The composition of silicon bricks

The composition of the silicon bricks is mainly squares of quartz and square quartz, and a small amount of quartz and vitreous. Scale quartz, square quartz and residual quartz at low temperatures due to crystal changes, the volume has a greater change, so the silicon brick is poor at low temperature thermal stability  . Use the process, below 800 ℃ to slow heating and cooling, so as to avoid cracks. It is not appropriate in the 800 ℃ below the temperature of the kiln to use.

The nature and process of the silica brick are closely related to the crystal transformation of SiO2. Therefore, the true proportion is the important quality index of silica brick. General requirements below 2.38, high-quality silica bricks should be below 2.35. The proportion of small, reflecting the brick in the amount of quartz and square quartz, the amount of residual quartz is small, so the residual line expansion is small, the use of low strength is also less.

The silica has seven crystalline variants and one amorphous variant. These variants can be divided into two categories: the first variants are quartz, squamous quartz and frontal quartz, whose crystal structures are very different and are very slow to convert from each other; the second variant is the subspecies of the above variants ─ ─ αβ and γ type, their structure is similar, faster conversion between each other.

The raw material for making silica bricks is silica. The higher the SiO2 content of the silica raw material, the higher the refractoriness. The most harmful impurities are Al2O3, K2O, Na2O, etc., which severely reduce the refractory properties of refractory products. Silica brick with SiO2 content of not less than 96% of the silica as raw materials, adding mineralants (such as scales, lime milk) and binders (such as molasses, sulfite pulp waste), by mixing, molding, drying, firing And other processes.