Sourcing Sustainable Solutions

Global mineral demand is increasing, driven by energy transition and CO2 reduction goals. Rising power costs, paired with declining ore grades and more difficult ores, require changes in equipment selection.1 As comminution remains one of the most energy-intensive stages in mineral processing, energy-efficient systems must be chosen. Water consumption also features heavily in the discussion for enhanced sustainability.

A well-known dry grinding system is the vertical roller mill (VRM), which provides substantial benefit regarding energy savings. Compared to traditional tumbling mill systems in the mining industry, the VRM system’s energy consumption is approximately 30 – 40 % lower. There is a need for a systematic approach, that is to evaluate not only machines, but to understand how each equipment technology can be integrated into the complete flowsheet.

As the VRM is a new technology in the mining industry, but well known and proven in many other industries, this article describes the special features of the VRM as an air-swept system. A comparison with high-pressure grinding rolls (HPGR) combined with air classification will also be presented, in addition to a discussion of the challenges of grinding part and mill internal wear.

The air swept vertical roller mill and pressure drop

Vertical roller mills combine grinding, drying, and classification in a single machine. The grinding plant operates under negative pressure, i.e. a system fan is installed downstream of the cyclone or bag filter for dust collection. Figure 1 shows a plant with a bag filter (right) and a cyclone system (left) for particle/dust separation. To obtain optimum adjustment flexibility, the system fan is equipped with a variable-speed drive using a frequency converter. The gas flow ensures the material transport; gas volume and gas velocities produce a relatively high pressure loss, and therefore the system has a higher mill fan power consumption compared to dry grinding ball mill systems.

 

This is a preview of an article that was originally published in the October 2025 issue of Global Mining Review. Subscribe to Global Mining Review for free to read this article in full and many more here.

Read the article online at: https://www.globalminingreview.com/special-reports/10112025/sourcing-sustainable-solutions/