The Pilot Production Of Nanotitania With Anatase Structure From TiCl₄ Aqueous Solution

Recently, because special physics and chemistry properties of nanosized TiO₂ particles such as heat, light, sensitive properties and surface stability were quite different from general materials, they were intensively applied in the environment, information, material, sources of energy, medical treatment and hygiene etc. The surface atom number, surface ability and surface tension of nanosized TiO₂ particles with high surface area were sharply increased along with the degression of the diameter with high additional value, great concern and striking development were caused in industry-advanced countries over 20 years. Their production districts focus in Western Europe and the northern America, and another bigger output in Japan and Korea. A wide range of research has been carried out in our country, and some enterprises also have much effort in pilot studying and scope production. The industrialization of nanometer TiO₂ powder has become a hot aspect of nanometer material science research.At present, the preparation of nanometer TiO₂ powder has always been one of the most important subjects of research in the whole world. Lots of methods of preparation had been developed, but most of them restricted the industrial production. As far as we know, only gas and liquid phase methods can be applied in the industry in spite of complicated technology and operation. The nanometer TiO₂ powder from the gas method with fast rate has many characterists, such as higher purity, nice dispersity, little agglomeration, higher surface activity and high properties, As the gas reaction was accomplished temporarily at the high temperature, the mould type of reaction devices, material nature of equipment and the way of heatingand charge-in were highly required. Up to now, the gas method in our country is still under the experimental stage. In order to realize an industrial scale, a series of engineering and equipment problems have to be solved. While the liquid phase method has been developed to product on a large scale because of low cost, and simple equipment. Of all the reports, TiCl₄ often serve as a source of liquid phase research. But with lower reactant concentration and longer reaction time and high temperature calcinations, they can just achieve psendospherical or needle-type particles with broad size distribution. In view of the advantage and disadvantage of available methods of nanometer TiO₂ industry production, we prepared nanometer TiO₂ powder from TiCl₄ as the raw material through forced hydrolysis under the boiling reflux method in our laboratory over several years. The method has some outstanding characteristics, such as simple equipment, high initial concentration, short reaction time, low reaction temperature, uniform distribution of particle size etc. The morphology, size and crystal structure can be controlled. In order to verify the magnifying effect of experimental conditions and provide theory and practice basis to realize the industrialization, we make the pilot scale research.In this paper, I have studied the optimization of preparing condition of nanometer titania in detail, and investigated the influence of different factors to the resulting product, and imitated complete set technology of industrialization. The main research aspects are as follows: (1) Selecting and installing of equipmentAccording to the production technology, properties of nanometer TiO₂, capacity of the pilot scale experimental, the scope of work place and economical factors, we select the appropriate equipments in the workshop. We choose intermission vitreous enamel reactor as the reaction devices, use the inorganic ceramic membrane to wash the chlorine ion, use the sedimentation centrifuge to separate the solid and liquid phase, and utilizeflash vaporization drying equipment, we got the TiO₂ powder in the end. According to the basis needs, we have selected a set of pure water system to prepare the distilled water. After each equipment was installed, we had co...