55 posts
198 posts
Re: VRM and ball mill circulating load
Mainly in USA , the term circulating load is more often used than the circulation factor.Circulating load is percentage of coarse return in relation to fines & it can be calculated by : Coarse return TPH X 100 / Mill output TPH.Normal range of cirulating load in a conventional close circuit ball mill is around 100-200%.
Vertical mill normally be operated with a circulating factor through the separator installed of about 3.Furthermore a preseparation does take place between the grinding section and the,mainly over and above the nozzle ring.A very high circulation of material does take place here.Often the circulation factor over the nozzle ring area will be in the range of 15-25, i.e. 1400% - 2400% circulating load
55 posts
138 posts
Re: VRM and ball mill circulating load
I guess this could be measured as usually based on the particle size distribution (PSD) of the separator feed, product and rejects. Based on these three PSD curves, the circulating factor (load) might be evaluated as well as the separation curve. See this reference for the full details:
http://www.mapei.it/dam/Pdf/DAMCatalogue.pdf
On page 34 you will see the Koulen formula that evaluates the circulating load.
I have no idea if the samples needed for these measurements can be obtained in practice or not.