Froth pumping stays one of the most complex engineering challenges in mineral processing. Here, Weir Minerals offers recommendation for dealing with the necessary thing challenges on this operation, tips on how to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, increasingly mine operators are investing in methods to extend the minerals reclaimed from froth pumping. However, when these techniques are deployed without making allowances for the design of the mine’s froth pumping equipment, it may find yourself in the lack of valuable minerals and income.
Froth pumping stays one of the most advanced engineering challenges in mineral processing. This is essentially because of the truth that air management issues within the hopper, sump and pump itself can sometimes result in inefficient pumping, increased upkeep and even lost product.
“We’ve began to note a pattern amongst our customers who’re having trouble with their froth pumps,” stated Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing more flocculants and different chemicals designed to enhance mineral recovery, they’re exacerbating existing issues in circuit design and lowering the returns they’re in search of.”
Close examination of the froth’s makeup and physical qualities is commonly needed to resolve points. Ensuring operators’ froth handling equipment adheres to finest design practices is a vital first step in resolving problems.
Maintaining strain The key problem in froth pumping is coping with air within the pump itself, as it tends to naturally centrifuge into the impeller’s eye, where it builds up into an “air lock” which impedes the motion of slurry via the pump.
In addition to decreasing the pump’s effectivity, the air build-up within the pump will scale back its flow and increase the slurry level in the suction hopper. The increased slurry level might push the pocket of air via the pump, inflicting surging and extreme vibration which may injury the pump bearings, impeller and shaft. “The greatest approach to handle air in a froth pump is to put cash into a froth pump with a continuous air removal system (CARS), which we 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 circulate inducer removes the air from the pump through a vent pipe. “It’s also เกจวัดแรงลม to place the pump’s discharge pipe at the top of the pump, or at a 45° angle as it will give air trapped at the prime of the casing a way to escape the pump.”
Solving issues “A persistent downside we see is when hoppers designed to satisfy the calls for of slurry pumping are used in a froth pumping software. Slurry hoppers require turbulence to prevent the mineral content material from settling, while turbulence in a froth pump prevents the air from escaping and results in blockages,” said Harvey.
Tanks designed for froth pumping promote continuous circular movement, where solids and liquids are despatched to the surface of the sump for further transport whereas air centrifuges into the centre where it can be removed. This ‘whirlpool’ movement may be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, rather than those with a flat or rounded floor, further improve the move of minerals and froth into the pump.
Smooth crusing To prevent blockages, the consumption pipe which hyperlinks the tank to the pump ought to have a big diameter and slope downwards in the course of the pump. เกจวัดแรงดันคือ permits escaped air to separate and travel back up the pipe where it could escape from the sump, quite than increase into blockages.
“The shorter your intake pipe, the harder it’s for blockages to construct up. However, along with a upkeep spool and isolation valve, it’s a good idea to depart sufficient house for a water injection port, which is helpful for flushing out any solids construct up,” said Harvey.
“To make maintenance easier, a dump valve could be included on the suction side of the pump, between the pump and the isolation valve. This will permit users 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 giant air bubbles that break simply, or tenacious, where air forms tight bubbles around minerals and is troublesome to separate. Froth being extra tenacious than was accounted for is a frequent reason for blockages as air can not successfully be eliminated.
“Two things are happening out there right now. On one hand, mine operators are grinding the product a lot finer than earlier than to liberate more from the waste rock. They’re also 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 customers to find ways to manage these extra tenacious froths, by taking a look at their circuit design and dealing with areas where the air may accumulate and block the system, paying explicit consideration to their pumps, pipes and sumps.