Sustainable Infrastructure Research and Development Center, Department of Civil Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, 40002, Thailand; Academy of Science, Royal Society of Thailand, Dusit, Bangkok, 10300, Thailand.
Construction Innovations and Future Infrastructures Research Center (CIFIR), Department of Civil Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok, 10140, Thailand.
J Environ Manage. 2023 Nov 1;345:118783. doi: 10.1016/j.jenvman.2023.118783. Epub 2023 Aug 18.
Calcium carbide residue (CCR) is a waste obtained from the production of acetylene gas by the hydration reaction of calcium carbide. This residue is generated in large quantities annually and requires appropriate disposal. The main composition of the residue is calcium hydroxide (Ca(OH)). Ca(OH) can react with CO gas and form CaCO particles. This process is well known but not very attractive since Ca(OH) is obtained from limestone using an energy-intensive thermal conversion process. This paper examined the synthesis of CaCO from CCR solutions by capturing CO with the aid of triethanolamine (TEA) solutions at doses of 0, 5, 10 and 20% w/w. The precipitated CaCO was characterized, and the application of CaCO as a filler in epoxy resin was tested. The results showed that the precipitated CaCO was mainly calcite, with a 76.6% yield. Cubic calcite was primarily obtained in TEA solutions, whereas small and agglomerated spherical vaterite and cubic calcite particles were formed in non-TEA solutions. The CaCO-filled epoxy composites showed higher compressive strength than the neat resin. However, the transparency of specimen plates was reduced. These results can serve as guidelines for the application of CCR slurry filtrate obtained from the sedimentation ponds of acetylene plants and help to reduce the amount of wastewater that needs to be treated. CO gas from industrial flue gas combined with TEA solution could be applied to precipitate CaCO for carbon-neutral manufacturing.
电石渣（CCR）是通过电石加水反应生产乙炔气时产生的一种废物。这种残渣每年都会大量产生，需要进行适当的处理。残渣的主要成分是氢氧化钙（Ca(OH)）。Ca(OH)可以与 CO 气体反应，形成 CaCO 颗粒。这个过程广为人知，但并不是很吸引人，因为 Ca(OH)是通过使用能源密集型热转化工艺从石灰石中获得的。本文研究了通过在 0、5、10 和 20%w/w 的三乙醇胺（TEA）溶液的帮助下，用 CO 气体从 CCR 溶液中捕获 CO 来合成 CaCO 的过程。对沉淀的 CaCO 进行了表征，并测试了 CaCO 作为环氧树脂填料的应用。结果表明，沉淀的 CaCO 主要是方解石，产率为 76.6%。在 TEA 溶液中主要得到立方方解石，而在没有 TEA 的溶液中则形成小而团聚的球形文石和立方方解石颗粒。CaCO 填充的环氧树脂复合材料的抗压强度高于纯树脂。然而，试件板的透明度降低。这些结果可为从乙炔厂沉降池获得的 CCR 浆滤液的应用提供指导，并有助于减少需要处理的废水量。工业烟道气中的 CO 气体与 TEA 溶液结合，可用于沉淀 CaCO，实现碳中和制造。
