Development of Improved Carbonation Technologies for Low-Cost Production of Rapid-Set Cement-Bonded Particleboards

Cement-bonded particleboard is an environmentally safe high-performance reconstituted wood product with desirable longevity, fire resistance and life-cycle cost position, presenting a great potential to maintain the competitive position of reconstituted wood boards in demanding construction markets. The low productivity of cement-bonded particleboard plants and the inhibitory effects of some wood species resulting from the slow setting and hardening of cement have led to relatively high initial costs. Early exposure of cement binders to carbon dioxide can substantially reduce the setting and hardening times. Industrial-scale implementation of the carbonation technology, however, has been hindered by the difficulties in achieving uniform carbonation effects and controlling the rate of carbonation reactions, and also by the high cost and unavailability of CO2 in large volumes. In order to overcome these obstacles, we propose to replace pure CO2 with a blend of CO2 and air, and eventually with CO2-enriched exhaust gases which are readily available at low cost and are responsible for the greenhouse effect. We have hypothesized that the air content of the exhaust gas opens channels into the board for thorough penetration of CO2, and also helps control the rate of reactions to make industrial-scale implementations more practical. Phase I research will determine the CO2 concentration and vacuum/gassing regime best suiting the production of particleboard. We will also evaluate various exhaust gases for introduction into the process, and will assess the commercial viability of the new approach to carbonation.