Fused-Cast Z80 Bricks for Glass Furnaces
Properties of Fused-Cast Z80 Bricks. Linear Thermal Expansion Rate: The linear thermal expansion rate is one of the key parameters for evaluating the performance of refractory materials. It reflects the dimensional changes a material undergoes in response to temperature fluctuations. This parameter is crucial for the selection of furnace body materials in fused-cast furnaces, as it directly impacts the structural stability and crack resistance of the furnace.
A comparison of the linear thermal expansion rates of Fused-Cast Z80 bricks and Fused-Cast AZS41# bricks reveals that the rates for both materials are quite similar at 1400°C. However, the variation in the linear thermal expansion rate of Fused-Cast Z80 bricks across different temperature ranges is significantly smaller. Consequently, Fused-Cast Z80 bricks present a lower risk of cracking during heating cycles or rapid temperature changes (thermal shock). By selecting Fused-Cast Z80 bricks as the refractory material, it is possible to more effectively mitigate structural damage to glass furnaces caused by temperature fluctuations, thereby enhancing the safety and reliability of fused-cast furnaces throughout their operational cycles.
Bubble Generation Rate. The bubble generation rate of Fused-Cast Z80 bricks stands at 0% at 1300°C and 0.1% at 1500°C—levels considered extremely low. Fused-Cast Z80 bricks exhibit the lowest bubble generation rate among comparable materials, demonstrating excellent efficacy in suppressing bubble defects in glass products caused by the refractory lining. This superior performance is attributed to the uniform elemental composition and density distribution of Fused-Cast Z80 bricks; as they undergo no changes in their phase structure, they are able to consistently maintain an exceptionally low bubble generation rate.
Physicochemical Properties of Fused-Cast Z80 Bricks
As a refractory material utilized in glass melting furnaces, the physicochemical properties of fused-cast Z80 bricks are of paramount importance. A comparative analysis against fused-cast AZS33#, AZS41#, and fused-cast 95% high-zirconia bricks reveals that the Z80 variety is characterized by a low impurity content, as well as high uniformity in apparent porosity and density. During service, the material exhibits no formation of glass phases, bubbles, or needle-like defects; furthermore, it possesses a relatively low coefficient of thermal expansion. Consequently, it demonstrates excellent resistance to corrosion, erosion, and thermal shock. Its comprehensive performance significantly surpasses that of fused-cast AZS33# and AZS41# bricks, placing it on par with fused-cast 95% high-zirconia bricks. However, given that its cost is lower than that of fused-cast 95% high-zirconia bricks, it offers an optimal balance between extending the service life of glass furnaces and managing investment costs.
Microstructure of Fused-Cast Z80 Bricks
The grain size of fused-cast Z80 bricks is significantly smaller than that of fused-cast 95% high-zirconia bricks—a characteristic that exerts multifaceted influences on the material’s overall performance.
First, a smaller grain size results in a higher density of grain boundaries. As key pathways for diffusion, grain boundaries effectively impede ion migration within high-temperature environments, thereby enhancing the material’s corrosion resistance and chemical stability. During the vitrification process of fly ash, fused-cast Z80 bricks demonstrate superior corrosion resistance, thereby minimizing material loss.
Second, a fine and uniformly distributed grain structure contributes to improved overall strength and toughness. Compared to materials with coarse grains, fine-grained materials exhibit reduced internal stress concentration and possess more tortuous crack propagation paths. Consequently, fused-cast Z80 bricks offer superior thermal shock stability and mechanical strength, resulting in a lower risk of fracture. In summary, the fine-grained microstructure of fused-cast Z80 bricks makes them an ideal choice for the refractory lining configurations of fly ash vitrification furnaces.
Fused-cast Z80 bricks possess exceptional resistance to thermal shock and exhibit favorable thermal penetration characteristics. During the furnace heat-up and commissioning process, fused-cast Z80 bricks remain free from cracking caused by thermal shock or linear thermal expansion variations; moreover, their efficient thermal penetration minimizes thermal shock-induced damage to the adjacent outer refractory layers.
Performance of Electrofused Z80/AZS Composite Bricks
Compared to electrofused AZS bricks, electrofused Z80 bricks exhibit superior resistance to corrosion and erosion, as well as excellent reheat performance; however, they come at a higher cost. Conversely, electrofused AZS bricks possess commendable mechanical strength and thermal stability. To extend furnace service life and reduce refractory material costs, a composite brick—comprising electrofused Z80 as the working face material and electrofused AZS as the backing support—has been developed. To ensure a robust bond between the two materials, a method combining physical structural design with the use of a high-temperature binder was adopted. During fabrication, mechanical interlocking was achieved through the precise control of interfacial roughness and geometry, while a high-temperature binder with a zirconia (ZrO₂) content of 90% by mass was selected to fill and reinforce the interface. Upon drying and curing at 200°C, this binder forms a strong bonding layer that enhances the structural integrity of the assembly and improves the composite material’s resistance to thermal shock and chemical attack.
In practical applications, the electrofused Z80/AZS composite brick has demonstrated excellent performance when compared against the electrofused AZS41# bricks and fused-cast 95# high-zirconia bricks produced by a renowned domestic manufacturer. The electrofused Z80/AZS composite brick offers several significant advantages in real-world usage:
- (1) It resolves the inherent challenge faced by single-material refractories—namely, the difficulty of simultaneously balancing manufacturing costs with performance requirements.
- (2) Through rational material pairing and optimized design, it enhances the cost-effectiveness of the refractory lining configuration, enabling users to achieve a longer furnace service life with a lower initial investment.
- (3) It reduces the frequency of maintenance and material replacements, thereby minimizing furnace downtime and generating substantial economic benefits for enterprises.
