Dissertation
Dissertation > Industrial Technology > General industrial technology > Industrial common technology and equipment > Powder technology

Study on Mechanical-Chemistry and Physical Properties of Mechanically Ground Fly Ash

Author WangXiaoJun
Tutor YangNanRu
School Nanjing University of Technology
Course Materials Science
Keywords Fly ash Mechano-chemical NMR Silicon oxide polyhedron Aluminum oxide polyhedron
CLC TB44
Type PhD thesis
Year 2003
Downloads 702
Quotes 18
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Since the eighties, the mechano-chemical is applied in the study of matter has been some development in the chemical properties and chemical reaction changes the mechanical energy, obtained from the object of study, the mechanical crushing method and means of research and analysis. progress. In the the premise of fly ash research and application of in-depth and wide-ranging, the principle of the present study, mechano-chemical investigate the changes of fly ash in the mechanical crushing some of the physical and chemical phenomena. Particle size analysis, thermal analysis, scanning electron microscopy techniques, especially the use of advanced means of NMR and high-resolution magic angle spinning nuclear magnetic resonance technology to explore these changes, and the results applied to other new materials or new areas under development. Thesis of fly ash and chemical study of the mechanical force comprehensive exposition, including the basic nature of the fly ash, fly ash application and refinement of measures of fly ash. Mechano-chemical development brief presentation applications, together with the fly ash of the mechano-chemical discussion can be seen: in the domestic and international research on fly ash mechano-chemical fly ash caused by the mechanical action of the changes in the thermal properties, especially the microscopic structure of fly ash on the mechanical polishing process has not been reported. Selected fly ash gray species, determine the grinding machine and grinding conditions and analytical methods, results and conclusions of the research are as follows: different the grinding conditions - including different grinding machinery, dry wet conditions, the isothermal and non-isothermal, the different grinding materials: ball: the proportion of water and other effects on the experimental results of fly ash obtained the influence of the above-mentioned conditions on the fly ash density, particle size, and fly ash surface. The experimental data show that: 1. Grinding machinery itself, a large mechanical force, fly ash becomes large, after polishing the density of the particle size becomes small. 2. The thermal effect generated by the grinding is one of the reasons of the \This can compare the results under isothermal and non-isothermal conditions: fly ash particle size in reducing the increase of grinding time remains at a constant temperature. Mechanical force is large enough, it can overcome the effect of the grinding heat. 3. Under wet grinding conditions, the particle morphology and dry under the conditions of fine particles independently distributed form, Suixiao particles attached to the surface of the large particles, mutual connection between the various particles, the is a flocculent phenomenon. The paper noted that the aqueous medium to form hydrogen bonds with fly ash, it is possible to procure the fly ash is ground under wet milling conditions and easily dispersed in water. With milled release adsorbed water, fly ash, the phase transition of quartz, the oxidation of carbon and calcium carbonate decomposition temperature are reduced, papers from a physical grinding fly ash DTA analysis confirmed: of which mechanism to explain the chemical point of view. Grinding fly ash [5104] 4 tetrahedron polymerization state trimethylsilylation analysis, NMR studies of solid 27AI and 2951, one-dimensional (ID) and two-dimensional (ZD). This is a solid-state NMR to study the mechanical grinding of fly ash for the first time. The results show: the four coordinated aluminum fly ash oxygen polyhedron structure and 6-coordinated aluminum oxygen polyhedron aluminum structure change in the mechanical polishing process: On the other hand, the fly ash in the silicon-oxygen polyhedra aluminum structure 4 ligand structure exists, it appears only minor changes in the mechanical polishing process. The study also showed that: fly ash long after grinding particles \environmental structure. These new findings to explore other alkali silicate materials to stimulate the activation and structural changes play a reference. Thesis of fly ash for the first time in two-dimensional multi-quantum magic angle spinning nuclear magnetic resonance the (ZD MQMASNMR) study clearly show: the 4 coordinated aluminum oxide polyhedron structure has three existing forms; 6-coordinated aluminum the oxygen polyhedra aluminum structure originally There are two forms of the fly ash after mechanical polishing another form of structural variation. NMR studies on such a structure different, reflecting the dry and wet grinding in the SEM is the corresponding different from the morphology of the fly ash sample. Be effectively utilized for the fly ash and grinding the fly ash, the trial will be grinding of the fly ash was incorporated into the resin matrix composites using, as a general filler. Obtained before and after addition the change in viscosity of the resin glue, the exothermic peak temperature changes, the gelling time of the change, the change of bending strength and acid corrosion of the variation of the process performance. With fly ash incorporated amount increased to increase the viscosity of the resin glue; exothermic peak temperature decreases; gelling time; bending strength also decreases. Experimental doped system gray resin composite articles a higher bending strength than a bending strength of doped a gray resin composite article. Can be seen by SEM observation: a gray glass beads and resin combined with a clear interface, ash and resin system after grinding to form a diffuse interface. Studies suggest that this is the reason for the change of the intensity of the product. HRjMAS NMR for the first time the new technology for the study of the solid and liquid samples. Curing resin after HR / MAS NMR spectra of the experiment were found to have side groups or degree of polymerization of reducing or reducing sharp peaks of resin crosslinking degree. Analysis: adding fly ash products after the bending strength decreased, the resin side yl phenomenon or because the polymerization inhibiting effect of fly ash makes the linear unsaturated polyester polymerization degree reduces or reduces the degree of crosslinking, the polymerization the junction reduced, eventually leading to the bending strength of the composite article is decreased. Side of H MAS NMR method pioneering study has been started successfully applied to biological glutamate new coating of rubber products, petrochemical and industrial solid catalyst activity changes, resistance to bone cancer drug development, in vivo biological cells to mutate, nanomaterials coated water and moso bamboo charring catalyst, etc. or sample studies, explained wherein glutamate polymerized form, the problem of the presence of the coating, the catalyst poisoning.

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