Within a circular economy approach, this study investigates the environmental impact of lightweight aggregates (LWAs) produced starting from different mixes of different clays with brewery sludge and cattle bone flour ash (CBA), used as poring and fertilizing agents, respectively. The environmental impact was evaluated by means of release tests, insulation capacity, carbon footprint (CFP), and particulate matter emission during pellet firing. Release tests representative of LWAs realistic application showed very high release of phosphate and satisfactory release of potassium. The thermal insulation of the LWAs was tested by thermal imaging camera and resulted highly variable depending on the composition, with the mix containing CBA performing best. This latter composition leads also to the smallest CO₂ equivalent emission, due to the calorific power of CBA, allowing lower consumption of fossil fuels during the LWA production. Finally, total particulate emissions during the thermal treatment resulted similar in terms of mass for all mixes, while differences in terms of particle morphology and composition occurred. Samples containing residue resulted with a quite good release behavior, CFP, and insulation properties, but higher emission of particles, particularly when glass is added.

中文翻译：

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从残渣开始的陶瓷轻质骨料生产对环境的影响估算

在循环经济方法下，本研究调查了轻质骨料（LWA）对环境的影响，这些轻质骨料分别由不同的粘土与啤酒污泥和牛骨粉灰（CBA）的不同混合物制成，分别用作制孔剂和施肥剂。通过释放测试，绝缘能力，碳足迹（CFP）和颗粒燃烧过程中的颗粒物排放来评估环境影响。LWA实际应用的代表性释放试验表明，磷酸盐的释放非常高，钾的释放令人满意。LWA的热绝缘通过热像仪进行了测试，结果根据成分的不同而变化很大，其中含CBA的混合物表现最佳。后一种成分也导致最小的CO ₂由于CBA的发热量大，所以在LWA生产过程中减少了化石燃料的消耗。最后，在热处理过程中，所有混合物的总颗粒排放物的质量相似，而颗粒形态和组成却有所不同。包含残留物的样品具有很好的脱模性能，CFP和绝缘性能，但颗粒排放量更高，尤其是在添加玻璃时。