METHOD OF REWORKING USED SILVER CATALYSTS FOR OBTAINING FINE SILVER OR SOLUTIONS OF ITS COMPOUNDS SUITABLE FOR PREPARATION OF CATALYSTS (VERSIONS)

摘要

methods of reworking used silver catalysts for obtaining fine silver or solutions of its compounds suitable for preparation of catalysts. SUBSTANCE: prior to leaching, catalyst is subjected to heat treatment in oxidizing or reducing medium at temperature of 700 to 1050 C; leaching is performed with nitric acid till silver is completely dissolved; then residue of catalyst carrier is separated and admixtures is separated; silver is recovered from liquid phase by reduction or concentration of liquid phase to definite content of silver nitrate in solution; silver may be precipitated from solution in form of silver chloride in presence of surface-active substance; silver may be also precipitated from silver nitrate solution in form of silver oxalate; precipitation of silver oxalate is performed at excess of precipitant. EFFECT: enhanced efficiency of reworking of silver catalysts; increased degree of extraction of silver from used catalysts. 11 cl, 6 tbl, 21 ex