Zircon REFR
Grade
REFR = bonded zircon refractory brick / shape
Choose for glass-tank paving, ladle and slide-gate refractories where slag/glass corrosion resistance matters more than strength.
Values for the REFR condition
Other Zircon tempers and conditions
Zircon is listed in 4 conditions; see the grade overview at Zircon.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
REFRThis page Bonded zircon refractory brick / shape | Choose for glass-tank paving, ladle and slide-gate refractories where slag/glass corrosion resistance matters more than strength. | — | — | — | 900 HV | 3 W/m·K |
Fused-cast / electrofused zircon | Choose for glass-furnace throat and paver blocks or high-grade refractory grain where maximum density and glass-corrosion resistance are required. | — | — | — | 1,100 HV | 4 W/m·K |
C728Default Dense sintered zircon porcelain | Choose for gas-tight, high-strength electrical/thermal ceramic parts: insulators, nozzles, thermocouple sheaths, foundry tooling. | — | — | — | 1,150 HV | 5 W/m·K |
Zircon sand / milled zircon flour | Choose as raw material: ceramic-glaze opacifier, investment-casting facecoat and foundry sand, or feedstock for zirconia production. | — | — | 0 | 1,200 HV | 5 W/m·K |
What is Zircon REFR?
Zircon REFR is Zircon in the REFR grade — choose for glass-tank paving, ladle and slide-gate refractories where slag/glass corrosion resistance matters more than strength. Zircon REFR has a tensile strength of 80 MPa (11.6 ksi), weaker than 53% of ceramic grades. The elastic modulus is 70 GPa (10.2 Msi). Zircon REFR has a density of 3.7 g/cm³ (0.134 lb/in³), lighter than 63% of ceramic grades. It melts at 1,687°C (3,069 °F). C728 is the default condition FabDigit quotes; REFR is available on request or by drawing note.
Advantages
- High service temperature — 1,650°C (3,002 °F), better than 88% of ceramic grades
- Low embodied carbon — 3 kg CO₂/kg, better than 88% of ceramic grades
Limitations
- Low stiffness — 70 GPa (10.2 Msi), worse than 79% of ceramic grades
- Poor heat conductor — 3 W/m·K (1.73 BTU/hr·ft·°F), worse than 77% of ceramic grades
Zircon REFR properties
Typical room-temperature values for Zircon REFR; 11 are specific to this condition. Other listed values are Zircon reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical4
Zircon REFR has a density of 3.7 g/cm³ (0.134 lb/in³), lighter than 63% of ceramic grades. It melts at 1,687°C (3,069 °F).
Mechanical11
Zircon REFR has a tensile strength of 80 MPa (11.6 ksi), weaker than 53% of ceramic grades. The elastic modulus is 70 GPa (10.2 Msi).
Thermal5
Zircon REFR is rated for continuous service to 1,650°C (3,002 °F). It conducts heat at 3 W/m·K (1.73 BTU/hr·ft·°F), worse than 77% of ceramic grades. Thermal expansion is 4.2 µm/m·K (2.33 µin/in·°F).
Electrical5
Zircon REFR is an electrical insulator with a dielectric strength of 12 kV/mm (304.8 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is excellent (85/100), better than 69% of ceramic grades.
Sustainability4
Producing a kilogram of Zircon REFR takes about 40 MJ of energy and emits 3 kg of CO₂ — less than 88% of ceramic grades. Typical recycled content is 3%.
Manufacturability3
Zircon REFR's machinability is not recommended (12/100, better than 78% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Zircon REFR
Is Zircon easy to machine?
Green or bisque bodies machine easily with carbide tooling; after firing only diamond grinding, lapping and ultrasonic/laser machining are practical.
Can Zircon be welded?
Not weldable — join by ceramic-to-metal brazing (Mo-Mn metallizing), glass frit sealing or high-temperature cements.
Can Zircon be formed, bent or molded?
Formed by dry pressing, isostatic pressing, slip casting or extrusion of milled zircon flour with clay/binder, then fired at 1500–1700 °C; allow ~12–18 % firing shrinkage.
What surface finishes work on Zircon?
Diamond grind and polish for sealing faces; glazing improves surface sealing and thermal-shock-crack resistance; no plating or anodizing applies.
Zircon chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| ZrO2ZrO2+HfO2 basis; stoichiometric ZrSiO4 = 67.2 % ZrO2 | 64 – 67.2 | 66 |
| HfO2naturally substitutes for Zr; usually reported inside ZrO2 | 0.8 – 1.8 | 1.2 |
| TiO2impurity from rutile | ≤ 0.2 | 0.08 |
| Fe2O3impurity | ≤ 0.15 | 0.05 |
| Al2O3impurity / bond phase | ≤ 0.6 | 0.25 |
| U+Th (trace)natural radionuclides — relevant to NORM handling rules | ≤ 0.05 | 0.02 |
| SiO2stoichiometric 32.8 % | ≥ 31.5 (balance) | — |
Zircon REFR — frequently asked
What is Zircon REFR used for?
Zircon REFR is typically used for foundry sand/refractories, ceramic glaze opacifier, kiln furniture, investment casting shell and raw material for ZrO2 production. In short: low-expansion refractory silicate; 1500 °C service capability; feedstock for zirconia.
What is the tensile strength of Zircon REFR?
Zircon REFR has a typical tensile strength of 80 MPa (11.6 ksi) — weaker than 53% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Zircon REFR easy to machine?
Not especially — machinability is rated not recommended (12/100, better than 78% of ceramic grades). Green or bisque bodies machine easily with carbide tooling; after firing only diamond grinding, lapping and ultrasonic/laser machining are practical.
Can Zircon REFR be welded?
Not weldable — join by ceramic-to-metal brazing (Mo-Mn metallizing), glass frit sealing or high-temperature cements.
What surface finishes work on Zircon REFR?
Diamond grind and polish for sealing faces; glazing improves surface sealing and thermal-shock-crack resistance; no plating or anodizing applies.
Can Zircon REFR be formed, bent or molded?
Formed by dry pressing, isostatic pressing, slip casting or extrusion of milled zircon flour with clay/binder, then fired at 1500–1700 °C; allow ~12–18 % firing shrinkage.
What is the maximum service temperature of Zircon REFR?
Zircon REFR is rated for continuous use to about 1,650°C (3,002 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ANSI/ASTM C728 — Standard Specification for Zircon Porcelain (technical ceramic classification) — ASTM International (2019)
- ASM Engineered Materials Handbook, Vol. 4: Ceramics and Glasses — ASM International (1991)
- Handbook of Refractory Practice / Refractories Handbook (zircon and zircon-bonded products) — Harbison-Walker / CRC (2005)
- GB/T 21114 — X (used for zircon assay); GB/T industry grades — SAC (2019)
- Technical zircon ceramic and fused-cast zircon datasheets — CoorsTek / Saint-Gobain / Iluka Resources (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.