The use of concentrated solar energy for the reduction of CuO in H2

Abstract

The reduction of copper (II) oxide was carried out under concentrated solar radiation in a stream of gaseous mixture 5/95 v/v H2/N2 in a 1.5 kW thermal power vertical axis parabolic concentrator at the PROMES-CNRS solar facility (Odeillo-Font Romeu, France). Experiments were performed using a commercial oxide in two different forms, powdered and compacted specimens. The reduction of CuO to elemental Cu was more effective for compacted specimen yielding a dendrite microstructured metallic copper with an electrochemical behavior similar to that exhibited by the commercial metal. In the case of powdered specimen, a composite metal/oxide (Cu/Cu2O) block was obtained as a macroporous material. The reduction process of CuO under concentrated solar energy tracks through the formation of Cu2O as the only intermediate phase, which was evidenced by X-ray diffraction and scanning electron microscopy.