C Arbon Dioxide-Hardened Sodium Silicate-Bonded Sand Regeneration Using Calcium Carbide Slag : The Design and Feasibility Study
Sodium silicate-bonded sand (SBS) is the foundry industry by-product, which recycling is considered too expensive. Being extensively piled-up or buried, SBS causes a huge waste of resources and environmental pollution. To mitigate this problem, this study proposed to regenerate CO 2 -hardened SBS using calcium carbide slag (CCS) as a cheap regeneration reagent, and provide a strong alkaline environment through causticization the wastewater. The CCS effect on the SBS regeneration ratio and speed were experimentally studied, the composition of regenerated wastewater was analyzed, and the regeneration mechanism was analyzed at the macro- and microlevels. The results showed that CCS enhanced the SBS regeneration ratio up to 92% in 20 min. The pH value of wastewater from regeneration was as high as 13-14, and the purity of NaOH alkaline solution reached 84%, allowing its further recycling. The bond strength of regenerated sand used as casting sand exceeded that of the new sand by more than twice, it will greatly extending the life cycle of SBS in foundry industry. The low regeneration cost of SBS makes it a cost-effective and feasible replacement of natural river sand as fine aggregate used in concrete. This work will greatly promote the recycling of SBS and reduce its threat to the environment
Year of publication: |
[2022]
|
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Authors: | Qiu, Yongxiang ; Pan, Huimin ; Zhao, Qingxin ; Zhang, Jinrui ; Zhang, Yangyang ; Guo, Weichao |
Publisher: |
[S.l.] : SSRN |
Saved in:
freely available
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