Weir’s solution for froth challenges

Froth pumping stays some of the complex engineering challenges in mineral processing. Here, Weir Minerals provides recommendation for coping with the key challenges on this operation, the method to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, increasingly more mine operators are investing in strategies 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 end up in the lack of priceless minerals and income.
Froth pumping stays one of the most advanced engineering challenges in mineral processing. pressure gauge is largely due to the reality that air administration points in the hopper, sump and pump itself can sometimes lead to inefficient pumping, increased upkeep and even lost product.
“We’ve started to note a sample amongst our customers who’re having trouble with their froth pumps,” mentioned Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing extra flocculants and different chemicals 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 makeup and bodily qualities is often wanted to resolve issues. Ensuring operators’ froth dealing with gear adheres to finest design practices is a crucial first step in resolving issues.
Maintaining stress 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 movement of slurry through the pump.
In addition to reducing the pump’s efficiency, the air build-up within the pump will cut back its move and enhance the slurry stage in the suction hopper. The elevated slurry degree could push the pocket of air by way of the pump, causing surging and excessive vibration which can harm the pump bearings, impeller and shaft. “The finest way to manage air in a froth pump is to spend cash on 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 permits air to maneuver from the pump’s impeller eye to an air collection chamber within the again by way of a vent hole in the impeller. From the chamber, a flow inducer removes the air from the pump by way of a vent pipe. “It’s also important to position the pump’s discharge pipe at the high of the pump, or at a 45° angle as this will give air trapped at the top of the casing a method to escape the pump.”

Solving issues “A persistent drawback we see is when hoppers designed to satisfy the calls for of slurry pumping are utilized in a froth pumping software. 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,” said Harvey.
Tanks designed for froth pumping promote continuous round motion, where solids and liquids are sent to the skin of the sump for further transport while air centrifuges into the centre the place it might be eliminated. 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 floor, further improve the move of minerals and froth into the pump.
Smooth sailing To stop blockages, the intake pipe which hyperlinks the tank to the pump ought to have a big diameter and slope downwards in the course of the pump. This design allows escaped air to separate and journey back up the pipe where it can escape from the sump, quite than build up into blockages.
“The shorter your intake pipe, the harder it is for blockages to build up. However, along with a maintenance spool and isolation valve, it’s a good idea to go away sufficient space for a water injection port, which is useful for flushing out any solids build up,” said Harvey.
“To make upkeep easier, a dump valve can be included on the suction facet of the pump, between the pump and the isolation valve. This will allow users to drain slurry from the pump and the discharge pipe system when stopping the pump for upkeep.”

Tenacious froths Froths are often categorised as both brittle, with large 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 explanation for blockages as air cannot effectively be removed.
“Two things are taking place available within the market today. On pressure gauge octa , mine operators are grinding the product much finer than earlier than to liberate extra from the waste rock. They’re also utilizing flocculants that produce a lot smaller bubbles which lock up the air a lot more than brittle froths,” stated Harvey. “We’re working together with prospects to find methods to manage these extra tenacious froths, by looking at their circuit design and coping with areas the place the air may accumulate and block the system, paying explicit consideration to their pumps, pipes and sumps.
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