In this paper, a low-grade copper oxide ore with highly alkaline was treated. The thermodynamic model of CuO-(NH4)2SO4-NH3-H2O was established in the leaching system of tenorite (CuO) under the condition of double conservation of mass and charge. The fitting function of MATLAB and the diff and solve functions were used to calculate the optimal ammonia concentration and total copper ion concentration of tenorite under different ammonium sulfate concentrations. The effects of different ammonia-ammonium salt (ammonium sulphate, ammonium carbonate, ammonium chloride) solution on copper leaching rate were investigated. Results show that under the conditions of ammonia concentration of 1.2 mol/L, ammonia-ammonium ratio of 2:1 and liquid-solid ratio of 3:1, the copper leaching rate from the ammonium sulphate and ammonium chloride solution reaches 70%, slightly higher than that of ammonium carbonate. Therefore, ammonia ammonium sulfate system is selected to leach low-grade copper oxide due to its lower corrosion to the equipment than the chlorination system.

High purity TiO2 and CuO powders were synthesized by the Pechini method, an inexpensive and easy-to-implement procedure to synthetize metal oxides. The variables of synthesis were the ethylene glycol:citric acid molar ratio and the pH. High reproducibility of the anatase and tenorite phase was obtained for all synthesis routes. The degree of purity of the powders was confirmed by XRD, FTIR, UV-vis absorption and XPS spectra. SEM and TEM images revealed the powders are composed by micrometer grains that can have a spherical shape (only in the TiO2) or formed by a non-compacted nanocrystalline conglomerate. FTIR spectra only vibrational modes associated to the TiO2 or CuO with a nanoparticle behavior. UV-vis absorption spectra revealed the values of maximum absorbance percentage of both systems are reached in the ultraviolet region, with percentages above 83 % throughout the entire visible light spectrum for the CuO system, a relevant result for solar cell applications. Finally, XPS experiments allow the observation of the valence bands and the calculation of the energy bands of all oxides.