Volatilisation of inorganic components during thermal processing of biomass

The content and composition of the ashes of three biomass substrates (wheat straw, rice husks and a sewage sludge from an urban waste-water treatment plant) were studied as a function of the ignition temperature in order to a nalyse the volatility at a laboratory level of the inorganic components. Th e ash content of these materials was established by gravimetric analysis at 600 degreesC. The ashes obtained at this temperature were then treated at 700, 800 and 900 degreesC, either in a furnace or a thermobalance system, a nd the volatilisation of each component was measured from the weight loss a nd the composition of the resulting residue. The composition of the ash sam ples was determined by ICPES and elemental analysis. Digestion of the ash s amples from wheat straw with nitric acid for the ICPES analysis proved to b e inefficient as it gave misleading results.