Department of Chemical, Environmental and Material Engineering. Higher Polytechnic School of Linares, University of Jaen, Scientific and Technological Campus of Linares, 23700, Linares, Jaén, Spain.
University of Castilla-La Mancha. Department of Physical Chemistry, Faculty of Environmental Sciences and Biochemistry, Avenida Carlos III, s/n, 45071, Toledo, Spain.
J Environ Manage. 2019 Sep 15;246:785-795. doi: 10.1016/j.jenvman.2019.06.059. Epub 2019 Jun 20.
A 70:30 black-white clay mixture (C) has been blended with different proportions of three wastes: bagasse from beer production (BG), a flux sludge used in galvanization (FS) and fly ash enriched to 60% with KO from a biomass plant (FA). A complete characterization of the raw materials was performed. Mixtures of C and FA for 15, 17.5 and 20 wt% of KO were blended with water, shaped into prismatic specimens, oven-dried, muffle-sintered at 1000-1200 °C, and finally crushed into lightweight aggregates (LWAs). The amounts of FA corresponding to KO = 20% for a temperature, T, of 1000 °C (LWA variety C20K-1000) yielded the best technological properties: oven-dry density of 1.22 g/cm, water absorption of 39.8% and open porosity of 48.6%. Therefore, other specimens containing BG and FS were sintered according to the same protocol considering KO = 20% and T = 1000 °C. White aggregates were also obtained at 1000 °C (C-1000 variety) from C-mixture (without FS, FA and BG). The addition of BG (5,7 and 10 wt%) did not mean any improvement with respect to C20K-1000, and in the case of FS (25-40%), the development of red color was fostered, which could be interesting for gardening or ornamental purposes. A leaching test conducted on the aggregate with 40 wt% FS showed that the concentration of heavy metals was below the permitted environmental thresholds. Although the leachable Zn concentration of the aggregate (205 ppm) was reduced by 85% with respect to the original residue, it is still high enough for crops that demand this metal. The outcome of this investigation proves the usefulness of recycling agricultural and industrial wastes to obtain high quality LWAs for agriculture or gardening.
一种 70:30 的黑白粘土混合物（C）与三种废物以不同比例混合：啤酒生产的甘蔗渣（BG）、镀锌用的通量污泥（FS）和从生物质工厂用 KO 富集到 60%的粉煤灰（FA）。对原材料进行了全面的特性分析。将 C 和 FA 的混合物（KO 含量分别为 15、17.5 和 20%wt）与水混合，制成棱柱形试件，在烘箱中干燥，在 1000-1200°C 下马弗炉烧结，最后粉碎成轻集料（LWAs）。在 1000°C 下 KO 对应 FA 的含量为 20%（T 为 1000°C）的 LWA 品种 C20K-1000 产生了最佳的技术性能：干燥密度为 1.22g/cm，吸水率为 39.8%，开口孔隙率为 48.6%。因此，其他含有 BG 和 FS 的试样根据相同的方案在 KO 含量为 20%和 T 为 1000°C 的条件下进行烧结。在 1000°C 下也从 C 混合物（不含 FS、FA 和 BG）获得了白色的 LWA（C-1000 品种）。添加 BG（5、7 和 10wt%）与 C20K-1000 相比并没有任何改善，而 FS（25-40wt%）的添加则促进了红色的发展，这可能对园艺或装饰目的很有趣。对含有 40wt%FS 的 LWA 进行的浸出试验表明，重金属浓度低于允许的环境阈值。虽然与原始残渣相比，LWA 中可浸出 Zn 的浓度降低了 85%，但对于需要这种金属的作物来说，它的浓度仍然足够高。该研究的结果证明了回收农业和工业废物以获得用于农业或园艺的高质量 LWA 的实用性。
