Skip to content
As a new generation of high-performance alkaline refractory materials, salt-impregnated magnesia-chrome bricks, with their unique process design and excellent high-temperature performance, are becoming the preferred protective materials for key parts in the metallurgical industry.
I. Technological Innovation: Salt-Impregnation Process Remolds Material Properties
Salt-impregnated magnesia-chrome bricks use high-purity magnesia (MgO content ≥90%) and chromite (Cr₂O₃ content 18-22%) as basic raw materials, which are sintered at ultra-high temperatures and then treated with vacuum salt-impregnation technology. Through the deep penetration of molten sodium chloride-potassium chloride salt solution, this process reduces the apparent porosity of the brick body by more than 5%, increases the bulk density by 0.05g/cm³, and enhances the compressive strength by 30MPa. Microstructurally, the salt solution fills the open pores between periclase and spinel crystal phases, forming a dense three-dimensional protective network, which effectively prevents the penetration and erosion of high-temperature slag. It is widely used in parts severely eroded by high-temperature alkaline slag, such as ladle linings, cement rotary kiln burning zones, and secondary refining furnaces.
II. Core Advantages: Multi-Dimensional Breakthroughs in Industry Bottlenecks
1. Ultimate Erosion Resistance
In harsh environments such as RH vacuum degassing furnaces and VOD ladle refining furnaces, the erosion rate of salt-impregnated magnesia-chrome bricks against CaO-SiO₂-MgO high-alkalinity slag is 40% lower than that of ordinary magnesia-chrome bricks. Their slag resistance mechanism stems from the high-temperature-resistant phase (e.g., MgCl₂·6H₂O) formed after salt solution solidification, which can maintain a stable physical barrier above 1600°C.
2. Long-Life Economy
Application data from the slag line of an AOD refining furnace in a steel plant shows that the service life of salt-impregnated magnesia-chrome bricks reaches 1200 heats, 60% longer than that of traditional direct-bonded bricks. This advantage results from the synergistic effect of low porosity (≤12%) and high bulk density (≥3.2g/cm³), which significantly delays the failure process of "slag infiltration - penetration - spalling".
3. Dual Breakthroughs in Energy Saving and Environmental Protection
The optimized sintering process (1680-1700°C) reduces energy consumption by more than 20% compared with traditional processes. Meanwhile, by adding modifiers such as aluminum nitride and citric acid, the hexavalent chromium leaching amount is controlled below 50ppm, fully complying with China's 2024 new regulations (chromium content ≤0.8%) and EU REACH standards.
III. Precise Adaptation: Full-Scenario Coverage of Metallurgical Equipment
The performance characteristics of salt-impregnated magnesia-chrome bricks enable their precise adaptation in high-temperature industries:
Steelmaking field: In vacuum environments such as RH immersion tubes and VOD vacuum degassing tanks, their resistance to vacuum damage can ensure more than 1500 cycles of use; after applying these bricks to the wall of ultra-high power electric arc furnaces, refractory consumption decreases by 35%.
Non-ferrous smelting: The service life of salt-impregnated magnesia-chrome bricks used in the slag line of copper flash smelters is 3 times longer than that of silica bricks, effectively coping with high-erosion slag with FeO content up to 45%; the magnesia-alumina-chrome bricks treated with vacuum salt impregnation used in the tuyere layer of zinc volatilization furnaces have their erosion resistance improved by 50%.
IV. Industry Trend: Balancing Environmental Compliance and Performance Upgrade
With the global improvement of environmental requirements for refractory materials, salt-impregnated magnesia-chrome bricks have achieved dual breakthroughs in performance and compliance through material modification and process optimization. Their hexavalent chromium leaching amount is 90% lower than that of traditional magnesia-chrome bricks; meanwhile, by introducing nano-titanate and rare earth sintering agents, the thermal conductivity is reduced by 18% compared with ordinary bricks, significantly reducing furnace heat loss. Under the background of the EU Carbon Border Adjustment Mechanism (CBAM), the low-carbon production process of these bricks (energy consumption per ton of product ≤1.2 tons of standard coal) can help export enterprises save more than 15% of carbon costs.
Salt-impregnated magnesia-chrome bricks, with their scientific material design and engineering applications, are redefining the protection standards for high-temperature industries. Whether coping with 1700°C molten steel scouring or meeting stringent environmental regulations, this material demonstrates irreplaceable technical advantages.
