Effect Of Microwave On Surface Properties Of Crystal Mineral Materials

With the development of chemical engineering science in cross fields, as a important direction of enhanced process of reaction and transfer, the microwave synergistic effect of field technology has attracted more and more attention. It has been found in many industrial process and laboratorial experiments that microwave has many unique effects such as rapid heating, accelerating some organic reactions, surface modification of some inorganic materials, etc. At present, the effect caused by microwave is mainly divided into "thermal effect" and "non-thermal effect", but the mechanism of which has not been discovered thoroughly. In order to study on microwave effect phenomenon, the variances of surface characteristic of some substances were investigated, which includes perovskite of titanium compounds system and calcium sulfate of sulfur-based compounds system in this paper.In this paper, the surface effects in slag of blast furnace and calcium sulphate etc. after exposure in microwave field, including surface energy and surface electric chargy, are investigated. It will not only offer the parameters of intensifying interface process in muti-phase reaction, but also open a new direction in industrialization.First, the dielectric property changes of calcium sulphate dihydrate, the main component of phosphate gypsum, at high temperatures is measured, and the possible method to dispose calcium sulphate is discussed. The dielectric constant shows slow increase with increasing temperature, but no sudden change is observed. As a result, the tentative plan of amorphous carbon mixing with calcium sulphate dihydrate is raised.To study the effect of microwave on surface properties of materials, based on Washburn penetration theory, Owens-Wendt-Kaelble approach and thin layer wicking technology, the surface free energy and their components of calcium sulphate dehydrate, blast furnace slag, titanium dioxide and pyrite has been investigated before and after microwave radiation. It denotes that the microwave radiation raised the surface free energy of all, and the surface energy raise of calcium sulphate dehydrate, blast furnace slag, titanium dioxide is due to the strengthen of polar component, while the surface energy raise of pyrite is due to the strengthen of no polar component. It will increase the adsorption ability between solid and liquid surface and is benefit to the reaction process of solid-liquid.Then the influence on surface electric charge in microwave is observed, which shows that the change of surfaceζpotential occurs after microwave radiation. This interesting phenomenon reveals electron migration on the surface in the microwave field. The electronic charge distribution on the surface with construction defect has been changed.To validate the thought that microwave is good to the reaction process of solid-liquid, traditional acid digestion rate is compared with the special method, in which raw material is handled with microwave radiation. It denotes that feed after microwave radiation raises the digestion rate, and the enhancement effect is proved.