The Study Of The Characters Of Superfine Tourmaline Trend To Nano-Particulate And Its Application Significances

With the continually advances of non-metallic mineral deep-processing, the mineral materials study has gradually become a new field of material research, manufacture and application in recent years. Nanometer technology, as one of the three central technologies in 21 century, is the basis of the development of information technology and life science and technology. Because of the particular physical and chemical properties of nano-material, the application of nanometer technology in mineral materials field has been the focus of new technology research. Tourmaline has widely applications for its physical and chemical properties. Clarity, clear and colorful ones can be accepted as gemstone and good piezoelectricity ones can be used in radio industry. In 1980's, there are some new characters found by Japanese scientists, such as far infrared radiation, releasing anion, adsorption effect, bioelectricity character, mineral substance and microelement. For these new characters, tourmaline has been applied to a lot of new fields, such as environmental protection, human health, medicament, chemical engineering and electromagnetic screen etc. Chinese scientists have begun to study the applications of tourmaline since 1995. At present, the particulate diameters of studied tourmaline are mostly in the micrometer size but rarely in the nanometer size. Therefore, the study of nano-tourmaline physical and chemical properties is an advanced research. On lots of home and abroad literatures basis, the study status quo, including constituent structure, classification, physical and chemical characters, origin and occurrence, geological significance, applications and superfine of tourmaline is analyzed and summarized detailedly. And the development trend of nano-tourmaline preparation is brought forward for the particular characters of tourmaline and nano-particles. Meanwhile, the concepts of minimum and optimum dimension particulate of nano-tourmaline are given in the dissertation. The minimum dimension of nano-tourmaline particulate should be in the range about 1~100nm, and the smaller dimension would make nano-tourmaline lose its particular characters. Moreover, the tourmaline with optimum particulate dimension would have the optimum performances. According to these concepts, the physical and chemical characters of tourmaline of different particulate dimensions are tested and analyzed, and the relation between them and the particulate dimensions concluded based on crystal structure and crystal chemistry theory. After synthesizing the theoretical and practical study, the optimum technical line of nano-tourmaline preparation will be given. The dissertation consists of five parts: 1. The mineralogical study of tourmaline The mineral association, crystalchemical formula, crystal cell parameter and calorifics, electricity, magnetics characters of tourmaline (Aletai region, Xinjiang) are described through various testing analysis, such as polarization microscope, X-ray diffraction, electro-probe microanalyzer, differential scanning calorimetry, thermogravimetry, conductance, electrical resistivity and magnetic capacity analysis. In the meantime, the piezoelectricity and pyroelectricity are discussed in theory. By all above study, the tourmaline sample is comfirmed as dravite, and (Na0.3920,Ca0.3587)0.7507(Mg2.1539, Fe0.3907, Mn0.0008, Ti0.0873)2.6327Al6.1200[Si5.8479O18][B1.0136O3]3(F0.1412, OH3.8588)4 and a0=b0=1.59261nm, c0=0.71786nm, α=β=90°, γ=120°, as the crystalchemical formula and crystal cell parameter, are obtained. The electrical resistivity and magnetic capacity data indicate aeolotropism and discrepancy of crystal structure in different crystallographic axial directions. On the basis of group theory and mathematical theory, the piezoelectricity and pyroelectricity of tourmaline are attributed to its particular crystal structure. Moreover, the origin, occurrence and resource allocation of tourmaline are summarized, and the advice for improving the national resource management is given. 2. The theoretic study of optimum dimension of tourmaline particulate The nano-structure characters are studied in theory since the widely applications of non-metallic minerals and the nano-characters of crystal cell parameter, volume and atomic distance of tourmaline are founded. According to the correlatability with the characters of nanometer particulate, the subjects investigated can be determined, which are the amount of crystal cell, molecule, atom and element, the amount of that and their proportion in the active surface layer, the amount of different chemical bonds and their proportion in active surface layer of different dimension particulates. The theoretic model of tourmaline minimum particulate is defined as a cuboid composed of 27 crystal cells, whose cross sectional area is 19.7691nm2, thickness is 2.1536nm and radius-thickness ratio is 2.2185:1. The relations between these subjects investigated and tourmaline particulate diameters are summed up through computational analysis based on the characters of tourmaline structure and nanometer particulate. From the analysis, the positive correlation between internal structure characters and particulate diameters while the negative correlation between surface layer activity characters and particulate diameters are proved. Meantime, it is also proved that sphericity particulate has more structure activity than that of rectangular particulate. In order to keep the good structure characters as well as the minor particulate dimension, the size of 175～195nm is considered as the optimum dimension particulate of tourmaline through graphic analysis, and for the rectangular particulate the thickness should be 78.88～87.90nm. 3. The study of nano-tourmaline preparation The superfine processes of non-metallic minerals can be divided into physical process and chemical process according to the analysis of their actuality. The physical process and chemical process comprise gas phase, liquid phase and solid phase process respectively. The mechanochemical process is determined to be the superfine process depending on the properties of tourmaline, and then the process flow is designed. Based on lots of experiments, the process parameters of superfine tourmaline, such as grinding time, solid to liquid ratio, liquid phase medium, and dispersant, is analyzed in detail through the test of scanning electron microscope (SEM), transmission electron microscope (TEM), laser particle diameter detector and so on. The optimum condition of superfine tourmaline (1μm) can be obtained from above study,that is the raw tourmaline powder is grinded for 3 hours by Minizeta031 sand mill under 30℃, with the deionized water as liquid phase medium, the solid to liquid ratio being 1:1 and the dispersant mass ratio being 3%. Finally, the dry power is obtained through the solving agent replacement process. Furthermore, the better effect of superfine is forecasted on the basis of further conditions optimization. 4. The performances study of tourmaline with different particulate diameters The origin mechanism and their significances of tourmaline particular characters are analyzed, and the influences of different particulate diameters on far infrared radiation and adsorption effect are got through the test. The test results of infrared spectrophotometer and infrared radiation detector show: (1) The smaller particulates are, the greater line strength of characteristic peaks are in infrared spectrogram; (2) There are the best intense infrared radiation whose wavelength is in the rage of 9.66～10.20μm; (3) All the infrared radiation emissivity values of different wavelengths are more than 9.0, which have little variances with different particulate diameters; (4) Corresponding with the infrared spectrogram, there are the best infrared radiation emissivity in the rage of 8～14μm, which is benefited to human health. After adsorption treatment of different particulate diameters tourmaline, the residual Cu2+ concentrations of CuSO4 solution are tested by atomic adsorption spectrophotometer, and the results show: (1) The smaller particulates are, the lighter residual Cu2+ concentrations are. There are the best adsorption effect of tourmaline in this experiment, whose particulate diameter is 208nm; (2) According to the national standard of discharge of sewage, the residual Cu2+ concentrations processed by tourmaline are much less than the primary standard. The origin mechanism and significance of tourmaline spontaneous polarization are analyzed, and it is considered that there are the close correlation between the piezoelectricity, pyroelectricity and the spontaneous polarization. While, the infrared radiation and adsorption effect are attributed to the variation of molecule electric moment and electrostatic field, which are considered as the results of spontaneous polarization. 5. The study of the applications of tourmaline The application of tourmaline is divided into two kinds, and one is traditional application, the other is new characters application. The fields of traditional application include jewellery and some industry (electronic industry, acoustoelectric materials, the test standard of material, component and parts of apparatus, abrasive material etc and so on). The fields of new characters application include environment protection, human health and agriculture. The adsorption of heavy-metal ion, cleaning up interface in water and air, neutralizing acid and alkali in water and marine environment protection of tourmaline play an important role in environment protection field. The functions of infrared radiation and releasing anion can be widely used in the fields of hairdressing, medical care, cosmetic, textile material, coating material, electromagnetic wave protection and so on. In the field of agriculture, the functions of bioelectric current, activating water and mineral substance of tourmaline can not only make the hair root of agricultural crop healthy and strong, but also make it adsorb water and nutrient well. Tourmaline even can replace the fertilizer that is harm to soil in the future. Therefore, tourmaline is a promising fertilizermineral, which can not only boost grain output but also improve earth environment. According to the surface effect and small-scale effect of nanometer and the particular characters of tourmaline, some new functions of nano-tourmaline are described. Meanwhile, their applications of composite and functional material in the future are forecasted. Further studies should be focused on the new processes in some particular conditions (high temperature, high pressure, strong acid, strong base and so on) of nano-tourmaline preparation, the influences of particulate specification (particulate diameter compounding ratio, configuration, array architecture and direction) on the performances and the operable control mechanism of dimension, shape, structure, array and orientation of tourmaline particulate.