In pH-swing mineral carbonation, several acid/base systems has been investigated. Currently the main acid/base systems employed are HCl/NaOH and NH 4 HSO 4 /NH 4 OH. However, the use of a HCl/NH 4 OH system was not yet elucidated. This study proposes to evaluate the feasibility of a pH-swing mineral carbonation based on HCl/ NH 4 OH system at atmospheric pressure and moderate temperatures using mining waste from asbestos production from Goiás State, Brazil (S-GO) for two conditions (i.e. stoichiometric conditions (T2E) and acid excess (T2)). Results indicated that the Fe 3+ content in S-GO acted as a catalyst, due to FeCl 3 hydrolysis in aqueous solutions. Thus, high Mg and Fe extraction efficiency (95 ± 2%), were achieved in the leaching stage for both conditions. The S 1 solid residue was mainly SiO 2 with 90 ± 1% purity content. In the purification stage 91.7 ± 1.9% of Fe t were removed, however, a loss of Mg of 13.6 ± 2.3% was also detected. On the carbonation stage, high purity hydromagnesite was formed in T2E; this stage had a 85% efficiency, thus, 36.7% of CO 2 was fixed. On T2, excess H 2 O and CO 2 promoted dypingite formation and reduced hydromagnesite formation. After carbonation, the formation of crystals was observed in the NH 4 Cl aqueous solution at 25°C, indicating NH 4 Cl supersaturation. The results of mass balance indicate that 4 ton of mineral waste will be employed for each ton of captured CO 2 , as well as 2.6 ton of HCl, and 4.5 ton of NH 4 OH. However, 1.7 ton of SiO 2 , 0.55 ton of iron oxides, and 2.7 ton of hydromagnesite could be produced.

Using Kraft lignin, bio-based adhesives have been increasingly studied to replace those petrochemical-based solutions, due to low cost, easy availability and the potential for biodegradability of this biomaterial. In this study, lignin-based phenol-formaldehyde (LPF) resins were synthesized using commercial Eucalypt Kraft Lignin (EKL), purified at 95%, as a phenol substitute in different proportions of 10%, 20%, 30% and 50%. The properties of bio-based phenol formaldehyde (BPF) synthesized resin were compared with phenol-formaldehyde resin (PF) used for control sampling. The results indicated that viscosity, gel time and solid contents increased with the addition of pure EKL. The shear strength test of glue line was studied according to American Society for Testing and Materials (ASTM), and BPF-based results were superior to samples bonded with the PF as a control sample, being suitable for structural purposes. Changes in the curing behavior of different resins were analyzed by Differential Scanning Calorimetry (DSC), and sample comparison indicated that the curing of the LPF resin occurred at lower temperatures than the PF. The addition of EKL in PF reduced its thermal stability compared to traditional resin formulation, resulting in a lower decomposition temperature and a smaller amount of carbonaceous residues.

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