Method of precipitating metals in metallic form

Claim 1

IN PRECIPITATING IN METALLIC FORM A METAL LYING BETWEEN SILVER AND CADMIUM IN AN ELECTROMOTIVE SERIES OF ELEMENTS, FROM AN AQUEOUS AMMONIACAL AMMONIUM SALT SOLUTION, SAID SOLUTION CONTAINING AT AMBIENT TEMPERATURES AT LEAST ONE SUCH METAL AS A GAS-REDUCIBLE WATERSOLUBLE COMPLEX WITH NH3, BY TREATING SAID SOLUTION WITH A REDUCING GAS UNDER SUPER-ATMOSPHERIC PRESSURE AND AT AN ELEVATED REDUCTION TEMPERATURE ABOVE THE NORMAL BOILING POINT OF THE SOLUTION AT ATMOSPHERIC PRESSURE, SAID SOLUTION ALSO CONTAINING AT LEAST ONE CONTAMINANT MATERIAL IN AMOUNT EXCEEDING ITS MAXIMUM SOLUBILITY AT SAID REDUCTION TEMPERATURE, THE IMPROVED PROCEDURE FOR STABILIZING THE SOLUTION AND IMPROVING THE PRODUCT METAL YIELD AND PURITY WHICH COMPRISES: ADJUSTING THE AMMONIA AND THE AMMONIUM SALT CONTENT OF SAID SOLUTION TO PRODUCE MAXIMUM RETENTION OF SAID METAL AT SAID REDUCTION TEMPERATURE; PREHEATING SO-ADJUSTED SOLUTION TO AN ELEVATED TEMPERATURE OF FROM ABOUT 250* F. TO ABOUT 500* F. IN THE ABSENCE OF REDUCING GAS AND UNDER A TOTAL PRESSURE AT LEAST EQUAL TO THE AUTOGENOUS PRESSURE AT THE TEMPERATURE; SEPARATING THEREFROM RESULTANT PRECIPITATE AND ONLY THEN SUBJECTING SO-TREATED SOLUTION TO THE ACTION OF SAID REDUCING GAS.