Grinding & Classification Circuits

Grinding & Classification Circuits

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Ocher milling (3 replies and 3 comments)

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nyala89
6 years ago
nyala89 6 years ago

I need some help. We need to mill ocher as fine as possible. To date we used an outdated Raymond mill. The company bought a small ball mill about 20 years ago and we would like to use it in our process. Do you think that with the ball mill, we would be able to mill to about 3 microns? Am i wrong to say that we could have a cyclone from the mill classifying the product and returning the oversize back to the mill. The system that is in-place  does not make sense as the cyclone was not working as it should be. Please if someone can help me with a diagram of a working process and more info. The company don't want to spend a fortune to get this plant running again. Thanks

S
saguero
6 years ago
saguero 6 years ago
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Hi Nyala, some questions/comments:

1.- Have you already verified the efficiency in different size fractions for your classification circuit?

2.- The problem is not the Raymond mill...it is a classification problem!...cyclone efficiency for small fractions is very low!...you should use a High Efficiency Separator!....

3.- A ball mill will never grind efficiently at that size!! 

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nyala89
6 years ago

Hi Saguero. Thanks for the comments. They did some grading analysis . I do feel the same about the classification. They will have to use a separator

K
KPvanderWielen
6 years ago
KPvanderWielen 6 years ago
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1 like by David

Dear Nyala, 

As mentioned above, a ball mill will not do anything at that size and classification becomes very important. 

With regards to milling, your only real option is to look at stirred mills (SMD, Isamill etc.). Running a ball mill for your target size is going to do nothing but waste energy.

Classification, as Saguero said, is very important. If you have to work dry you'll need to look at air classifiers. If you can work wet, then centrifuges may be an alternative route to consider.

Regarding wet/dry milling, as a general rule of thumb in the 2 - 5 micron P80 range wet grinding+drying starts to be more economic than dry milling depending on price of the finished product.

Hope this helps, 
Klaas

http://www.grindingsolutions.com/

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nyala89
6 years ago

Thank you for your comments. We will have to go back to the drawing board.

W
Wayne
6 years ago
Wayne 6 years ago
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1 like by David

Hi Nyala,

We needed to get our concentrate down to 7 micron and the small ball mill we had at the time would not do it.  It used to run three shifts to try to keep up.

We invested in an Netzch ISAmill now a couple of passes gets 7 micron easily and the mill only needs to run one shift instead of three.

I have no Idea on the cost involved or what size you would need but our grind cylinder is only about 4L and charged with 5.5 - 6 L of 1.5mm ceramic media.

Here is a link to a sub-micron dry grind device by the same company

https://www.netzsch-grinding.com/en/header/about-netzsch/news/details/dry-finest-grinding-into-the-submicron-range-fivefold-increase-in-throughput/

Cheers,

Wayne

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nyala89
6 years ago

Thanks Wayne for your comments. I will really put it on the table.

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