Background:
Since 1986, High-pressure grinding rolls (HPGRs) have been used in the cement industry for energy-efficient grinding of clinker, limestone, and slag. Compared to ball or vertical mills, HPGRs significantly reduce energy consumption by inducing fractures in material through compressive forces.
Challenge:
HPGR roller surfaces suffer from significant wear. This can lead to high maintenance costs and downtime, reduced energy efficiency, and an increased CO₂ footprint.
Additionally, newer feed materials such as alternative fuels and supplementary cementitious materials (SCMs), are more abrasive, which leads to accelerating deterioration.
Conventional wear protection methods (e.g., welded hard-facing or studded rollers) offer only partial or short-term solutions. Welded rollers crack and spall over time, and studded rollers can’t withstand high pressing forces (needed for clinker grinding) and may break, leading to costly failures.
Solution:
Köppern’s hexadur® wear protection technology was developed using powder metallurgy and Hot Isostatic Pressing (HIP) to create a composite roller surface.
The wear protection technology features hexagonal tiles bonded to a ductile steel base and was designed with intentional interspacings that fill with feed material to form a self-renewing autogenous protective layer (APL).
Additionally, the wear protection technology can withstand high specific forces (up to 6500 kN/m²), and is maintenance-free, with a service life exceeding 100,000 hours.
In parallel, Köppern’s gravity feeder system optimizes material flow to the rollers, stabilizing throughput and reducing vibrations, uneven loads, and wear.
Results:
After 76,000+ hours, Köppern’s hexadur® rollers showed minimal wear (1.5–3 mm per 10,000 hours), and required no maintenance.
In a Thailand case study, upgrading a third-party manufactured HPGR with Köppern’s hexadur® and feeder system led to a 9% increase in hourly production, a 14% decrease in specific energy consumption, and €1.5 million in savings over 5 years.
Köppern’s hexadur® and feeder system enhanced control over the grinding process, reduced CO₂ output, and created a greater process stability.