Synthesis, characterization and sinterability of pure and Ni-doped nano layered double hydroxides from aluminum dross

Abstract

Synthesis of pure and Ni-doped nano Mg-Al layered double hydroxides (LDHs) using aluminum dross is the main goal of the present study. Moreover, the sintering of prepared LDHs to produce sintered spinel at relatively low temperature was also performed. Extraction of nano Al(OH)3 from aluminum dross was firstly conducted and the extracted hydroxide was utilized in preparation of LDHs in the presence of Mg(NO3)2.6H2O and Ni(NO3)2.6H2O. LDHs were synthesized by co-precipitation method followed by hydrothermal treatment up to 180 °C. The synthesized powders and/or suspensions were investigated by different tools such as XRD, FTIR, SEM, TEM, particle size distribution and zeta potential. The prepared LDHs were uni-axially pressed and sintered at 1500 °C.The physical properties and microstructures of sintered bodies were also investigated. The results revealed that Al(OH)3 synthesized using NaOH had lower particle size than that prepared using NaOH and HCl. The optimum hydrothermal temperature at which LDHs completely formed was 180 °C. Both Al(OH)3 and LDH were successfully prepared in the nano range. The sintering of nano LDHs led to production of sintered spinel with improved properties at relatively lower temperature (1500 °C). The developed microstructure was composed of nano grains agglomerated together forming micro-sized grains.