In the disclosed process, the winning of noble or relatively electronegative metals (e.g. Au, Ag, Cu, Ni, etc.) from substantially aqueous solutions containing ions of the metal through the use of relatively electropositive precipitant metals (e.g. Fe, Zn, Al, etc.) is carried out along with recovery or utilization of some of the energy which can be produced by chemical or electrochemical action. In this process, an electrochemical primary cell-like arrangement with a one-fluid or two-fluid electrolyte (wherein the precipitant metal can be an anode) can also provide improvements in the character (orderliness, efficiency, purity of product, etc.) and control of the cementation reactions. For example, bright (high purity) copper can be obtained in a cathode compartment in a two-fluid cell using a scrap iron anode, a pregnant hydrometallurgical cuprous or cupric leach solution as the catholyte, and an external circuit connecting the cathode to the anode. Good copper is also obtained and cementation rates are increased, when the leach solution is used as a one-fluid electrolyte, and an external circuit is maintained. Under some conditions it is advantageous to exclude oxygen from the system.