From: nobody@nospam.not   
      
   Morris Dovey  wrote in   
   news:jdqlg2$sh6$1@speranza.aioe.org:   
      
   > On 1/1/12 2:37 PM, Han wrote:   
   >> Morris Dovey  wrote in news:jdpvbl$9na$1   
   >> @speranza.aioe.org:   
   >>   
   >>> I'm still planning to do initial testing with pure nickel, so   
   >>> (hopefully) pyrophoricity shouldn't enter into the picture just yet.   
   >>   
   >> I'm not an expert, but it seems to me that many "lower grade"* metals   
   >> might catch fire if sufficiently finely distributed - just as steel   
   >> wool can catch fire, and is sometimes used as firestarter.  However,   
   >> under the circumstances you might be using the nickel, I'd assume   
   >> that there is no oxygen, hence no fire hazard until you open up the   
   >> containing device, intentionally or unintentionally.   
   >>   
   >> *  "lower grade" here means lower on the scale of metal nobility.   
   >   
   > I have two batches of powder, a half-kilogram jar from a reagent   
   > supply company and a one-pound ZipLoc bag from an eBay vendor. Neither   
   > was particularly well-sealed and I haven't seen any problems. The   
   > safety sheet for powdered nickel warns against inhaling, ingesting, or   
   > absorbing powder through skin/eyes. I'm being careful.   
   >   
   > The plan is to load the Ni into the reactor chamber/containment   
   > vessel, then seal and evacuate the chamber to remove the oxygen before   
   > introducing hydrogen. At this stage of the planning process, I'm a lot   
   > more concerned with H2 safety than I am with Ni problems.   
   >   
   > The control software design is centered about finding any deviation   
   > from "tame" behavior, and automatically shutting the reactor down if   
   > any such deviation is found. It appears that a full ("cold") automatic   
   > shutdown can be completed within about a tenth of a second - which   
   > should make it much safer than the big fission reactors.   
      
   I don't know the properties of your Ni powder, Morris.  I was afraid that   
   you'd have to rigorously exclude oxygen and water, but to my surprise for   
   reduction reactions with H2 and Raney-nickel that doesn't seem necessary,   
   based on at least one example here:   
      
      
   I got to this from:   
   http://en.wikipedia.org/wiki/Nitrile_reduction, which I got from googling   
   for "reduction reaction with hydrogen and raney nickel"   
      
      
   --   
   Best regards   
   Han   
   email address is invalid   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)