Originally Posted by Yogesh

Dear Friends,

In our plant we have a ball mill of length 9m and dia

4.6m of capacity 230t/h of raw meal grinding. Presently we have a grinding media charge of 145MT of seize 20 to 70mm. Filling of media comes to around 28% by volume of the mill. Mill feed contains only -4mm particles

(Cement Raw mix) and the mill feeding rate is 190 t/h.

The problem we are facing is some times the mill filling goes high and it will not come down for a long time and at this time the mill main drive power increases from 2250Kw to 2400 Kw. The observations near mill suggests that filling is high near mill inlet(less noise of media) and the filling is low near the mill outlet(very high noise of the media).The folaphone level indicator is placed near mill inlet.Mill ventilation is very good.

Finally we need to cut the feed for 10 minutes to decrease the mill filling. I'm unable to understand this strange behaviour of the mill. Is there anything to look at the grinding media distribution? Please suggest..

Regards,

Yogesh

Greetings and salutations

Asalaam Malaaikum

Namaskar

The proverbial how many pennys in the jar problem

always enjoyable at least by me anyway.

It may be time to examine the mill to see how much build up you have on the walls of the ball mill (my thought only) and examine it safely by locking out the power boxes and the mechanic entering the ball mill will carry ALL the keys for his locks in his pocket to be sure.

My other thought is the larger media is overtaking the smaller media in actual total tonnage-

Perhaps a piece count for each size for the total tonnage is required to obtain the actual volume if unknown for all media sizes.

It may be the larger media is taking more of the media tonnage than you have had previously if there is build up on the in ner walls of the ball mill.

Is it at all possible to segregate the batches of grinding media to guarantee the proper weight of the sized media by using a bridge crane carrying a bucket

(making sure the buckets tare weight is made zero on the scale)

that has a trap door to release the sized and weighted media in use?

I am honestly trying to make the job harder but perhaps the mix of media is wrong?

lzaharis ■

Without knowing your details, one point can be observed.

Typical ball mill feed is set at about 5% of ball size in order for the product to mix and allow it to be nipped by ball to product size ratio.

Your feed, given top size of -4mm (4 x 20 = 80 mm larger ball size), may give some grief, especially if the product has a plastic rheology. Ball wear creates a distribution range that must mate with product range.

Interesting that the feed does not transport down the shell in a normal fashion. Kind of like it is not digested by the ball charge.

Need to know a lot more detail on mill operation (mill speed), water flow details, retention regulators, control algorithm. Kind of outside the forum, due to the complexity.

Suggest you contact some mill builders who would also like to become involved with a paying project. ■

Dear All

Greetings

I think all a question of the intermediate diaphragm separating the two chambers of drying and grinding and often clogged holes or longitudinal defect in the system of lifting and push materials to the next chamber . Mostly it is common

My regards

Ali ■