MFMP: Automated experiment with Ni-LiAlH

  • magicsound

    It looks like I forgot/overlooked that the first step of LiAlH4 decomposition also forms elemental Al. I do still stand by my previous point.

    I'm interested in those references showing the alternate decomposition paths you mentioned.


    This thread is about another Ni+LiAlH4 replication, so I thought it would be in-topic to revise the subject before the experiment actually starts (I guess within hours?).

  • can

    BTW, Ed Storms says that Li will not wet to Ni but Li-Al will wet to Ni. That close wetting is something we have seen in MFMP powders, Lugano, and Parkhomov.


    Eric

    I will look, but I am in the middle of testing right now. The Mizuno paper was the one where he was reporting isotopic shifts in the M=2,3,4 range as I recall.

  • BobHiggins

    Oxygen was a substantial fraction of the atomic composition of the ash, as well as the fuel, from Parkhomov's AP2 reactor whose analyses were presented during ICCF19. If this was due to oxidation of the metal particles, wouldn't the Al more "stick" to them in oxide form rather than wetting them? If the same also happened to some extent with initially less oxidized metal powder would one be able to tell with EDX analysis?


    http://www.e-catworld.com/wp-c…015/10/sochiparkhomov.jpg

    Source: this page

  • can


    Here's my summary of the LAH phases:

    https://drive.google.com/open?…xJkjesxe4kZFVuMG9paFJncjA


    The second referenced paper by Oksana Bodak has further details:

    goo.gl/vLG8Uc


    Note that the melting temperatures of LiH and Al are very close. When both are molten, it seems likely that an ionic solution of LiAl*H- may form. For that reason, the Glowstick temp profile includes a pause at ~700°C for that process to complete. BobG found additional references supporting this theory, but unfortunately I didn't add them to my doc. If you come up with anything relevant, I'll include it.

  • can ,

    Yes, there was oxide going in, and oxide coming out. When the Al2O3 getters the oxygen, it precipitates out from the molten metal as a solid - alumina - which is the same as the tube. It will not take much of the Al to getter the oxide out of the system and you will still be left with a Li-Al alloy that can wet to the Ni. How would you know where the alumina in the ash came from? Tube dust or alumina from gettered oxide?


    None of the ashes that have been examined have been kept in-vacuo from the time of reaction completion until put under the microscope. So the EDS/EDX will show oxygen regardless. The Li will instantly form LiOH upon contact with humidity in the air. It is hard to determine how oxide free the fuel was before it was removed as ash from the reactors.

  • Son of a gun - I think I finally tracked down my elusive 2nd leak. I have a 6" length of 1/16" OD stainless steel tubing connecting the manifold to the reactor tube with compression seals. I was certain that the leak must be with one of the compression seals, but I couldn't find anything wrong with them. Those small compression seals get a lot of force on a small area and they just seal.

    So, in a last ditch scratching my head effort, I examined the tube itself under the microscope. Sure enough, there it was - strange crack-like pinhole leaks in the stainless tubing. Apparently this tubing is made in a welding process and then is ground circular. Here the weld was bad.

    Who would have thought bad tubing would be the problem!



  • @BobH Congratulations on finding the leak.


    I see McMaster-Carr only offers 1/8" OD in welded construction. Swagelok offers it in seamless construction 316L, but the minimum order looks like 20 feet or 6 meters.

    "Small Parts" on Amazon has 1/8" x 12" seamless 316L for under $9, probably the best price, and usually quick delivery.

  • @Alan,

    Yes, but this is 1/16" OD tubing. It came from McMaster Carr. I just sent them a picture and asked them to send me new tubing and 2 new ferrule sets for my compression fittings. I am sure they will respond quickly. In the mean time I have just put some JB Weld over the holes. Hopefully that will work and tomorrow I an re-start the experiment. That is, heaven forbid, I don't find yet another leak!

  • I see McMaster-Carr only offers 1/8" OD in welded construction. Swagelok offers it in seamless construction 316L, but the minimum order looks like 20 feet or 6 meters.


    Has nobody acces to a lathe or drilling machine ? This is the very cheapest method. With "tube switching" you can drill 20cm with drilling it from both sides, using an about 10,1cm long tool!

  • Has nobody acces to a lathe or drilling machine ? This is the very cheapest method. With "tube switching" you can drill 20cm with drilling it from both sides, using an about 10,1cm long tool!


    Sorry, I had the wrong size in my reply. Bob is using 1/16" (1.6 mm) OD capillary tubing. I don't think anyone is going to make that by end-drilling a solid rod! Apparently it is welded, then drawn to this small size, so it isn't so surprising to find a defect.

  • can

    You have identified the correct tube. The leak is about 1" to the left of your arrow. When I was pumping and monitoring the pressure, I put a piece of tape over the holes and it made a big difference in the leak. I put some epoxy over the leak, but it was unsuccessful in sealing the leak, even temporarily. I emailed McMaster Carr last evening about the bad tube. They replied even last night (Sunday) that they would ship out a new tube and new ferrules today. I will probably have them tomorrow.


    Of course, in this context, SS is stainless steel.