Froth pumping stays one of the most complicated engineering challenges in mineral processing. Here, Weir Minerals offers recommendation for dealing with the key challenges in 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 methods to increase 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 can end result in the lack of priceless minerals and income.
Froth pumping stays some of the advanced engineering challenges in mineral processing. This is basically because of the fact that air management points in the hopper, sump and pump itself can typically result in inefficient pumping, elevated upkeep and even lost product.
“We’ve started to note a sample amongst our clients who are having trouble with their froth pumps,” said Les Harvey, regional product supervisor for Slurry Pumps at Weir Minerals. “By utilizing more flocculants and different chemicals designed to enhance mineral recovery, they’re exacerbating current problems in circuit design and lowering the returns they’re looking for.”
Close examination of the froth’s makeup and bodily qualities is commonly wanted to resolve issues. Ensuring operators’ froth dealing with tools adheres to best design practices is an important first step in resolving problems.
Maintaining pressure The key problem in froth pumping is dealing with air within 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 movement of slurry via the pump.
In เกจวัดแรงดันถังแก๊ส to decreasing the pump’s effectivity, the air build-up in the pump will cut back its circulate and improve the slurry level within the suction hopper. The increased slurry degree could push the pocket of air via the pump, inflicting surging and excessive vibration which may damage the pump bearings, impeller and shaft. “The best way to manage air in a froth pump is to invest in a froth pump with a steady air removing 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 again by way of a vent hole in the impeller. From the chamber, a circulate inducer removes the air from the pump by way of a vent pipe. “It’s additionally necessary to place the pump’s discharge pipe on the high of the pump, or at a 45° angle as this will give air trapped at the prime of the casing a method to escape the pump.”
Solving problems “A persistent drawback we see is when hoppers designed to satisfy the calls for of slurry pumping are utilized in a froth pumping application. 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,” mentioned Harvey.
Tanks designed for froth pumping promote continuous circular motion, where solids and liquids are sent to the skin of the sump for additional transport whereas air centrifuges into the centre where it can be removed. This ‘whirlpool’ motion can be inspired by introducing the slurry from the highest of the tank at a tangential angle. Conical designs, somewhat than those with a flat or rounded floor, additional enhance the circulate of minerals and froth into the pump.
Smooth crusing To stop blockages, the consumption pipe which links the tank to the pump ought to have a large diameter and slope downwards in path of the pump. This design allows escaped air to separate and journey again up the pipe where it may possibly escape from the sump, rather than increase into blockages.
“The shorter your intake pipe, the more durable it’s for blockages to construct up. However, along with a upkeep spool and isolation valve, it’s a good idea to leave sufficient space for a water injection port, which is helpful for flushing out any solids construct up,” mentioned Harvey.
“To make upkeep easier, a dump valve can be included on the suction aspect 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 upkeep.”
Tenacious froths Froths are often categorized as both brittle, with large air bubbles that break simply, or tenacious, where air varieties tight bubbles round minerals and is tough to separate. Froth being extra tenacious than was accounted for is a frequent explanation for blockages as air can’t successfully be eliminated.
“Two things are taking place in 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 a lot smaller bubbles which lock up the air a lot more than brittle froths,” mentioned Harvey. “We’re working along with clients to seek out methods to handle these extra tenacious froths, by looking at their circuit design and dealing with areas where the air might accumulate and block the system, paying explicit consideration to their pumps, pipes and sumps.
Share