Emerging lithium extraction sector takes advantage of peristaltic pumps

Metallurgical laboratory and consultancy service, Grinding Solutions, is using a 500 series peristaltic pump from Watson-Marlow Fluid Technology Group (WMFTG)  as part of a new pilot plant for Cornish Lithium. The pump features six pumpheads to dose reagents into all six streams of the flotation process simultaneously. As part of the same pilot plant, the company is also using a Qdos metering pump from WMFTG to dose flocculant into settling tanks. Grinding Solutions has taken advantage of pumps from WMFTG for many years as part of bench testing operations, but the move to pilot scale operations is a first-time venture for this progressive company.

With the push towards electrification and renewable energy sources, companies, countries and regions are exploring sources of lithium and other battery metals. Cornish Lithium, for example, is looking at the extraction of lithium from brines and hard rock. After successful bench testing, Grinding Solutions is now undertaking pilot plant testing for Cornish Lithium, helping the company to develop a process to extract lithium from micas.

Pilot scale operations enable Grinding Solution to confirm bench test results, build confidence and generate concentrate which Cornish Lithium can use for further testing. The pilot plant will also help its client to verify processes, understand costs and minimise risks.

Battery metals will be critical in the future as the world moves towards more environmentally friendly transportation and infrastructure. Cornish Lithium is an eco-technology mineral exploration company focussed on the sustainable extraction of lithium and other battery metals in the historically significant mining district of Cornwall. It is one of only five regions worldwide for lithium-enriched granites. The company has secured extensive mineral rights agreements across more than 500km2 of Cornwall, as it looks to establish a strong, sustainable and environmentally responsible lithium extraction industry in the UK.

Partnerships are key to this ambition, which is why the company works closely with Grinding Solutions, based near Truro, Cornwall. In turn, Grinding Solutions partners with pump specialist WMFTG, which also has its global headquarters in Cornwall. “We’ve been working with Cornish Lithium for a couple of years now,” says Jon Rumbles, project metallurgist at Grinding Solutions. “Steadily, we’ve progressed from bench-based mineral processing and testing to a pilot plant. Rather than processing tens of kilograms we’re now processing hundreds of kilograms.”

Pumps Prove Critical

Grinding Solutions crushes, mills and separates the mineral into different size fractions, processing it to generate a lithium concentrate. Vital to the success of the pilot plant is the accurate dosing/pumping of materials.

Through the pilot plant’s flotation stage, which promotes mineral separation, there is a need to dose reagent (collector and thickener) at a constant addition rate. Here, the company takes advantage of a Watson-Marlow 530SN peristaltic pump with six 313 pumpheads.

“The use of six pumpheads means we can use a single pump to dose all six streams through the rougher and scavenger as part of the flotation process, which is very efficient,” says Rumbles.

In addition, the company is leveraging the benefits of a Qdos 30 metering pump from WMFTG for dosing flocculant into settling tanks at a rate of 10-15 ml/min. The flocculant allows for better settling, permitting quicker extraction of the water ready for recirculation back through the system. 

Many Advantages

“We’ve been using Watson-Marlow pumps for years, for both dosing and slurry transfer,” explains Rumbles. “They are really easy to calibrate and their wide-ranging flow rate capabilities are invaluable. We have a number of 500 series pumps on site for reagent dosing, plus the Qdos 30. A couple of the 500 series pumps are fitted with larger pump heads for slurry transfer, while some of our 600 pump series models are linked to density meters. In fact, to facilitate automatic adjustment, we’re now looking at using the 4-20 mA input for even more control from live meters.”

As well as dosing viscous reagents, Grinding Solutions uses its Watson-Marlow pumps to dose sulphuric acid, which helps the system maintain a pH of 2-3. “By using peristaltic pumps we’ve not had to think about issues like strong acidity and high viscosity,” concludes Rumbles. “As the pumpheads are self-contained, we can change a reagent – and a pump head – without having to worry about damage to pump parts or cross contamination. In addition, we get accurate dosing and continuous flow from Watson-Marlow pumps, with no reliability issues whatsoever.”