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In a cost-sensitive commercial environment such as mining, there are a number of key benefits associated with using peristaltic pump technology. For instance, reduced water use means significantly less cost. On average, water savings of 71% can be achieved in comparison with some centrifugal pumps, while the treatment of less water also ensures less chemical usage.
Other benefits afforded by the adoption of peristaltic pumps include the elimination of mechanical seal flush water needed by centrifugal pumps, less storage requirement for tailings (the number of basins can be reduced), and lower environmental risk.
Management responsibilities
The importance of water cannot be underestimated, and consequently all mines must assess the impact of mining on local and regional water quantity and quality in order to retain a social licence to operate. With this in mind, best practise water management is the new trend that defines credibility for the mining industry while negating the potential impact of additional costs.
Among the key drivers for water reduction in the mining sector are the increasing price of water and the limited availability of water at mines located in desert areas or at altitude. What’s more, there are a number of additional processes associated with the use of water which are costly and time consuming. For instance, intake water needs to be conditioned and effluent water needs to be treated.
The less time a mine requires to pump, add or remove water in the course of processes usually translates into reduced operating costs. Peristaltic pumps can be considered water-saving devices, not simply because they can accommodate very high solids-content materials found commonly in mining operations, but because they do not require seal gland water, thus eliminating the requirements to either treat process wastewater or provide pump service water. Pumps such as these can play a key role in new management trends like water balance modelling.
Benefits of peristaltic
Peristaltic pumps can be considered as inherent metering pumps, offering high repeatability. Furthermore, many models include integral digital drives with Profibus or SCADA control. As a result, there is no need for separate VFDs or complex control devices. Peristaltic hose pumps accommodate high continuous flow rates and are extremely durable. There are no internal universal joints, valves, dead corners or glands to impede flow, and they are reversible for back-flushing.
Although one main goal of mine operators is to use less water in the transportation process, doing so creates thicker, more paste-like slurries, which in turn creates other issues. More product can be transferred at lower velocities, but pump and hoses must be designed to handle thicker flows.
Leading types of high pressure peristaltic hose pumps can handle undiluted tailings and thickener underflow up to 80% solids by weight. No seal water flush systems, strainers, dampeners, in-line check valves, run-dry protection devices or other ancillary equipment is needed. This innovative technology fits with wider current research into more efficient modes of high concentration slurry transport. The ultimate aim is to reduce water use, energy consumption and capital costs, as well as improve slurry transport reliability by establishing a more fundamental understanding of slurry flow behaviour and design.
Paste backfill and accommodating solids
One of the most commonly pumped materials in mining operations is paste backfill, and the goal for the high density paste formulations is to produce a ‘pumpable’ material that does not segregate when placed – the fines content should be a minimum of 15% by weight of the paste. Naturally, choosing the right pump technology for the task is vital.
Similarly, the pumping of solids such as rocks, sand and ore presents a real challenge. Mining slurries often feature sub-micron solid contents of 80% by weight, with specific gravity often greater than 2.0. In addition to offering abrasion resistant slurry pumping performance in arduous conditions for extended periods, the selected pump must be capable of high operating pressures and flow rates to ensure a smooth liquid passage and deny the opportunity for the product to settle.
For the mining sector, the wear-free performance of peristaltic pumps is arguably the most attractive benefit. Obviously, the longer a pump can operate without maintenance or failure, the better. The wear-free performance of peristaltic pumps is an attribute that results from a unique operating principle. Unlike other pumps, the abrasive nature of the product has no bearing on pump life and the need for routine maintenance and spare parts is reduced greatly.
Hose is at the heart of peristaltic operations
In a peristaltic pump, nothing but the hose touches the fluid, eliminating the opportunity for fluid to contaminate the pump. Fluid is drawn in and trapped/squeezed between two shoes before being expelled. The complete closure of the hose gives the pump its positive displacement action.
The hose is in direct contact with the slurry, so it needs to be both flexible and tough. The best hoses are those composite in nature, made from compounded rubbers reinforced with layers of braided nylon and finished by precision machining for enhanced suction, pressure and flow performance over its expected lifetime.
Design features such as these are important because over-occlusion of the hose stresses both the pump and hose, reduces hose life and places unplanned loads on the pump bearings. Similarly, under-occlusion results in loss of pump efficiency and damaging back-flow, which also reduces hose life.
Accurate chemical metering
Another potential area of savings for mine operators is through accurate chemical metering. Peristaltic pumps will maintain the floatation rates of ore extracts to ensure economical use of expensive chemicals and create significant process efficiencies. The upshot is that peristaltic pumps have become first choice in mines throughout the world for applications that include dosing process reagents and pumping shear-sensitive polymers for flocculation and coagulation, abrasive lime slurries for pH control, or corrosive chemicals like cyanide for gold recovery.
Ultimately, more and more mining industry customers are turning to peristaltic technology. This is because peristaltic pumps can help reduce downtime and operating costs, and manage and reduce water inventories. Chemical usage and maintenance costs are also minimised, while greater conformance to environmental regulations is assured.
The Watson-Marlow Pumps Group comprises of:
• Watson-Marlow Pumps: peristaltic tube pumps for pharmaceuticals and industry
• Watson-Marlow Tubing: precision tubing for pumping and other purposes, in a range of materials
• BioPure processing components: single-use tubing connector systems for biopharmaceutical customers
• Bredel Hose Pumps: heavy-duty hose pumps
• Flexicon Liquid Filling: aseptic filling and capping systems
• MasoSine Process Pumps: sinusoidal pumps
Part of the Spirax-Sarco Engineering Group, Watson-Marlow Pumps Group is an international operation based in Falmouth, Cornwall, UK. Watson-Marlow Pumps has offices in Argentina, Australia, Austria, Belgium, Brazil, China, Denmark, France, Germany, India, Italy, Malaysia, Mexico, the Netherlands, New Zealand, Poland, Russia, Singapore, South Africa, South Korea, Sweden, Switzerland and the USA.
