Alfa Laval Australia mining & minerals key account manager, Paul Tuckwell, shares the capabilities of the company’s solid bowl centrifuges in overcoming challenges associated with the filtration and operation of tailings dams.
Increasingly, the mining industry is looking for technical solutions to dewater mine tailings slurries.
This can extend the life of existing tailings storage facilities or eliminate the risk of tailings dam failures altogether, with associated cost, environmental and risk advantages.
A number of technologies exists that all promise to deliver a dry tailings result.
Mechanical dewatering with solid bowl centrifuges is emerging as an effective solution for many tailings applications involving ultra-fine solids.
The capital, infrastructure and operating costs associated with these offer benefits compared with other technologies.
Alfa Laval offers customers not only solid bowl centrifuges with very large capacity (up to 70 dry tonnes per hour). These are specifically designed for high density slurries and the durability required for tailings slurries.
The company helps customers optimise the entire process from concept to operation, building on its strong research and development (R&D) commitment and significant in-house engineering expertise.
Alfa Laval prides itself on a strong local heritage, with more than 95 years’ market presence in Australia.
Its service and support capabilities include a specialised service centre in Sydney and field service/ commissioning engineers based around Australia.
This gives its customers confidence in maintaining their equipment performance and reliability.
Alfa Laval also provides remote condition monitoring and troubleshooting.
Can tailings with a high slimes and ultra fines content be dewatered with a solid bowl centrifuge?
Slimes and ultra fines (particularly those containing metallurgical clays) are often a challenge to both filtration and operation of tailings dams.
Newer methods which reduce the slurry volume though improved thickening, both in the process plant and consolidation at the disposal area have evolved. However, they all require a slurry discharge and containment in a dedicated area.
Valuable water is also lost through evaporation rather than directly recycling it to the process plant or water storage dam. Many sites would benefit from recycling this water.
While filtration can struggle with clay, a gravity-based method such as a thickener commonly separates out the water and solid phases with the assistance of flocculent.
They create an overflow that is normally clear enough for use in the process plant, and a pumpable underflow.
Logic suggests that artificially increasing the gravitational (G) force in a solid bowl centrifuge will achieve an even better solid-liquid separation result – and it does. You may like to see this demonstrated.
How can I trial the solids bowl centrifuge technology?
Alfa Laval is able to test the full scale of testing, from small samples to large thickener underflows.
Many projects pass through several testing steps prior to commitment of a full-scale plant.
Common key evaluation criteria that mining companies consider while selecting technologies for the dewatering of tailings are rheology of dewatered solids (cake) for transport and stacking; clarity of cleaned water phase (centrate) for recycling to the process plant; and operational experience and demonstration of concept.
Testing assists with evaluating these factors. Larger scale tests on operating mine sites enable collection of data for scaling up to full-scale operation.
Smaller scale pilot tests provide proof of concept and demonstration of the cake and centrate achievable, and measurement of the flocculent dose requirements.
Lab testing is a good screening step to provide an indication of the results achievable.
Alfa Laval can provide operators with a detailed technical proposal for its mining solid bowl decanter centrifuges.
The company also offers several full scale to pilot scale skid mounted trial solid bowl tailings centrifuges for on-site or off-site tests.
Austmine 2021 Conference presentation
As associate sponsor, Alfa Laval is proud to present on day one (May 26, 2:45–3:05pm) of the Austmine 2021 Conference.
The presentation is titled, Recover, Recycle and Reuse: Extracting Value from Tailings, forms part of the Breakout Stream 2 – Water & Tailings.
Alfa Laval will also have a stand at the Austmine Exhibition (#112).
Meet Tuckwell and his senior mining engineering colleagues to discuss your process optimisation strategy and dewatering requirements.
Book at meeting with Alfa Laval experts
This story also appears in the May issue of Australian Mining.