Re: Copper/Zinc Concentrate Reclaim & Loadout System
Dear Mr. John Doyle,
It seems that you intend to feed copper concentrate having 80% material less than 25 microns, at the rate of 800 mtph. This material is to be fed from hopper to conveyor at controlled rate. 25 microns size material is a powdery material (10 micron particle size is the limit of visibility for human eye). To me it seems it would be advisable to use the totally enclosed type of feeder, such as chain feeder or screw feeder, etc. Won’t and open feeder result in to dusting? There must be many manufacturers who are specialised in feeding of such powdery material. Their experience / opinion needs to be considered. Handling of such fine powdery material is quite common in cement plants or some boilers using fine coal powder.
Regards,
Ishwar G Mulani.
Author of Book : Engineering Science and Application Design for Belt Conveyors.
Author of Book : Belt Feeder Design and Hopper Bin Silo
Advisor / Consultant for Bulk Material Handling System & Issues.
Email : parimul@pn2.vsnl.net.in
Tel.: 0091 (0)20 25882916 ■
Loadout System
Dear Mr. Doyle,
I agree with Iswar on this as you will have quite the dust problem.
A 24 inch full length apron feeder unloading from a tapered bottom rectangular hopper feeding the entire length of the hopper plus a few feet on the tail end onto a 36" enclosed belt seems like a good choice which would allow for a door opening in one end of the hopper wall to allow for cleaning and inspection in the hopper and eliminates the need for a lot skirting for the hopper bottom.
Apron feeders are simple to operate and just plain easy to take care of providing maintenance is done on them in additon by having an apron feeder the entire length of the hopper eliminates nearly all possibility of plug ups and material hanging up in a narrow hopper with a tapered bottom that is the entire length of the hopper.
The brute force of the apron feeder moving the material en mass will also facilitate in keeping the hopper free of hang ups as it scours the bottom on a continuos basis and you will be able to reverse it if the need arises to clear a blockage. You can always add an air cannon or two if you need one later on.
Three phase electric 480 volt power is a good choice for this. I am unaware of who makes apron feeders these days so I am of little help in that regard.
As an example of an apron feeder in use the mine
i worked at had an 24 inch feeder 72 inches long under a 75 ton bin that ran continuosly for 23 years almost around the clock moving ROM rock salt at 450-550 tons per hour with very few problems relating to its operation.
Since you are not deasling with ROM ore you will not suffer from oversize that was not broken by a belt feeder breaker jambing the mouth of the apron feeder, been there done that :^(.
Making a 1/140 scale model of the narrow hopper using the material to be moved will provide much insight into its flow patterns and will definetely show you how well an apron feeder will work as it will move everything at once and gravity will do all the work for you as it will
behave no diferently.
This can easily be done with a 1/140 scale hopper made from 2 by 4's with a piece of narrow web belt supported by another 2 by 6 acting as the bed of the apron feeder that would be connected to a hand crank connected to a pulley to move the material through the hopper and to the end of it to show the viability of an apron feeder on a larger scale.
Also an apron feeder with its reduction gearing and drive sprokets will create huge amounts of torque to move the material in question.
My two cents- the simpler and dumber it is the easier it is to keep running and operate with fewer headaches and call outs. ■
Re: Copper/Zinc Concentrate Reclaim & Loadout System
I have been involved in a few projects where the concentrate was fed by a wide belt feeder although this was usually from a silo. In fact many mills seemed to go away from aprons to belts in the 1980's.
Belt Feeder Advantages:
- no leakage through pans like apron feeders (less cleanup)
- heavy belt may need replacing more often than apron pans but will be cheaper and less work
- better delivery and more vendors available
- wide long belt feeder means steep slopes are possible in hopper and full bucket of 966 loader can be accomodated, maybe arrange the hopper so that the loader drops onto hopper side to avoid pounding on the belt and puffing material out the skirt seals.
If you are going to feed with a loader you are going to get dust no matter what feeder you use at the bottom of the hopper.
Make sure you have a good distance from the hopper to discharge to avoid flushing if material gets dry and aerated. Full skirts are essential. Belt should be picking style rolls or flat belt with flanged edge to contain minor amounts of material escaping through skirts. ■
Copper/zinc concentrate reclaim & loadout system
Dear friends,
I am presently in the process of designing a hopper/feeder/conveyor system out of a new storage shed to be constructed in western Newfoundland, Canada. The concentrate is to be loader fed into a hopper/ vibratory feeder just above floor level and down onto a 75ft. conveyor in a tunnel that will feed onto an existing conveyor- tunnel system that goes to a shiploader. The copper concentrate has a density of 2.25 t/m3,moisture content of 6-9%, angle of repose 40 deg., surcharge angle of 20 deg. and 80% < 25 microns. The loadout rate is 500 - 800 tph. I am presently looking at a rectangular type hopper fed by a 966 Cat Loader dropping onto some type vibratory feeder which will transfer the material onto a 36 in. conveyor then onto the shiploading system. One suggestion has been a chain type bar feeder, another is a vibratory pan feeder,which depending on the type may not work. Other options are vibrators on the hopper, air blasting, lining the hopper. I am wondering if there any suggestions from past experience from any readers.
thanks,
john doyle ■