Weir’s solution for froth challenges

Froth pumping stays one of the complicated engineering challenges in mineral processing. Here, Weir Minerals offers recommendation for dealing with the key challenges in this operation, the way to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, increasingly mine operators are investing in techniques to increase the minerals reclaimed from froth pumping. However, when these techniques are deployed with out making allowances for the design of the mine’s froth pumping equipment, it can lead to the lack of valuable minerals and income.
Froth pumping stays some of the complex engineering challenges in mineral processing. This is basically as a end result of the truth that air administration issues in the hopper, sump and pump itself can generally lead to inefficient pumping, elevated maintenance and even lost product.
“We’ve began to notice a pattern amongst our customers who’re having trouble with their froth pumps,” said Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By using more flocculants and other chemical compounds designed to enhance mineral recovery, they’re exacerbating present problems in circuit design and reducing the returns they’re looking for.”
Close examination of the froth’s make-up and bodily qualities is commonly needed to resolve issues. Ensuring เกจวัดแรงดันถังแก๊ส to best design practices is a vital first step in resolving issues.
Maintaining stress The key challenge in froth pumping is dealing with air in 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 movement of slurry by way of the pump.
In addition to lowering the pump’s efficiency, the air build-up within the pump will cut back its flow and increase the slurry degree in the suction hopper. The elevated slurry level might push the pocket of air through the pump, inflicting surging and excessive vibration which might damage the pump bearings, impeller and shaft. “The greatest way to manage air in a froth pump is to put cash into a froth pump with a continuous air elimination system (CARS), which we’ve 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 through a vent gap within the impeller. From the chamber, a flow inducer removes the air from the pump through a vent pipe. “It’s also essential to place the pump’s discharge pipe at the prime of the pump, or at a 45° angle as it will give air trapped at the top of the casing a way to escape the pump.”
Solving issues “A persistent downside we see is when hoppers designed to fulfill the demands of slurry pumping are used in a froth pumping application. Slurry hoppers require turbulence to prevent the mineral content from settling, whereas turbulence in a froth pump prevents the air from escaping and results in blockages,” stated Harvey.
Tanks designed for froth pumping promote continuous round motion, the place solids and liquids are despatched to the surface of the sump for additional transport whereas air centrifuges into the centre the place it may be removed. This ‘whirlpool’ motion may be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, quite than those with a flat or rounded flooring, additional enhance the flow of minerals and froth into the pump.
Smooth sailing To prevent blockages, the intake pipe which hyperlinks the tank to the pump should have a large diameter and slope downwards towards the pump. This design allows escaped air to separate and travel again up the pipe where it may possibly escape from the sump, rather than build up into blockages.
“The shorter your intake pipe, the harder it’s for blockages to construct up. However, along with a maintenance spool and isolation valve, it’s a good idea to leave sufficient space for a water injection port, which is helpful for flushing out any solids build up,” said Harvey.
“To make maintenance simpler, a dump valve can be included on the suction aspect of the pump, between the pump and the isolation valve. This will enable customers to empty slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”
Tenacious froths Froths are sometimes categorized as either brittle, with giant air bubbles that break easily, or tenacious, the place air forms tight bubbles around minerals and is difficult to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air can’t effectively be eliminated.
“Two things are taking place available in the market 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 utilizing flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths,” said Harvey. “We’re working together with prospects to seek out methods to manage these extra tenacious froths, by taking a glance at their circuit design and coping with areas the place the air may accumulate and block the system, paying particular attention to their pumps, pipes and sumps.

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