Abstract: A process for automatic filling with products, particularly of gas into gas cylinders, utilizes electronic comparison of the data stored in a data carrier located on the tank with the actually measured weight of the tank makes it possible to determine the degree of residual filling in the tank as well as to ascertain whether the tank weight is too low which, under certain circumstances, can give rise to safety risks and, in response, to either remove the tank from the filling process or else to fill it.The process and the device function fully automatically, so that it is possible to save personnel costs.

Abstract: A device for filling and emptying pressure gas cylinders includes a manifold attached to the pallet via a shut-off valve. The fill and emptying stations are provided with nipples connected by a hose to one of the pressure gas cylinders.

Abstract: Copper sulfate solution obtained by the sulfuric acid leaching of cupriferous material and containing impurities such as Fe, As, Sb, Bi, Se, Te, Sn, Pb, Cl, Ag, Hg, and PO.sub.4, are subjected to a two step purification process. In the first step, the pH is adjusted to 2.7-3.3 with, e.g. Ca(OH).sub.2, and the potential in relation to the standard hydrogen electrode is adjusted to at least 575 mv with an oxidizing agent, e.g. air. The temperature is 50.degree.-90.degree. C. Impurities precipitate and are separated. Se, Cl, and possibly Ag and Hg remain in solution and are removed in the second step, wherein the potential is reduced to below 350 mv by addition of a cupriferous reducing agent, e.g. Cu or Cu.sub.2 O. The pH is below 3 and the temperature is below 50.degree. C. Impurities precipitate as copper (I) compounds, and are separated to provide the solution in condition for the electrolysis. The copper produced is of high purity, having a conductivity of at least 58.8 mho .times. m/mm.sup.