In-situ mineralization of calcium carbonate of tropical hardwood species from fast-crown plantations in Costa Rica

Chemical modifications of the cellular structure of wood aiming at solving problems of dimen-sional stability, durability and fire resistance, such as mineralization, have been applied in the past. However, knowledge of these treatments applied to tropical wood is almost inexistcnt. For this reason, the aim of the present work is to impregnate nine hardwood species used in commercial reforestation in Costa Rica, by means of subscqucntial in-situ mineral formation based on a solution-exchange process of two solution-cxchangc cycles by impregnating with CaCh in cthanol and NaHCC>3 in water with CaCOt. The results showed that the absorption of the CaCk and NaCO? solution in the different wood species varied from 42.2 to 168.01 m"3 and 69.5 to 214.6 1 m"3 respectively, while the retention of in-situ CaCOj varied from 2.8 to 9.2 kg/m3. Although the different wood species showed high absorption of the solutions, it was found that in some of them the percentage of CO32" did not react, while in others the Ca2~ ion was unrcactcd salt. The SEM analysis showed the distribution of the CaCC>3 crystals in the different anatomical features and showed the formation of calcitc and vatcritc type crystals, which was also evidenced in the X-ray diffraction and FTIR spectrum.