Weir’s answer for froth challenges

Froth pumping remains one of the complex engineering challenges in mineral processing. Here, Weir Minerals provides recommendation for coping with the key challenges in this operation, the way 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 methods are deployed without making allowances for the design of the mine’s froth pumping equipment, it can end result in the lack of useful minerals and income.
เพรสเชอร์เกจ4นิ้ว pumping remains one of the complicated engineering challenges in mineral processing. This is largely because of the fact that air management issues within the hopper, sump and pump itself can generally lead to inefficient pumping, elevated maintenance and even misplaced product.
“We’ve started to notice a pattern amongst our prospects who’re having hassle with their froth pumps,” said Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing more flocculants and other chemical substances designed to enhance mineral restoration, 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 crucial first step in resolving problems.
Maintaining stress The key challenge in froth pumping is coping 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 motion of slurry via the pump.
In addition to lowering the pump’s efficiency, the air build-up in the pump will cut back its move and enhance the slurry stage within the suction hopper. The increased slurry level may push the pocket of air by way of the pump, causing surging and excessive vibration which might damage the pump bearings, impeller and shaft. “The greatest approach to handle air in a froth pump is to put money into a froth pump with a steady air removal 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 in the again by way of a vent gap in the impeller. From the chamber, a flow inducer removes the air from the pump through a vent pipe. “It’s additionally essential to place the pump’s discharge pipe at the top of the pump, or at a 45° angle as this will give air trapped at the prime of the casing a method to escape the pump.”
Solving issues “A persistent drawback 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 stop 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 steady circular motion, the place solids and liquids are despatched to the skin of the sump for further transport while air centrifuges into the centre where it can be eliminated. This ‘whirlpool’ motion can be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, somewhat than those with a flat or rounded floor, additional improve the move of minerals and froth into the pump.
Smooth crusing To forestall blockages, the consumption pipe which hyperlinks the tank to the pump ought to have a large diameter and slope downwards in the path of the pump. This design permits escaped air to separate and journey back up the pipe the place it could escape from the sump, somewhat than building up into blockages.
“The shorter your consumption pipe, the more durable it is for blockages to construct up. However, along with a maintenance spool and isolation valve, it’s a good suggestion to go away sufficient house for a water injection port, which is beneficial for flushing out any solids build up,” stated Harvey.
“To make upkeep 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 upkeep.”
Tenacious froths Froths are sometimes categorized as both brittle, with giant air bubbles that break simply, or tenacious, the place air varieties tight bubbles around minerals and is tough to separate. Froth being more tenacious than was accounted for is a frequent reason for blockages as air cannot effectively be removed.
“Two issues are taking place available within the market at present. On one hand, mine operators are grinding the product a lot finer than earlier than 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 together with clients to search out methods to handle these more tenacious froths, by looking at their circuit design and coping with areas the place the air could accumulate and block the system, paying particular attention to their pumps, pipes and sumps.

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