Magnesia Series Refractory Bricks

Magnesia Chrome Brick

Name: Magnesia Chrome Brick
Brand: XZK

Magnesia chrome bricks are made from magnesia and chrome ore, fired to a direct bond between periclase and chromite grains. That bond gives the brick high hot strength and strong resistance to alkali vapour and sulphate condensates, which is why it has long been the classic material for the top...

MgO:≥40%

Cr₂O₃:≥8%

Cold Crushing Strength:≥25MPa

Apparent porosity:≤22%

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Magnesia Chrome Brick Overview

XZK Group supplies direct-bonded and fused-rebonded magnesia chrome bricks across a range of chrome contents. Lower-chrome and chrome-free alternatives are available where the handling and disposal of chrome-bearing material is a concern.

What Is a Magnesia Chrome Brick?

The brick combines magnesia, usually sintered or fused, with chrome ore, and is fired at high temperature so that periclase and chromite grains bond directly to each other rather than through a silicate matrix. Chrome content commonly runs from about 8% to more than 25% as Cr₂O₃, with MgO making up most of the balance. The direct bond is what raises hot strength and resistance to chemical attack above that of a silicate-bonded brick.

In a glass furnace regenerator the top courses and the crown see the highest temperature in the checker system together with alkali vapour carried in the flue gas. Magnesia chrome resists both: the magnesia is stable against alkali, and the chromite phase resists the sulphate condensates that form in the cooler part of the chamber. Its high hot strength also lets it carry the load of the structure above, which matters in the upper courses. Thermal shock resistance is moderate and improves with a well-developed direct bond.

The one caution is environmental. Under oxidising and alkaline conditions chrome-bearing refractories can form hexavalent chromium, which raises handling and disposal requirements. For that reason many new linings specify lower-chrome or chrome-free grades. XZK supplies both, and where alkali resistance is the requirement, a magnesia alumina spinel brick delivers comparable performance without chrome.

Key Properties

Composition: magnesia with typically 8–25% or more Cr₂O₃.
Bond: direct periclase-chromite bond from high-temperature firing, or fused rebonded for the most demanding positions.
Alkali and sulphate resistance: strong, making it a classic regenerator top-course and crown material.
Hot strength: high, with good resistance to creep under the load of the courses above.
Thermal shock resistance: moderate, improved by a well-developed direct bond.
Consideration: chrome-bearing material needs controlled handling and disposal; lower-chrome and chrome-free grades are available.

Technical Specifications

	MgO /%	Cr₂O₃ /%	Apparent Porosity /%	Compressive Strength at Normal Temperature /MPa	Initial Softening Temperature under 0.2 MPa Load / °C
MGe - 20A	≥ 50	≥ 20	≤ 18	≥ 35	≥ 1700
MGe - 20B	≥ 45	≥ 20	≤ 19	≥ 30	≥ 1650
MGe - 20C	≥ 40	≥ 20	≤ 22	≥ 25	≥ 1550
MGe - 16A	≥ 55	≥ 16	≤ 18	≥ 35	≥ 1700
MGe - 16B	≥ 50	≥ 16	≤ 19	≥ 30	≥ 1650
MGe - 16C	≥ 45	≥ 16	≤ 22	≥ 25	≥ 1550
MGe - 12A	≥ 65	≥ 12	≤ 18	≥ 40	≥ 1700
MGe - 12B	≥ 60	≥ 12	≤ 19	≥ 35	≥ 1650
MGe - 12C	≥ 55	≥ 12	≤ 21	≥ 30	≥ 1550
MGe - 8A	≥ 70	≥ 8	≤ 18	≥ 40	≥ 1700
MGe - 8B	≥ 65	≥ 8	≤ 19	≥ 35	≥ 1650
MGe - 8C	≥ 60	≥ 8	≤ 21	≥ 30	≥ 1530

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

Available Grades and How to Choose

Grades differ by chrome content and by bond type. Direct-bonded grades with moderate chrome are used for regenerator top courses and chamber walls; a higher-chrome or fused-rebonded grade is reserved for the most severe chemical and thermal service. Reducing chrome content lowers the environmental burden at some cost in sulphate resistance.

Where chromia must be avoided, the same duties are covered by chrome-free alternatives. A magnesia alumina spinel brick is the usual choice for the regenerator condensation zone, and a high-purity magnesia brick covers stable hot zones. For the condensation zone and bottom courses, chrome corundum bricks are the established companion material.

Industry Applications

Metallurgical Industry: Linings of converters, electric arc furnaces, ladles, and blast furnaces.
Glass Industry: Regenerators and upper structures of melting furnaces.
Cement Industry: Firing zone and transition zone of rotary kilns.
Petrochemical Industry: Linings of cracking furnaces and gasifiers.

Where Magnesia Chrome Bricks Are Used in a Glass Furnace

Magnesia chrome bricks are used where alkali attack and high temperature meet:

Regenerator top courses and crown. The hottest part of the checker chamber sees alkali vapour and sulphate attack, and magnesia chrome resists both while carrying the structural load.
Regenerator chamber walls, where alkali-laden flue gas passes continuously and the brick must resist chemical attack as well as heat.
Target wall and port crowns, where the brick faces both radiant heat and alkali vapour.
Cement rotary kiln burning and transition zones, where basic clinker chemistry and high temperature require a magnesia-based lining.
Copper, nickel and lime kilns, where basic or sulphide-bearing charges attack an aluminosilicate lining.
Where chrome is restricted, it is replaced by chrome-free spinel grades.

Manufacturing and Quality Control

Manufacturing is controlled from raw material through to finished brick. Four automatic batching lines feed 20 CNC presses ranging from 630 to 2000 tonnes, so density is set by press force rather than operator judgement, and firing runs through four 108-metre fully automatic tunnel kilns and five ultra-high-temperature shuttle kilns for a uniform soak.

Every batch is tested for bulk density, apparent porosity, cold crushing strength and refractoriness under load, and ships with a certificate of analysis. XZK Group holds ISO 9001, ISO 14001, ISO 45001 and ISO 50001 certification and operates the Henan Provincial Engineering Technology Research Center for Sintered Refractories for Glass Furnaces.

Related Refractory Products

Magnesia chrome bricks belong to the magnesia refractory range with magnesia bricks, magnesia alumina spinel bricks, magnesium iron spinel bricks and magnesia carbon bricks. For regenerator zoning see regenerator refractory bricks and all refractory products.

Proven Global Projects

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.