SAG Mill
SAG Mill
(OP)
At another web site someone asked about modeling a SAG Mill. Not knowing what this was I googled it-a rotating rock crusher. What struck me was that the rock crushing seems to be about 5% efficient. Dosen't this beg for a new solution with a much higher efficiency?





RE: SAG Mill
There are many other solutions however if the efficiency of a SAG mill is not what you are after all of the other options cost more in terms of maintenance and materials (eg. pure ball mills, hammer mills and rod mills).
AG and SAG mills are cheap to operate and some inefficiency is okay due to cost/benefit.
RE: SAG Mill
RE: SAG Mill
<one of the maintenance issues with SAG mills is when doing liner changes the balls get imbedded in the liner - when removed and sit for a while, the steel balls can explode!>
Can you share the mechanics of this? Is it due to continued compressive stress from the liner? I'd appreciate any info or links to papers on this.
Thanks!
Keep the wheels on the ground
Bob
RE: SAG Mill
RE: SAG Mill
Careful about the efficiencies, they can get called out in different ways, and especially can be misleading when comparing different types of mills.
My most comprehensive literature is twenty years old:
N.L. Weiss, 1985, SME Mineral Processing Handbook, Vol. 1,ISBN 0-89520-433-6.
Browse through Sections 3A (General Aspects of Comminution) and 3C (Grinding).
SME (now Society of Mining, Metallurgy, and Exploration) can be located most readily at www.smenet.org.
Anyway, SAG mills can be calculated as inefficient, except they do not require a large grinding load like ball and rod mills. Capital and operating costs have to be compared, system vs. system in order to assist with the selection. The feed suitability vis-a-vis the grind method is critical.
As far as the balls, and rods for that matter - wear hardening is a fascinating thing. Yeah, they can blow up.
Ruble3, nice to see you again. I'm bemused that it was an environmental manager who smoked his office. The milling operations I am aware of have been careful about allowing used balls out as souvenirs. Sometimes that spalling, especially on old cast balls, can get fairly energetic.
Have a safe shift.
RE: SAG Mill
RE: SAG Mill
RE: SAG Mill
RE: SAG Mill
I always thought that the balls exploded due to the internal stress generated by the outside cooling (and shrinking) faster than the inside. If we wait long enough before entering the SAG mill, the balls are no longer cooling and stop exploding.
Just yesterday, one of the operators said the balls can explode even after a long time. I had never heard of the balls exploding after they have cooled down. Has anyone else out there ever heard of the balls exploding after a long time?
If the exlosion is due to differential cooling, I just don't see how they could explode after they have been out the SAG mill for more than a few hours.
RE: SAG Mill
RE: SAG Mill
Exploding balls. Who'd a' thunk it.
RE: SAG Mill
http://www.donhad.com.au/forgedballs.html
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