Liu Jun, Zeng Canrong, Li Zhenlin, Liu Guang, Zhang Weizhuo, Xie Guangming, Xing Feng
College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, PR China; Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen 518060, PR China.
College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, PR China.
Sci Total Environ. 2023 Dec 1;902:166065. doi: 10.1016/j.scitotenv.2023.166065. Epub 2023 Aug 4.
Carbonation technology resolves the volume expansion of steel slag by combining CO with f-CaO, but the previous stringent carbonation conditions (99%vol) significantly limit the application prospect of steel slag. To achieve the carbonation of steel slag at lower CO concentrations, a novel cold-bonded artificial aggregates (CASSAs) based on steel slag and biochar is produced in this paper. The carbon capture capacities of CASSAs with different biochar contents (5 wt%, 10 wt%, and 15 wt%) are investigated in a low-CO concentration environment (10.79 % vol) and natural environment using the porosity and CO adsorption capacity of biochar. The changes in the performance of CASSAs before and after carbonation are investigated at different curing ages (7 d and 28 d). The results reveal that biochar increases the pores of the CASSAs. At 7 d, B15 achieves complete carbonation at low concentrations and can uptake 6.5 wt% of CO. CO adsorption capacity by biochar in the natural environment facilitates the diffusion of CO in CASSAs. Regarding mechanical properties, the addition of biochar makes B15 at 7 d half as strong as B0, but B15 exhibits long-term strength development. B15 at 7 d has a strength of 8.49 MPa after carbonation, which is almost the same as B0. In addition, B15 achieves a net CO emission of -39.9 kg/ton. This study combines biochar with CASSAs to provide a potential method to carbonate steel slag at low CO concentrations. A new methodology was also used to quantitatively assess the ability of biochar CASSAs to solidify CO under low concentration conditions and natural environments from a macroscopic perspective. Biochar CASSAs have great potential to realize resource utilization and carbon capture from steel slag.
碳酸化技术通过将CO与游离氧化钙结合来解决钢渣的体积膨胀问题，但先前严格的碳酸化条件（体积分数99%）显著限制了钢渣的应用前景。为了在较低的CO浓度下实现钢渣的碳酸化，本文制备了一种基于钢渣和生物炭的新型冷粘结人造骨料（CASSAs）。利用生物炭的孔隙率和CO吸附能力，在低CO浓度环境（体积分数10.79%）和自然环境中研究了不同生物炭含量（5 wt%、10 wt%和15 wt%）的CASSAs的碳捕获能力。研究了不同养护龄期（7 d和28 d）下CASSAs碳酸化前后性能的变化。结果表明，生物炭增加了CASSAs的孔隙。在7 d时，B15在低浓度下实现了完全碳酸化，可吸收6.5 wt%的CO。生物炭在自然环境中的CO吸附能力促进了CO在CASSAs中的扩散。关于力学性能，添加生物炭使7 d时的B15强度仅为B0的一半，但B15表现出长期强度发展。7 d时的B15碳酸化后强度为8.49 MPa，与B0几乎相同。此外，B15实现了-39.9 kg/吨的净CO排放。本研究将生物炭与CASSAs相结合，提供了一种在低CO浓度下使钢渣碳酸化的潜在方法。还采用了一种新的方法从宏观角度定量评估生物炭CASSAs在低浓度条件和自然环境下固化CO的能力。生物炭CASSAs在实现钢渣资源利用和碳捕获方面具有巨大潜力。
