COMBUSTION OF CARBONACEOUS MATERIALS BY CU-K-V BASED CATALYSTS .1. ROLE OF COPPER AND POTASSIUM VANADATES

Several formulations of a Cu-K-V catalyst supported on alpha-Al2O3 wit h different Cu:K:V atomic ratios and with different loadings of the ac tive components on the support were prepared by impregnation with aque ous solutions of KCl, CuCl2 . H2O and NH4VO3, drying and calcination. The composition of these catalysts, suitable for greatly accelerating the combustion of carbonaceous materials, was investigated by X-ray di ffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Their activity in the combustion o f amorphous carbon was assessed by differential scanning calorimetry ( DSC). The latter showed that the combustion peak temperature can be de creased from 617 degrees C (uncatalysed oxidation) down to 382 degrees C for the best prepared Cu-K-V catalyst (atomic ratio: Cu:K:V = 2:2:1 ). The results of activity tests and the identification of the compoun ds present in the catalyst samples suggested that the catalyst activit y is mainly due to the synergic action of some vanadates (Cu-3(VO4)(2) , KVO3, K0.7Cu0.3VO3, CuVO2) and chlorides (KCl, Cu-2(OH)(3)Cl). Other catalysts based on each of these vanadates + KCl were prepared, chara cterised and tested, getting slightly lower activities than that of th e best Cu-K-V catalyst.