Laboratory Testing & General Mineral Processing Engineering

Laboratory Testing & General Mineral Processing Engineering

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Determine screen cloth size (4 replies)

(unknown)
8 years ago
(unknown) 8 years ago

How do you determine screen cloth sizes for limestone crushing. An existing lime crushing plant produces 0.5 mm to 1.5 mm finished product using a double deck vibrating screen with mesh No. 8 on the top deck and 12 mesh on the second deck. Aren't the screen clothes sizes too big for the target product sizes?

Victor Bergman
8 years ago
Victor Bergman 8 years ago
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I'm not an authority on this, but I recall that the particles strike the screen openings at an angle, depending on slope and vibration, etc., so the particles see a smaller opening than the nominal screen opening. But that would mean that you are right. The screen in place would have to have slightly larger than your desired products. You need to get feedback from someone who works with this more than I do. Some actual field tests wouldn't hurt either.

(unknown)
8 years ago
(unknown) 8 years ago
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For start from scratch opening sizing we like to use one mesh size larger than the target size. This can be adjusted once some actual results are known. Given that, it looks like the top screen opening is about right for a new plant. The bottom opening might be a little large, but this could depend on things like screen loading, moisture, etc.

Screens have a D50 size and partition curve just like cyclones and other classifiers do. The partition curve tends to be steeper than the other devices, but it is not vertical like a lab screen should be.

(unknown)
8 years ago
(unknown) 8 years ago
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We know about lab sieves. I think it might be useful to check separations with a couple of laboratory test sieve to see what you are actually getting with you vibrating #8 and # 12 screens. That should give you a starting bench mark.

(unknown)
8 years ago
(unknown) 8 years ago
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Thank you for your responses. Gave me points to think of.

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