Froth pumping remains one of the complicated engineering challenges in mineral processing. Here, Weir Minerals presents recommendation for coping with the key challenges in this operation, tips on how to maximise pump availability and minimise upkeep in operators’ flotation circuits.
To counteract declining ore grades, increasingly more mine operators are investing in methods to increase the minerals reclaimed from froth pumping. However, when these methods are deployed without making allowances for the design of the mine’s froth pumping equipment, it may find yourself in the loss of priceless minerals and profits.
Froth pumping remains some of the complicated engineering challenges in mineral processing. This is basically due to the truth that air management issues in the hopper, sump and pump itself can generally lead to inefficient pumping, elevated maintenance and even misplaced product.
เกจ์วัดแรงดันลม ’ve started to note a sample amongst our clients who’re having bother with their froth pumps,” stated Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By utilizing extra flocculants and different chemicals designed to enhance mineral restoration, they’re exacerbating present issues in circuit design and decreasing the returns they’re in search of.”
Close examination of the froth’s make-up and physical qualities is commonly wanted to resolve points. Ensuring เกจวัดแรงดันแก๊สอาร์กอน to best design practices is a vital first step in resolving issues.
Maintaining strain The key challenge in froth pumping is coping with air within 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 movement of slurry through the pump.
In addition to reducing the pump’s effectivity, the air build-up in the pump will reduce its circulate and improve the slurry degree within the suction hopper. The increased slurry stage might push the pocket of air through the pump, inflicting surging and excessive vibration which can harm the pump bearings, impeller and shaft. “The finest way to manage air in a froth pump is to put money into a froth pump with a steady air removal system (CARS), which we now 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 assortment chamber in the back by way of a vent hole within the impeller. From the chamber, a flow inducer removes the air from the pump through a vent pipe. “It’s additionally important to place the pump’s discharge pipe on the high of the pump, or at a 45° angle as this can give air trapped on the top of the casing a approach to escape the pump.”
Solving problems “A persistent drawback we see is when hoppers designed to fulfill the demands of slurry pumping are used in a froth pumping application. Slurry hoppers require turbulence to stop the mineral content from settling, whereas turbulence in a froth pump prevents the air from escaping and results in blockages,” mentioned Harvey.
Tanks designed for froth pumping promote steady round movement, where solids and liquids are despatched to the outside of the sump for additional transport while air centrifuges into the centre the place it may be eliminated. This ‘whirlpool’ movement can be encouraged by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, rather than those with a flat or rounded flooring, additional improve the flow of minerals and froth into the pump.
Smooth sailing To forestall blockages, the consumption pipe which links the tank to the pump should have a big diameter and slope downwards in path of the pump. This design permits escaped air to separate and journey again up the pipe the place it can escape from the sump, quite than build up into blockages.
“The shorter your consumption pipe, the more durable it is for blockages to build up. However, in addition to a maintenance spool and isolation valve, it’s a good idea to leave sufficient house for a water injection port, which is helpful for flushing out any solids build up,” mentioned 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 permit users to empty 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 massive air bubbles that break simply, or tenacious, where air forms tight bubbles around minerals and is troublesome to separate. Froth being extra tenacious than was accounted for is a frequent cause of blockages as air can not successfully be removed.
“Two issues are taking place available within the market right now. On one hand, mine operators are grinding the product much finer than before to liberate extra from the waste rock. They’re also utilizing flocculants that produce much smaller bubbles which lock up the air a lot more than brittle froths,” mentioned Harvey. “We’re working along with clients to search out ways to handle these extra tenacious froths, by looking at their circuit design and coping with areas where the air may accumulate and block the system, paying explicit attention to their pumps, pipes and sumps.