Nickel Chrome Plating Sludge (NCPS) is a hazardous waste containing 25%-30% nickel and chromium. Previous attempts to immobilize NCPS into fired clay bricks resulted in weakened strength due to porosity and microstructure deterioration. This study introduces co-valorization of NCPS and fly ash in fired clay bricks to address these issues. Factory-scale firing of green bricks, alongside conventional clay bricks, assessed the commercialization potential. The optimal proportion of NCPS, fly ash, and clay was found to be as 12.5:37.5:50.0, respectively. Fly ash addition significantly improved brick properties, causing compressive strength to increase from 3.2 MPa to 11.6 MPa for a NCPS content of 12.5%. Microstructural analysis highlighted fluxing oxides in NCPS, amorphous silica-alumina in fly ash, synergistic ceramic bond formation, enhanced sintering and pore filling during vitrification. The study also demonstrated substantial fuel savings of 40%-50% due to NCPS's high heat of combustion causing internal firing of green bricks. The developed bricks exhibited almost double linear attenuation coefficients, indicating enhanced gamma radiation shielding. Leaching tests confirmed successful heavy metal immobilization. This co-valorization approach not only overcomes previous drawbacks but also offers significant environmental and economic benefits in utilizing NCPS in brick production.

中文翻译：

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烧结粘土砖协同稳定有害镍铬镀层污泥和粉煤灰：性能评估

镍铬电镀污泥（NCPS）是一种含有25%-30%镍和铬的危险废物。之前尝试将 NCPS 固定到烧制粘土砖中，但由于孔隙率和微观结构恶化，导致强度减弱。本研究引入了 NCPS 和粉煤灰在烧制粘土砖中的共价化来解决这些问题。工厂规模的生砖烧制以及传统的粘土砖评估了商业化潜力。 NCPS、粉煤灰、粘土的最佳配比分别为12.5:37.5:50.0。粉煤灰的添加显着改善了砖的性能，当 NCPS 含量为 12.5% 时，抗压强度从 3.2 MPa 增加到 11.6 MPa。微观结构分析强调了 NCPS 中的助熔氧化物、飞灰中的无定形硅铝、协同陶瓷键的形成、玻璃化过程中增强的烧结和孔隙填充。研究还表明，由于 NCPS 的高燃烧热导致生砖内部燃烧，因此可节省 40%-50% 的燃料。开发的砖表现出几乎双倍的线性衰减系数，表明伽马辐射屏蔽增强。浸出测试证实了重金属固定化的成功。这种共价方法不仅克服了以前的缺点，而且在砖块生产中使用 NCPS 时还提供了显着的环境和经济效益。