Study on the processes controlling the rate of glass batch melting

Abstract

The first objective of this thesis work is to study the processes controlling the rate of glass batch melting. The main focus is on three processes, i.e., heat transfer from the furnace atmosphere to the batch blanket, chemical reaction taking place in the blanket upon heating, and drainage flow from the blanket to the melts. The second objective is to develop a method suited for investigations in the field of batch melting in more realistic dimensions. Finally, the melting behavior of individual batches are observed. The experimental procedure can be divided into two parts, i.e., the pre-tests on 100 g batches and the main tests on 10 kg batches. For the pre-tests, an individual raw material, or a selected combination of raw materials are heated from room temperature to 900 C. Both temperature and resistivity are continuously recorded. The primary liquid phase formation temperatures are determined by interpretation form the results and by consulting phase diagrams. For the main tests, 7 kg of cullet are molten first. When the temperature approaches 1200C, 4 kg of typical soda lime glass batch is charged onto the melt. The temperature and resistivities at different positions in the batch blanket are recorded. The relation among temperature, resistivity, primary liquid phase formation, and the time are compiled. As a major results, the local heating rate is found to be the main parameter controlling the rate of glass batch melting.