Abstract:The invention relates to a method for enriching silver or other precious metals by means of flotation from a suspension, for example from zinc-leaching residues, a metal comprising the following steps: a metal which is baser than
hydrogen is added; an acid up to a pH value of 2.0 to 5.0 is added, especially 3.5 to 4.5; an organic additive in a concentration of 50 ppm to 1000 ppm is added; the mixture is contacted; and the mixture is fed into a flotation device for separating off the part containing the precious metal. The method ensures good enrichment with an equally good yield of the valuable substance desired.http://www.s4zn.com/index.php?hk=17&pats=30&h...
Metal sulfide powder coated with copper is produced by mixing powder of a metal and/or an alloy baser than copper
with powder of a metal sulfide, and then adding an acidic solution containing copper ions to the resulting mixture with stirring. The metal sulfide particles are coated with metallic copper that results from a cementation reaction. Where the metal sulfide powder contains too coarse or fine particles, it is ground, granulated, and sized before the mixing.http://www.freepatentsonline.com/4221828.html