A MICROWAVE METHOD FOR OBTAINING AND MELTING GLASS CHARGE BASED ON LEAD METASILICATE
Keywords:
sodium silicate, lead metasilicate, hydrothermal - microwave synthesis, thermal analysis, X-ray phase analysis, transmission, absorptionAbstract
Studies of the process of preparation and melting of glass charge of the composition (in wt. %): PbO-78.8; SiO2-21.2 are carried out on the basis of silica-containing rocks by the hydrothermal-microwave method. The physicochemical properties and melting characteristics of the charge of the PbO-SiO2 composition are studied.
Studies have been conducted on Low-melting glass based on lead hydrometasilicate is obtained. The melting process of the charge is carried out in an electric furnace of the company “Naberterm" brand LHT 08/17. The conducted studies show the effectiveness of MW treatment in the production of lead hydrometasilicate and glass based on it. MW processing requires much less energy (70...80%) compared to traditional heating. It is established, that the complex charge is melted at lower temperatures (900oC), and the energy of microwave (MV) radiation intensifies the process of both hydrothermal treatment and drying of the charge in comparison with the traditional heating methods. The total melting time of the glass is also sharply reduced (by 2...3 times), the loss of components during melting is also reduced.
The acceleration of the glass-melting process in comparison with the traditional charge is explained by the fact that when heating the traditional charge, lead oxides are melted, and various forms of silica - containing rock are dissolved to form silicates at high temperatures, while in a hydrothermal charge, this stage is already completed at the stage of synthesis at lower temperatures (20…100°C), and during melting, the obtained silicates are melted.
MW synthesis provides a nanodispersed powder of lead metasilicate. The reflection coefficient of the samples synthesized by the MW method and heat-treated at 200°C is higher than that of the crystalline phase obtained at 700°C, which makes it a valuable material also for obtaining thermoregulating coatings. MW synthesis of lead metasilicate from aqueous solutions based on rocks is promising and economical.
