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Classification and Application Scenarios of Magnesia-Chrome Bricks

Release time:

2025-12-02 14:44

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Magnesia-chrome bricks are refractory materials made primarily from magnesia sand (MgO) and chromite ore (Cr₂O₃). They feature high refractoriness (>2000℃), excellent resistance to alkali slag erosion, and good thermal shock resistance. As such, they are widely used in high-temperature metallurgical furnaces and kilns.
I. Classification of Magnesia-Chrome Bricks
According to their bonding methods and chemical compositions, magnesia-chrome bricks are mainly classified into the following major categories:
By combination method
Direct-bonded magnesia-chrome bricks
MgO directly reacts with Cr₂O₃, FeO, and other components in chromite to form a spinel-bonded phase, exhibiting excellent slag resistance.

Silicate-bonded magnesia-chrome bricks
It contains a relatively high proportion of silicate phases (CMS, M₂S), offering good resistance to thermal shock but slightly poorer resistance to slag.

Also combine with magnesia-chrome bricks.
Made by firing pre-synthesized magnesia-chrome spinel clinker, it features uniform composition and excellent thermal shock resistance.

Half-recombined magnesia-chrome brick
Partially uses pre-combined materials, with performance intermediate between directly bonded and re-bonded products.

Classified by Cr₂O₃ content
Common magnesia-chrome brick
Cr₂O₃ 8–18%

High-chromium magnesia-chrome brick
Cr₂O₃ >20% (up to 30–40%)

Categorized by special purpose
Electrofused recombined magnesia-chrome bricks
Bricks made from electrofused magnesia-chrome material have extremely low porosity and excellent resistance to corrosion.

Chrome-free/Low-chrome eco-friendly magnesia-chrome bricks
Replace chromite with magnesio-spinel and ferro-spinel (due to environmental concerns regarding hexavalent chromium).
Currently, the mainstream products are directly bonded magnesia-chrome bricks and electrofused re-bonded magnesia-chrome bricks.
II. Major Application Areas and Typical Use Locations
Iron and Steel - Nonferrous Metallurgy Industry
RH Vacuum Refining Furnace (Immersion Tube)
Slag line, molten pool area
Electrofused recombined magnesia-chrome bricks

AOD/VOD refining furnace
Slag line, tuyere area, furnace bottom
Direct-bonded/electrofused re-bonded magnesia-chrome bricks

Converter (still used in some regions)
Ear shaft, slag line (gradually being replaced by magnesia-carbon bricks)
Direct-bonded magnesia-chrome bricks

Electric arc furnace
Hotspot area, slag line (partially replacing magnesia-carbon bricks)
Direct-bonded magnesia-chrome bricks

Nonferrous Metallurgy Industry
Copper, nickel, lead, and zinc flash furnaces
Reaction tower, sedimentation tank, rising flue
Direct-bonded magnesia-chrome bricks and electrofused re-bonded magnesia-chrome bricks

Copper converter (PS converter)
Furnace mouth, slag line
Direct-bonded magnesia-chrome bricks

Cement industry
Cement rotary kiln
Sintering zone and transition zone (previously widely used, but now replaced by magnesia-alumina spinel bricks and magnesia-ferrospinels bricks due to Cr⁶⁺ contamination)
Ordinary/Direct-bonded magnesia-chrome bricks (phased out gradually)

Glass industry
Glass furnace (colored glass, soda-lime silicate glass)
Upper part of the pool wall, clarification section, and heat-storage chamber grid structure
Direct-bonded magnesia-chrome bricks

Other industries
Waste incinerator, hazardous waste incinerator
High-temperature corrosion zone
Electrofused recombined magnesia-chrome bricks
III. Current Trends (Status as of 2025)
1. Steel Industry: RH and AOD/VOD remain the primary consumption sectors for magnesia-chrome bricks, while the proportion of electrofused recombined magnesia-chrome bricks is steadily increasing.
2. Cement Industry: Due to stringent international and domestic restrictions on Cr⁶⁺, magnesia-chrome bricks have largely been replaced in cement kilns by chromium-free alkaline bricks (magnesia-alumina, magnesia-zirconia, and magnesia-ferrospinel bricks).
3. Environmental Alternatives: The development of chromium-free or low-chromium magnesia-chrome bricks—such as magnesia-alumina spinel plus magnesium-rich spinel pre-synthesized materials—has become a hot topic.
Magnesia-chrome bricks remain one of the most resistant refractory materials to alkali slag corrosion and are still irreplaceable in harsh slag-corrosion environments such as vacuum refining and non-ferrous metallurgy. However, due to concerns about hexavalent chromium pollution, they are gradually being phased out or replaced by eco-friendly products in industries like cement and glass.

Magnesia-chrome brick,Direct-bonded magnesia-chrome bricks,Electrofused recombined magnesia-chrome bricks,Also combine with magnesia-chrome bricks.

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