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Modification of Ball Charge Regime of wet ball Mill and hydrocyclone dimensions to achieve lower K80 (4 replies and 2 comments)
Some thoughts on improving milling throughput:
- Survey circuit to develop baseline information. Aspects for consideration as they are levers for improving performance:
- What is recirculating load? Is there opportunity to increase this and value to increasing this?
- Mill Charge – is space available for greater charge? Is power available to add charge?
- Calculate ball size using basic equations. These are indicative, but is there opportunity to reduce ball size?
- Determine cyclone efficiency. Some issues – what fraction of product size material is being recirculated?
Hello Dear Robert
Firstly I appreciate that answering my question. We can't increase ball charge in this present condition.
How can I calculate the optimum ball size? Is there any procedure?
How can we analyse the distribution size fractions?
Best Regards
S H A
Dear Solaris,
First step, can you increase Ball Filling Level? If you can, go ahead.
You F80 is 4.0 mm. I think is better if you do a grinding test in laboratory for determinating which Media Charge Stream allow you to achieve reduce the P80 on ball mill discharge. For example, maybe it's better a Media Charge Stream: 70% of 60mm and 30% of 40mm ball diameter. You should check Selection Function-Curves from Grinding Test. When you improve grinding circuit, then you should check Hydrocyclones (you must do differents simulations with Apex and Vortex diameters).
Regards,
FR
Hello Dear Otlanto40
Thank you for answering my question. We aren't able to increase the filling ratio of our ball mill. Is there any standard procedure for doing this experiment in lab? which ball sizes we should use in lab test?
In fact I am looking for a way to optimize the ball size and charge ratio by sampling and measuring of ball size fractions at inside of ball mill.
Hello sir;
For your grinding performance test in a actual scale, you can take some samples from ball mill discharge and evaluate the effect of ball sizes on the grinding fractions. For instance, if you plot cumulative percent passing of ball mill discharge sample vs particle size, if your ball arrangement is not correct you can easily observe on the plot as it drops in some cases. An because your feed particles size is a little large for such grinding, I think the max ball size should be more than 60 mm as Rowland law highlights. I think for your case ball size could be around 70 or 80 mm. (I am highlighting that you first should draw that mentioned plot first) . Also notice that you should charge your ball mill with a series of balls such as 70, 60, 40 mm and I think this sequences can initially give a better result. Also, remember that your ball rotation speed is a critical factor and empirical result based on the discharge quality can be a good idea to choose the last optimum point.
Also, your liner should be both abrasion and collision effective. It is better to take advise from others as for first glimpse I think High-low liners can be a good selection.
Also, if it is possible you can use a vibrating linear screen prior to the ball mill to increase ball mill capacity or at least your final product size which can be easily reached.
If you checked these, you then go to hydrocyclone performance. you did not mentioned the hydrocyclone diameter and I think your apex is a little large and you can decrease its size. Because your hydrocyclone pressure is high so I think you should double check the capacity of your hydrocyclone with the manufacturer. Your pressure is good but it can increase circulating load and finally destabilize your ball mill grinding performance. Your feed density, number of hydrocyclones, apex size, hydrocyclone diameter, hydrocyclone capacity and etc can effect your final product.
As a result, I think you first should focus on the ball mill performace improvement and then go to hydrocyclone.
Best Regards
Aghazadeh
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
Length: 10.5 m
Make-up regime of ball charge: sizes 40 and 60 mm with equal ratio
Hydrocyclone:
Operatioal pressure: 1.5 bar
No. of hydrocyclones: 3
Apex size: 120 mm
Vortex finder size: 160 mm
Current overflow P80: 125 microns
Which steps and experiments we should do to change hydrocyclone dimensions and ball charge regime For decreasing P80 and achieving to P80=100 microns?Thank you for consideration.
Best Regards
S H A