Boost Product Yields and Performance with Custom Attrition Scrubbers

Written By:

In this industry, demanding applications require high performance with low wear and this is no different when it comes to the liberation of high-value minerals. 

To show how prepared we are, the following covers two examples of impellers we offer to help you succeed with your operation:

CHV 332 impeller

The Sepro axial flow, high solidity, CHV 332 impeller offers a high solidity rate and high velocity operation in viscous pulp. Features include:

  • Minimum by-passing and maximum shear between the impeller zones.
  • Limited radial loss at the tips of the blades due to its aerofoil design. This is important because typical radial components at the tips can cause turbulence and erosion, resulting in premature blade wear. 
  • Rubber-covered bolted blades. 
  • Plate-protected bolt heads, which can be site-patched after assembly with suitable rubber compounds being used to fill cavities. 
  • Site patching can be easily removed for necessary blade replacement. 

Sepro CRF 690 BS

Attrition scrubbing systems also require a steady flow through the cells in order to maintain retention time and provide stable operating conditions –  and this is where the Sepro CRF 690 BS comes in, featuring: 

  • A uniquely-designed impeller that provides a combination of flow and shear, lifting the flow over the launder baffle at the required flow rate through the system. 
  • Retention control that is in excess of 94% as the flow has nowhere to go but through the upper orifice. 
  • A fully fabricated upper disc with six blades specially curved to provide the necessary velocities through the head box.  
  • Secure construction; the impeller is bolted to a disc welded to the shaft.  
  • Pre-rubber covered assembly that is site-patched after assembly.
  • A complete removable internal section as an assembly for maintenance.

The Finer Details

Sepro Mixing Icon

Agitator Components

Agitator Shafts

Shafts are manufactured to a stringent straightness tolerance of 1mm/metre of shaft length. Often, half of this limit is achieved with other standard agitator shafts. Ears are attached to circular hubs using deep penetrating continuous welds, which are systematically dye penned. Ears are never attached directly to hollow shafts. Hubs and ears are machined using CNC machines to minimise clearances between ear and hub; this ensures weld strength.

Mounting Bases

Mounting bases are critical components in ensuring gearboxes are correctly aligned and mounted to the beams or structure. This reduces the potential for twisting or flexing of the gearbox housing — a common cause of failure of proprietary gearboxes. All large, top entry Sepro Mixing agitators are fitted with integral mounting bases, or pedestals where necessary. All bases have machined pads, at the top and bottom, to ensure accurate and positive alignment

Large Sepro Mixing Impeller Blades

Impeller Blades

Sepro Mixing manufactures impellers for all applications, including high viscosity duty. However, as most applications are either flow or shear dependent, the Sepro Mixing CHF range of high flow impellers, or the Sepro Mixing CHG range of high efficiency gas dispersers, are the workhorses of the Sepro Mixing stable. Other impellers available are flat blade radials, pitch blade turbines, high viscosity anchors and helical impellers. We also build specialized impellers for pumping, foam breaking dispersion and Solvent Extraction.

Impellers can be manufactured in all materials, including exotics. They can  be supplied coated in rubber, urethane, epoxy or other specialized materials. Impeller blades are carefully checked to ensure that tolerances on angle, camber and curve are maintained. Out-of-spec blades are rejected. Blades are machined where hub and ear attach to ensure flatness. Often, the problem of loose blades is caused by blade flexing, resulting from a lack of flatness and poor contact with the hub ears.

Impeller blades in excess of 2″ thick and 21ft in diameter have been manufactured by Sepro Mixing in Canada.

Safety icon

Receive an open and information evaluation for your project

Contact our experts to find a solution that is right for you.

Request a Quote

We Can Also Help With:

Installation Supervision Icon

Installation Supervision

We ensure your factory-spec equipment is installed properly to maximize your operation’s success.

Commissioning Icon


We provide commissioning when your new equipment is integrated into a new – or existing – operation to improve bottom-line results and safety.

Customer Support Icon

Customer Support

Sepro’s team is comprised of experienced and knowledgeable engineers and support staff, with a combined experience of more than 45 years.

Automation Support Icon

Automation Support

With installations in more than 94 countries around the world, Sepro’s technical team are experts in using automation training to drive recovery volumes and safety.

Training Icon


To ensure a safe and productive operation of your equipment, Sepro will train key personnel and supervise the installation and commissioning of the equipment.

Lab Work Icon

Lab Work

Our in-house metallurgical testing facility is available to provide insightful lab work no matter which stage your project is at.