WEMCO II: The best in flotation just got better

With 40,000 machines in operation around the world, WEMCO flotation devices have been the industry standard for more than 50 years. The broad appeal is attributed to easier start-up, simpler operation and lower reagent consumption. Yet, we knew we could take an evolutionary approach and further improve the WEMCO design.

Inside each WEMCO II cell is a newly designed rotor-disperser system that delivers intense mixing and aeration. Our new WEMCO II design features better air control and froth maintenance, which elevate kinetic performance and lower operational costs. We tested multiple iterations to identify the right combination of the rotor and stator/hood that would improve hydrodynamics and optimise performance. 

These design changes allow for application of expert control and improved response to operational demands. WEMCO II is designed to be easily retrofitted into all types of existing WEMCO cells. The downtime and cost associated with a retrofit are minimal and produce a quick return on your investment.

Your results?

• Improved kinetics and performance
• The ability to control air without an external air supply
• Optimised energy efficiency
• Better hydrodynamics and circulation
• Improved surface and froth stability compared to previous generation cells 

• Highest recovery rates

For decades, WEMCO flotation cells have consistently delivered the highest recovery. WEMCO II’s combination of efficient aeration and optimum solids suspension not only increases recovery and concentrate grade performance, but also reduces reagent consumption.

• Improved power consumption

Improvements to the rotor and stator/hood design have produced a noticeable change in power consumption.

• Increased air flow and control

Our redesigned rotor draws 2.5 times more air flow into the pulp, without the need for a forced-air supply system. This design allows you to throttle the air, resulting in better control, a more stable surface and improved recovery.

• Exceptional performance

The new design features better air control and froth maintenance without the need to operate blowers and install distribution piping — all of which work to elevate kinetic performance and lower your operational costs. 

In redesigning the rotor-disperser system, our engineers applied computational fluid dynamics (CFD) to tweak the WEMCO rotor and stator configuration for more efficient pumping. Our goals included the ability to create smaller, more uniform bubbles while increasing vortex formation. These vortices dissipate energy to improve bubble contact efficiency.

WEMCO II CFD results, water velocity:

• 87% greater pumping
• 36% greater air intake
• Even draft tube flow distribution

WEMCO II CFD results, air volume fraction:

• Improved air dispersion
• 21% greater turbulent kinetic energy
• 31% greater turbulent vortex dissipation

The WEMCO II design draws 2.5 times more air than its predecessor. This is more air than necessary, but it allows throttling of the air for improved control without adding a blower. At the same time, the design provides a more stable surface and improves recovery.

Following CFD work, we built a prototype and lab-tested the WEMCO II design. In 22 tests run on copper ROM, recording kinetic data and hydrodynamic observations, the results we obtained indicated both higher recovery and higher grade.

We then implemented the final WEMCO II design in a pilot plant, where we verified further improvement in mechanical advantages such as air flow, pumping, sheer and bubble size.