Patterns of metals and PACs during heating of biologically treated deinking byproducts

The experiments simulating events taking place during multizone combustion of fibrous deinking byproduct generated in pulp and paper mill were conducted. The multizone heating consisted of the low-temperature region (< 1000 degrees C), followed by the high-temperature zone (1500 degrees C), and a second low-temperature region (much less than 1000 degrees C) proceeded by sudden quenching. The simulation of such Low-High-Low temperature process (LHL) was conducted in a high-temperature Cahn TG-171 thermogravimetric furnace coupled with a Mattson Galaxy 5020 Fourier transform infrared spectrometer. Morphological changes of the fibrous byproduct, from a mixture of fibers through sintered particles formed between 1100 and 1400 degrees C and molten ash particles observed above 1400 degrees C, caused encapsulation and immobilization of heavy metals (Cd, Cu, Pb) within the ash. It was also found that the temperature-time history and CH:OH ratio are important physical/chemical parameters affecting the polycyclic aromatic compounds (PACs) formation. The PACs destruction occurred during the LHL process before PACs were emitted into the atmosphere. It seems that the multizone burning may be an attractive way for the clean and efficient disposal of contaminated industrial byproducts.