Weir’s solution for froth challenges

Froth pumping stays some of the advanced engineering challenges in mineral processing. Here, Weir Minerals offers recommendation for coping with the important thing challenges on this operation, the means to maximise pump availability and minimise maintenance in operators’ flotation circuits.
To counteract declining ore grades, more and more mine operators are investing in techniques to increase the minerals reclaimed from froth pumping. However, when these strategies are deployed with out making allowances for the design of the mine’s froth pumping gear, it may end up in the lack of valuable minerals and profits.
Froth pumping remains some of the complex engineering challenges in mineral processing. This is basically as a result of the fact that air management points in the hopper, sump and pump itself can generally lead to inefficient pumping, increased maintenance and even misplaced product.
“We’ve began to notice a pattern amongst our prospects who are having bother with their froth pumps,” said Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By utilizing extra flocculants and different chemicals designed to improve mineral restoration, they’re exacerbating present problems in circuit design and lowering the returns they’re looking for.”
Close examination of the froth’s make-up and physical qualities is usually wanted to resolve points. Ensuring เกจวัดแรงดันแก๊ส dealing with tools adheres to best design practices is a crucial first step in resolving problems.
Maintaining stress The key problem in froth pumping is coping with air in the pump itself, because it tends to naturally centrifuge into the impeller’s eye, where it builds up into an “air lock” which impedes the motion of slurry via the pump.
In addition to lowering the pump’s efficiency, the air build-up within the pump will reduce its move and enhance the slurry stage within the suction hopper. The elevated slurry degree could push the pocket of air through the pump, causing surging and excessive vibration which may injury the pump bearings, impeller and shaft. “The finest method to handle air in a froth pump is to invest in 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 move from the pump’s impeller eye to an air collection chamber within the again via a vent hole in the impeller. From the chamber, a circulate inducer removes the air from the pump via 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 can give air trapped on the high of the casing a method to escape the pump.”
Solving problems “A persistent downside we see is when hoppers designed to satisfy the demands of slurry pumping are utilized in a froth pumping utility. Slurry hoppers require turbulence to prevent 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 skin of the sump for additional transport while air centrifuges into the centre where it could be eliminated. This ‘whirlpool’ motion can be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, rather than these with a flat or rounded flooring, further enhance the move 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 big diameter and slope downwards towards the pump. This design permits escaped air to separate and travel again up the pipe where it might possibly escape from the sump, rather than building up into blockages.
“The shorter your intake pipe, the harder it’s for blockages to construct up. However, along with a maintenance spool and isolation valve, it’s a good suggestion to leave sufficient house for a water injection port, which is useful for flushing out any solids build up,” stated Harvey.
“To make maintenance easier, a dump valve can be included on the suction side of the pump, between the pump and the isolation valve. This will allow 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 massive air bubbles that break simply, or tenacious, the place air forms tight bubbles round minerals and is difficult to separate. Froth being more tenacious than was accounted for is a frequent cause of blockages as air can not effectively be eliminated.
“Two things are occurring available within the market today. On one hand, mine operators are grinding the product a lot finer than earlier than to liberate extra from the waste rock. They’re additionally using flocculants that produce much smaller bubbles which lock up the air much more than brittle froths,” mentioned Harvey. “We’re working together with prospects to find methods to handle these extra tenacious froths, by looking at their circuit design and dealing with areas where the air may accumulate and block the system, paying specific attention to their pumps, pipes and sumps.
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