The Influence of Fe Additives on Silica Brick Microstructure

Mineralogical composition has a decisive influence on the durability of silica materials built into heating aggregates as well as their dense. This paper describes the influence of Fe aditives and the influence of firing temperatures on the physical and mechanical properties and on final mineralogical composition of silica materials. The paper compares the properties of silica prepared without Fe additives with that prepared using Fe additives of varied granulometry.

Phase Behavior of Silica Brick Used in Carbothermal Reduction

In this study we observed the phase behavior of silica brick used in the process of carbothermal reduction. At 1550°C, there are liner β-SiC in clumps huddled together; At 1550°C, short line clumps changed into filamentous, mixed together. There are many particles and some β-SiC lines and few filamentous β-SiC at 1600°C . Different ratio of carbon coke also effect the phase behavior. From the results we obtained SiC powders. SiC refractory powders were prepared via carbothermal reduction method using used silica bricks as raw materials. The effects of carbon content, temperature and holding time on the phase composition and microstructure were analyzed. XRD and SEM analyses show that: β-SiC refractory powders were synthesized at 1600°C for 6 h with100 wt% excessive of carbon content. With the increase of carbon content, the reaction temperature and holding time, content of β-SiC gradually increased while that of cristobalite decreased.