| 摘要 |
<p>PURPOSE:To inhibit a charge exchange reaction between a noble metal and an undissolved base metal and to increase the efficiency of dissolution of the noble metal by forming a metal mixture contg. the noble metal into the shape of a sheet or the like, subjecting the mixture to oxidation treatment by heating, and dissolving it in an oxidizing acid. CONSTITUTION:A metal mixture contg. a noble metal such as gold or silver is formed into the shape of a sheet, foil, powder or granules and heated in an oxidizing atmosphere to oxidize a base metal in the mixture. The metal mixture subjected to oxidation treatment is then dissolved in an oxidizing acid such as nitric acid to produce a noble metal soln. The dissolved noble metal can be recovered by the conventional separating and recovering method. A side reaction, that is, an exchange reaction between the dissolved noble metal and the undissolved base metal 1 is inhibited and the amt. of the acid used can be reduced by making the metal mixture porous.</p> |
