January 21, 2026
The scientific selection of refractory bricks for flash smelting furnaces is a crucial foundation for ensuring the safe and stable operation of non-ferrous metal smelting equipment. A flash smelting furnace is a large-scale non-ferrous metal smelting device, mainly composed of three parts: the reaction tower, the settling tank, and the rising flue. Due to significant differences in temperature levels, media characteristics, and airflow erosion conditions in each part, the selection of refractory materials and structural configuration needs to be specifically designed according to the specific working conditions.
Overall Structural Characteristics and Refractory Material Selection Principles of Flash Smelting Furnaces
Different functional areas of the flash smelting furnace perform different process functions, and therefore have significantly different requirements for refractory material performance. The reaction tower is mainly responsible for high-temperature rapid reactions, the settling tank is responsible for melt storage and separation, and the rising flue is responsible for high-temperature flue gas transportation. Therefore, the selection of refractory bricks should comprehensively consider high-temperature resistance, slag erosion resistance, airflow erosion resistance, and maintenance and replacement conditions, rather than simply pursuing high-grade materials.
Reaction Tower: Refractory Brick Configuration under High-Temperature and Strong Erosion Conditions
The reaction tower is the most critical part of the flash smelting furnace, with the highest temperature and the most concentrated material reactions. The maximum temperature inside the furnace can reach 1400-1500℃. High-temperature furnace materials and airflow pass through the tower body rapidly within seconds, accompanied by some molten material flowing along the inner wall, causing strong erosion and chemical corrosion to the refractory bricks. Given that the reaction tower is suspended above the settling tank and difficult to replace, its main lining usually uses electrofused magnesia-chrome bricks or electrocast magnesia-chrome bricks to meet the comprehensive requirements of high-temperature resistance, erosion resistance, and corrosion resistance.
The working conditions of the top lining of the reaction tower are relatively mild. This area mainly bears radiant heat, the temperature is lower, and it does not directly contact the furnace materials. Semi-recombined magnesia-chrome bricks or high-grade direct-bonded magnesia-chrome bricks can be used. Under conditions of high-purity oxygen-enriched smelting and enhanced cooling, the reliance on high-grade magnesia-chrome bricks can be further reduced.
Settling Tank: Differentiated Refractory Material Application in Multiple Areas
The settling tank is the most complex area in terms of refractory material configuration in the flash smelting furnace. The upper space of the settling tank is mainly subjected to high-temperature gases above 1350°C. Since it does not directly contact the molten material, the degree of erosion and corrosion is relatively light. Semi-re-bonded magnesia-chrome bricks or high-grade direct-bonded magnesia-chrome bricks are usually used, along with a water-cooled beam structure to reduce the furnace roof temperature and extend its service life.
The slag line of the settling tank and the area below the reaction tower are the most severely eroded areas. The flash furnace slag is alkaline, rich in FeO and SiO₂, and has strong corrosive properties towards refractory bricks. It is also affected by molten material erosion and frequent slag tapping operations. This area usually uses high-quality semi-re-bonded magnesia-chrome bricks with excellent slag resistance and erosion resistance. Electro-fused re-bonded magnesia-chrome bricks are more suitable for the slag line area.
The furnace bottom and the area below the slag line form the load-bearing foundation of the furnace lining structure. Although the degree of erosion is relatively light, at least one side is in long-term contact with high-temperature liquid, requiring high compressive strength, low apparent porosity, and high load softening temperature. In practical engineering, high-compressive-strength semi-re-bonded magnesia-chrome bricks or electro-fused re-bonded magnesia-chrome bricks are often used. The lower and middle layers of the furnace bottom are combined with refractory clay bricks and high-temperature insulation bricks to meet both load-bearing and insulation requirements.
Refractory Material Selection for Connecting Parts and Upward Flue
The connecting parts of the reaction tower, settling tank, and upward flue are subjected to the most concentrated airflow erosion. This area usually uses a cooling copper tube as a framework, with amorphous refractory castable material filled inside. The material is required to have good corrosion resistance and erosion resistance at high temperatures, as well as good fluidity during construction and sufficient curing time.
The upward flue is the channel for the collection and discharge of flash furnace flue gas. The normal operating temperature is generally 1250–1300°C, and the flue gas velocity varies from 5.0 to 9.0 m/s in different areas. The refractory bricks in this area are subjected to airflow erosion and are also prone to dust accumulation. Semi-re-bonded magnesia-chrome bricks or direct-bonded magnesia-chrome bricks are usually used. The area near the settling tank and above the slag discharge port has higher temperatures and significant airflow changes, making semi-re-bonded magnesia-chrome bricks more suitable. Some projects use water-cooled copper plate structures to reduce maintenance frequency. Conclusion
The selection of refractory bricks for flash smelting furnaces should be guided by the principle of suitability to the operating conditions. Practical experience shows that the rational allocation of refractory materials in different parts of the furnace should achieve a balance between performance and cost-effectiveness, while meeting the requirements of high temperature resistance, corrosion resistance, and structural safety. It is not simply a matter of using the highest grade materials available.
