Defining energy-efficient slurry pumps with KREBS®

Slurry pump selection for efficient mining and minerals processing

These tough machines move high volumes of often abrasive and corrosive slurries between processing steps. Pump selection is thus a key factor in both productivity and profitability. In this blog, Roman Van Ommen, Head of Pumps, Valve and Cyclones for Europe, Central Asia, NW Africa explains some of the main factors to consider.

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Slurry pumps: operating at the extremes

Slurries are generally characterised as abrasive, viscous – sometimes also corrosive – liquids that are high in solids and quick to settle. These characteristics mean more energy is required to pump slurries than is needed for clean water. Slurries also expose pumps for substantially higher levels of wear. Beyond these generalities, however, slurries vary widely, even within the same mining or mineral processing operation, based on the specific application.

When selecting a slurry pump for a mining or mineral processing application, key factors therefore include:

Long and predictable wear life to reduce downtime and the number of shutdowns
High efficiency for reduced energy consumption
Ease of maintenance and adjustments to protect workers from hazards
Quick and reliable availability of high-quality spare parts

Centrifugal pumps for slurry applications

Centrifugal pumps have a long history of use in slurry applications and are commonly used for slurry handling in mining and mineral processing operations today. As the name suggests, these pumps generate centrifugal force via the rotation of an impeller, which is transferred as kinetic energy into the slurry to move the liquid through the pump.

When selecting a centrifugal pump for slurry handling, there are a wide range of additional factors that go into ensuring an appropriate pump design for the application. These include the size and design of the impeller (which must allow passage of solids through the pump); type of shaft seal; casing design; and choice of materials.

Given the complexities involved, it is important to work with an expert supplier, who understands the particular process challenges and can provide the most appropriate pump type and model for the job.

The innovative wear ring assembly: redefining centrifugal slurry pumps

A key technological milestone in the history of centrifugal slurry pumps was the development of the patented wear ring assembly for KREBS® millMAX™ slurry pumps. This innovation completely transformed the slurry pump industry and continues to be the defining factor that sets KREBS pumps apart from their competitors.

The wear ring assembly is a proprietary suction-side sealing system, which incorporates a wear ring, wear ring carrier, and wear ring adjustment bolts. By allowing the suction-side gap to be closed when the pump is running, the wear ring eliminates two of the major issues faced by conventional slurry pumps: mechanical grinding of solids between the suction liner and the impeller; and flow recirculation to the impeller eye on the suction side.

These two challenges limit pump life and raise power consumption in traditional pumps. In solving them, the wear ring thus delivers high-efficiency pumping with significantly lower power draw of 10% compared to alternative slurry pump design. It also extends wear life: a major benefit, given that it is not uncommon for annual parts costs to equal up to 50% of the original capital cost. KREBS pumps thus offer unparalleled total cost of ownership.

And because the wear ring can be adjusted as the pump is in operation, it allows on-the-go optimisation of pump performance, while reducing the safety risks posed to pump operators.

KREBS®: A legacy of excellence in pump technology

Founded in 1952 as a family business, KREBS originally specialised in hydrocyclones, where it now leads the market. As a compliment to its hydrocyclone offering, in 1999 the company acquired the rights to the millMAX™ centrifugal slurry pump. KREBS would later be acquired and incorporated into FLSmidth.

FLSmidth now offers a wide range of KREBS centrifugal slurry pumps, covering most slurry handling requirements. These include the original KREBS millMAX, along with its sister pumps specialized for high head and high efficiency applications, the millMAX-HH and millMAX-e. Other pumps in the KREBS product line include the slurryMAX™ and slurryMAX XD, the gravelMAX™ range, the UMD™ ultimate mill discharge pump, the hMAX pump, and the vMAX™ vertical slurry pump.