Chrome Corundum Bricks

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Introduction of Chrome Corundum Bricks

Chrome corundum bricks are a type of corundum refractory product that contains Cr₂O₃. It is made by using α-Al₂O₃ as the main raw material and adding an appropriate amount of chromium oxide powder and chromium corundum clinker fine powder. The bricks are then sintered at a temperature of 1700℃. At high temperatures, Cr₂O₃ and Al₂O₃ form a continuous solid solution, making the high-temperature performance of chromium corundum products better than pure corundum products.

The most widely used chromium corundum products have a Cr₂O₃ content of 9%~15%, and the main mineral composition is α-Al₂O₃• Cr₂O₃ spinel phase. The chromium oxide content in chrome refractory brick ranges from 1% to 30%. There are two types: fused cast chromium corundum bricks and sintered chromium corundum bricks.

Properties of Chrome Corundum Bricks

1. Good wear resistance

2. Good thermal shock resistance

3. Good acid and alkali resistance

4. Good chemical stability

5. High fire resistance

6. High strength and low porosity

7. Great high-temperature performance

8. High refractoriness under load

9. Good chemical attack assistance

Performances of Chrome Corundum Bricks

Fire resistance property: Adding pure chromic oxide into high-purity corundum materials does not reduce the fire resistance of materials, but it can improve the materials’ fire resistance properties. Chrome corundum bricks' refractoriness is over 1790℃, and refractoriness under load is over 1700℃, which are both higher than high-purity corundum.

Product strength: High-performance chrome corundum brick’s cold crushing strength is generally over 150Mpa, which is higher than corundum. This is because the firing process forms the Al₂O₃ - Cr₂O₃ solid solution between particles and fines, like a bridge connecting particles and fines, which greatly enhances the strength of materials.

Thermal shock resistance: Normally, the thermal shock resistance of chrome corundum brick reduces when the Cr₂O₃ content is about 10~66%. However, when the chrome corundum brick has a low level of Cr₂O₃ content, its thermal shock resistance is better than the one with a higher level of Cr₂O₃ content.

Slag erosion resistance: The solubility of Cr₂O₃ in the coal gasifier slag and all kinds of glass melt is much smaller than other oxide materials. So Cr₂O₃ or refractory materials with Cr₂O₃ have good corrosion resistance to steel slag, nonferrous metallurgy slag, coal gasifier slag, and all kinds of glass melt. Liquid viscosity formed by Cr₂O₃ melt or Cr₂O₃ reacting with furnace slag is higher than other low melting materials, which prevents the molten slag from infiltrating into the brick interior along with the capillary pore and avoiding the structure spalling caused by forming a metamorphic layer.

Application of Chrome Corundum Bricks

Chrome corundum bricks are mainly used in the linings of decomposing furnaces for the petroleum and chemical industry, as well as the chemical fertilizer industry. They are also used as high-temperature kiln linings and furniture in the metallurgical industry.

Chemical & Physical Index

Item		Chrome Corundum Bricks
		XHJGGZ5	XHJGGZ12	XHJGGZ20	XHJGGZ30
Cr₂O₃, %	υ≥	5	12	20	30
Cr₂O₃, %	σ	0.40
Al₂O₃, %	υ≥	88	81	73	63
Al₂O₃, %	σ	0.6
Bulk Density, g/cm³	≥	3.10	3.20	3.40	3.50
Apparent Porosity, %	≤	18	18	18	18
Cold Crushing Strength MPa	≥	100	100	100	100
Refractoriness Under Load ºC	0.2MPa,0.6% ≥	1700	1700	1700	1700
* Only as an optional index *Special product technique requirements should be confirmed by supply and requisitioning parties