Re: Powder Mixing.

Dear Gregg:

First of all, I have to say you are amazing. I asked this question
around, but no one has given me such a valuable and awesome answer. All
the questions you asked in the first reply would be answered firstly,
and some confusing points will be asked again.

All the information related to your questions will be supplied.
1. Are you working with small lab batches or with production
equipment?
I do work with small lab batches, but my project is industry
supported. For this reason, I hope some valuable results could go to
the industry production processing.
2. I assume you are damp pressing the parts and need a plastic mix -
is this correct?
Sorry, I didn't quite get the "damp pressing", but in my case
the hydraulic pressing equipment and square mould were applied.
Plastic mix? Some kind of resin binder is in my hand. Samples are
preheated in inert gas before my experiments. (Hope this information is
useful)
3. What kind of mixing equipment are you using?
I tried the mould grinding(a iron column inside of the mould is shake),
but the homogeneity wasn't checked.
4. What type of equipment is available.
Ball mill equipment(no speed adjustment) is available, but the
media(balls & surfactant) need be bought.

Also, you mentioned the digital camera for homogeneity test. There is
an optical microscope with digital camera in my lab; it should be ok,
isn't it? One more thing, some suggestion for the software, any way I
will sear by myself.

Lastly, can I use the alumina balls to instead the zirconia ball during
ball mill. I know this would introduce the impurity, is it that worse
for the whole mixing system.

Thanks again.

Gregg wrote:
Gavin wrote:
Dear folks:

I am currently working with the ZrO2-C refractories, and the problem is
how to mix the ZrO2 and C uniformly. The mean particle size of Zirconia
is 40 microns, and the graphite particle size reaches around 125
microns.



-Ahhhhh yes
A classical ceramic processing problem!
How do you achieve homogeniety and how do you evaluate it?
Evaluation of refractory performance is not easy - you need to work with
a good customer or with someone who has a lot of experience with the
systems of interest.

You have a tough problem - so I need to ask some questions to in the
hope I can provide a useful answer.
1. Are you working with small lab batches or with production equipment?
2. I assume you are damp pressing the parts and need a plastic mix - is
this correct?
3. What kind of mixing equipment are you using?
4. What type of equipment is available.

To give a short answer to some of the questions you asked.....

To evaluate homogeneity - use microscopy and Topography - I'll try to
dig up some methods I use to use.
There are some very good free image analysis software tools available
and you can use a consumer digital camera on a light microscope so cost
will be low.





> Is it possible to be uniform for these two materials to be mixed? How
> could I judge it is uniform or not, and is it important for refractory
> usage of uniform mixing?
>
> One idea I am thinking is to reduce the particle size of graphite, does
> the ball milling work? If it works, how could choose the balls and
> liquid? If not, how could do the reduction of the graphite particle
> size? Maybe the particle sizes are meaningless to mixing.
>

Yes, you can ball mill graphite - Dry or wet. - use zirconia media and
water with the right surfactant (unless your working on a lab scale)
Particle size and distribution are the essence of Homogieneity and
mixedness. The particle size will also determine your finial mix formulation

> I was suggested sieve both powders 5-6 times to mix uniformly, but I
> dont think works.

You're right - you can sieve those materials until hell freezes over and
not get a good mix - in fact, you can make it worse

Gregg

.

Relevant Pages

  • Re: The aether is made out of ordinary protons and electrons
    ... An aether particle has little excess electrostatic force ... more like forcing a ball though a table full of billiard balls. ... >> matter) and then take a comb and charge it up by ...
    (sci.physics)
  • Re: Dirac and particle physics
    ... single particle through the two slits and to find that it always goes ... through only one slit, this can be easily explained because if you turn ... So then why particle physics has been so successful is it is the physics ... Lets expand that equipment now and make a giant collider. ...
    (sci.physics)
  • Re: Baseball Strength Training Information
    ... been playing ball most of my life, and this is the real deal. ... "expert" and find baseball players training alongside football ... we fit all of our equipment in the trunk of our cars - with room to ...
    (rec.sport.baseball)
  • Dirac and particle physics
    ... If you consider the two slit experiment objectively, then to get a single particle through the two slits and to find that it always goes through only one slit, this can be easily explained because if you turn down your dial until no waves are going through the slits, then slightly gradually increase your dial until a single particle goes through a slit, that is merely because the strength of the wave is such that it cannot register through both slits at once, and in fact, you will never get the detector to register two photos exactly simultaneously and as such what you get is the first photon, because there must always be a first photon due to the imperfection of your apparatus. ... So then why particle physics has been so successful is it is the physics of electrical equipment. ... When you realize for instance that normal physics includes mass and particle physics does not, you see that physics that does not include mass has limitations. ...
    (sci.physics)
  • Re: Legality of Gilchrists innings questioned
    ... Did the squash ball help? ... squash ball provide Gilchrist the required assistance ... Cricketers are not allowed to change the conditions of the cricket equipments (in this case the glove) to correct their techniques or what ever. ... External protective equipment is any visible item of apparel worn for ...
    (rec.sport.cricket)