Silicon in container glasses, its solution kinetics and dissolving potential in container glass furnaces

Abstract

The forming proeess of sihcon stones in differently colored container glasses under the action of different aluminum pieces will be discussed and some special features during the generation reported. The dissolution of formed silicon stones was analyzed in dependence on melting time, temperature and color of the glass. With the knowledge of these parameters the rate constant and the diffusion coefficient of the dissoludon were calculated. The main results are: first, it is not possible to generate large silicon stones anyway, indicated by big aluminum pieces which will be divided when they become liquid. Second, the dissolving of the silicon stones does not go on homogenously about the whole temperature range analyzed. But it can be divided into three fields: an area below, an area around and an area above the melting point of the silicon. The reason for these differences is found in the SiO2-rich layer around the stones which will be formed and dissolved by different rates in colored container glasses. On the basis of these dissolving rates and of the temperature profiles in glass meldng furnaces the dissolving potential in furnaces could be calculated. Three possible routes of silicon stones through special types of furnaces show the respective dissolving potential for silicon. The potential for dissolution of elementary Silicon for the calculated types of Container glass furnaces is nearly the same. The dissolution rates could be improved by raising the temperature of the glass bath in the furnace and by raising the dwell time of the silicon stones in the furnace.