THERMAL-DECOMPOSITION OF BASIC COBALT AND COPPER CARBONATES - THERMAL-STABILITY OF THE PRODUCED OXIDES AS INFLUENCED BY GAMMA-IRRADIATION

Basic cobalt and copper carbonates were prepared by precipitation from solutions of their nitrates using KHCO2 at room temperature in CO2 at mosphere. The thermal decomposition of the prepared basic carbonates w as studied by means of TG and DTA techniques and the phases produced w ere identified by XRD measurements. The products obtained at 400 degre es C were subjected to different doses of gamma-rays (40-160 M rad) an d the thermal stabilities of these solids were investigated. The resul ts obtained revealed that basic cobalt carbonate decomposed at 335 deg rees C to produce Co3O4 which remained stable up to 850 degrees and th en decomposed above this temperature giving CoO which transformed into Co3O4 on cooling to room temperature. Basic copper carbonate dissocia ted at 290 degrees C yielding CuO which yielded Cu2O and metallic copp er at 1060 and 1150 degrees C, respectively. However, the produced cup rous oxide and metallic copper solids were converted into CuO and Cu2O , respectively by cooling in air to room temperature. Gamma-irradiatio n decreased the thermal stability of Co3O4 to an extent proportional t o the dose employed. On the other hand, this treatment increased the t hermal stability of both CuO and Cu2O.