Chrome-Corundum Castable
Chrome-corundum castable incorporates Cr₂O₃ (3-8%) to form viscous slag films at high temperature that block penetration. 1750℃ max service, outstanding resistance to non-ferrous slags.
Learn More →Smelter Roof Castable Burn-out
Copper Smelting Furnace · Roof
Problem Details
Background
The roof of copper smelting furnaces (flash, converter, anode) endures high-temperature gas and molten splash. Roof gas runs hot and dust-laden; splashed matte and slag adhere and attack the roof. Castable over-fires and spalls—a weak point of smelter linings.
Failure Mechanism
Hot-gas over-firing: roof gas temperature is high (flash reaction shaft top can exceed 1600℃); prolonged high temperature over-fires the castable and lowers strength. Splash attack: molten splash (matte, slag) adheres to the roof and reacts with the castable. Thermal shock: shutdown cooling and charge fluctuations cause rapid temperature changes; thermal-shock stress spalls the lining. Anchor failure: high-temperature oxidation and thermal shock fail anchors; the lining loses restraint and detaches.
Consequences
After roof burnout and spalling, the shell overheats and deforms, roof sealing degrades and heat loss rises; in severe cases the roof burns through, melt and gas escape, threatening safety and forcing shutdown for repair.
Solution
Material Selection and Parameters
Select smelter roof for "high-temperature resistance + melt resistance + reliable anchoring":
- Material system: chrome-corundum castable (Al₂O₃≥90%, Cr₂O₃ 3–8%) or high-alumina castable (Al₂O₃≥70%). Chrome-corundum resists high temperature and melt attack for flash-furnace roofs; high-alumina offers value for cooler roofs;
- Anchors: densified heat-resistant steel anchors with ceramic caps against oxidation;
- Thickness design: size by roof thermal load, thickening hot zones with burnout allowance.
Installation Essentials
Formwork casting: precise formwork and continuous placement for large roof areas. Vibration: vibrate fully for density. Water control: keep at the datasheet lower limit. Bake-out: follow the curve and complete dehydration before commissioning.
Maintenance
Control temperature swings and avoid prolonged over-temperature; inspect roof surface and shell temperature, treating hot spots promptly. At maintenance, check anchor condition and residual lining thickness, patching thinned zones and replacing failed anchors.
Recommended Products
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Corundum-mullite castable combines the hot strength of corundum with the thermal-shock resistance of mullite. Al₂O₃≥80%, 1700℃ max service.
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High-Alumina Castable LA-60
LA-60 high-alumina castable uses bauxite clinker aggregate with Al₂O₃≥60% and a max service temperature of 1600℃. Its low-cement bond gives high density and good thermal-shock resistance.
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