My new Ball Mill

[Barren Realms 007]

Hello, guys!
Could You pls help me with one issue?

What is the main idea of using variable speed (frequency converter) at huge ball mill?
Traditionally it's used constant speed (calculated critical speed), but recently on metal/concrete factories have been using frequency converters for the motors. I could not understand, why? May be on different stage of grinding material it's better to switch speed?? :roll:

You answered your question with you last sentance.

DUMB,DUMB,DUMB :roll:

 

[Anonymous]

No goof ball.It's to control the landing spot of your media.If the media is landing on one side,or the other,of your material,then you simply adjust the speed so it lands directly on top of it.Im my case I have a motor that you can not run a reostat on,so I created an elevated lifter bar and shave it until the media landed on the sweet spot.

 

[Barren Realms 007]

No goof ball.It's to control the landing spot of your media.If the media is landing on one side,or the other,of your material,then you simply adjust the speed so it lands directly on top of it.Im my case I have a motor that you can not run a reostat on,so I created an elevated lifter bar and shave it until the media landed on the sweet spot.

I guess I was asleep whn I read that message....My reply was totaly wrong. I'v been looking at too many chips. :lol: 8) :roll:

Blinded by the snow....

 

[Anonymous]

It's all good bud.

 

[dtectr]

No goof ball.It's to control the landing spot of your media.If the media is landing on one side,or the other,of your material,then you simply adjust the speed so it lands directly on top of it.Im my case I have a motor that you can not run a reostat on,so I created an elevated lifter bar and shave it until the media landed on the sweet spot.

Mic, your understanding of machine engineering completely blows me away, i'm serious.
Or, as BR007 & i say say in our neck of the woods, "That's the diff'ernce 'tween book-larnin' & real-life larnin'!" :lol: :lol: 8)

 

[Anonymous]

(blushing)
Thank you very much,but I owe a lot to harold and gill for my engineering skills.However I will gladly take credit for the elevated lifter bar.I am pretty sure I am the only person to have it.They may be in use,but if they are I have never seen any.

 

[Barren Realms 007]

No goof ball.It's to control the landing spot of your media.If the media is landing on one side,or the other,of your material,then you simply adjust the speed so it lands directly on top of it.Im my case I have a motor that you can not run a reostat on,so I created an elevated lifter bar and shave it until the media landed on the sweet spot.

Mic, your understanding of machine engineering completely blows me away, i'm serious.
Or, as BR007 & i say say in our neck of the woods, "That's the diff'ernce 'tween book-larnin' & real-life larnin'!" :lol: :lol: 8)

Amen to that, I will take someone with life experience over book learning anytime

 

[Barren Realms 007]

(blushing)
Thank you very much,but I owe a lot to harold and gill for my engineering skills.However I will gladly take credit for the elevated lifter bar.I am pretty sure I am the only person to have it.They may be in use,but if they are I have never seen any.

Keep at it, you will make it to the red neck hall of fame yet.

 

[dtectr]

(blushing)
Thank you very much,but I owe a lot to harold and gill for my engineering skills.However I will gladly take credit for the elevated lifter bar.I am pretty sure I am the only person to have it.They may be in use,but if they are I have never seen any.

glad you mentioned gill - what he can engineer with a welder, motor & angle grinder (OK, there's more to it than that, but you get my point 8) ) borders on genius.

 

[Anonymous]

No goof ball.It's to control the landing spot of your media.If the media is landing on one side,or the other,of your material,then you simply adjust the speed so it lands directly on top of it.Im my case I have a motor that you can not run a reostat on,so I created an elevated lifter bar and shave it until the media landed on the sweet spot.

so, as I clearly understood, the principal idea using variable speed drive at ball mill is getting speed, when balls will be rising on the top and fall down with max efficiency? Is it true?

 

[Barren Realms 007]

Yes

 

[Anonymous]

the principal idea using variable speed drive at ball mill is getting speed, when balls will be rising on the top and fall down with max efficiency? Is it true?

I am sorry xalebor but I do not fully understand the question.If you insinuating that you need more speed to get more power from the media(balls,slugs,crushing material),then no.If you are talking about the speed being adjusted so that the media falls in the correct place then yes.
If the speed is set too high,or your lifter bar is too tall,then the media will fall behind the material,defeating the purpose of the mill.Also on the other hand,if its too slow or the lifter bar is too short then the media falls in front of your material.In my case I do not have any way to control the speed of my mill unless I change my pulleys.So what I did was I found the correct combination that made my material fall just a little too far behind my material,then I shaved my lifter bar until the media fell directly on top of the material.It is important that I also remind people that size does matter.The larger the diameter tank you use,the farther the media falls before it strikes the material,hence building more kinetic energy before striking.
ALso I know a lot of you already know how my elevated lifter bar is and why I designed it that way,if anyone else wants to know,just ask and I will explain it.I think it is absolutely crucial to the efficiency of the mill.

 

[Harold_V]

I think it is absolutely crucial to the efficiency of the mill.

You are far better served to calculate the proper speed and run the ball mill accordingly. That's not to suggest the lifter isn't an improvement when one isn't running at the most desirable speed.

Harold

 

[Anonymous]

I think it is absolutely crucial to the efficiency of the mill.

You are far better served to calculate the proper speed and run the ball mill accordingly. That's not to suggest the lifter isn't an improvement when one isn't running at the most desirable speed.

Harold

in your opinion according to the experience: does the changes in input raw material (hardness, diameter etc), media (balls) wear will be so critical to cause necessity in speed regulation using frequency converter?

 

[Harold_V]

I think it is absolutely crucial to the efficiency of the mill.

You are far better served to calculate the proper speed and run the ball mill accordingly. That's not to suggest the lifter isn't an improvement when one isn't running at the most desirable speed.

Harold

in your opinion according to the experience: does the changes in input raw material (hardness, diameter etc), media (balls) wear will be so critical to cause necessity in speed regulation using frequency converter?

I'm not convinced speed matters as to the charge. You get the very best action from the balls when they are sized properly for the size of the feed, and they ride to the apex and fall on the charge, below. Speeding up changes that sequence, and may deter proper action. Slower action is most likely to fail to lift the balls to the apex of the curve, seriously deterring grinding action.

Ball mills that don't operate at the proper speed do a portion of their grinding by attrition----simply wearing out the material instead of hammering. When that is the case, a correspondingly high degree of wear occurs on the ball mill as well. Speed alteration would be effective only if you were running an improper speed at the outset. In the case of a lifter, that has the potential to correct for minor speed error----but you're still better off running the proper speed. It can be calculated, then established by the use of an adjustable pulley (available from Browning). Once set properly, there is no need for further adjustment.

I do not recall the source of my information, as it's been more than 25 years since I built my ball mill, but it may have been Rose's The Metallurgy of Gold.

Harold

 

[Anonymous]

Ball mills that don't operate at the proper speed do a portion of their grinding by attrition----simply wearing out the material instead of hammering. When that is the case, a correspondingly high degree of wear occurs on the ball mill as well. Speed alteration would be effective only if you were running an improper speed at the outset. In the case of a lifter, that has the potential to correct for minor speed error----but you're still better off running the proper speed. It can be calculated, then established by the use of an adjustable pulley (available from Browning). Once set properly, there is no need for further adjustment.

I do not recall the source of my information, as it's been more than 25 years since I built my ball mill, but it may have been Rose's The Metallurgy of Gold.

Harold

thank You a lot for well clarifying the process...

 

[artart47]

I got the idea last night after having coffee with a friend who is a mechanic at the local concrete ready-mix plant! I'm going to talk to him about using one of the concrete trucks. I could put a bunch of steel balls in the mixer drum and perhaps a hundred pounds at a time of boards, cards, those pesty cable ends ect... and let it spin. I don't like the idea that a refiner is going to magneticly remove the Fe and probably some of the gold pins with it. If I was to reduce every thing to a powder and remove the Fe myself I could recover and particles that are on the iron and return it to my load. any feed back?
art

 

[Barren Realms 007]

I got the idea last night after having coffee with a friend who is a mechanic at the local concrete ready-mix plant! I'm going to talk to him about using one of the concrete trucks. I could put a bunch of steel balls in the mixer drum and perhaps a hundred pounds at a time of boards, cards, those pesty cable ends ect... and let it spin. I don't like the idea that a refiner is going to magneticly remove the Fe and probably some of the gold pins with it. If I was to reduce every thing to a powder and remove the Fe myself I could recover and particles that are on the iron and return it to my load. any feed back?
art

Not a good idea. What ever concrete breaks off and mixes with your material will neutralize your acid. And you have the possability that some of you gold will be smashed and crushed into the side of the tank without the possability of recovery. You will loose more than you gain. IMHO

 

[Anonymous]

Agreed.Not to mention the cost to operate the machine for hours and hours at a time will bite hard into your profits.

 

[rusty]

mic curious if your recovering any silver and palladium from your milled chips.