Hydrochar from EWC 19.12.12 as a substitute of carbon black

The EWC 19.12.12, by-product obtained from the mechanical treatment of the residual part of municipal solid waste, has an organic content and a humidity that make it suitable for hydrothermal treatment. Moreover, because at present this substrate is landfilled, the recovery of this material for energy or more noble purposes can represent a new and interesting challenge, providing both economical and environmental benefits. For this purpose, hydrothermal carbonization was investigated, since the obtained hydrochar can be a candidate substitute of carbon black, which is mainly used as color pigment in paints, inks and plastics or as reinforcing filler in tires and other rubber products. Hydrothermal carbonization tests were performed at three temperatures (180, 220 and 250 °C) and three residence times (1, 3 and 8 h). The hydrochar obtained was subsequently analyzed in terms of energy content, elemental composition (CHNSO, microelements, ash), thermal stability and morphological structure. A mass balance was assessed, to evaluate the mass of hydrochar produced at different process conditions. The preliminary results shown in this paper show that the raw hydrochar must be post treated to be used as a renewable substitute of carbon black.