The hydrometallurgy of silver

At Argo, Colorado and enriched roasted matte was first leached with water extracting as much silver as possible. The residue was then smelted and the matte thus obtained given an oxidizing roast forming copper bottoms later treated for gold and argentiferous copper matte which was treated by the Ziervogel Process. Before sulphating roasting a little sodium sulphate was added to aid in the conversion of the silver to sulphate. The Ziervogel Process is cheaper than the Augustin Process.