Froth pumping stays one of the complex engineering challenges in mineral processing. Here, Weir Minerals presents advice for coping with the key challenges in this operation, how 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 methods are deployed with out making allowances for the design of the mine’s froth pumping tools, it may find yourself in the lack of valuable minerals and income.
Froth pumping remains one of the advanced engineering challenges in mineral processing. This is essentially as a outcome of the truth that air administration points within the hopper, sump and pump itself can generally lead to inefficient pumping, increased maintenance and even lost product.
“We’ve began to notice a sample among our prospects who’re having bother with their froth pumps,” stated Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By utilizing more flocculants and different chemical substances designed to improve mineral restoration, they’re exacerbating current issues in circuit design and decreasing the returns they’re on the lookout for.”
Close examination of the froth’s makeup and bodily qualities is often needed to resolve issues. Ensuring operators’ froth dealing with tools adheres to best design practices is a vital first step in resolving issues.
Maintaining strain The key challenge in froth pumping is dealing 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 movement of slurry through the pump.
In addition to decreasing the pump’s effectivity, the air build-up within the pump will reduce its flow and increase the slurry stage in the suction hopper. The elevated slurry level may push the pocket of air through the pump, causing surging and extreme vibration which might injury the pump bearings, impeller and shaft. “The greatest way to manage 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 move from the pump’s impeller eye to an air assortment chamber in the back by way of a vent gap within the impeller. From the chamber, a flow inducer removes the air from the pump through a vent pipe. “It’s also 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 problem we see is when hoppers designed to fulfill the demands of slurry pumping are utilized in a froth pumping utility. Slurry hoppers require turbulence to stop the mineral content material 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 steady circular movement, the place solids and liquids are sent to the outside of the sump for further transport while air centrifuges into the centre the place it can be removed. pressure gauge trerice ราคา ‘whirlpool’ motion can be encouraged by introducing the slurry from the top of the tank at a tangential angle. Conical designs, quite than those with a flat or rounded floor, further enhance the move of minerals and froth into the pump.
Smooth sailing To stop blockages, the intake pipe which hyperlinks the tank to the pump should have a big diameter and slope downwards in course of the pump. This design permits escaped air to separate and travel back up the pipe where it might possibly escape from the sump, somewhat than increase into blockages.
“The shorter your consumption pipe, the harder it is for blockages to build up. However, in addition to a upkeep spool and isolation valve, it’s a good idea to leave sufficient house for a water injection port, which is beneficial for flushing out any solids construct up,” stated 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 customers to drain slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”
Tenacious froths Froths are sometimes categorised as both brittle, with large air bubbles that break easily, or tenacious, the place air forms tight bubbles round minerals and is troublesome to separate. Froth being more tenacious than was accounted for is a frequent reason for blockages as air cannot effectively be eliminated.
pressure gauge วัด แรง ดัน น้ำ are taking place in 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 using flocculants that produce much smaller bubbles which lock up the air much more than brittle froths,” said Harvey. “We’re working along with clients to find methods to manage these more tenacious froths, by taking a look 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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