Crushing, Screening & Conveying

Crushing, Screening & Conveying 2017-04-04T06:57:13+00:00
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Crush Quartz Glass Tubes (8 replies)

Paul Morrow
2 years ago
Paul Morrow 2 years ago

What is the most suitable way to crush quartz glass tubes of different tength/diameter with lowest contamination?

I have tried a jaw crusher or a toothed roll crusher as primary, followed by regular roll crusher and/or hammer mill for secondary but that is resulting in to high contamination - electroshock fracturing would be too expensive for that project, so I am searching for ideas.

Am referring to ultra high purity quartz glass. My goal is to crush contamination free in order to feed a grinder. Alternative is to contaminate at a way, what easily can be removed. With jaw crushers I will get iron contamination on the particle surface, which I have to leach later on - I do want to avoid leaching.
Anyhow thanks for your contribution!

Maya Rothman
2 years ago
Maya Rothman 2 years ago

You could use a roll crusher with a ceramic roll or a coated roll. Alternatively place in a impervious cloth container then run through the crusher.

Then again, how big/thick are the tubes? You can get glass lined ball mills (or vibratory mills) with glass media, it can be made of the same glass as the product - not cheap, but if it's high value, it's the way to go....

And to go fine, opposed jet mills are also an option, I heard they are used to make some high purity glass powder for LCD screens (a claim by netsch-condux).

If they are too big to be broken by glass balls, glass lined pressure rolls could be a first step, but would the roll lining last?
I would just make sure I had a wide enough mill and a few larger balls....

Paul Morrow
2 years ago
Paul Morrow 2 years ago

Thanks! We are talking up to 5 cm diameter and thickness 1 mm - tubes; I am aware of quartz glass coated rollers (mainly used in China) but I am afraid of high wear. Same will be with ball mills - the problem is high invest and wear cost.

With jet milling not only fine grinding contamination free is possible. We have developed with a partner years ago a jet mill to grind quartz contamination free in order to produce 0.1 - 0.3 mm with minimum amount of fines (- 15 % compared to other processes, where you end up in approx. 30 %).

Maya Rothman
2 years ago
Maya Rothman 2 years ago

Yeah if you want a high yield of grains 100-300um, jet milling might not be great; slow compression is better for minimising fines - high speed impact causes shattering. I think some hard (tungsten?) linings may offer low enough contamination, you can do trials maybe at KHD/Weir:

http://www.weirminerals.com/pdf/Weir%20Minerals%20-%20KHD%20HPGR%20brochure.FINAL-LOW%20RES--082011.pdf

Paul Morrow
2 years ago
Paul Morrow 2 years ago

Thanks! Anyhow the focus is on the crushing itself - more or less contamination free.

John Koenig
2 years ago
John Koenig 2 years ago

Bare in mind you need:

1) -5ppm contamination
2) high recovery after grinding ( 100-300 micron)
3) non needle shaped particles

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

the spec of final product should even be less, but we do have the experience.
The grinding itself is not critical - we are not talking about ultra high purity quartz. Also the shape is not important in that process.
Again: for me it is important to find the most suitable crushing process with minimum amount of contamination and the contamination must to be removed in the following processes.

Bob Mathias
2 years ago
Bob Mathias 2 years ago

It sounds like you have a very interesting problem on your hands!

Depending on tonnage and downstream processes, have you considered wet high intensity magnetic separation (WHIMS) as an alternative to leaching for removing iron contamination?

It sounds like your ideal crusher would be 100% autogenous. Unfortunately I don't think you will find a crusher that meets this criterion off the shelf, but some that may at least partially meet this criteria would be high pressure grinding rolls or vertical shaft impactors (rock-on-rock type). You would need to perform some R&D to develop a way to make these crushers approach 100% autogenous conditions.

Perhaps you could pilot an AG mill of some sorts? Not sure if the tubes will fall with enough gravitational force to achieve sufficient breakage. you might be able to play with water addition to help generate an autogenous layer on the wear surfaces (1-5% moisture w/w)?

I would imagine that glass tubes with smooth edges are not going to create much wear in themselves. It is the shards generated post-crushing that would cause issues. Perhaps you could use a jaw crusher with rubber liners to gently "nip" the tubes. I would recommend a double toggle crusher with an overhead pivot as these have the least amount of lateral moment. You may need to give special consideration to the feed system to ensure that the tubes are fed to the crusher in the right orientation to minimize wear.

If these ideas don't help, then maybe a crusher is not the right piece of kit. Have you considered thermal shock? E.g. heat the glass and rapidly cool it with a suitable medium? Perhaps you can used ultrasound to shatter the tubes? There are also other funky comminution technologies under development, e.g. microwave comminution.

These are some ideas, hopefully they help in some way.

Good luck,

Paul Morrow
2 years ago
Paul Morrow 2 years ago

Thanks for sharing your ideas! Yes - you are right: a VSI will be the best choice for grinding subsequently followed by physical and chemical purification processes. Still the first stage: crushing. As you see a tricky task.
I do have experience going nearly 20 years behind with fancy crushing methods as electroshock crushing, which unfortuately will not be the right choice in my project.
I also think a double toggle crusher with a special feeding system will be the most suitable one.

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