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quadropol® vertical roller millThe compact, low-vibration VRM for raw material, coal, slag and cement grinding
thyssenkrupp Polysius is one of the few full-range suppliers for the cement industry –, and has been for decades. Today's kiln lines reach capacities of up to 10,000 tonnes per day, and lines of 12,000 t/d have already been built with polysius® technology. Vertical roller mills are an essential part of that process, and the quadropol® is our answer for grinding raw material, coal, slag and cement.
The quadropol® – advantages at a glance
quadropol® vertical roller mill – improve your plant's performance
Applications & mill types
Vertical roller mills combine drying, grinding and separating in a single unit and are central to the production process. The quadropol® concept uses the same design philosophy across all applications – a true holistic approach – with a dedicated mill type for each duty:
QMR² – raw material grinding. Feeds the kiln and therefore co-determines clinker quality; supported by our newly developed HDZX double cyclones for raw grinding.
QMK² – coal & pet-coke grinding. Adapted table speed and a sepol® high-efficiency separator ensure safe operation and reliable kiln firing; ATEX compliance is a non-negotiable part of the design.
QMC² / QMS² – cement & slag grinding. For cement and increasingly for binding agents and granulated blast-furnace slag, with high-efficiency separators for the required fineness.
A sepol® high-efficiency separator secures the desired product fineness across all applications. Mill sizes are denoted by a table/roller code such as QMR² 48/24.
Mechanical design
Fully pre-assembled roller units. On a medium-sized mill the four roller units weigh about 50 % of the total mill-and-separator weight – cutting assembly, alignment and welding, and shortening erection time and cost.
Smart, compact hydraulics. One hydraulic unit serves all four roller units; the grinding force is generated by a single hydraulic cylinder per roller, and just one piston accumulator acts as the spring system.
Low-maintenance bearings. The fixed bearing is maintenance-free; the roller bearing is fully encapsulated with no shaft sealing inside the mill. As no dust can enter, no sealing-air fan is needed, and minor maintenance is possible without removing the roller unit.
Reinforced-concrete pylons. They simplify civil works and, thanks to strong damping, keep vibration low – during unstable operation loads are transmitted vertically into the foundation.
Benchmark vibration levels. A sensor in each tension frame measures at the grinding bed; in nearly all installed mills the value stays below 2 mm/s horizontally, while the gear-unit base sits at roughly 0.5 mm/s vertically.
Fast, safe servicing. A roller tyre can be changed within two shifts on the pylon, with no extensive scaffolding required under OSH rules.
Extract of our references
Over time, VRMs lose performance, resulting in reduced throughput, higher energy consumption and increasing process instability. These developments are often not caused by a single component, but by the interaction of mechanical condition, process settings and operating practices.
To address these challenges, thyssenkrupp Polysius offers an Expert Service for vertical roller mills. This Service is based on an in-depth mechanical and process-technological evaluation of the entire grinding circuit. Its objective is to create full transparency regarding the current operating condition of the mill and to identify concrete measures to stabilize operation, recover lost performance and improve energy efficiency.
During the Expert Service, specialists analyze not only the mill itself, but the complete grinding system.
This includes the separator, coarse feed valve, fan, cyclone and filters. Measurements are carried out during operation, complemented by inspections during stoppages, for example inside the grinding Compartment. This holistic approach ensures a complete picture of both the mechanical condition and the actual process conditions. Based on the collected data, clear statements can be made regarding key aspects such as:
condition of dam ring, guide vanes and separator
grinding bed height and material behavior
quantities of false air and gas flow volumes
air velocity in the nozzle ring area
wear behavior and specific energy consumption
A 3,000 t/d kiln line commissioned in 2019 under an EPC contract to the polysius-Imasa-Valoriza consortium, with a QMR² 38/19 for raw grinding and a QMC² 45/23 for cement grinding; all process guarantees were met quickly.
A QMC² 40/20 for different cement types, with a compact service-tower arrangement, main filter and a digitalization package including an intelligent mill controller; operating successfully since mid-2021.
Mombasa Cement (Kenya): a QMK² 24/12 with three roller units for a 5,000 t/d line, plus a QMR² 48/24 for raw grinding. Shiva Cement (India): a QMK² 32/16 for pet coke on a 4,000 t/d line. Indonesia: the same QMK² 32/16 has been grinding and drying lignite for years.
Two 10,000 t/d lines with four QMR² 48/24 for raw grinding and four polycom® high-pressure grinding rolls as a combi system for cement. Running since mid-2021 at feed moisture of 2.61 % with only 0.78 % injected water on the table.
A 4,000 t/d line with a QMR² 45/23 (raw), two identical QMC² 45/23 (cement) and a QMK² 32/16 (coal); interchangeable parts across all three mills, and cement fineness up to 5,000 cm²/g Blaine.
Why choose the quadropol® concept
Compact plant arrangement; approx. 50 % pre-assembled mill & separator.
Lowest downtime through mechanical simplification – less assembly, alignment and welding, and lower total cost.
Simple hydraulic system: one piston accumulator, one roller bearing, no confining air.
Roller lubrication with a single pump; return flow by gravity.
Lowest market vibration level < 2 mm/s (horizontal, at the point of comminution); gearbox forces vertical only, < 0.5 mm/s.
No extensive scaffolding for maintenance (OSH); roller-tyre change within two shifts on the pylon.
Highest mill availability and reliability; efficient grinding at low specific power consumption.
System monitoring and Advanced Mill Control for stable, digitalised operation.
International Cement Review reported that the equipment lets staff monitor and control every process variable in real time, for a stable process and consistently high product quality.
Flyers & brochures
Articles & interviews
The compact, low-vibration VRM
for raw material, coal, slag and cement grinding