Magnesia (MgO) Refractory Bricks

Supplier and exporter from Rajkot, India. Fired pure-magnesia bricks — the basic refractory workhorse for steel BOF converters, EAF walls and cement burning-zone back-up linings.

MgO≥ 90% (premium ≥ 95%)
Max temp1800 °C
Bulk density≥ 2.85 g/cm³
CCS≥ 40 MPa
RUL T₀.₅≥ 1700 °C
Standard size230 × 114 × 65 mm

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About this product

What magnesia refractory bricks are — and where they fit

Magnesia (MgO) refractory bricks are fired basic refractory products with a minimum 90% MgO content (premium grades ≥ 95%), balanced against CaO, SiO₂ and Fe₂O₃ as minor oxides. They are manufactured from selected sintered or fused magnesia aggregates, pressed and fired to dense ceramic bodies at controlled kiln temperatures above 1600 °C. The grade represents the chemical-resistance backbone of the basic refractory family — alkaline-slag-resistant, high-melting-point, and the only refractory category genuinely suited to BOF and EAF steelmaking duty.

What is a magnesia brick? A magnesia refractory brick is a basic refractory brick whose principal phase is periclase (crystalline MgO). The MgO crystals melt at approximately 2800 °C and maintain structural integrity against basic slags (CaO-, MgO-rich) that would aggressively dissolve acidic refractories such as fireclay, silica or even high-alumina bricks. The brick is "basic" in the chemical sense — it reacts compatibly with basic slag chemistry rather than being attacked by it.

Compared to magnesia-carbon bricks, pure magnesia is fired (not resin-bonded), contains no graphite, and is used where graphite oxidation would be a problem (oxidising atmospheres, lower-cycle applications). Compared to high-alumina bricks, magnesia handles basic slag and higher temperatures but is more expensive and more thermal-shock-sensitive. The two are often used together in steel-industry linings: high-alumina back-up and magnesia hot-face, or magnesia hot-face and alumina-spinel back-up. See also steel & foundry applications and cement & lime industry.

firebrickssource.com supplies magnesia refractory bricks in the standard 230 × 114 × 65 mm size, plus arches, wedges, taper bricks and large-format BOF/EAF shapes to drawing. Standard chemistry is BIS / IS-aligned; premium ≥ 95% MgO and low-CaO chemistries are available on indent. The grade is regularly exported to integrated steel mills in the Middle East, Southeast Asia and Africa, and to cement plants worldwide. firebrickssource.com is a refractory bricks manufacturer-cum-merchant exporter from Rajkot, Gujarat, India.

Technical specifications

Full property data — magnesia bricks

Magnesia Refractory Bricks — certified property values
Property	Value	Test method
MgO content	≥ 90 % (premium ≥ 95 %)	IS 1528-7
CaO content	≤ 2.5 %	IS 1528-7
SiO₂ content	≤ 3.5 %	IS 1528-7
Fe₂O₃ content	≤ 3 %	IS 1528-7
Apparent porosity	≤ 18 %	IS 1528-8 / ASTM C20
Bulk density	≥ 2.85 g/cm³	IS 1528-12
Cold crushing strength (CCS)	≥ 40 MPa	IS 1528-4 / ASTM C133
Refractoriness under load (RUL T₀.₅)	≥ 1700 °C	IS 1528-2
Permanent linear change	± 0.3 %	IS 1528-6
Max service temperature	1800 °C	—
Standard size	230 × 114 × 65 mm	—
Custom sizes	Arches, wedges, BOF/EAF 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 magnesia refractory bricks

Steel BOF converter linings
EAF wall and back-up linings
Cement rotary kiln burning-zone back-up
Cement transition zone (alkaline duty)
Non-ferrous reverberatory furnaces (copper, lead)
Glass-tank regenerator checker work
Lime-kiln calcining zone
Magnesia processing rotary kilns
AOD/VOD vessel back-up (with dolomite hot-face)
Steel reheat furnace skid-rail seats

Datasheet

Download technical datasheet

PDF with all certified properties, dimensional tolerances and applicable IS / ASTM test methods. Use this for tender attachments and procurement files.

Download magnesia datasheet (PDF)

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Frequently asked

Magnesia bricks — questions buyers ask

What is the maximum temperature for magnesia refractory bricks?

Magnesia (MgO ≥ 90%) refractory bricks have a refractoriness under load (T₀.₅) of ≥ 1700 °C and a maximum service temperature of approximately 1800 °C, subject to slag chemistry and atmosphere.

What is the difference between magnesia and magnesia-carbon bricks?

Pure magnesia (MgO ≥ 90%) bricks are fired ceramic refractory products with no graphite. Magnesia-carbon (MgO-C) bricks contain 10 – 18% graphite plus antioxidants, are resin-bonded (not fired), and offer significantly better slag-line and thermal-shock performance — making them the standard for BOF slag-lines and EAF hot-spots.

Where are magnesia refractory bricks used?

Typical applications include steel BOF converter linings, EAF walls and back-up, non-ferrous reverberatory furnaces, cement rotary kiln burning-zone back-up, glass-tank regenerator checkerwork, lime-kiln calcining zone and magnesia processing equipment.

What is the standard size of magnesia bricks?

Standard rectangular size is 230 × 114 × 65 mm. Arches, wedges, taper bricks, key bricks and large-format custom shapes (300 – 400 mm length) for BOF and EAF are produced on indent orders.

What is the typical MOQ for magnesia refractory bricks?

Standard MOQ is 10 – 20 MT for stocked sizes; custom BOF/EAF shapes are quoted per project. One 20-foot container typically carries 22 – 25 MT of magnesia bricks.

What Incoterms are offered for export shipments?

We typically quote FOB Mundra or FOB Kandla. CIF, CFR and EXW are available on request. Sea-freight rates are confirmed at the time of booking.

Do you provide samples and test certificates?

Yes. Samples can be dispatched on request — normally chargeable plus courier. Every production batch is tested for chemistry (MgO, CaO, SiO₂, Fe₂O₃), apparent porosity, bulk density, CCS and RUL; a test certificate ships with each consignment.