Product Details

Acid Resistant Silica Bricks

Introduction

Silica Bricks (also be called silica refractory brick or silicate firebrick) are made of silica sand material, the content of SiO2 is more than 94%. And Al2O3 is lower than 1.0%, apparent porosity is under 22%. Silica bricks belong to acid refractory brick, which have the excellent ability to resist acid slag and acid erosion. Silica bricks have good strength in high temperature, high refractoriness under load about 1640-1680℃, high softening point with temperature. and, Silica bricks are also featured with high dense characteristic, good heat conduction. The refractoriness can reach at the most 1730°C. they are ideal high-temperature furnace construction materials. They are normally used in the iron & steel industry, and the super grade will be the necessary refractories in glass industry.

The silica refractories are manufactured as multiple asymmetric shapes, which are normally keyed or interlocked with each other by means of tongues and grooves.

Silica brick is widely used in the bottom and wall of coke oven.

Features

Silica refractories consist mainly of silicon dioxide (SiO₂). Silica refractories also contain calcium compounds formed from calcium hydroxide which is used as a bonding agent.

The fired silica brick contains the crystalline SiO₂ modifications cristobalite, tridymite and some residual quartz. During the firing process, the lime reacts with the finest quartzite components to form wollastonite (CaO•SiO₂). The matrix also contains very small quantities of calcium ferrite, hematite, magnetite, calcium olivine and hedenbergite [calcium ferrous silicate, CaFe(SiO₃)₂], which are formed from impurities. These crystalline phases are the reason for the discoloration and spot formation on the fired bricks.

The transformed coarse grain generally consists of cristobalite, a proportion of residual quartz corresponding to the degree of transformation and very little tridymite, whereas the fine grained matrix is enriched with tridymite, glass and wollastonite.

The density of a fired silica brick is lowest when the degree of transformation is farthest advanced and attain the value of 2.33 g/cm3 with complete transformation.

Porperties

Good corrosion resistance of acid slag.
The refractoriness of silica brick is not quite high, about 1600-1730℃
Good stability under the high temperature.
Poor thermal resistance performance.
Good air tightness.
True density 2.35g/cm³.
Total volume expansion 1.5~2.2% at the temperature of 1450℃.

Chemical & Physical Index

Item / Model		XHJSIB94	XHJSIB96	XHJSIB98
Chemical Composition	SiO₂	≥94	≥96	≥98
	Al₂O₃	≤3.0	≤1.0	≤0.5
	Fe₂O₃	≤1.3	≤1.0	≤0.5
Apparent porosity	%	≤22(24)	≤22(24)	≤22(24)
Cold crushing strength	Mpa	≥45(35)	≥45(35)	≥45(35)
Refractoriness under load	0.2Mpa/ ºC	≥1650	≥1680	≥1710
Remaining quarts	%	≤1.0	≤0.8	≤0.8
Compressive Creep	%	≤0.8	≤0.8	≤0.8
Thermal expansion coefficient	1000ºC, %	≤1.28	≤1.25	≤1.23
Apparent density	g/cm³	≤2.32	≤2.32	≤2.32

Characteristics:

Mortar required for providing plaster on calcium silicate bricks is very less.
Color and texture of these bricks is uniform.
Compressive strength of sand lime bricks is about 10N/mm². So, they are well suitable for multi storied buildings.
For constructions in clay soils, these bricks are more preferable.
Trouble of Efflorescence does not arise in the case of sand lime bricks.
Not only bricks, blocks and tiles can also be made using calcium silicate.
Sand lime bricks provides more comfort and accessibility for architects to attain desired shape and designs.
These bricks have accurate shape and size with straight edges.
Solar heat effect is reduced on exposed walls made of calcium silicate bricks.
Colored sand lime bricks do not need any finish to the wall, so, cost reduces.
These bricks have great fire resistance and water repellant properties.
Calcium silicate brick walls resists noise from outside.
Cost of construction gets reduced about 40% of total cost due to following factors.

Application :

l For lay coking chamber of coke oven and partition wall of combustor, kiln crown and wall of glass furnace and calcining kiln of silicate product.

l Use high dense silica fire brick to lay Large-scale coke oven, which can thin the wall of coking chamber and combustor to improve the production capacity.

l Used in flow aluminum tanks, aluminum gates and is suitable for upper wall of a furnace for masonry of low alkali borosilicate glass.

Package
Wooden pallet wrapped with plastic film & bundled belts