In early 2013, Watson-Marlow Pumps Group supplied 21 positive displacement pumps to British Fluorspar, the UK’s sole fluorspar producer located in Derbyshire. The pumps, which include 12 of the latest Qdos no-valve metering pumps, are all working on chemical dosing in the flotation banks at the company’s Peak District facility. The mine reopened in May 2012 following closure 18 months beforehand. With the help of Watson-Marlow pump technology, the site produces some 60,000 t/y of acid grade fluorspar.

The company today comprises an underground operation at Milldam mine, open pit extraction at Tearsall quarry, and processing operations at Cavendish mill. When the site was re-opened in 2012, British Fluorspar was looking to source new pumps that represented the latest technology – efficient, reliable, precise, low maintenance, clean and user-friendly – and was advised to consider peristaltic pump technology. “We knew about the peristaltic concept but in all honesty never had the financial backing to make the change,” the mining company states. “However, with the new investment we were able to take a look at the market and soon realised that Watson-Marlow were the people to approach.”

Following consultation, Watson-Marlow recommended 12 Qdos 30 universal pumps offering flow rates from 0.1 to 500 ml/min at 7 bar; eight 520UN/REL process pumps providing flow rates up to 3,550 ml/min ; and a single 620UN/RE with flow rate from 0.004 to 18 litre/min. Regarding the latter, a probe is used to control the dosing in line with pH fluctuations. All of the pumps offer IP66 protection and NEMA 4X classification. This is a marked contrast from the equipment used prior to the site’s reopening – which relied on a bucket and wheel feeder/proportioner. The emphasis on the Qdos 30 range reflects a design which is aimed specifically at chemical metering. These high performance pumps accurately dose chemicals without the need for any valves or ancillary equipment, keeping costs to an absolute minimum – in fact, the total cost of ownership is less than that of a typical solenoid or stepper-driven diaphragm pump.

All 21 Watson-Marlow pumps have been deployed successfully in the flotation process at British Fluorspar. Reagents are pumped up from mixing tanks into the head tank, from where they follow plastic pipes down into flotation. Among the chemical reagents handled by the pumps include methyl isobutyl carbinol, sodium isopropyl xanthate, sodium carbonate, sodium sulphide, caustic soda pearl and sodium silicate. In total, British Fluorspar produces 60,000 t/y of fluorite ore, which is extracted from 300,000 t of ROM material. Limestone is a byproduct of the process and sold in its own right.