Hydrometallurgy of copper

Hydrometallurgical methods for the extraction of copper are by no means new. The ancient Greeks noted the blue tinge given to mine waters and accidentally found that from these waters copper could be recovered by metallic iron, although they were under the impression that the water had the power of transmuting iron into copper. Longmaid may be considered as the founder of the wet methods of extraction of copper of today. He obtained a patent dated October 20, 1842 and another in January 1844, both relating to the treatment of pyritic cinder by roasting with salt. he work the process out on a large scale and in England today there are over twenty plants which may be said to be the outgrowth of his researches. Gassage first employed sponge iron as a precipitant for copper from copper solutions. Henderson carried the work of these two men to greater perfection and from them has grown up the beautiful Longmaid-Henderson process.