Metso Vertimill VTM-800-WB

The Metso Vertimill VTM-800-WB is a vertical stirred grinding mill with a 600 kW installed power rated for a ball charge of up to 800 metric tons, designed for fine and ultra-fine grinding of mineral slurries in the 25–150 µm product fineness range. Unlike conventional horizontal ball mills — which grind by impact and cascading — the Vertimill uses a helical screw agitator rotating at low speed (60–80 rpm) to induce high-intensity attrition between grinding media and mineral particles in a dense, fully flooded grinding chamber. This mechanism is significantly more energy-efficient than tumbling mills at fine grind sizes: Metso's benchmarked data shows 20–40% lower specific energy consumption (kWh/t) versus a ball mill producing the same P80 product below 100 µm, a saving that is economically transformative in high-throughput mineral processing plants where energy is a major operating cost component.

The VTM-800-WB's vertical orientation and small footprint — roughly one-third the plan area of an equivalent horizontal ball mill — makes it particularly attractive for plant expansions and retrofits where grinding circuit capacity must be increased without major civil works. The Vertimill's gentle grinding mechanism also produces a narrower particle size distribution (PSD) than impact-based mills, reducing overgrinding of soft minerals and preserving crystal liberation — a quality factor that improves flotation recovery rates in complex sulphide and phosphate ore processing circuits. The screw agitator is manufactured from wear-resistant Ni-hard or white iron alloy, and routine wear inspection is performed through the mill's top access hatch without draining or dismantling the grinding chamber.

In Saudi Arabia and the broader GCC, the energy efficiency credentials of the Vertimill are increasingly significant as the Saudi Electricity Company (SEC) raises industrial tariffs and as mining operations at remote sites (such as Maaden's Ad Duwayhi and Mansourah-Massarah mines) face high diesel generation costs. A Vertimill regrind circuit replacing a secondary ball mill at a 4,000 t/d gold processing plant typically saves 600–1,200 kWh per day — equivalent to 60–100 tonnes of diesel per year at remote sites — while improving flotation recovery by 1–3% through better PSD control. Phosphate beneficiation plants at Maaden's Wa'ad Al-Shamal facility are also candidates for Vertimill regrind integration to improve P₂O₅ grade and recovery in the flotation concentrate.

Razz Middle East provides Vertimill supply, installation, commissioning, and aftermarket support across the Kingdom. We stock screw agitator replacement assemblies, body liner segments, and classifier components and can arrange Metso process engineering consultations for circuit integration and product fineness optimisation.