CaO 35 – 58% · MgO 35 – 40% · Max 1700 °C
Dolomite Refractory Bricks (CaO-MgO)
Supplier and exporter from Rajkot, India. Fired or stabilised dolomite basic refractory bricks — the standard hot-face for stainless-steel AOD/VOD vessels and a chrome-free option for cement kiln transition zones.
- CaO35 – 58%
- MgO35 – 40%
- Bulk density≥ 2.75 g/cm³
- CCS≥ 40 MPa
- RUL T₀.₅≥ 1650 °C
- Stabilised gradeAvailable
About this product
What dolomite refractory bricks are — and where they fit
Dolomite refractory bricks are basic refractory bricks produced from sintered dolomite — a calcined dolomitic carbonate raw material containing CaO (35 – 58%) and MgO (35 – 40%). The brick is fired to dense ceramic bodies (apparent porosity ≤ 15%, bulk density ≥ 2.75 g/cm³) with CCS ≥ 40 MPa and RUL T₀.₅ ≥ 1650 °C. Maximum service temperature is approximately 1700 °C, governed in practice by the CaO-MgO eutectic and by the specific slag chemistry.
What is a dolomite brick? A dolomite brick is a basic refractory brick whose key chemistry is the CaO-MgO binary. The high CaO content makes the brick exceptionally compatible with calcium-rich slag — a property that is critical in stainless-steel AOD/VOD vessels, where high-chromium slag chemistries would attack magnesia-chrome refractory and reduce campaign life. Dolomite is the industry-standard hot-face for these vessels, and a long-running chrome-free alternative for cement-kiln transition zones.
One handling consideration: free CaO in standard fired dolomite can slowly hydrate in humid storage conditions, causing brick swelling and surface damage before installation. Stabilised dolomite is available — typically MgO-enriched or with controlled fired structure — and has dramatically improved storage humidity tolerance, longer shelf life and reduced installation losses. For tropical-export shipments and long lead times, stabilised dolomite is the standard recommendation; we share the stabilisation classification on dispatch.
Compared to pure magnesia bricks, dolomite has lower max temperature but is more cost-effective and chemically better-matched to high-Cr stainless slag. Compared to magnesia-chrome bricks, dolomite is chrome-free and avoids the Cr (VI) compliance issue. firebrickssource.com is a refractory bricks manufacturer-cum-merchant exporter from Rajkot, Gujarat, India — see also steel & foundry industry for AOD/VOD application context and the basic refractories index for adjacent grades.
Technical specifications
Full property data — dolomite bricks
| Property | Value | Test method |
|---|---|---|
| CaO content | 35 – 58 % | IS 1528-7 |
| MgO content | 35 – 40 % | IS 1528-7 |
| SiO₂ content | ≤ 2.5 % | IS 1528-7 |
| Fe₂O₃ content | ≤ 2 % | IS 1528-7 |
| Apparent porosity | ≤ 15 % | IS 1528-8 / ASTM C20 |
| Bulk density | ≥ 2.75 g/cm³ | IS 1528-12 |
| Cold crushing strength (CCS) | ≥ 40 MPa | IS 1528-4 / ASTM C133 |
| Refractoriness under load (RUL T₀.₅) | ≥ 1650 °C | IS 1528-2 |
| Permanent linear change | ± 0.5 % | IS 1528-6 |
| Max service temperature | 1700 °C | — |
| Stabilised grade | Available — improved storage humidity tolerance | — |
| Standard size | 230 × 114 × 65 mm | — |
| Custom sizes | AOD/VOD vessel shapes, cement-kiln rotary shapes — to drawing | — |
*Typical certified values — actual batch values issued on the per-shipment test certificate. Values aligned with IS 1528 / ASTM C-series / EN 993 test methods.
Applications
Where to use dolomite refractory bricks
- Steel AOD (argon-oxygen decarburisation) vessel hot-face
- Steel VOD (vacuum-oxygen decarburisation) vessel hot-face
- Stainless-steel converter slag-line
- Cement rotary kiln transition zone (chrome-free)
- Cement kiln preheater outlet (CaO-rich zones)
- Steel ladle back-up linings
- Lime-kiln calcining zone
- Tundish back-up linings
- Non-ferrous high-CaO slag furnace zones
- Magnesia/lime calcining rotary kilns
Datasheet
Download technical datasheet
PDF with all certified properties, fired vs stabilised variants, dimensional tolerances and applicable test methods. Use this for tender attachments.
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Frequently asked
Dolomite bricks — questions buyers ask
What is a dolomite refractory brick?
Dolomite refractory bricks are basic refractories produced from sintered dolomite (CaO 35 – 58%, MgO 35 – 40%). The brick combines high refractoriness (max 1700 °C) with excellent compatibility with calcium-rich slag chemistries, which makes it the preferred lining for AOD/VOD stainless-steel vessels and certain cement-kiln zones.
Why are stabilised dolomite bricks specified?
Free CaO in standard dolomite bricks can hydrate in storage humidity, causing brick swelling and surface damage before installation. Stabilised dolomite — typically MgO-enriched or with controlled fired structure — has dramatically improved storage humidity tolerance, longer shelf life and reduced installation losses. For tropical-export shipments and long lead times, stabilised dolomite is the standard recommendation.
Where are dolomite refractory bricks used?
Typical applications include steel AOD and VOD stainless-steel converter vessels, cement rotary kiln transition zone (chrome-free alternative to magnesia-chrome), steel ladle back-up linings, and certain non-ferrous reverberatory furnace zones with high-CaO slag chemistry.
What is the difference between dolomite and magnesia bricks?
Pure magnesia bricks (MgO ≥ 90%) are higher-temperature, more slag-resistant in general BOF service, but more expensive and slightly more thermal-shock-sensitive. Dolomite bricks (CaO + MgO) are more cost-effective, have superior compatibility with calcium-rich AOD/VOD slag and cement-kiln chemistries, but lower max temperature (1700 °C vs 1800 °C). The choice depends on slag chemistry and budget.
What is the storage life of dolomite bricks?
Standard fired dolomite has limited storage life in humid conditions — typically 3 – 6 months when packed with moisture-barrier film. Stabilised dolomite extends shelf life to 12 months or longer. We ship in shrink-wrapped, moisture-sealed packaging on heat-treated pallets; for tropical destinations stabilised grade is recommended.
What is the typical MOQ and packaging?
Standard MOQ is 10 – 20 MT. Bricks are individually shrink-wrapped, edge-protected, on heat-treated wooden pallets, with desiccant pouches for tropical exports. One 20-foot container typically carries 22 – 25 MT of dolomite refractory bricks.
Do you provide samples and test certificates?
Yes. Samples can be dispatched on request — normally chargeable plus courier. Every batch is tested for CaO, MgO, SiO₂, free-lime, bulk density, porosity, CCS and RUL; a test certificate and stabilisation classification ship with each consignment.
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Primary application