Gold Precipitant 8 ozs

8 ounces Sodium Metabisulfite, (Na2S2O5) 99% pure food/photo grade. Also known as SMB, Pyrosulfite, and Disodium. Used in gold refining as a gold precipitant. To be used as a gold precipitant for aqua regia. Use 1 oz of SMB mixed in 20-30 ml of water per ounce of...