The Application Of Stemming

Sep 29, 2025

The Application of Stemming

Stemming is a refractory product used in blast furnace tapping ports and must have the following properties.

1. High temperature resistance.
2. Good plasticity and bonding performance, which is easy to squeeze into areas filled with gaps and cracks.
3. Suitable porosity to discharge the moisture during drying.
4. Low volume shrinkage at high temperatures to prevent cracking.
5. Good sintering performance, high strength, and resistance to scouring and erosion.
6. Easy to open, ensuring that the molten iron and slag can flow out at a uniform speed.

The Stemming ratio for large and medium-sized blast furnaces is as follows: 30-40% for<3mm fused alumina, 12-16% for ≤ 3mm coke, 12-16% for silicon carbide, 15-20% for clay, and 20 ± 2% for asphalt or resin binder.
In addition, an appropriate amount of silicon nitride and talc powder can be added to the Stemming. Silicon nitride can improve corrosion resistance, reduce shrinkage and prevent infiltration by molten iron, while talc powder can improve plasticity, sintering and high-temperature volume stability.