Grinding & Classification Circuits

Grinding & Classification Circuits 2017-03-23T09:46:37+00:00
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Best Grinding Mill (11 replies)

Sachin Prakash
1 year ago
Sachin Prakash 1 year ago

Who knows what is the best machine or grinding mill for size reduction when the feed size is 3 -8mm and we want product size be( 200 -900)micron and -200 micron be minimum% because 0-200 micron is reject sizethe material is calcium carbonate

Sturmbann
1 year ago
Sturmbann 1 year ago

If you can mill as wet slurry, then a rod mill should be your first choice. If the grinding must be dry, there may be air-swept devices that are suitable - but some are low-throughput machines.

Sachin Prakash
1 year ago
Sachin Prakash 1 year ago

As you know calcium carbonate is not hard and its dry process what do you think about hammer mill with 5-10 t/h

Carl Jenkins
1 year ago
Carl Jenkins 1 year ago

This needs a screening process with recirculation of oversize to a crusher. Hammer mills will work but the re-circulating load will be high thereby restricting productivity. You could try a Barmac which will give good pulverization. We had a "baby" Barmac (2000 series) set up in a screening plant which sounds ideal for this situation. Not sure if they still make them though, but if you can't get hold of a 2000 then the smallest one they do will still work but will obviously take up more space and be over capacities. The "baby" we had coped with feed size up to 16mm and our throughput on much harder material (fused Alumina) was around 15t/hr.

Bob Mathias
1 year ago
Bob Mathias 1 year ago

At first place I would choose the ball mill with suitable grinding charge (steel balls). At second place I would choose vertimill. This option could be better solution.

Carl Jenkins
1 year ago
Carl Jenkins 1 year ago

Are you sure you would want to do this in a mill - it is to all intents trying to make a calcium carbonate sand, the size he is quoting is 0.9mm to 0.2mm a ball mill or verti-mill would produce far too many fines (-0.2mm) which he has stated is waste. I still maintain that screening with oversize pulverization is the optimum solution.

Hauptsturm
1 year ago
Hauptsturm 1 year ago

Your tonnage requirements are not listed, but if they are large, you might investigate the use of a smaller high pressure grinding roll followed by dry screening. Have you a use for the reject. Sounds like it would make a good amendment for potting soil etc.

Sachin Prakash
1 year ago
Sachin Prakash 1 year ago

I agree because this is screen line and the feed material does not have any powder % and our crushing and screen line should not make more powder during the crushing. What do you think about roller crusher and close circuit with tumbler screen for over feed size(x>.9mm)and for cleaning the product of screen we using a bag filter and zigzag classifier and 2 silo for 0 -0.2mm and .2 -0.9 in dry system?

Bill Fraser
1 year ago
Bill Fraser 1 year ago

In the case where wet grinding is possible, a rod mill would be most suitable as the over grinding to below 200 micron would be minimized. A ball mill will tend to produce more unwanted fines. I also agree with regard to the HPGR. What you want to avoid as much as possible would be impact grinding as this will generate too much fines.

Carl Jenkins
1 year ago
Carl Jenkins 1 year ago

The roll crusher is much better option for this soft mineral, than the Barmac I suggested, as the crushing action is much less aggressive; my apologies as due to the hardness of the materials I usually deal with, roll crushers are not on my immediate horizon. The squeezing action of the roll will develop much less fines than any impact crushing. Your challenge will be to ensure that the rolls can be positioned to less than 0.9mm apart without fouling. I would suggest that if a new crusher isn't installed then any second had machine has the rolls and support replaced to eliminate any "play" in them with could cause fouling at this narrow gap requirement.

Oberstorm
1 year ago
Oberstorm 1 year ago

In lieu of a rolls crusher that would require an extremely fine set up gap, a HPGR in closed circuit with a screen and bag filter to eliminate dust (and possibly remove the sub 200 micron waste) will allow you to process the throughput you require (presently not given). The operating pressure can be adjusted to not generate too much fines, and as you may know, HPGR produces a very steep PSD.

HPGR is definitely better than a rolls crusher; ball milling would also work (wet or dry) but would require careful control to avoid over-grinding.

John Koenig
1 year ago
John Koenig 1 year ago

Recently we have made some tests to produce a granulated material which contains no more too fine sandy, to thereby employ a hammer mill feed 15-18 t/h, F50= 3.5 mm and D50 = 0.6 mm. The Raymond mill is very expensive and sprayed almost entirely the product leave. The roller mill is very sensitive to environmental moisture and high circulating load. Our material contains 50% calcite, completely dry. The air classification was the best selection for the dry sand.

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