Desulfurization performance of sorbent derived from waste concrete

This study examines the desulfurization performances of a sorbent derived from waste concrete through thermal gravimetric analysis in the temperature range from 303 to 1173 K. The sorbent is fine particles having a mean diameter distribution of 10-200 μm generated as a byproduct in a recycling process of aggregates from waste concrete. The sorbent is mainly composed of hydrated cement component, i.e. calcium silicate hydrate (C-S-H) and calcium hydroxide (Ca(OH)₂). The sorbent showed SO₂ removal activity over the temperature range studied. The desulfurization rate was lower under a lower temperature range up to 773 K, where the desulfurization rate gradually decreased with increasing temperature. The desulfurization activity at the lower temperatures can be attributed to the direct reaction of SO₂ with C-S-H and Ca(OH)₂. For the higher temperature range, the desulfurization rate was much higher, being almost half that for pure calcium carbonate, a conventional sorbent for dry desulfurization.