Weir’s resolution for froth challenges

Froth pumping stays one of the complicated engineering challenges in mineral processing. Here, Weir Minerals presents recommendation for coping with the vital thing challenges in this operation, tips on how to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, increasingly more mine operators are investing in methods to increase the minerals reclaimed from froth pumping. However, when these strategies are deployed with out making allowances for the design of the mine’s froth pumping gear, it can lead to the lack of priceless minerals and profits.
Froth pumping remains one of the complicated engineering challenges in mineral processing. เกจ์วัดความดัน is basically due to the truth that air administration issues within the hopper, sump and pump itself can generally result in inefficient pumping, increased upkeep and even misplaced product.
“We’ve started to notice a sample among our customers who are having bother with their froth pumps,” said Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By using more flocculants and different chemical compounds designed to improve mineral restoration, they’re exacerbating current problems in circuit design and lowering the returns they’re in search of.”
Close examination of the froth’s make-up and physical qualities is usually needed to resolve issues. Ensuring operators’ froth handling gear adheres to finest design practices is a crucial first step in resolving problems.
Maintaining pressure The key problem in froth pumping is coping with air in the pump itself, as it tends to naturally centrifuge into the impeller’s eye, the place it builds up into an “air lock” which impedes the motion of slurry via the pump.
In addition to decreasing the pump’s efficiency, the air build-up in the pump will scale back its move and increase the slurry degree in the suction hopper. The increased slurry stage might push the pocket of air through the pump, inflicting surging and excessive vibration which can damage the pump bearings, impeller and shaft. “The greatest approach to handle air in a froth pump is to spend money on a froth pump with a continuous air elimination system (CARS), which we now have in our Warman AHF, MF and LF pumps,” says Harvey.
This system allows air to move from the pump’s impeller eye to an air assortment chamber within the again via a vent hole in the impeller. From the chamber, a flow inducer removes the air from the pump via a vent pipe. “It’s additionally important to place the pump’s discharge pipe at the high of the pump, or at a 45° angle as it will give air trapped at the prime of the casing a approach to escape the pump.”
Solving issues “A persistent downside we see is when hoppers designed to satisfy the demands of slurry pumping are used in a froth pumping utility. Slurry hoppers require turbulence to forestall the mineral content from settling, whereas turbulence in a froth pump prevents the air from escaping and leads to blockages,” said Harvey.
Tanks designed for froth pumping promote steady round movement, the place solids and liquids are sent to the surface of the sump for additional transport whereas air centrifuges into the centre where it can be removed. This ‘whirlpool’ movement can be inspired by introducing the slurry from the top of the tank at a tangential angle. Conical designs, quite than these with a flat or rounded flooring, further enhance the flow of minerals and froth into the pump.
Smooth crusing To prevent blockages, the consumption pipe which links the tank to the pump should have a large diameter and slope downwards towards the pump. This design permits escaped air to separate and journey back up the pipe where it could escape from the sump, quite than building up into blockages.
“The shorter your intake pipe, the harder it’s for blockages to build up. However, along with a upkeep spool and isolation valve, it’s a good suggestion to depart enough house for a water injection port, which is useful for flushing out any solids build up,” said Harvey.
“To make upkeep easier, a dump valve could be included on the suction aspect of the pump, between the pump and the isolation valve. This will enable customers to drain slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”
Tenacious froths Froths are sometimes categorized as both brittle, with large air bubbles that break simply, or tenacious, where air forms tight bubbles round minerals and is difficult to separate. Froth being extra tenacious than was accounted for is a frequent explanation for blockages as air can’t successfully be removed.
“Two things are occurring in the market right now. On one hand, mine operators are grinding the product a lot finer than before to liberate extra from the waste rock. They’re additionally using flocculants that produce a lot smaller bubbles which lock up the air much more than brittle froths,” mentioned Harvey. “We’re working along with clients to search out ways to handle these more tenacious froths, by taking a look at their circuit design and coping with areas where the air might accumulate and block the system, paying explicit attention to their pumps, pipes and sumps.
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