[Shashbaugh]

   I have been cleaning mercury metal with a process based on a Dow Chemical Patent 3,437,476.  Patented April 8, 1969

   A summary of the process is mixing contaminated mercury at elevated room temperature 80 to 90 F. with concentrated ammonium hydroxide or a number of different amines. I believe that the contaminants are removed by multiple complexation reactions.
The proof of the function is the ammonium hydroxide solution darkens as the contaminants precipitate. The precipitate is washed away
with 150 degree F. water. The patent specifically mentions iron and nickel as removed contaminants. There are a host of other metals
that are also removed by the process.
 
   I use 30% ACS, semiconductor grade ammonium hydroxide. The process generally works well.
  The mercury has been analyzed to contain Sodium, Silicon, Chlorine, Calcium, Copper, Zinc, Tin, Thallium, Lead, Bismuth, Silver, and Gold. All of these contaminants add to a total of 1.55 parts per million contamination.

   Lately new batches of ammonium hydroxide from the original vendor and from a new vendor have failed to clean the mercury.
   The same mercury mixed with some of the old ammonium hydroxide turns black and cleans as expected.

    My original theory was that the new ammonium hydroxide contained some sort of inhibitor that stopped the reactions from occurring. But when more new ammonium hydroxide failed to clean, I changed my mind.

     I now believe that there is something "extra" in the old ammonium hydroxide that enhances the complexation reactions that is missing from the new material.

     I have researched complexation reactions to the best of my ability and I cannot determine what may inhibit or catalyze the reactions.  All help with inhibitors and catalysts of ammonium hydroxide complexation reactions is appreciated.

        Thank You,                         Shawn     

 

[Shashbaugh]

     A question above mine requests suggestions for good inorganic chemistry textbooks.

     Could someone suggest a textbook that is very good on complexation theory and practice?

         Thank You,                 Shawn