Crushing, Screening & Conveying

Crushing, Screening & Conveying 2017-03-23T09:38:14+00:00
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Crusher surveys (10 replies and 4 comments)

Goldman
9 months ago
Goldman 9 months 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
9 months ago
Marshal Meru 9 months ago

Hello,

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

What tonnage/size is that crushing circuit? 

Goldman
9 months ago
Goldman 9 months 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
9 months ago
David 9 months 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.

Paul Morrow
9 months ago
Paul Morrow 9 months 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?

Goldman
9 months ago

Yes that's right Paul.

Goldman
9 months ago
Goldman 9 months 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
9 months ago
Marshal Meru 9 months ago

What is the approximate P80 of your secondary crusher discharge?

Goldman
9 months ago

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

Bob Mathias
9 months ago
Bob Mathias 9 months ago

Hi Goldman,

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

Goldman
9 months ago

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

David
9 months ago
David 9 months 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.

David
9 months ago
David 9 months 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!

Goldman
9 months ago

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

lordi
6 months ago
lordi 6 months 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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