During the last few years we have been doing considerable experimenting on methods of precipitating copper. The first patent on precipitating from sulphate solutions by heating with SO2 under pressure was taken out by us (U. S. Pat. 723,949). This reaction, CuSO4 + SO2 + 2H2O = Cu + 2H2SO4, is interesting, but there are … Read more

The solvent we would use; how we would precipitate the copper from the solution, and what we would do with the iron in the electrolyte. Without going into the details of the reasons, we decided that sulphuric acid would be the most satisfactory solvent and that we would recover the copper from the solutions by … Read more