Zirconia Series Refractory Bricks

Zircon Brick

Name: Zircon Brick
Brand: XZK

Zircon bricks with 65% ZrO2 for glass furnace crown corners, tank bottom paving and forehearths. High density and low thermal expansion block alkali penetration and upward drilling. Grades XZK-ZR65-A and XZK-ZR65-B.

ZrO₂:≥65%

Bulk densit:y≥3.75g/cm³

Cold crushing strength:≥80MPa

Load - softening temperature at 0.2MPa:T0.6≥1650℃

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Zircon Brick Overview

Zircon bricks are refractory materials whose crystalline matrix is dominated by zirconium silicate (ZrSiO₄), with a ZrO₂ content of 65% or more. They are produced by high-temperature sintering and are valued for a combination of properties that few other refractories offer together: exceptional resistance to glass melt and slag, very low thermal expansion, and near-total chemical stability.

XZK Group supplies zircon bricks in two grades — XZK-ZR65-A (aggregate type) and XZK-ZR65-B (ordinary type) — from our Xinmi plant in Henan. In glass furnaces they are a critical material in the crown corner, the tank bottom paving and the forehearth.

Why Zircon Performs in Glass Contact

Zircon's defining behaviour in a glass furnace is that it is almost inert to molten glass. Where other refractories are progressively dissolved by the melt, zircon resists corrosion and, critically, resists the "upward drilling" that damages tank bottoms.

Very high melting point (2430°C) and a refractoriness under load of 1650–1680°C, allowing service in the hottest glass contact zones.
Low thermal expansion of roughly 4.2 × 10^-6/°C, which gives zircon excellent thermal shock resistance — the material tolerates the rapid cycling that occurs during batch charging and furnace reversals.
High density from 3.75 to 3.80 g/cm³, creating the tight, low-permeability structure that blocks melt penetration between bricks.
Chemical stability against acid and alkali media, molten metals and glass melt. Zircon also has low wettability by glass, so the melt tends to bead rather than spread along the brick surface.
High hardness of about 7.5 on the Mohs scale and cold crushing strength up to 100 MPa, giving strong structural performance under the load of a full tank bottom.

Technical Specifications

Technical Properties	XZK-ZR65-A (Aggregate)	XZK-ZR65-B (Ordinary)
ZrO₂ (%)	≥ 65	≥ 65
SiO₂ (%)	≤ 33	≤ 33
Fe₂O₃ (%)	≤ 0.2	≤ 0.2
Bulk Density (g/cm³)	≥ 3.80	≥ 3.75
Apparent Porosity (%)	≤ 17	≤ 17
Cold Crushing Strength (MPa)	≥ 100	≥ 80
Refractoriness Under Load (0.2MPa, ℃)	≥ 1680	≥ 1650

Test methods follow GB/T and ISO practice; ASTM equivalents and full certificates of analysis are issued with every shipment.

Aggregate Type or Ordinary Type?

Both grades carry the same 65% ZrO₂ minimum; the difference is body structure and performance ceiling.

XZK-ZR65-A (aggregate type) uses a graded aggregate structure that raises bulk density to 3.80 g/cm³ and cold crushing strength to 100 MPa. Specify it for the most demanding positions: bottom paving in high-pull furnaces and load-bearing sub-layer courses.
XZK-ZR65-B (ordinary type) delivers 3.75 g/cm³ and 80 MPa, and is cost-effective in general positions where the mechanical load is lower.

Where the application demands resistance to both glass melt and alkali vapour at higher severity, zircon mullite bricks extend the same chemistry with improved thermal shock behaviour, and the patented Three-Resistant brick combines zirconia with chromia for combined spalling, erosion and thermal shock resistance.

Industry Applications

Glass Industry: Key parts such as the flame space, feeder channel covers, and charging ports of glass kilns.
Metallurgical Industry: Linings of steel ladles, continuous casting sizing nozzles, and linings of induction furnaces.
Other Fields: High - temperature scenarios such as ceramic kilns and enamel firing equipment.

Where Zircon Bricks Are Used in a Glass Furnace

Zircon appears in four locations in a glass tank, each for a different reason:

Crown corner (crown springing) and tuck stones. This is the junction between the crown and the breastwall, where structural stress concentrates and alkali vapour migrates upward. Dense zircon bricks block the alkali path that would otherwise open the joint.
Tank bottom paving and sub-layer. This is zircon's most critical glass application. Heavy metal contaminants in the batch settle on the bottom paving and, if the joints are permeable, drill upward through the bottom structure. Zircon's density and low wettability form an effective barrier; in most designs zircon paving works together with a zircon ramming mass sealing layer beneath it.
Forehearth and feeder channel covers. Zircon resists the glass melt without contaminating it, protecting glass quality in the conditioning section.
Doghouse and charging ports. The charging area experiences thermal cycling and batch dust erosion; zircon's low expansion and hardness handle both.

Manufacturing and Quality Control

Zircon bricks are produced from high-purity zircon sand, pressed on CNC presses of 630 to 2000 tonnes and fired in fully automatic tunnel kilns for a uniform soak. Because zircon's performance depends on achieving consistently low porosity, density is controlled by press force rather than operator judgement, and every batch is verified for bulk density, apparent porosity, cold crushing strength and refractoriness under load before shipment.

XZK Group holds ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certification, is recognised as a National High-Tech Enterprise, and operates the Henan Provincial Engineering Technology Research Centre for Sintered Refractories for Glass Furnaces. We have contributed to national and industry standards including GB/T 4984-2023 (Chemical analysis methods for zirconium-containing refractories).

Related Refractory Products

Zircon bricks are usually specified as part of a complete bottom and superstructure system, alongside zircon mullite bricks, zircon ramming mass, sintered AZS bricks, fused cast AZS blocks and corundum bricks. Browse all refractory products or see the zircon bricks range for zoning guidance.

Proven Global Projects

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Wuliangye Group

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Wujiang CSG Glass Co., Ltd.

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About XZK Group

Strengths

Innovation

R&D Team

Facilities

Honors

Product Portfolio

Specializing in premium zircon, corundum, sintered AZS, and monolithics. With a $70M+ annual output, we deliver durable linings for global high-temp industries.

Capacity

✔ 4 automated microcomputer batching systems.

✔ 4 ultra-high-temp tunnel kilns & 5 shuttle kilns.

✔ 20+ CNC hydraulic presses (630-1500T).

✔ Digitalized workshops with 100,000T annual capacity.