Froth pumping stays one of the complex 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 upkeep 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 with out making allowances for the design of the mine’s froth pumping tools, it can lead to the lack of useful minerals and earnings.
Froth pumping stays one of the most complicated engineering challenges in mineral processing. This is essentially as a outcome of the fact that air administration issues within the hopper, sump and pump itself can generally result in inefficient pumping, elevated upkeep and even misplaced product.
“We’ve started to notice a sample among our clients who’re having bother with their froth pumps,” said Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing extra flocculants and different chemicals designed to improve mineral restoration, they’re exacerbating existing problems in circuit design and lowering the returns they’re on the lookout for.”
Close examination of the froth’s make-up and bodily qualities is commonly wanted to resolve issues. Ensuring operators’ froth handling tools adheres to finest design practices is a vital 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, the place it builds up into an “air lock” which impedes the motion of slurry by way of the pump.
In addition to lowering the pump’s efficiency, the air build-up within the pump will scale back its move and increase the slurry degree within the suction hopper. The increased slurry degree may push the pocket of air through the pump, inflicting surging and excessive vibration which may injury the pump bearings, impeller and shaft. “The greatest method to handle air in a froth pump is to spend cash on a froth pump with a continuous air removal system (CARS), which we 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 assortment chamber in the again by way of a vent gap in the impeller. From the chamber, a move inducer removes the air from the pump via a vent pipe. “It’s additionally necessary to place the pump’s discharge pipe on the high of the pump, or at a 45° angle as it will give air trapped on the high of the casing a way to escape the pump.”
Solving issues “A persistent problem we see is when hoppers designed to satisfy the calls for of slurry pumping are used in a froth pumping software. 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,” stated 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 whereas air centrifuges into the centre the place it can be removed. This ‘whirlpool’ motion can be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, somewhat than these with a flat or rounded ground, further enhance the circulate of minerals and froth into the pump.
เกจวัดแรงดัน1บาร์ crusing To forestall blockages, the intake pipe which hyperlinks the tank to the pump should have a big diameter and slope downwards in the direction of the pump. This design allows escaped air to separate and journey back up the pipe where it could possibly escape from the sump, quite than building up into blockages.
“The shorter your intake pipe, the harder it’s for blockages to build up. However, along with a upkeep spool and isolation valve, it’s a good idea to go away sufficient house for a water injection port, which is beneficial for flushing out any solids build up,” stated Harvey.
“To make maintenance simpler, a dump valve could be included on the suction side of the pump, between the pump and the isolation valve. pressure gauge น้ำมัน will allow users to drain slurry from the pump and the discharge pipe system when stopping the pump for upkeep.”
Tenacious froths Froths are sometimes categorised as either brittle, with giant air bubbles that break easily, or tenacious, the place air types tight bubbles around minerals and is tough to separate. Froth being extra tenacious than was accounted for is a frequent explanation for blockages as air cannot successfully be eliminated.
“Two issues are taking place out there 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 a lot smaller bubbles which lock up the air much more than brittle froths,” mentioned Harvey. “We’re working together with prospects to search out ways to manage these extra tenacious froths, by taking a glance at their circuit design and coping with areas where the air could accumulate and block the system, paying explicit attention to their pumps, pipes and sumps.
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