Weir’s solution for froth challenges

Froth pumping stays one of the most complicated engineering challenges in mineral processing. Here, Weir Minerals offers advice for dealing with the key challenges in this operation, how to maximise pump availability and minimise upkeep 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 tools, it may find yourself in the lack of valuable minerals and profits.
Froth pumping remains some of the complicated engineering challenges in mineral processing. This is largely because of the fact that air administration points in the hopper, sump and pump itself can sometimes lead to inefficient pumping, increased maintenance and even misplaced product.
“We’ve started to notice a pattern among our clients who are having bother with their froth pumps,” stated Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By using extra flocculants and other chemicals designed to enhance mineral restoration, they’re exacerbating present problems in circuit design and decreasing the returns they’re in search of.”
Close examination of the froth’s makeup and physical qualities is often wanted to resolve points. Ensuring operators’ froth handling tools adheres to greatest design practices is a vital first step in resolving problems.
Maintaining strain The key problem in froth pumping is dealing with air in the pump itself, because 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 reducing the pump’s effectivity, the air build-up within the pump will scale back its flow and improve the slurry degree within the suction hopper. The elevated slurry degree may push the pocket of air by way of the pump, causing surging and excessive vibration which may harm the pump bearings, impeller and shaft. “The greatest method to manage air in a froth pump is to invest in a froth pump with a steady air elimination system (CARS), which we now have in our Warman AHF, MF and LF pumps,” says Harvey.
This system allows air to maneuver from the pump’s impeller eye to an air collection chamber in the back via a vent hole within the impeller. From the chamber, a flow inducer removes the air from the pump via a vent pipe. “It’s also essential to place the pump’s discharge pipe on the prime of the pump, or at a 45° angle as this can give air trapped on the high of the casing a way to escape the pump.”
Solving เกจ์วัดแก๊สหุงต้ม “A persistent drawback we see is when hoppers designed to satisfy the demands of slurry pumping are utilized in a froth pumping utility. Slurry hoppers require turbulence to forestall the mineral content from settling, while turbulence in a froth pump prevents the air from escaping and results in blockages,” mentioned Harvey.
Tanks designed for froth pumping promote continuous round motion, where solids and liquids are sent to the surface of the sump for further transport while air centrifuges into the centre where it may be removed. This ‘whirlpool’ movement can be encouraged by introducing the slurry from the top of the tank at a tangential angle. Conical designs, quite than these 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 direction of the pump. This design allows escaped air to separate and journey back up the pipe where it can escape from the sump, rather than increase into blockages.
“The shorter your intake pipe, the tougher it’s for blockages to construct up. However, in addition to a upkeep spool and isolation valve, it’s a good idea to leave sufficient space for a water injection port, which is useful for flushing out any solids build up,” mentioned 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 permit users to drain slurry from the pump and the discharge pipe system when stopping the pump for upkeep.”
Tenacious froths Froths are often classified as either brittle, with large air bubbles that break simply, or tenacious, the place air forms tight bubbles round minerals and is difficult to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air cannot effectively be eliminated.
“Two things are occurring available in the market today. On one hand, mine operators are grinding the product a lot finer than before to liberate more from the waste rock. They’re additionally utilizing flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths,” said Harvey. “We’re working along with clients to search out ways to handle these more tenacious froths, by taking a glance at their circuit design and coping with areas where the air might accumulate and block the system, paying particular attention to their pumps, pipes and sumps.
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