摘要 |
<p>In a method of treating raw glass material containing easily volatilizable additives, the raw material containing the additives, of which at least one easily vaporizes giving off poisonous gases, is mixed with powdered cullet in the range 0.05 to 30% by weight with respect to the cullet, the resulting mixture then being sintered in the temperature range 500 DEG to 1200 DEG C. before charging to a furnace. This enables a larger proportion of the volatile ingredient fed into the furnace to be retained in the final glass. To give better results the batch mixture may be subjected to pressures of from 60 to 500 kg./cm.2 before sintering for example, to form pellets or briquettes. The volatile ingredients used are chosen from antimony, arsenic, selenium, sulphur, and tellurium.</p> |