Weir’s solution for froth challenges

Froth pumping stays one of the most advanced engineering challenges in mineral processing. Here, Weir Minerals presents advice for coping with the vital thing challenges in this operation, tips on 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 techniques are deployed with out making allowances for the design of the mine’s froth pumping tools, it can lead to the lack of priceless minerals and earnings.
Froth pumping remains one of the complex engineering challenges in mineral processing. This is essentially because of the truth that air management issues in the hopper, sump and pump itself can typically lead to inefficient pumping, elevated maintenance and even lost product.
“We’ve started to note a sample amongst our clients who are having hassle with their froth pumps,” mentioned Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By using more flocculants and other chemical substances designed to improve mineral restoration, they’re exacerbating present issues in circuit design and decreasing the returns they’re looking for.”

Close examination of the froth’s make-up and physical qualities is usually needed to resolve issues. Ensuring operators’ froth handling gear adheres to greatest design practices is a crucial first step in resolving issues.
Maintaining stress The key challenge in froth pumping is dealing with air in the pump itself, because it tends to naturally centrifuge into the impeller’s eye, the place it builds up into an “air lock” which impedes the movement of slurry via the pump.
In addition to reducing the pump’s efficiency, the air build-up within the pump will scale back its move and improve the slurry degree in the suction hopper. The increased slurry level might push the pocket of air through the pump, causing surging and excessive vibration which might harm the pump bearings, impeller and shaft. “ ตัววัดแรงดันน้ำมัน to handle air in a froth pump is to invest in a froth pump with a continuous air removing system (CARS), which we’ve 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 through a vent gap in the impeller. From the chamber, a circulate inducer removes the air from the pump via a vent pipe. “It’s also necessary to place the pump’s discharge pipe at the top of the pump, or at a 45° angle as this can give air trapped on the high of the casing a way to escape the pump.”

Solving issues “A persistent drawback we see is when hoppers designed to fulfill the calls for of slurry pumping are utilized in a froth pumping software. Slurry hoppers require turbulence to forestall the mineral content material from settling, while turbulence in a froth pump prevents the air from escaping and results in blockages,” said Harvey.
Tanks designed for froth pumping promote continuous circular motion, the place solids and liquids are sent to the outside of the sump for further transport whereas air centrifuges into the centre the place it could be removed. This ‘whirlpool’ movement may be encouraged by introducing the slurry from the top of the tank at a tangential angle. Conical designs, quite than these with a flat or rounded floor, additional enhance the circulate of minerals and froth into the pump.
Smooth crusing To prevent blockages, the consumption pipe which links the tank to the pump should have a big diameter and slope downwards in the course of the pump. This design allows escaped air to separate and journey again up the pipe the place it could possibly escape from the sump, somewhat than building up into blockages.
“The shorter your intake pipe, the tougher it’s for blockages to build up. However, in addition to 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 maintenance 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 empty slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”

Tenacious froths Froths are often categorized as either brittle, with giant air bubbles that break simply, or tenacious, where air forms tight bubbles round minerals and is troublesome to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air can not effectively be removed.
“Two issues are happening in the market right now. 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 using flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths,” stated Harvey. “We’re working together with clients to search out methods to handle these extra tenacious froths, by looking at their circuit design and dealing with areas the place the air could accumulate and block the system, paying specific attention to their pumps, pipes and sumps.
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