Abstract: Silica sand, aluminium oxide and magnesium oxide have always been selected as main raw materials for the production of S high-strength fiber glass in the SiO₂-Al₂O₃-MgO system. The high purity of these chemicals helps to improve the stability of product composition and performance, which bring highly energy-consuming, require higher temperature and have difficulties in glass melt clarification and homogenizing meanwhile. To improve the melting process performance of SiO₂-Al₂O₃-MgO system S-glass, the influence of kaolin and talc in S-glass melting is studied in this paper. The characteristic temperature of glass is analyzed by DSC, the phase transformation in the batch melting process is characterized by XRD. The batch melting experiment has been carried out in a muffle furnace, and the strength test of the new born glass fiber was carried out. Studies have shown that use of the batch of kaolin and talc can significantly lower the melting temperature about 50 ℃, reduce energy consumption and improve the system of S-glass melting process performance. Also it is found that minerals of Fe²⁺ content in raw materials is larger, which increase the temperature gradient in glass melt and is not conducive to glass clarification. So, in order to improve the glass clarification and avoid the glass fiber performance affected, measures should be taken to reduce the content of Fe²⁺ in S-glass batch melting.

Key words: kaolin, talc, melting, S-glass