Crushing, Screening & Conveying

Crushing, Screening & Conveying

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Crusher surveys (10 replies and 4 comments)

S
Goldman
8 years ago
Goldman 8 years ago

Hi, I'm just wondering if anyone has any info on how to conduct a survey to calculate recirculation load on a crushing circuit? The circuit consists of a jaw crusher and a secondary and tertiary crusher. Any assistance would be helpful.

Marshal Meru
8 years ago
Marshal Meru 8 years ago

Hello,

where the screens are located?  Open circuit jaw + closed circuit secondary + closed circuit tertiary crusher?

What tonnage/size is that crushing circuit? 

S
Goldman
8 years ago
Goldman 8 years ago
1 like by David

The average tonnes for the crushing circuit are between 80-100T/hr. See flowsheet for circuit

 

 

https://www.911metallurgist.com/wp-content/uploads/2016/07/Crusher.png
David
8 years ago
David 8 years ago

Hello Mr Goldman and welcome to 911Metal.

For now please carefully review https://www.911metallurgist.com/blog/open-or-closed-circuit-crushing

Have you done such a survey before? Not sure if you realise it is a large undertaking. 

The sampling of coarse particles, for example from the feed conveyor to the jaw crusher, will produce a large amount of sample. A recommended procedure requires 4-6 people, collects from 500 to 800 kg of rock, and takes up to 30 minutes to complete (that sample alone).

I will have more details for you tomorrow.

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Paul Morrow
8 years ago
Paul Morrow 8 years ago

Since you refer to wanting to calculate the circulating load; you'd only want to sample around your tertiary crusher?  You have no technical interest in the performance at the Jaw and secondary cone crushing?

S
Goldman
8 years ago

Yes that's right Paul.

S
Goldman
8 years ago
Goldman 8 years ago

Hi David

Thanks for the link.

Yeah I know it involves lots of belt cuts and sizings!!! Just trying to find the easiest and most efficient way to do it, to get an idea of the recirc load in our crushing circuit.

 

Marshal Meru
8 years ago
Marshal Meru 8 years ago

What is the approximate P80 of your secondary crusher discharge?

S
Goldman
8 years ago

Approx P80 based on design specs are Primary=80mm, Secondary=32mm, Tertiary=15mm

Bob Mathias
8 years ago
Bob Mathias 8 years ago

Hi Goldman,

are you willing/ready to crash stop your whole circuit with loaded conveyor belts?

S
Goldman
8 years ago

Yes Bob, we would have to crash stop the belts to be able to do belt cuts safely.

David
8 years ago
David 8 years ago

Goldman, this job relates much to your screen efficiency around the 3rd crush. Also be sure to review the PDF at the bottom of https://www.911metallurgist.com/blog/formula-to-calculate-a-classifier-and-screen-efficiency + https://www.911metallurgist.com/blog/ball-mill-circulating-load-formula and all of https://www.911metallurgist.com/blog/screening 

Have a detailed read and do a visual review of your screen to insure nothing obviously bad is going on.

The video applies to your whole situation.

https://www.youtube.com/watch?v=YP4dFfU_xnM

I think this should cover you. Comeback after you read/watch all this and do your plant review.  You should write out an action plan as to who does what. 

Doing the math is easy if you have good samples.

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David
8 years ago
David 8 years ago

Last one Goldman.  You should have all you need now https://www.911metallurgist.com/blog/determination-circulating-load-crushing-circuit

Anyone else, please jump in!

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S
Goldman
8 years ago

Thanks David for all the literature, I'll have a read through it all when I get a chance.

S
lordi
8 years ago
lordi 8 years ago
1 like by David

Calculation of rough calculation of closed circuit

Qs=Q(1/E + B+/B-), where

Qs - Total screen load, tph

Q - Fresh load, tph

E - efficiency of screening

B+ - content of larger than cells class  in fresh load

B-- content of ready class in crusher product

Circulation load (Qc) is

Qc=Qs-Q

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