Synthesis of a Mg2+-Al3+-So2-4-hydrotalcite-type compound from the acid wastewaters of the aluminum-anodizing industry

The synthesis of a Mg2+-Al3+-SO42- hydrotalcite-type compound from the acid wastewaters of the aluminum-anodizing industry has been studied as a possible means of recovering the unused Al resource materials as a useful mineral. The synthesis has been carried out from wastewaters of different concentrations (from 6.7 g Al/L to 134 mg Al/L) using the method of precipitation at constant pH, proving that all of them are suitable for such a process. The mineral was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis and chemical analysis, all of which indicated characteristics typical of the desired compound. Almost 100% of the At initially present in the wastewater solutions is recovered in the form of the Mg2+-Al3+-SO42-- hydrotalcite-type compound.