Pumps manufacturer and supplier Weir Minerals Africa exhibited its flagship Warman MCR 450 mill circuit pump at Africa’s largest trade exhibition, Electra Mining Africa, held in September this year.

Weir Minerals Africa slurry pumps product manager Marnus Koorts explains that one of the largest consumables spends on mine sites is the pump system, which is also one of the largest contributors to high energy consumption. Therefore, the Warman MCR 450 has received increased interest, driven primarily by its improved total cost of ownership.

“The mill circuit pump is the most important pump in a process circuit, and the first point of contact for slurry as it leaves the mill. It is usually also the largest pump; the MCR 450 measures 2.5 m in diameter.”

The Warman MCR 450 has been specifically engineered for use in demanding applications and offers clients the most cost-effective solution, adds Koorts.

The pump’s hydraulic performance and the latest material technology make the Warman MCR 450 the best choice for mill circuit applications. Warman MCR pumps easily manage large-size particles in dense abrasive slurries, such as ball and semi-autogenous grinding mill cyclone feeds, as well as water-flush crushing in mineral processing plants.

“The MCR pump is specifically designed for mill discharge and cyclone feed duties, incorporating a number of elements that enhance performance in aggressive wear applications,” notes Koorts.

The pump hydraulics are based on several years of research and supported by wear performance field trials. The pump’s unique design also ensures the highest efficiency and optimum life cycle, extending the pump’s wear life.

“The pump was engineered for improved material flow as well as energy efficiency. Weir’s research and development team has spent extensive resources on modelling and understanding how material moves through the pump,” says Koorts.

MCR pumps have enabled end-users to achieve step changes in the operational costs of a plant by increasing productivity and decreasing downtime, Koorts says.

“Significant efficiency gains have been achieved with the Warman MCR 450 mill circuit pump, with one installation in South Africa showing a 14% increase in throughput. The pump also reduces energy consumption, ultimately resulting in significant cost savings,” he says.

The Warman MCR 450 offers several advantages to end-users, including superior safety and decreased cost of ownership, as well as outstanding performance and reliability.

Features, such as the impeller design with its large diameter and reduced tip speed, liner material, and bearing assembly, offer the right combination of ruggedness, durability, hydraulics and materials for the harsh African environment.

Koorts notes that the easily adjustable throatbush allows for easy maintenance of the impeller seal face clearance without having to adjust the bearing assembly or the drive. The adjustable frame plate liner insert allows for easier maintenance of the drive side clearance and sealing performance to protect the stuffing box.

The pump has several unique features, with reduced recirculation being achieved by the deep expelling vanes on the front of the hard alloy impellers.

“Large, open internal passages reduce velocities, which subsequently reduces wear inside the pump, while patented shrouds that extend past the periphery of the impeller and expelling vanes provide improved flow and reduced wear at the expelling vane tips. Turbulence is therefore minimised and prevents localised scouring on the throatbush face.”

The adjustable stuffing box allows for it and the lantern restrictor to be centred to the shaft sleeve. The stuffing box can be adjusted after piping loads have been applied to compensate for the associated casing displacement. This, in turn, can reduce gland seal water consumption, which is an important factor in water-scarce areas.

A further advantage is the full front throatbush adjustment that aids pump efficiency and performance. This is critical to efficient operation, while the quick-change feature enables technicians to replace the wet end of the pump on site.

The split cover and frame plates also allow for easy access when replacing the impeller and throatbush. By adjusting the throatbush and frame plate liner inserts tight against the impeller, the mounting bolts can be removed, the impeller can be unscrewed from the shaft and the outer casing, liners and impeller can be pulled off as one piece. Impeller and liner inspection can then be completed at a more convenient time in the workshop.

“Mill circuit applications are undoubtedly among the toughest in a mineral processing plant, and the Warman MCR pump is capable of reliable performance while reducing the total cost of ownership,” Koorts concludes.