In this work, the use of waste dust filter of secondary aluminum industry (DFA) to obtain geopolymer foams has been studied. The waste was used as source of alumina and foaming agent. As precursor and principal reactive silica supplier rice husk ash was used. Precursors were chemically activated by means of a sodium hydroxide aqueous solution and a commercial sodium silicate solution. The influence of the DFA content or Si/Al molar ratio (4–7) were determined by keeping the Si/Na molar ratio of 0.7 M constant and the concentration of sodium hydroxide in the activating solution equal to 8.5 M. The geopolymer foams obtained were studied by X-ray Diffraction (XRD), adsorption/desorption of nitrogen, infrared spectroscopy (FTIR), and scanning electron microscope (SEM) techniques. The results indicated that geopolymer foams presented low values of bulk density (643–737 kg/m3) high values of apparent porosity (62–70%), low, but sufficient values of compressive strength (0.5–1.7 MPa) and good values of thermal conductivity (0.131–0.157 W/mK). Lower values of thermal conductivity were obtained for Si/Al = 4 and 5 M ratios, due to the highest apparent porosity and the highest total pore volume. These geopolymer foam materials have similar properties to other construction materials sector such as gypsum boards, foamed concrete, or insulating materials. In addition, its use in other applications of interest such as catalyst support or gas filtration materials could be investigated.

中文翻译：

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作为地质聚合物泡沫原料的再生铝工业的除尘器


在这项工作中，研究了利用再生铝工业 （DFA） 的废尘过滤器获得地质聚合物泡沫。废物被用作氧化铝和发泡剂的来源。作为前驱体和主要活性二氧化硅供应商，使用了稻壳灰。前驱体通过氢氧化钠水溶液和市售硅酸钠溶液进行化学活化。通过保持 0.7 M 的 Si/Na 摩尔比恒定且活化溶液中氢氧化钠的浓度等于 8.5 M，确定 DFA 含量或 Si/Al 摩尔比 （4-7） 的影响。通过 X 射线衍射 （XRD）、氮气吸附/解吸、红外光谱 （FTIR） 和扫描电子显微镜 （SEM） 技术研究了获得的地聚合物泡沫。结果表明，地质聚合物泡沫的体积密度较低 （643-737 kg/m3）、表观孔隙率高 （62-70%）、抗压强度较低但足够 （0.5-1.7 MPa） 和良好的导热系数 （0.131-0.157 W/mK）。由于最高的表观孔隙率和最高的总孔隙体积，Si/Al = 4 和 5 M 比率的热导率值较低。这些地质聚合物泡沫材料具有与其他建筑材料领域（如石膏板、泡沫混凝土或绝缘材料）相似的特性。此外，还可以研究其在其他感兴趣的应用中的使用，例如催化剂载体或气体过滤材料。