Grinding & Classification Circuits

Grinding & Classification Circuits 2017-04-04T06:57:16+00:00
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Started by anjanisail
Based on test work I have designed a flow sheet for the Beneficiation of Hemetitic Iron ore. I have selected Ball mill for the grinding of rejects coming from Jig for further recovery of iron values from WHIMS. Optimum mesh of grind is 0.15 mm . From...
Last replied to by Jorge Ganoza
It is important to know if the grindability testing program tested several ore types to determine the ore hardness variability. Also, how were selected the samples to perform the testing program?, wer...
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Started by longz
I am working in a plant with single stage grinding using a ball mill we operate the mill power at around 1400KW& the feed size is 20mm. we use 78mm/64mm steel balls. the ball mill is in closed circuit with classification cyclones. there are 3 cyclone...
Last replied to by David
Just to shown you that if you really are at 38um, your will need 50um maybe... and 10" cyclones are not designed for that. Larger +20" are best suited for this coarse cut. in the mean time = increa...
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Started by Usman Konneh
Hello everyone, I was given the responsibility of testing the cyclone efficiency of the process plant. Our current operation required percentage should be 80% passing the 75um screen. What should I do as a Metallurgical Laboratory Technician to meet...
Last replied to by David
start by organising your data.
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Started by alaz
hello everyone  my problem is we hardly get 80% smaller than 75µm  we have a SAG mill and ball mill and we are running 300 TPH on the sag mill the pulp S.G is 1.8  the sag mill KW around  4500 and we are using 125 mm steel ball  the ba...
Last replied to by KRISHNADAS
The suggestion given by Richard is practical & I would also like to add thta- Please check your gratings in the SAG mill , maybe it is worn out and needs repair. Krishna
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Started by Hamid72
Hello everyone I'm hamid and from iran I am working in a plant. At our plant we have a ball mill that grinds the strontium carbonate. this material is sticky and makes the mill choke. The informations of our mill are: Diameter: 76 cm Length: 282 ...
Last commented on by Hamid72
Thankyou a lot dear Robert
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Started by Shashank
What are the reasons of failure of viton rubber plugs in a ball mill? Can iron fines produced during dry grinding accelerate the process of rubber failure? One of the reasons will be self hardening due to continuous exposure to high temperature. Alt...
Last replied to by David
How long do they take to fail?
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Started by Pablo
Hello, I'm working on a project involving a ISAMILL LME4 (I do not have the machine right know). I'd like to know which phenomenon is predominant when it comes to size reduction of my ore. F80 = 75um Media size = 1.5mm diameter of the mill : 30cm...
Last replied to by Robert
Look at this paper: http://www.isamill.com/EN/Downloads/Downloaded%20Technical%20Papers/Development%20of%20the%20Larson%20Morrison%20IsaMill%20JKSimMet%20Model.pdf "The IsaMill is a high intensity h...
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Started by mran haider
Why cement grinding ball mill is floating towards the Gear box (MAAG) which has resulted the damage of the second stage of gear box. As we have replaced the gear box now but still we are unable to find out the solution how to control the mill which i...
Last replied to by AJNeale
This is a tough one, and you may have to get an alignment specialist and/or vibration specialist to examine the mill to really diagnose the problem.  You will have to confirm that the ball mill is "...
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Started by hovan
Greetings there, I work at a phosphoric acid plant where we have a ball mill. Recently the mill has not been producing enough output, this is due to not being able to increase amount of ore going into the mill as air circuit temperature is dropping,...
Last replied to by ASHUTOSH SHANDILYA
Dear Hovan , Are you having a hot air generator  in the grinding circuit if so just try to operate it at earlier temperature when mill was running smoothly . i.e analyze the crude first . Are you o...
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Started by Hamid72
I am from Iran and I am student in mineral processing. I can't understand these sentences about Hydrocyclone pressure drop at overflow. can you explain me easier? thank you so much Should the overflow be discharged against a positive head, some of ...
Last commented on by Hamid72
Can I see the outcomes too? Thank you
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Started by Helen
Hello all... I found out the scales forming are that of carbonate due to the lime and hardness of the process water. A little confusion i have is how can very large scales of carbonate form on a highly agitating component? the vibrating screen agit...
Last replied to by Helen
Thanks for the information!
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Started by Helen
Hello, I work in a gold processing plant where we have a vibrating trash screen in our milling circuit made from a polywedge material. We have a considerable amount of thin scales forming on the screens which are removed every shut down with Sulphami...
Last replied to by Stewart Fernandez
I did a bit of poking around and I wonder if you are using  that sort of screen layout, cause if you are - there is absolutely no surprise that you are having issues, that will not work - its way to ...
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Started by banyechan
why lead zinc ore grinding mills prefering casting high chrome grinding balls not forged balls? Can anyone give me some ideas?
Last replied to by Metsol
Max is quite correct re: the chrome balls are harder but after some laboratory and plant work a few years ago it was clear that the forged balls have an adverse effect on the redox potential of the fe...
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Started by mebrahtu
1.Hello everyone.we have a FOS with a total capacity of around 3000tonnes. All the day at the end of every month we take the stock by deducting the total tonnes milled from total tonnes crushed of that month but this no longer continued bcz on time s...
Last replied to by mebrahtu
See the photos plse    
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Started by Mshindo jr
How does  mill power draw affect grindability?  
Last replied to by Mike Rockandel
Cart before the horse. The question I think should have been "How does grindability affect mill power draw". When you say grindability I assume that you mean, "How much size reduction can you achieve ...
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Started by Johannes
We are attempting to successfully grind Micaceous iron oxide (Hematite) down to -63 micron average 40/50 micron but maintaining the bulk of its lamellar structure,platelets after grinding should show up red under a bottom lit microscope, any one had ...
Last replied to by AJNeale
Hi Johannes - I don't have any direct experience with this, but if "micaceous" and "lamellar" mean that your are liberating flat platelets, then you might think about separation using a shaking table....
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Started by Langton
Am looking to design a 4 to 5 ton per hour dry ball mill. What factors should I be looking for? The following is what I have: Feed size 20mm, product size 75microns, Wi 16.5kWh/ton.  I do not what want to use any water as its washing away a lot of ...
Last replied to by Langton
Thanks for the advice Andrew. We do have a concentrator on the site but still the gold is being washed away after stamp milling to -2mm. There is also water issues on the site hence we looking at amal...
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Started by Tony Johnston
Does anyone have a couple of examples where iron ore is being ground using a ball mill with an inverter for mill speed control? And if you do, can you offer any commentary on how successful, in technical and economic terms, that approach is proving ...
Last replied to by David
My friend from https://sagmilling.com/ says most iron ore mines don't use ball mills for a couple of reasons: 1. The grind is coarse enough that you can do it in a single stage (Eg. Labrador Trench) ...
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Started by Simeon
How long would a hydrocyclone typically last (Barrel, lower cone, mid cone, spigot) before being worn out? It can be rubber lined, Polyurethane whatever material...  When feeding rough like d50 1mm - 4mm ?  High pressure range 90 - 120 kPa  F...
Last replied to by czambrano
Interesting and useful comments. Something to take into consideration specially with high pressure cyclones and coarse material is the underflow launder lining, which finally could shutdown the circui...
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Started by vekian
Hi people. I've put this idea by 2 metallurgists at the gold plant I work at. 1 agrees with me that it is worth trying. The other disagrees. They want a COF density target of 46 with a SG of 2.7. Extra water is needed to be added to the mill discha...
Last replied to by Dielgarcia
Vekian: Hi, can you tell me the thickener u/f?, if you have 46% in the COF, but, what density have in your CIL tanks?
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Started by Pabloski
Hello everyone, After the SAG mill there is a SAG box, where the output of the SAG is transferred into. There are 4 pumps (2 operational and 2 in stand-by) that transfers the material to a cyclones battery and then to two ball mills. When the ma...
Last replied to by kam81
Using an intermediate chute or box to evenly distribute the feed into the pump box could help. The main problem however is the floor slope and suction locations. If you don't mind losing some volume ...
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Started by mohamedkrafi
I want know if you have an idea about the best  comminution circuit selection basing on Ore hardness and competency (SABC, AG, ROMBALL MILL) we have two type of ore compétent and hard (AxB=24, ball work index = 18) and moderate and soft  (AxB=40,...
Last replied to by Robert
There has been a good discussion of this subject in recent years. Much of this has been summarised in a matrix fashion with axes the major factors to consider and secondary factors discussed within ...
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Started by THIRU
Dear sir, We need grinding machine for grinding scrap of iron mill scale chips in size 25 mm width, thick 2 mm can be reduced into 1 to 2 mm powder. Also the iron mill scale chips contaminated with some another hardened iron lumps may thickness 10 ...
Last commented on by THIRU
1.5 M.T / Hour
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Started by Fabian Rebolledo
I would like to know if there is some technologies that can measure the mass flow of an open channel that carries pulp from grinding and feeds milling
Last replied to by OberstGruppen
Fabian, What are you trying to achieve?
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367
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Started by sajid
My grinding mill has length and diameter of 4.57 m. the maximum size of the balls selected is 77 mm, as there are two or three kinds of ball sizes used..how to select the second ball size. are there any formula or equation that i can calculate the ba...
Last commented on by sajid
thanks for valuable information. i already calculated it for the first charge. but now i need calculation for the second charge. if you could give me some guideline it would be appreciated.
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Started by Helena Russell
Is it the right practice to increase the density when too much material is reporting to the cyclone underflow for a diamond processing plant? Cyclone pressures were a bit down but within specs, manual and instrument densities were right but still too...
Last replied to by David Kano
If cyclone feed pressure and operating density are within acceptable ranges, you might want to have a look at the media density differentials. By measuring the feed and overflow stream densities you c...
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Started by AR
How to decrease Copper lost in tail and what should upstream plant (grinding) to do to decrease Cu lost in tail ? Thanks you
Last replied to by Robert
Root cause analysis would be good preliminary before altering grinding conditions. This is working to understand what particles are being lost. Suggest sampling feed, con, tails, determining size...
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Started by SAKAR
Dear Friends, Hi....I have one question about type of Wear Resistant Liner for Grinding mills. Why & Where to use metal Liner & Rubber liner ? I want to know about type of Grinding Mill Liners and where to use it.... Thanks & Good day. Jignesh
Last commented on by Alex Doll
FYI, the attachment Stuart provided is a chapter from the SME "Advances in Comminution" (Ed. S.K. Kawatra). It is a great book and I would recommend anyone interested in comminution pick up a copy of...
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Started by AR
What corellation between efficiency hydrocyclone and valuable mineral lost in tail? What corellation between grind size P80 overflow product of cyclone and valuable mineral lost in tail? Thank you
Last replied to by Zander Barcalow
In a rougher flotation circuit: if you are more than 55-60% liberated on your target mineral = a coarser or finer P80 will not immediately matter. If you are say 80% liberated = coarser P80 may red...
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Started by Romain CADENAT
Dear All  I have a hydrocyclone for which I need to send the overflow +1.5m above the head of the hydrocyclone. Is this configuration possible ?  On the file attached I show standard configuration and the one I want. The feed pressure of the hyd...
Last replied to by Romain CADENAT
Ok, thank you for your help Andrew.  Thank you for the links Jean, interesting. In fact it is not a grinding circuit but a classification line. 
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Started by Ibrahim
Hello, We measured the thickness of sheet plate and lifter bar rubber liner in a ball mil for a gold mine to estimate when we have to change them. What is the minimum thickness of sheet plate to preserve the drum of the ball mil? And what is the mi...
Last commented on by David
It's about time you show up Stewart 🙂
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Started by joy1484
We started our hammer mill (Williams mill) after doing several maintenance to solve some electric problems. The plan was to get in spec and then not make any adjustments and watch grind. With a starting grind of 76 (spec is 74-86) we let the mill go...
Last replied to by Robert
Did material sit in the feed hopper/silo during maintenance shut? When you checked for obstructions did you check to see if flow from feed silo? 
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Started by AR
What the correlation between throughput and grind size, throughput and power utilize, throughput and ore characteristic (WiBM), grind size and recovery Cu lost on tail? Thank you
Last replied to by AJNeale
Hi AR - Max and Bob have summarized it very well.  In terms of optimization you need to relate metal production to metal recovery, throughput, and head grade, where metal recovery is a function of gr...
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Started by Josh Wright
How does a "modified bond ball mill work index" test vary from a standard ball mill work index test?
Last replied to by Josh Wright
Hi Dave, Peter, Chris, and Greg, Firstly, thank you so much for taking the time to reply. One of my colleagues mentioned that a recent RFQ requested a modified bond ball mill work index. We had susp...
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Started by Takue
I need help in the determination of the power drawn by a wet pan mill in gold milling
Last replied to by Alex Doll
Short answer is you measure the root-mean-square Amps and Volts going into the motor driving the mill, correct for the motor efficiency (and possibly power factor) and calculate power using equation P...

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