The mostly applied type of refractory in the glass industry, in direct contact with the glass melt, is fused cast AZS block. The fused cast AZS block is available in a number of grades, principally distinguished by zircon content: 33#, 36# and 41#. The fused cast AZS 33# block is the most common product used for less severe glass contact areas in the glass furnace.

1. Fused Cast AZS 33# Block For Glass Furnaces
The mostly applied type of refractory in the glass industry, in direct contact with the
glass melt, is fused cast AZS block. The fused cast AZS block is available in a number
of grades, principally distinguished by zircon content: 33#, 36# and 41#. The fused
cast AZS 33# block is the most common product used for less severe glass contact
areas in the glass furnace.
The fused cast AZS 33# block contains 33% ZrO2. The process of the production of
the fused cast AZS 33# block includes molds, melting, casting and annealing. First the
raw materials are melted in an electric arc furnace at about 2200-2400 ℃. The melt
is treated with oxygen to oxidize zirconium oxy-carbo-nitride or other reduced
constituents, produced by the reaction with the graphite electrodes during melting.
The molten material is then cast into molds to, or very near to, the final shape of the
block desired. The mold with the fused cast ceramic is cooled down very slowly in
order to anneal (free of thermal stresses) the fused cast product.
Fused cast AZS 33# block has dense micro structure which ensures its great erosion
resistibility to molten glass. It is unlikely to cause defections of stones, blisters and
cords. It also has good thermal shock resistibility and high compression resistance. It
is available in a variety of formats and shapes for different working areas of glass
furnaces.
The fused cast AZS 33# block is most suitable for superstructures of melters, side
walls of refiners, paving blocks, port Area, port Lining and forehearth channel blocks.
They are particularly useful in electric furnace (cold crown type melters), sidewalls
and orifice assembly protection blocks where exceptional thermal shock
characteristics and resistance to high alkali glass is required or in other applications
where resistance to hot corrosive slags is needed.

2. According to the casting method, fused cast AZS 33# block can be divided into
Normal casting(PT), Tilt casting(QX), Semi-Void-Free casting(ZWS) and Void-free
casting(WS).
The fused cast AZS 33PT block
The unique technology of PT casting changes distribution of shrinkage voids of
regular casting bricks, reduces shrinkage voids, and increases the dependability of
bricks. It is recommeded for superstructure, working end and feeder channel, etc.
Due to the material’s excellent castability, this product can be made into kinds of
different shapes and sizes such as Feeder channel block, thermocouple block, tuck
stone, crown and burner block.
The fused cast AZS 33ZWS block
The voids are small and located at bottom of the brick, which should be down when
the brick is used. This product is designed for the sidewalls of flame furnaces with
embedded melted bottoms, for total, security with average pulls and campaign
lengths. This product is only available for straight brick or approximate ones.
The fused cast AZS 33WS block
The fused cast AZS 33WS block is cast from exclusive riser, which assures the melted
liquid cast into the model almostly. This product is designed for the special places of
flame furnace, such as side wall, tank bottom, superstructure, feeder channel, bowl,
bleeder, C shaped brick, etc.
The fused cast AZS 33# block from Sunrise Refractory has passed the ISO
international certified. High purity raw material, scientific formula, advanced
technology and professional guide all contribute to our qualified azs blocks
production.
Article Source: http://www.fusedazs.com/news/74.html