Kang Sukpyo, Kang Hyeju, Lee Byoungky
Department of Architecture, Woosuk University, Jincheon 27841, Korea.
Department of Construction Engineering, Woosuk University, Jincheon 27841, Korea.
Materials (Basel). 2020 Sep 16;13(18):4107. doi: 10.3390/ma13184107.
Red mud is a highly alkaline waste by-product of the aluminum industry. Although recycling of red mud is being actively researched, a feasible technological solution has not been found yet. In this study, we propose that neutralization of red mud alkalinity could assist in its use as a construction material. Neutralized red mud (LRM + S; pH 6-8) was prepared by adding sulfuric acid to liquefied red mud (LRM; pH 10-12). After adding LRM and LRM + S to cement paste, the heat of hydration, compressive strength, and hydration products were examined. The experiments revealed that the calorific value of the cement paste with LRM was low, and its peak was delayed, when compared with that of plain cement paste (referred to as Plain), whereas the calorific value of the cement paste with LRM + S was similar to that of Plain. At the age of 28 d, the compressive strength of the cement paste with 10% LRM + S was 99% whereas that with 20% LRM was only 55% of the strength of Plain. Thus, our results help to resolve the issue of strength degradation of cementitious materials observed upon the addition of red mud and enable its reuse as a construction material.
赤泥是铝工业产生的一种高碱性废弃物副产品。尽管对赤泥的回收利用正在积极研究，但尚未找到可行的技术解决方案。在本研究中，我们提出中和赤泥的碱性有助于其用作建筑材料。通过向液化赤泥（LRM；pH值为10 - 12）中添加硫酸来制备中和后的赤泥（LRM + S；pH值为6 - 8）。在向水泥浆中添加LRM和LRM + S后，对水化热、抗压强度和水化产物进行了检测。实验表明，与普通水泥浆（简称Plain）相比，含LRM的水泥浆的热值较低，且峰值延迟，而含LRM + S的水泥浆的热值与Plain相似。在28天龄期时，含10% LRM + S的水泥浆的抗压强度为99%，而含20% LRM的水泥浆的抗压强度仅为Plain强度的55%。因此，我们的研究结果有助于解决在添加赤泥后观察到的胶凝材料强度降低的问题，并使其能够作为建筑材料再利用。
