# Grinding & Classification Circuits

Grinding & Classification Circuits 2017-03-23T09:46:37+00:00
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## Ball Mill mass balance in steady state (3 replies and 2 comments)

pitachikondi
12 months ago
pitachikondi 12 months ago

A ball mill is operated in closed circuit with sieve bend under steady state conditions as shown in the attached diagram.The % solids in each stream are indicated.The water addition to the sump is  100 cubic metres per hr and to the mill feed is 67cubic metres per hr.

1. Calculate mass flow of solids from screen undersize.
2. The mass flow of solids to the ball mill
3. Water split at the sieve bend.

pitachikondi
12 months ago
pitachikondi 12 months ago
1 like by JOHN

The ball mill is in a closed circuit loop with sump and sieve bend.

The sump has a feed of 60.1% solids,water addition to sump is 100 cubic meters per hr and outflow from sump constitutes 49.1 % solids.This feeds onto a sieve band which has an under-screen flow of 42.9% solids. The overflow from the sieve bend (56.1% ) feeds into the ball mill which has a water addition of 67 cubic meters per hr.The ball mill outflow consists of 49.6% solids and this goes into the sump to complete the closed circuit.

1. Calculate mass flow of solids from screen undersize.
2. The mass flow of solids to the ball mill
3. Water split at the sieve bend.
(unknown)
4 months ago
David
12 months ago
David 12 months ago

OK, this is obviously a classroom assignment you were given. Have a look at https://www.911metallurgist.com/blog/milling-calculations-formulas it will have most of what you need.

JOHN
12 months ago
JOHN 12 months ago
1 like by David

Let me give u some points which might help u in solving your task.

1. what is in = what is out.''the feed to the sump is the slurry coming out through undersize''

2. follow the same procedure to the ball mill, since it is a close circuit with the sump. mass to the ball mill is same as the discharged mass. mind that, we are not talking about water balance yet.

3.amount of water in to the sump( in the feed + added water + water from circulating load) = amount of water leaving

4.amount of water in to the ball mill = amount of water leaving

5. apply water balance to the sieve

then u are done

if u cant, look at the attached file.

David
12 months ago

thanks John. your Doc must be PDF