Grinding & Classification Circuits

Grinding & Classification Circuits 2017-04-04T06:57:16+00:00
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Started by Jean Rasczak
Hi, A lot of this is just theorizing. We will have to try the ore out to know what sort of grind we really need. But, that said, there are several potential issues. Zinc, according to the initial feasibility test work needs to be reground in order...
Last replied to by Dave Tahija
If high pH of the cleaner tails is the only issue preventing sending them to a flotation/tin stage, why not lower the pH with carbon dioxide?
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Started by babygenius76
I have a West African project where we use a pendulum roller mill along with classifier to dry-grind high purity (95% to 98%) calcite to d50 10 micron with a relatively steep PSD curve.  The top feed size into the mill is 5000 microns (5 mm) because...
Last commented on by babygenius76
Robert, Yes, the grinding from 5000 to 10 microns is highly energy intensive. As you see above, I have even tried a 2 stage grinding where in the first stage, I reduced it from 5000 to 74 micron. In ...
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Started by georger
Anyone have access to a operating manual or any documentation for a Vickers Ruwolt 48x20" Rolls Crusher? 
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171
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Started by polyroly
Good Evening Everyone. First time posting in the forum here! We just recently relined our SAG mill and we have had some operational issues since starting back up. We have had a massive amount of filings ending up in the discharge magnet and I examin...
Last replied to by dassahd
Sorry I am late in joining, does it happen during every startup? If yes then I recommend you do as Alex suggested. You may need to test the balls as well. Probably adding a new batch to the mill.
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Started by Okay
Hello Everyone, I am dealing with the calculation of Bond Work Index. The flowsheet is attached. I have calculated primary ball mill bond index but for the calculation of second ball mill bond index I got trouble. In a bond energy equation,  where ...
Last replied to by Alex Doll
F80 is the feed size to the primary BM; T80 is the transfer size (prim mill product size), P80 is the final product (cyclone overflow) The F80 is the feed to the primary ball mill. The T80 (is t...
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Started by Nicolau Ismael Lazaro
Hi all. I am new in mining industry and I have two task to do and I would like your help: Perform Reflux Classifier Capacity Test and; Optimize the Reflux Classifier Performance Can the anyone give some insight on how to do this tasks. Thank y...
Last replied to by Nicolau Ismael Lazaro
Thank you Rahil. I would like to get optimum parameter (bed density, fluidization and feed flow rate) for the reflux classifier processing -1.0 +0.25mm particles from the deslime screens to get produc...
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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 KPvanderWielen
If you don't want to do full PSDs you can do a quick check as follows: Take Marcy bucket sample and determine slurry SG Run sample over 75mic screen, wash thoroughly so no undersize is retained on...
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Started by williamcavalier
Assuming a new technology allowed economical and rapid 1 micron grinding - What material would you grind to achieve high recovery rates and take advantage of a lower processing cost of fine material? Asking the same question in a different way - Wha...
Last replied to by KPvanderWielen
For most applications 1 micron is too fine, you'll slime the feed. Industrial minerals do go this fine though for making products for specific applications, and as said before gold leaching may benefi...
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203
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Started by Hamid72
Hello everybody In our plant sometimes freezing of the charge happens for the ball mill and if we cant solve this issue after three times the ball mill will be stopped for 5 hours. I want to know why this issue (the load cementing) happen? And what ...
Last commented on by Hamid72
hello David. thanks. when the ball mill stops suddenly for example because of the high temperature of the oil and we cant run it for half an hour frozen charge happens.
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587
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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 BAUD
Thank you David. This site is unique in the world in what it offers in the profession. When googling, I was agreeably surprised by the quality and quantity of reading materials it contains and I have ...
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108
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Started by dasun
My plant has a pulverise machine (3-5t/h). It's like as VSI machine. Are there any methods to select suitable input particle size to increase the percentage of yield without increasing the RPM of rotor? Because, when check the samples of pulverise ou...
Last replied to by Jorge Quintanilla
The losses are associated with dry powder that leaves to the environment. The key to better control these losses is moisture. The fine thread of balance. Not so wet as to not spray and / or block equi...
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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 commented on by Robert
Definition of ore types and selection of adequate number of samples from within each ore type volume is critical. One interpretation of your comments is a single sample run by you and by the consulti...
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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 commented on by mran haider
Dear sir, we already have done the proper alignment by an Expert of the Gearbox as the Gearbox was newly installed & we have done alignment twice with Expert. Finally he quit that this is not an alig...
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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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233
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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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284
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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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387
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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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237
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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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203
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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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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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259
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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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