Grinding & Classification Circuits

Grinding & Classification Circuits 2018-04-04T16:41:40+00:00
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Started by samuel82
Whats your opinion for TPL (turbo pulp lifter) for SAG mill? It seems that by adding a TPL could help increase energy efficiency and reach the SAG mill maximum capacity.    
Last replied to by David
Samuel, here is an excerpt of a paper by https://www.linkedin.com/in/david-royston-02765013/ Modern Semi-Autogenous (SAG) Grinding Mills can be up to 12 metres in diameter (absorbing up to 20 MW of ...
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Started by FarshidBsr
Hello Dear Friends, We are working in a plant with single stage grinding using three parallel wet three compartment ball mill. Each ball mill operates in a close circuit with Classifier. The fineness of ball mill product is OK so the circulating loa...
Last commented on by FarshidBsr
There are 3 ball mills in our plant so we should differentiate between ball mill power and total power of ball mills which is sum of each ball mills power. By increasing throughput the mill power will...
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Started by Guelb22
Hi All, The shell liner of the SAG mill wear in different rate depend on the position of the liner ring. Do we replace the half shell liner due to only wearing discharge end ring ? how we can manage that to replace the worn ones in time without repl...
Last replied to by David
What you are trying to do is not something I have ever done or seen. We change either the complete shell or half (in a High/Low setup).  We do not change half the DE or FE. You need to review your ...
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Started by hulk
hi,how are you What are the reasons and solution for Sag mill bolt breakage? Tell us about effect of changing liner geometry type of material and metallurgical operation conditions on bolt  breakage. thanks
Last replied to by sslupsky
As mentioned earlier, there could be a number of reasons.  We helped investigate bolt breakage of a rod mill by monitoring bolt tension.  The key finding from that work was minimizing liner movement...
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Started by mokhtaraazami
Hi everybody I work in a iron ore beneficiation plant in Iran. in this plant the feed size is less than 10 mm which first enter to the HPGR (in open circuit) and its product size is less than 6 mm which goes to the open circuit ball mill. my questi...
Last replied to by adamlevine
oh...
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Started by Devon2017
Hello, I am a Placer gold miner in Desperate need of professional answers about an old, large abandoned Gold Ball Mill I found, and contents that were left behind. The answers I need are mainly how the recovery methods are completed once run ...
Last replied to by Devon2017
And the town high school here takes all my used nitric acid and recycles it for free for me as they have to recycle they’re own every so often and since it’s paid for by the school board and I’m...
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Started by Simba marshy
how can I reduce the the tonnes of rejected by a grate discharge ball mill    
Last replied to by Todd H
Further to above - did the amount of rejects suddenly increase? Ore type change; Feed rate change; Pulp density changes; Feed size change? Has the grind size changed? Is this a new mill with an ungr...
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Started by sajjadaghazadeh
Hello Dear Friends, I hope all of you are doing great. I do have a question related to ball mill liner types.  We are using a ball mill with diameter 3m and length 4.5 m in our plant. The ore is Magnetite with low amount of hematite. Gangue minera...
Last commented on by sajjadaghazadeh
Hi sure; Ball mill 1: 700kw with current working amper 1000 A average. Product size D80:45 micron. Critical Speed 75-80%. Ore work index 12kwh/t. Solid percent 70-80%. Ball mill charge 40 and 60 mm. N...
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Started by Solaris1987
Hello In our iron concentrator plant we use a wet ball mill for grinding of fresh feed. It operates in a close circle with hydrocyclones. The overall data of ball mill and hydrocyclones are following:  Ball mill: F80: 4 mm Diameter: 5.5 m Lengt...
Last replied to by Robert
You might find this approach (see article and webinar) useful.   >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>...
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Started by banyechan
what reasons for the increasing ball consumption after converting my overflow mill to grate discharge mill?
Last replied to by Robert
From SME Mineral Processing Handbook, Ed. N. Weiss, SME, 1985, page 3C-28 and surrounding article on grinding: “In grate-discharge mills, due to the lack of pulp in the zone just in front of the gr...
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Started by facostam
Hello 911MetallurgistI am currently working on a concentration plant, specifically on the liner change of the ball mills. I have to determine the difference in wear behavior between mineral (copper sulfide)-steel and steel-steel, all this according t...
Last replied to by Miguel
Hello Francisco, It's quite evident that if you run the mill at a low tph as it is being designed for and at a high rpm it will be quite certain that the contact between steel liners to steel balls w...
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Started by Hauptsturm
How to increase the density when too much material is reporting to the cyclone underflow? 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...
Last replied to by Tony Verdeschi
I presume we are talking heavy media cyclones here? If so then you should increase the medium density to reject a higher proportion of light minerals to the overflow. But as with everything there is a...
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Started by courio
Hello friendsWe have a problem to solve and a conclusion that I do not think is the reason.MOLINO BALLS DOMINION (4X72metros D by 6.4metros L) 2300KwThe mill is supported by a pair of hydrostatic bearing journals (2159 mm diameter x 483 mm wide), equ...
Last replied to by Robert
Is this a recent change? Previously were there any concerns with maintaining ball charge? Would you describe past behavior before this problem originated?  
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Started by richardh
Hi I am trying to build up a library of papers on the function of a hydrocyclone in a closed ball mill circuit and not as a means 'of doing any grinding'. I am often faced with the question "We have a grind of 'A' micron in our ball mill circuits b...
Last replied to by Robert
Not knowing your situation re accessing technical literature? For some additional details look at: Seitz, R.A. and Kawatra, S.K., Further studies on the use of classifiers for the control of wet gri...
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Started by nyala89
I need some help. We need to mill ocher as fine as possible. To date we used an outdated Raymond mill. The company bought a small ball mill about 20 years ago and we would like to use it in our process. Do you think that with the ball mill, we would ...
Last commented on by nyala89
Thanks Wayne for your comments. I will really put it on the table.
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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 commented on by dasun
Dear Mr. Jorge. My plant is fully sealed plant.Samples of dust collectors are regularly checking. So, I haven't notices any large particles in the dust collectors. So, do you have any idea...?
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Started by jovanifirebird
hi guys. i am working at a small scale mining industry. they have been operating at about 80t/h feed to ball mill. the cyclones operates at about  85MPa feed pressure. 2 cyclones run at a time. however they don't maintain water balance .we all know ...
Last commented on by jovanifirebird
Thanks for the suggestion ashutosh. But I dont think u understand the problem. My cyclone feed percent is 55%. But that works out when feed is 90t/h. If feed goes down to 40 t/h , you cant do the corr...
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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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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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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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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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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 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 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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