Applications of zirconium bricks in the glass industry

Zirconium bricks are an indispensable key refractory material in the glass industry. Their core purpose is to construct an “inner liner” for the glass melting furnace, resisting high temperatures and chemical corrosion, directly affecting the furnace’s lifespan and the quality of the glass products.

In glass production, zirconia bricks primarily play a dual role as a “protective barrier” and a “quality guardian.” Their specific applications vary depending on the zirconium oxide content and brick type performance, and they are precisely deployed in various key parts of the furnace:

Main Force: Fused Zirconia-Corundum Bricks (AZS bricks, ZrO₂ content 33%-45%)

This is the most widely used series of zirconia bricks. Its name AZS is derived from the first letters of its main components: alumina (A), zirconium oxide (Z), and silicon dioxide (S). Due to its excellent resistance to molten glass corrosion and low contamination of the molten glass, it is widely used in areas that come into direct contact with molten glass.

Core areas resisting high-temperature corrosion: Its performance and applications vary depending on the zirconium oxide content. AZS-33# has good castability and is commonly used in the upper structure of kilns and the walls of working tanks. AZS-36# offers better corrosion resistance and is suitable for tank wall areas with high glass flow rates or high temperatures. AZS-41# has the strongest corrosion resistance and is the preferred material for protecting the kiln’s “throat”—critical areas such as flow channels, charging port corners, and kiln sills—which often determine the lifespan of the entire kiln.

Ensuring Glass Purity: Through advanced processes such as oxidation melting, modern AZS bricks can reduce the carbon content to extremely low levels (e.g., 0.005%), significantly reducing contamination of the molten glass and effectively controlling bubble precipitation, preventing defects such as stones and bubbles in the glass. Latest technologies can even reduce the bubble precipitation rate to levels comparable to more expensive αβ alumina bricks, allowing for applications in the cooling and forming parts of high-end products such as electronic glass and photovoltaic glass.

Specialty Elite: High Zirconium Bricks (ZrO₂ content ≥ 89%)

For specialty glasses with extremely stringent quality requirements, high zirconium bricks with extremely high zirconium content are necessary. Its mineral phase is almost entirely composed of zircon, exhibiting extremely low contamination of the molten glass and excellent thermal shock resistance. Therefore, it is widely used in critical parts of furnaces in the production of specialty glasses such as television glass, borosilicate glass, aluminosilicate glass, and fiberglass.

In general, the main use of zirconium bricks in the glass industry is as “armor” for the melting furnace. AZS series bricks serve as the “conventional force” providing primary protection, while high zirconium bricks are the “special forces” protecting high-end specialty glass production lines.