Pumps cope with aggressive fluid from electronics recycling

One of the UK's leading recyclers of IT and telecommunications equipment is Engelhard, part of the BASF Group. Typical products recycled at the company's plant in Cinderford, Gloucestershire, include computers, monitors, printers, fax machines, photocopiers, mobile phones and pocket calculators. Integral to the business is the recovery of precious metals - such as gold, silver, platinum, palladium and rhodium - from circuit boards and other electronic components.

Part of the process involves using a high-temperature scrubber to burn off the plastics that cannot be economically recycled. However, this results in fumes laden with hydrochloric acid, which have to be neutralised with a caustic liquid. The resulting liquor gradually becomes contaminated with mainly carbon particulates until it reaches the point where it has to be filtered and processed, ready to be reused. Twice a day, hundreds of gallons of this highly aggressive, hot (50-60°C), particulate-laden fluid have to be pumped from the scrubber to the filter bed in under one hour.

The peristaltic pump that was originally specified for this task soon proved to be troublesome, requiring monthly hose changes and, even then, hoses still occasionally burst due to high back-pressures caused by blockages. Other pump-related failures also occurred, and spare parts were not readily available from the manufacturer, which was based in mainland Europe. As a result of this pump's problems, Engelhard was suffering from downtime, the cost of spare parts, additional costs for stocking hard-to-get spare parts, and each time the maintenance engineers were called to attend to the pump, they were unable to continue with their other work. Over a period of several years, virtually every part on the original pump failed, including the guard, the rollers on the rotor, and even the geared motor.

Two-year warranty and UK spares

Crest Process Engineering, which helps Engelhard to maintain the plant, recommended upgrading to a Watson-Marlow Bredel pump. Despite initial reservations over the slightly higher cost of the Watson-Marlow pumps, Engelhard agreed to purchase an SPX50 peristaltic pump, which is capable of delivering a maximum flow rate of 62 litres/minute (800 gallons/hour) and, much to Engelhard's relief, benefits from a two-year warranty and UK-sourced spares.

One year on, Gary Williams, the Maintenance Supervisor, is extremely pleased with the pump's performance, saying: "We have not even had to change the hose yet, let alone any other components. Compared with what we had before, it has been unbelievably reliable - totally maintenance-free. Considering that each pump failure was resulting in 12 to 15 hours of downtime, plus we have not had to spend any money on spare parts, the new SPX hose pump has probably paid for itself already."

Perhaps as importantly, the pump is no longer a headache for the maintenance department, enabling resources to be better deployed in keeping other parts of the plant in first-class condition. Given that the plant meets the requirements of ISO 14001 for its environmental management systems, maintaining the plant in good order is essential if potentially environmentally damaging incidents are to be avoided.

Gary Williams concludes: "The Watson-Marlow Bredel SPX pump has really proved itself in this application. We have other peristaltic pumps in operation around the site and, although they do not give as much trouble as the liquor pump did, it is likely that we will be replacing them with Watson-Marlow units when the time comes to change them."

For more information about the SPX50 high-pressure peristaltic pump, please contact Watson-Marlow Bredel.