Failure-Resistant Copper Staves for Blast Furnaces

Blast Furnace Copper Staves are a cooling solution designed to enhance wear resistance and prevent bending in blast furnaces. As a leading supplier of copper staves for more than 20 years, Primetals Technologies recognizes that optimal furnace cooling design begins with understanding the furnace profile and process conditions. Leveraging this expertise, Primetals Technologies optimizes the design of copper staves to best accommodate the varying conditions within the blast furnace, ensuring long-lasting, trouble-free operation.

Bend-Resistant Copper Staves for Blast Furnaces

The use of copper staves in the higher heat and melting zones of blast furnaces has proven effective for cooling and maintaining the structural integrity of the furnace shell. However, premature failures due to stave bending, commonly referred to as the "banana" effect, have proven to be a major challenge to stave life. The bend-resistant copper stave technology significantly reduces the need for maintenance, intensive leak detection, and repairs to both compensators and the staves themselves. This anti-bending copper stave technology can be applied to existing blast furnace shells without necessitating any modifications to the existing openings, offering a practical solution to enhance durability and operational efficiency.

Benefits of Bend-Resistant Copper Staves

• Proven anti-bending solution prevents bending of the copper stave corners, eliminating premature failure of cooling pipe connections
• Optimum copper stave fixing allows for thermal expansion without bending
• Standard solutions for new blast furnaces and blast furnace relines, with minimal installation and downtime requirements
• Significant reduction in unplanned maintenance results in a long campaign lifetime

Wear-Resistant Copper Staves for Blast Furnaces

Blast Furnace Copper Stave wear is a phenomenon experienced by many operators globally. The wear is caused by the presence of relatively cold, abrasive materials at the furnace walls, combined with excessive forces from the descending burden. Events such as process disturbances, changes in the position of the cohesive zone, high rates of reductant injection, errors in furnace charging patterns, and poor burden quality can also contribute to wear.

Excessive stave wear can lead to the exposure of stave cooling water channels, resulting in water leaks into the furnace and loss of the copper staves. Without significant and costly intervention, this can ultimately lead to furnace shell damage.

By installing patented hexagonal inserts on the hot face of the copper staves, a three-factor protective layer is formed between the soft copper of the stave and the burden material in the blast furnace.

The Three Layers Consist Of

• Hard-wearing hexagonal-shaped metallic inserts which slide into place between the stave ribs
• Burden material trapped between the hexagonal-shaped inserts
• Liquid material frozen to the copper and the inserts

This combination effectively protects copper staves from abrasive materials and challenging process conditions. In addition to preventing wear, the layers reduce heat loss from the process to the cooling system. By installing multiple rows of copper staves with hexagonal inserts, the reduced heat losses can enable a lower fuel rate during operation, which directly reduces the CO₂ emissions from the blast furnace.

The integration of anti-bending technology with wear-resistant hexagonal inserts yields staves that are resistant to the most common stave failures. Furthermore, this design can decrease the energy consumption of the process, enhancing overall efficiency and sustainability.

Benefits of Wear-Resistant Copper Staves

• Hexagonal inserts offer a "3-point lock" mechanism that retains burden material between the inserts.
• Hexagonal inserts provide additional stiffness, further minimizing the bending of blast furnace copper staves.
• A more stable insulating layer is formed on the stave face, reducing heat losses and fuel rate by up to 5 kg per metric ton of hot metal, equivalent to a 1% reduction in CO₂ emissions.
• Available as both standard and retro-fit solutions for new furnaces and furnace relines, ensuring minimal installation and downtime requirements.
• Significant reduction in wear leads to less unplanned maintenance, resulting in a longer campaign lifetime.

"This solution has been in use at HOA since 2004. We didn't find [any stave] deformations or leaks. We have installed the same [technology] in 2018."

- voestalpine Stahl, Linz, Austria

"The hexagon [inserts] are definitely going to extend the life of the staves, I wish we had installed a full row of them.”

- Site CTO in North America