Role of hydrazine and hydrogen peroxide in aluminium hydroxide precipitation from sodium aluminate solution
(1. Academy of Scientific and Innovative Research, New Delhi 110025, India;
2. Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research,
Bhubaneswar 751013, India;
3. National Aluminium Company, Bhubaneswar 751013, India;
4. Chemical and Mathematical Sciences, Murdoch University, Murdoch WA 6150, Australia)
2. Institute of Minerals and Materials Technology, Council of Scientific and Industrial Research,
Bhubaneswar 751013, India;
3. National Aluminium Company, Bhubaneswar 751013, India;
4. Chemical and Mathematical Sciences, Murdoch University, Murdoch WA 6150, Australia)
Abstract: Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs (SEM) show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed.
Key words: aluminium hydroxide; hydrazine; hydrogen peroxide; sodium aluminate; precipitation