Magnesia chrome brick

Chromium-magnesium brick is a refractory brick, the main components of which are magnesium oxide and chromium oxide, and the main mineral components are periclase and spinel. Fired at 1600–1800°C in an oxidizing atmosphere, It can also be used to make unfired bricks using chemical binders, such as liquid glass. Magnesia-chrome bricks have high fire resistance, strong corrosion resistance to alkali slags, good thermal stability and certain resistance to acidic slags.

Production of magnesia-chrome bricks

The main raw materials for the production of magnesia-chrome bricks are sintered magnesia and chromite. In the process of producing magnesia-chrome bricks, the purity of magnesia raw materials must be high. The chemical composition standard for chrome ore is 30-45% Cr2o3, ≤ 1-1,5% Cao.

Composition of magnesia-chrome brick

• Ordinary sintered magnesium chrome bricks: The purity of the raw materials is low, lightly burned magnesia is used, and the sintering temperature is low.
• Magnesia-chrome bricks with direct connection: The raw materials are of high purity, dead-fired magnesia is used, and the sintering temperature of bricks in a tunnel kiln is higher, than conventional sintered magnesia-chrome bricks.
• Fused semi-recombined magnesia-chrome bricks: The raw materials are calcined magnesia and fused magnesia, and the sintering temperature is higher, than conventional sintered magnesia-chrome bricks.
• Fused and recombined magnesia chrome brick: The raw material is made from fused magnesia, and the cost is high.

Physico-chemical indicators of magnesia-chrome brick

Physico-chemical indicators of ordinary magnesia-chrome brick：：

Subject	Index
	MG-16A	MG-16B	MG-12A	MG-12B	MG-8A	MG-8B
MgO %	≥50	≥45	≥60	≥55	≥65	≥60
Cr2O3  %	≥16	≥16	≥12	≥12	≥8	≥8
Apparent porosity %	≤19	≤22	≤19	≤21	≤19	≤21
Cold crush strength MPa	≥35	≥25	≥35	≥30	≥35	≥30
0.2Mpa Fire resistance under load ℃	≥1650	≥1550	≥1650	≥1550	≥1650	≥1530

Physico-chemical indicators of fused semi-recombined magnesia-chrome brick：：

Subject	Index
	ZMG-16A	ZMG-12A	ZMG-8A	ZMG-6
MgO %	≥60	≥68	≥75	≥75
Cr2O3  %	≥16	≥12	≥8	≥6
SiO2  %	≤1.5	≤1.5	≤1.5	≤2.5
Apparent porosity %	≤18	≤18	≤18	≤18
Cold crush strength MPa	≥40	≥45	≥45	≥45
0.2Mpa Fire resistance under load ℃	≥1700

Physico-chemical indicators of fused semi-recombined magnesia-chrome brick :

Subject	Index
	BMG-26	BMG-24	BMG-22	BMG-20A
MgO %	≥50	≥50	≥55	≥58
Cr2O3  %	≥26	≥24	≥22	≥20
SiO2  %	≤2.0	≤2.0	≤2.0	≤2.0
Apparent porosity %	≤16	≤16	≤16	≤16
Cold crush strength MPa	≥40	≥45	≥45	≥45
0.2Mpa Fire resistance under load ℃	≥1700

Subject	Index
	BMG-18	BMG-16A	BMG-12A
MgO %	≥58	≥60	≥68
Cr2O3 %	≥18	≥16	≥12
SiO2 %	≤2.0	≤2.0	≤2.0
Apparent porosity %	≤16	≤16	≤16
Cold crush strength MPa	≥40	≥45	≥45
0.2Mpa Fire resistance under load ℃	≥1700

Physico-chemical characteristics of fused recombined magnesia-chromium brick：：

Subject	Index
	DMG-26	DMG-24	DMG-22	DMG-20	DMG-16	DMG-12
MgO %	≥50	≥50	≥55	≥58	≥62	≥68
Cr2O3  %	≥26	≥24	≥22	≥20	≥16	≥12
SiO2  %	≤1.5	≤1.5	≤1.5	≤1.5	≤1.5	≤1.5
Apparent porosity %	≤16	≤16	≤16	≤16	≤16	≤16
Cold crush strength MPa	≥40	≥40	≥40	≥40	≥40	≥40
0.2Mpa Fire resistance under load ℃	≥1700	≥1700	≥1700	≥1700	≥1700	≥1700

Features of magnesia-chrome brick

1. High frequency and low impurity content
2. High temperature and softness
3. High corrosion resistance
4. Low porosity
5. Long service life
6. Not easy to wear out
7. Production meets the standard

Temperature range of magnesia-chrome brick

The fire resistance of magnesia-chrome brick exceeds 2000°C, and the load softening temperature usually exceeds 1550°C. It has good volumetric stability at high temperatures and good resistance to rapid cooling and heating.

Scope of application of magnesia-chrome brick

Magnesia chrome brick can mainly be used in rotary cement kilns, glass furnace regenerators, lining of steel-smelting furnaces, permanent layer of refining ladles, non-ferrous metallurgy furnaces, lime kilns, mixed cast iron furnaces, lining of refractory high-temperature furnaces, etc..

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