for 18 hours and the contents are removed and separated into three components noble metal usually 95 or higher concentration silver pig iron and slag is recovered both the silver and pig iron are placed into a second melting oven where additional soda ash is added and the oven is brought to approximately 1800 u00b0 f once it is determined that the batch is molten by stirring the bath approximately one pound of black iron is added to the molten bath and allowed to completely melt the bath is then stirred to verify that the black iron has melted after stirring is completed the molten bath is poured into a pre heated buggy mold that has been coated with carbon black to prevent the molten material from sticking to the sides of the mold the mold is allowed to cool for approximately 14 hours at which time the mold is emptied the recovered products are removed from the mold and separated into three layers consisting of a noble metal such as silver with a purity of from 97 to 99 9 a layer of pig iron containing all of the impurities i e aluminum cadmium chromium cobalt copper iron manganese nickel and zinc and a layer of black slag the black slag.