The article is about thermodynamic calculations of waste honeycomb SCR catalysts in sodium roasting process under different conditions.Temperature and sodium carbonate addition were variable during the process,and the corresponding phase diagrams were made by thermodynamic software HSC Chemistry while their effect on leaching rate of tungsten and vanadium was analyzed.The leaching rates of tungsten and vanadium under different roasting conditions were studied.The optimum conditions were obtained:the additio...