Williams Jonah M, Zhang Ning, Moment Aaron J
Department of Earth and Environmental Engineering, Columbia University, New York, New York 10027, United States.
Lenfest Center for Sustainable Energy, Columbia University, New York, New York 10027, United States.
ACS Omega. 2024 Jun 26;9(27):29776-29788. doi: 10.1021/acsomega.4c03393. eCollection 2024 Jul 9.
The use of carbon mineralization to produce carbonates from alkaline industrial wastes is gaining traction as a method to decarbonize the built environment. One of the environmental concerns during this process is the use of acids, which are required to extract Ca or Mg from the alkaline waste to produce carbonates. Conventionally, acids such as hydrochloric, nitric, or sulfuric are used which allow for the highest material recovery but are corrosive and difficult to regenerate as they are utilized in a linear fashion and generate additional process waste. An alternative is to use regenerable protonatable salts of ammonia, such as ammonium chloride (AC) or ammonium sulfate, the former of which is used globally during the Solvay process as a reversible proton shuttle. In this study, we show that regenerable ammonium salts, such as AC (NHCl) and ammonium bisulfate (NHHSO), can be effectively used for material recovery and the production of calcium carbonate during the leaching of waste cement paste as an alternative to conventional acids such as HCl. Leaching kinetics, postreaction residue, and carbonate characterization were performed to assess the productivity of this system and potential uses of these materials downstream. The stabilization of vaterite was observed in the case of AC leaching, suggesting its importance in the kinetic stability of vaterite and suppression of calcite nucleation. Overall, this study motivates the use of alternative leaching agents, such as salts of ammonia, to facilitate material recovery and carbon capture from alkaline industrial wastes.
利用碳矿化从碱性工业废料中生产碳酸盐作为一种使建筑环境脱碳的方法正越来越受到关注。此过程中的一个环境问题是酸的使用，从碱性废料中提取钙或镁以生产碳酸盐需要用到酸。传统上使用盐酸、硝酸或硫酸等酸，这些酸能实现最高的材料回收率，但具有腐蚀性且难以再生，因为它们以线性方式使用并产生额外的工艺废料。一种替代方法是使用可再生物质的铵盐，如氯化铵（AC）或硫酸铵，其中前者在全球索尔维制碱法中用作可逆质子穿梭体。在本研究中，我们表明可再生物质的铵盐，如AC（NH₄Cl）和硫酸氢铵（NH₄HSO₄），作为替代盐酸等传统酸的物质，在废水泥浆浸出过程中可有效地用于材料回收和碳酸钙的生产。进行了浸出动力学、反应后残渣和碳酸盐表征，以评估该系统的生产率以及这些材料在下游的潜在用途。在AC浸出的情况下观察到球霰石的稳定性，表明其在球霰石动力学稳定性和抑制方解石成核方面的重要性。总体而言，本研究推动使用替代浸出剂，如铵盐，以促进从碱性工业废料中回收材料和捕获碳。
