1 Physics Department, Aristotle University of Thessaloniki, Greece.
2 Chemistry Department, Aristotle University of Thessaloniki, Greece.
Waste Manag Res. 2018 Sep;36(9):818-826. doi: 10.1177/0734242X18775488. Epub 2018 May 31.
In the present work, the stabilization/solidification of a Cr-rich ash obtained from the anoxic incineration of tannery hazardous wastes was studied. Chromium in the starting waste was exclusively in amorphous form and in trivalent state. The waste was embedded in fly ash-based cementitious material matrices. Calcium and sodium hydroxides, as well as sodium silicate, were used as activators. The proposed process combines mechanical activation with hydrothermal curing. Successful immobilization of chromium was achieved, as attested by standard leaching tests. Backscattered electron images revealed the existence of the C-S-H gel, and elemental mapping by energy dispersive X-ray spectroscopy showed a good interdispersion of chromate and aluminosilicate species, verifying that chromium was well distributed in the final amorphous cementitious matrix. X-ray diffraction confirmed the absence of Cr-rich crystalline phases of calcium aluminosilicates, where chromium can enter in hexavalent state. The stiffness of the stabilized samples was reduced with increasing the amount of added Cr-rich ash, as attested by measurements of the dynamic Young's modulus.
在本工作中，研究了用缺氧焚烧制革危险废物得到的富铬灰渣的稳定/固化。起始废物中的铬全部以非晶态和三价形式存在。废物被嵌入基于粉煤灰的胶凝材料基质中。使用氢氧化钙和氢氧化钠以及硅酸钠作为活化剂。所提出的工艺将机械活化与湿热养护相结合。标准浸出试验证明成功实现了铬的固定。背散射电子图像显示存在 C-S-H 凝胶，通过能量色散 X 射线光谱的元素映射显示出铬酸盐和铝硅酸盐物种的良好分散，证明铬在最终的无定形水泥基质中分布良好。X 射线衍射证实不存在富铬的钙铝硅酸盐晶体相，其中铬可以进入六价状态。通过动态杨氏模量的测量证明，随着添加的富铬灰渣量的增加，稳定样品的刚性降低。
