Froth pumping remains one of the most advanced engineering challenges in mineral processing. Here, Weir Minerals provides advice for dealing with the necessary thing challenges in this operation, the way to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, increasingly mine operators are investing in techniques to increase the minerals reclaimed from froth pumping. However, when these strategies are deployed without making allowances for the design of the mine’s froth pumping equipment, it can outcome in the lack of useful minerals and profits.
Froth pumping remains one of the advanced engineering challenges in mineral processing. This is essentially because of the fact that air administration issues within the hopper, sump and pump itself can sometimes result in inefficient pumping, increased upkeep and even lost product.
“We’ve began to notice a sample among our prospects who’re having trouble with their froth pumps,” said Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing more flocculants and other chemical compounds designed to enhance mineral restoration, they’re exacerbating existing issues in circuit design and decreasing the returns they’re in search of.”
Close examination of the froth’s make-up and bodily qualities is usually wanted to resolve points. Ensuring operators’ froth dealing with tools adheres to finest design practices is a vital first step in resolving problems.
Maintaining ที่วัดแรงดันน้ำ 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 scale back its circulate and increase the slurry level in the suction hopper. The increased slurry degree may push the pocket of air via the pump, causing surging and extreme vibration which may injury the pump bearings, impeller and shaft. “The best method to manage air in a froth pump is to invest in a froth pump with a continuous air elimination system (CARS), which we 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 again via a vent hole in the impeller. From the chamber, a move inducer removes the air from the pump via a vent pipe. “It’s additionally important to place the pump’s discharge pipe at the high of the pump, or at a 45° angle as this will give air trapped at the high of the casing a approach to escape the pump.”
Solving problems “A persistent downside 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 prevent the mineral content from settling, while turbulence in a froth pump prevents the air from escaping and leads to blockages,” said Harvey.
Tanks designed for froth pumping promote steady round movement, where solids and liquids are sent to the surface of the sump for further transport whereas air centrifuges into the centre where it could be removed. This ‘whirlpool’ movement could be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, quite than these with a flat or rounded ground, additional improve the circulate of minerals and froth into the pump.
Smooth sailing To prevent blockages, the intake pipe which hyperlinks the tank to the pump should have a large diameter and slope downwards towards the pump. This design allows escaped air to separate and travel back up the pipe where it can escape from the sump, somewhat than increase into blockages.
“The shorter your consumption pipe, the tougher it is for blockages to build up. However, along with a maintenance spool and isolation valve, it’s a good idea to depart sufficient area for a water injection port, which is useful for flushing out any solids construct up,” stated Harvey.
“To make maintenance simpler, a dump valve can be included on the suction side of the pump, between the pump and the isolation valve. This will allow users to empty slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”
Tenacious froths Froths are sometimes classified as both brittle, with massive air bubbles that break simply, or tenacious, the place air varieties tight bubbles round minerals and is difficult to separate. Froth being extra tenacious than was accounted for is a frequent cause of blockages as air cannot effectively be eliminated.
“Two issues are occurring available within the market at present. On one hand, mine operators are grinding the product much 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 along with customers to seek out methods to handle these more tenacious froths, by taking a glance at their circuit design and dealing with areas the place the air could accumulate and block the system, paying specific consideration to their pumps, pipes and sumps.
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