Use of CO2 in cryogenic grinding

[covelo]

I would be very grateful if someone could provide some info (or where I could get it) about the use of CO2 in cryogenic grinding. All the info I've found about cryogenic grinding deals with the use of liquid nitrogen as the cryogenic agent. We have performed some tests on our product that show that CO2 would be enough to achieve an efficient grinding. Therefore, I need some basic data such as typical consumptions, handling, operation conditions, etc. Thanks in advance.

 

[ricklin6]

I have worked in the area of cryogenic grinding for many years. The vast majority of grinders use liquid N2(lin) for this application. The reasons are: ease of use, high cooling capability, complete phase change to gas, low pressure operation, ect. CO2 on the other hand can become a problem in grinding operations. Three issues in particular - 1. Phase change is to both gas & solid form - This causes extra ampere loading on a grinding mill, hence less efficiency. 2. Solids will carry over with the ground product and accumulate in product containers, hence continued phase change from solid to gas can cause pressure problems or O2 depleted atmosphere at collection points.
3. CO2 is not as easily controlled as N2. You may be able to do the job with CO2 but history says N2 does it better. Consumption depends on several factors such as material, start size, finish requirement, mill type, ect. I have found over the years the only accurate way to arrive at consumption and rate data is to conduct a trial on the material. That is why all the large gas companies have test labs. Hope this helps.