Weir’s resolution for froth challenges

Froth pumping stays some of the complicated engineering challenges in mineral processing. Here, Weir Minerals provides recommendation for dealing with the vital thing challenges on this operation, the means to maximise pump availability and minimise upkeep in operators’ flotation circuits.
To counteract declining ore grades, increasingly more mine operators are investing in techniques to increase the minerals reclaimed from froth pumping. However, when these techniques are deployed without making allowances for the design of the mine’s froth pumping gear, it may end up in the loss of valuable minerals and profits.
Froth pumping remains one of the most complicated engineering challenges in mineral processing. This is basically due to the truth that air management issues within the hopper, sump and pump itself can sometimes result in inefficient pumping, increased upkeep and even misplaced product.
“We’ve began to notice a pattern amongst our clients 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 other chemical compounds designed to improve mineral restoration, they’re exacerbating present problems in circuit design and lowering the returns they’re on the lookout for.”
Close examination of the froth’s make-up and physical qualities is usually wanted to resolve points. Ensuring operators’ froth dealing with tools adheres to greatest design practices is an important first step in resolving problems.
Maintaining strain The key problem in froth pumping is dealing 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 lowering the pump’s effectivity, the air build-up in the pump will scale back its move and increase the slurry degree within the suction hopper. The increased slurry stage could push the pocket of air through the pump, causing surging and extreme vibration which can damage the pump bearings, impeller and shaft. “ หลักการทำงานของเกจ์วัดแก๊ส to manage air in a froth pump is to spend cash on a froth pump with a continuous air removing 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 collection chamber within the back by way of a vent gap within the impeller. From the chamber, a move inducer removes the air from the pump through a vent pipe. “It’s additionally necessary to place the pump’s discharge pipe on the top 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 problems “A persistent drawback we see is when hoppers designed to satisfy the demands of slurry pumping are used in a froth pumping software. 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,” mentioned Harvey.
Tanks designed for froth pumping promote continuous circular motion, where solids and liquids are sent to the surface of the sump for further transport whereas air centrifuges into the centre the place it may be removed. This ‘whirlpool’ motion could be encouraged by introducing the slurry from the top of the tank at a tangential angle. Conical designs, rather than these with a flat or rounded flooring, further improve the move of minerals and froth into the pump.
Smooth crusing To forestall blockages, the intake pipe which hyperlinks the tank to the pump ought to have a big diameter and slope downwards in the direction of the pump. This design permits escaped air to separate and journey again up the pipe the place it could possibly escape from the sump, rather than increase into blockages.
“The shorter your consumption pipe, the harder it’s for blockages to build up. However, in addition to a upkeep spool and isolation valve, it’s a good idea to go away enough area for a water injection port, which is useful for flushing out any solids construct up,” said Harvey.
“To make upkeep simpler, a dump valve may be included on the suction aspect of the pump, between the pump and the isolation valve. This will enable users to empty slurry from the pump and the discharge pipe system when stopping the pump for upkeep.”
Tenacious froths Froths are sometimes classified as both brittle, with large air bubbles that break easily, or tenacious, the place air varieties tight bubbles around minerals and is tough to separate. Froth being extra tenacious than was accounted for is a frequent reason for blockages as air can not successfully be eliminated.
“Two issues are happening in the market today. On one hand, mine operators are grinding the product much finer than before to liberate more from the waste rock. They’re additionally utilizing flocculants that produce a lot smaller bubbles which lock up the air much more than brittle froths,” said Harvey. “We’re working along with customers to seek out methods to manage these extra tenacious froths, by looking at their circuit design and coping with areas the place the air could accumulate and block the system, paying particular consideration to their pumps, pipes and sumps.
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