I want to mix two different ceramics powders using ball milling machine. In the same time I need not any reduction or reducing in particles size. How can I do that? I have some suggestions:
1. Use very small balls
2. Use very few balls
3. Use very low speed
4. Use a short milling time
5. Do not use high energy ball milling machine
If one or more of the above suggestions is right please confirm and give more details. Also I need other useful suggestions.
Dear Khalid,
I agree with Pratama and Behzad.
However, I think using an ultrasonic stirrer with ethanol as the mixing media may be a solution.
I think you can use liquid media (water for example) and then you can use a shaker machine to mix homogeneously the two ceramic powders. After you get it, you can separate the powders aforementioned from the media by filtration method then let it to dry on atmospheric pressure and ambient temperature.
Thanks to Pratama, I should add another suggestion:
I recommend you use plastic (Polyethylene) balls, which are lightweight and approximately soft, then they will not lead to crashing the powder particles.
Also, any remained particle of polyethylene in the powder mixture will be evaporated easily upon you start the heating process. alternatively you can use polyethylene glycol to remove the remained PE particles.
Good Luck
Dear Khalid,
I agree with Pratama and Behzad.
However, I think using an ultrasonic stirrer with ethanol as the mixing media may be a solution.
Dear Kalhid,
The best option to mix two different powders is suing a mixer or shaker instead of a ball milling. Although ceramics are not ductile, the balls always produce a reduction in grain size, in a greater or lesser extent. If you have access to several equipment, a recommend you a mixer type TURBULA (brand name). This kind of mixer produces a very homogeneous blends due to the type of movements
You can use the same mill without any balls at all, but you will have to increase the weight ratio liquid : powder, use effective surfactant and increase operational time.
Thank you all for your answers and suggestions.
For D. Igor L Shabalin, I want to know more about [ weight ratio liquid : powder]. Which is best ratio can be used. Because I have no information about this ratio
Thanks
It depends on many factors such as pycnometric densities of your powders, the ratio diameter : length of your mill and others... Please, read textbooks (or even technical instructions) on hard alloys (WC-Co and related materials) technological processing, in particular - the preparation of powdered mixtures for pressing. I believe you will find plenty of usefull things exactly there. Good luck!
Dear Khalid
I think that mixing ceramic powders can be done through the ball milling machine, but without the use of any kind of balls. Where these powders are mixed without adding any solvent only dry situation. It can also be placed plastic container for containing powders with constant speed rotation of the machine.
Good luck
THANK YOU FOR ALLS SO I TAKE MORE INFORMATION ABOUT YOUR QUESTION Mr
Hello
Any measure conducing to reduce the total energy of the ball-to-ball and ball-to-bottom of the tank collision will help you in mixing but not reducing size. Al the five suggestions about usin light balls, less balls, less speed, less time, etc. will work in that direction.
I can only add one possible tip regarding the use of liquid in the milling. If you use more than enough liquid to get a paste, the falling balls will lose energy when dropping on liquid and impact will be greatly reduced. Note that density and size seggregation proceed rapidly in liquid media. Also, media selection is important as not to dissolve.
You can rather use the tank without balls, just place the proper amount of liquid and the particles and spin it. You cal also increase viscosity to minimize seggregation. Liquid and additives should be eliminated in firing.
Ball is probably not the best method for blending powders without altering particle size. There is a great introductory article to the topic of powder mixing and blending at:
http://www.powderbulksolids.com/article/mixing-blending-1
In general I agree with Nader Hedayat and Daniels, you shouldn’t use spherical grinding media and also you may pay attention to the mixing time, which should be short as possible
I must say THANK YOU SO MUCH to all of you. All of you gave many good answers and I will try them starting from the easiest one.
Thank you again and best regards
Khalid
Use the Retsch MM400 and the adapter for up to 8 conical centrifugation tubes (50ml Falcons) for mixing the powders. this should work.
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