Corrosion And Erosion Wear Of Fused Cast AZS In Glass Furnaces

Nowadays, refractory materials are important in the glass furnace. Refractory materials are considered mechanically and chemically high performance at temperatures above 1400℃. The requirements for refractory materials are good physical and mechanical resistance to thermal shock and to attack by molten glass.
The refractory materials for the glass industry has made significant progress. Refractories for glass furnaces are normally based on A12O3, ZrO2, and SiO2, with or without Cr2O3. Refractories for the glass furnace are expected to have higher corrosion resistance to molten glass, no defects in glass environmental compatibility, reliable properties and improved methodology to identify origins of defects.
The major objective in the glass furnace is to optimize the entire process by reducing the maximum temperature of melting, improving refractory performance and/or improving fuel efficiency. The required physical and chemical properties of refractories are: thermal shock resistance, corrosion resistance, controlled expansion behavior, low thermal conductivity, and adequate creep resistance.
The fused cast manufacturing process was introduced by Fulcher in 1925 based on research conducted at Corning Glass Co. A characteristic of this manufacturing is that the materials have a low porosity. It is of great importance to the refractory, since this minimizes the glass refractory interface. Because the ZrO2 has a high melting point and has good corrosion resistance to the molten glass, fused cast AZS is widely used in the production of glass.
Fused cast AZS block generally consists of 33-41% zirconia crystals, interlocked with corundum, and minor interstitial glass. They perform well in contact with many glasses melted at 1500℃ or lower. But it can react with new developmental glasses, particularly rare earth alumino-silicates which has much higher melting temperatures, resulting in erosion of crystalline particles which cause stones in the glass.
The chemical reactions at the surfaces of refractories may take place between molten slag, fluxing agents, and gaseous substances. The corrosion of the refractories may be due to batch carryover, volatile fluxes, and melt attack, mainly at the metal line. Erosion often follows the initial corrosion, washing away refractory grains after the original bond has dissolved.
Fused cast AZS in contact with molten glass form a viscous silicate layer adjacent to the refractory thus restricting contact, and therefore, increasing corrosion resistance. When fused cast AZS are used in superstructures, they are exposed to high temperature combustion products. Superstructure and crown refractories are subjected to corrosive reactions with the vapor species of the batch components and batch carryover. In the melting of soda-lime glasses, the vapor species are primarily soda and sodium sulfates, while for borosilicate glasses, they are Na-tetraborate and B2O 3 predominate.
Zhengzhou Sunrise is a refractory material supplier from China, offering high quality refractory materials for glass furnaces, including fused cast AZS block, fused cast alumina block, fused cast high zirconia block, mullite brick, zircon brick, alumina bubble brick, magnesia brick, sillimanite brick, corundum brick, low porosity fireclay brick, high alumina brick, all kinds of glass furnace ramming masses, etc..