Froth pumping remains one of the most complicated engineering challenges in mineral processing. Here, Weir Minerals provides recommendation for coping with the key challenges in this operation, the method to maximise pump availability and minimise upkeep in operators’ flotation circuits.
To counteract declining ore grades, increasingly mine operators are investing in techniques to extend the minerals reclaimed from froth pumping. However, when these methods are deployed without making allowances for the design of the mine’s froth pumping tools, it may find yourself in the loss of useful minerals and profits.
Froth pumping remains one of the complex engineering challenges in mineral processing. This is basically as a outcome of the fact that air administration points in the hopper, sump and pump itself can generally result in inefficient pumping, increased upkeep and even lost product.
“We’ve began to note a pattern among our customers who’re having trouble with their froth pumps,” stated Les Harvey, regional product manager for Slurry Pumps at Weir Minerals. “By utilizing extra flocculants and other chemicals designed to improve mineral restoration, they’re exacerbating current issues in circuit design and decreasing the returns they’re looking for.”
Close examination of the froth’s make-up and bodily qualities is commonly wanted to resolve points. Ensuring operators’ froth dealing with gear adheres to best design practices is a crucial first step in resolving problems.
Maintaining stress The key problem 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 motion of slurry by way of the pump.
In addition to reducing the pump’s efficiency, the air build-up within the pump will reduce its move and enhance the slurry level in the suction hopper. The elevated slurry degree may push the pocket of air through the pump, causing surging and extreme vibration which might harm the pump bearings, impeller and shaft. “The greatest method to manage air in a froth pump is to invest in a froth pump with a steady air removing 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 gap in the impeller. From the chamber, a flow inducer removes the air from the pump via a vent pipe. “It’s additionally important to position the pump’s discharge pipe on the top 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 drawback we see is when hoppers designed to meet the calls for of slurry pumping are used in a froth pumping software. Slurry hoppers require turbulence to prevent the mineral content material from settling, whereas turbulence in a froth pump prevents the air from escaping and results in blockages,” said Harvey.
Tanks designed for froth pumping promote steady round motion, where solids and liquids are despatched to the outside of the sump for additional transport whereas air centrifuges into the centre where it may be removed. This ‘whirlpool’ motion could be inspired by introducing the slurry from the top of the tank at a tangential angle. Conical designs, somewhat than those with a flat or rounded ground, further enhance the move of minerals and froth into the pump.
Smooth crusing To prevent blockages, the intake pipe which hyperlinks the tank to the pump ought to have a large diameter and slope downwards in direction of the pump. This design allows escaped air to separate and travel again up the pipe where it could escape from the sump, quite than increase into blockages.
“The shorter your consumption pipe, the more durable it is for blockages to build up. However, in addition to a upkeep spool and isolation valve, it’s a good idea to go away enough house for a water injection port, which is beneficial 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 customers to drain slurry from the pump and the discharge pipe system when stopping the pump for maintenance.”
เกจแรงดันน้ำ are sometimes classified as both brittle, with giant air bubbles that break easily, or tenacious, where air forms tight bubbles round minerals and is difficult to separate. Froth being extra tenacious than was accounted for is a frequent cause of blockages as air cannot successfully be removed.
“Two issues are taking place available in the market at present. On one hand, mine operators are grinding the product much finer than earlier than to liberate extra from the waste rock. pressure gauge ออก หลัง ’re also using flocculants that produce a lot smaller bubbles which lock up the air a lot more than brittle froths,” said Harvey. “We’re working together with customers to search out ways to manage these extra tenacious froths, by taking a glance at their circuit design and coping with areas the place the air might accumulate and block the system, paying explicit attention to their pumps, pipes and sumps.