GL&V Australia has developed a variable dilution feed system for thickeners that provides greater flexibility in dilution control on thickener feed systems.
The new system is based on the technology introduced with the company’s patented Eimco E-Duc feed dilution system. Released in 1999, the E-Duc system uses the head of the undiluted feed as the driving force for the eductor nozzle, which is located just below the liquid level.
In operation, slurry is pulled into the open-top mix channel and water from the clear zone of the thickener is educted into the mix channel for feed dilution.
Flocculant is added at the nozzle where it is thoroughly mixed in a low-shear environment to minimise floc break-up.
All mixing is completed in the open-top channel prior to the feedwell, which allows for a visual inspection of the flocculant impact on the feed slurry.
Now in use at more than 150 sites around the world, E-Duc feed dilution systems are an integral part of the processing circuit for a wide range of mineral types. Along with production efficiencies, anecdotal evidence indicates the system is delivering lower operating costs. Ssome sites advise of substantially reduced water consumption and, in some cases, upwards of 60% savings on flocculant costs.
GL&V’s new variable dilution feed system builds on and expands the engineering and technology introduced with the E-Duc system.
The obvious difference with the original system design are the axial flow pumps for infinite flow regulation of the dilution to match any variation in feed solids or changes in the settling characteristics of different orebodies.
Along with eliminating any need for additional head requirements to meet variations in feed/slurry characteristics, the pumps also maintain the flocculant and dilution levels at the optimum ratio.
The system requires the same driving head as a conventional feed system without feed dilution, which makes it a suitable choice for gravity fed thickener feed systems such as CCD circuits.
According to GL&V design engineers, the new variable speed pump-driven system successfully and accurately addresses the “flow versus density” equation to deliver an accurate and reliable feed dilution system.
The company says the system exhibits the benefits proven by E-Duc, including easy installation/retrofitting, increased thickener capacity and increased underflow concentration.
Already in use in Australia, GL&V is now preparing to design, supply and install the new variable dilution system on a series of 70m diameter CCD thickeners at the giant Goro nickel project in New Caledonia.