Direct Gas–Solid Carbonation Kinetics of Steel Slag and the Contribution to In situ Sequestration of Flue Gas CO₂ in Steel‐Making Plants

Abstract

Direct gas-solid carbonation of steel slag under various operational conditions was investigated to determine the sequestration of the flue gas CO2 . X-ray diffraction analysis of steel slag revealed the existence of portlandite, which provided a maximum theoretical CO2 sequestration potential of 159.4 kg CO 2 tslag (-1) as calculated by the reference intensity ratio method. The carbonation reaction occurred through a fast kinetically controlled stage with an activation energy of 21.29 kJ mol(-1) , followed by 10(3) orders of magnitude slower diffusion-controlled stage with an activation energy of 49.54 kJ mol(-1) , which could be represented by a first-order reaction kinetic equation and the Ginstling equation, respectively. Temperature, CO2 concentration, and the presence of SO2 impacted on the carbonation conversion of steel slag through their direct and definite influence on the rate constants. Temperature was the most important factor influencing the direct gas-solid carbonation of steel slag in terms of both the carbonation conversion and reaction rate. CO2 concentration had a definite influence on the carbonation rate during the kinetically controlled stage, and the presence of SO2 at typical flue gas concentrations enhanced the direct gas-solid carbonation of steel slag. Carbonation conversions between 49.5 % and 55.5 % were achieved in a typical flue gas at 600 °C, with the maximum CO2 sequestration amount generating 88.5 kg CO 2 tslag (-1) . Direct gas-solid carbonation of steel slag showed a rapid CO2 sequestration rate, high CO2 sequestration amounts, low raw-material costs, and a large potential for waste heat utilization, which is promising for in situ carbon capture and sequestration in the steel industry.

Mineral carbonation of a desulfurization residue for CO2 sequestration

“…38 The activation energy determined in this study was slightly lower than those reported by Tian et al, 36 which was 21.29 kJ mol À1 and slightly higher than those reported by Sun et al, 37 which was 14.84 kJ mol À1 for the kinetically controlled stage. 38 The activation energy determined in this study was slightly lower than those reported by Tian et al, 36 which was 21.29 kJ mol À1 and slightly higher than those reported by Sun et al, 37 which was 14.84 kJ mol À1 for the kinetically controlled stage.…”

“…ln[(1 À h) À2/3 À 1] and ln t in Fig. 36 The rate constant k 1 could be derived and was showed in Table 5. While, ln[1 À 2h/3 À (1 À h) 2/3 ] and ln t in Fig.…”

Construction Materials from Stainless Steel Slags: Technical Aspects, Environmental Benefits, and Economic Opportunities

“…Therefore, use of CO 2 from flue gases could improve environmental performance (Tian et al. ). With respect to alkali activation, the production of alkaline activators is a major environmental drawback.…”

Acidification Optimization and Granulation of a Steel‐Slag‐Derived Sorbent for CO2 Capture

“…To increase the total CO 2 capture capacity of steel slag, the use of steel slag as the calcium precursor to prepare CaO‐based sorbents for use in the calcium looping process (CLP) has recently been studied , . The CLP relies on the use of a regenerable CaO‐based sorbent for CO 2 capture during cyclic carbonation and calcination reactions .…”