natural mineral. It is highly important for our country to take-off in economic development. Firstly, CaSiO3: Eu3+ phosphor powder was prepared by ceramics method in this chapter. The optimal synthetic conditions of CaSiO3 were investigated as follows: sintering temperature is 1200oC, sintering time is 3h, concentration of the fluxing agent is 3%. A series of concentration of Eu3+ doped CaSiO3: Eu3+ were also prepared by the condition mentioned above. The luminescence intensity of phosphor first increase with doping concentration, reaching a maximum value when the concentration of Eu3+ is 2 mol% of that of Ca2+, and then decreasing sharply with increasing Eu3+ concentration due to the concentration quenching effect. So molar matching of the activating agent is 2%. The fluorescence spectrum of the phosphor powder was measured. The emission spectrum has shown sharper and more effective peaks at 609 nm and 588 nm corresponding to the 5D0→7F2 and 5D0→7F1 transition of Eu3+. The excitation spectrum revealed that the broad band from 200 nm to 300 nm is attributed to charge transfer between the Eu3+ and the surrounding O2-ions (CT band of Eu3+ ─O2-), while the lines from 350 nm to 420 nm are due to f-f transition within the Eu3+ 4f6 configuration. Secondly, ferrous ion of natural wollastonite was selective solubility by oxalic acid-phenanthroline system, and technological process that leaching-out quenching agent from natural wollastonite was created. Determined the optimal leaching conditions such as, solid-to-liquid ration is 1:60, concentration of oxalic acid is 100g/L, leaching time and temperature is 4h and 80 oC. Under the optimum leaching conditions, the leaching-out ratio of ferrous ion is up to 98.35%. The luminescence material was synthesized by solid-state reaction with Eu3+ doped wollastonite. Luminescence (excite and emission) spectra were measured using spectrofluorometer. The spectrograms indicate that the emission intensity is the weakest at 613 nm and 254 nm of which the luminescence material...