Abstract

The seawater neutralization process is currently used in the alumina industry to reduce the pH and dissolved metal concentrations in bauxite refinery residues through the precipitation of Mg, Al, and Ca hydroxide and carbonate minerals. This neutralization method is very similar to the co-precipitation method used to synthesize hydrotalcite (Mg₆Al₂(OH)₁₆CO₃.4H₂O). This study looks at the effect of temperature on the type of precipitates that form from the seawater neutralization process of Bayer liquor. The Bayer precipitates have been characterized by a variety of techniques, including X-ray diffraction (XRD), Raman spectroscopy, and infrared spectroscopy. The mineralogical composition of Bayer precipitates largely includes hydrotalcite, hydromagnesite, and calcium carbonate species. Analysis with XRD determined that Bayer hydrotalcites that are synthesized at 55 °C have a larger interlayer distance, indicating that more anions are removed from Bayer liquor. Vibrational spectroscopic techniques have identified an increase in hydrogen bond strength for precipitates formed at 55 °C, suggesting the formation of a more stable Bayer hydrotalcite. Raman spectroscopy identified the intercalation of sulfate and carbonate anions into Bayer hydrotalcites using these synthesis conditions.

Quantitative elemental analysis of high silica bauxite using calibration-free laser-induced breakdown spectroscopy

Muhammad Fahad, Sajjad Ali, Khizar Hussain Shah, Asim Shahzad, and Muhammad Abrar
Appl. Opt. 58(27) 7588-7596 (2019)

White-light hydrotalcite-like compound emission from the incorporation of red-, green-, and blue-emitting metal complexes

Hong Chen, WenGong Zhang, ZhengHuan Lin, and QiDan Ling
Opt. Mater. Express 3(1) 105-113 (2013)

Anion–water hydrogen bond vibration revealed by the terahertz Kerr effect

Hang Zhao, Yong Tan, Rui Zhang, Yuejin Zhao, Cunlin Zhang, and Liangliang Zhang
Opt. Lett. 46(2) 230-233 (2021)

Effect of different in situ temperatures on the crystallinity and optical properties of green synthesized 8-hydroxyquinoline zinc by saffron extract

Shima Bakhshipour, Zahra Shahedi, Farkhondeh Mirahmadi, Rahele Fereidonnejad, and Mohadeseh Hesani
Opt. Continuum 1(6) 1401-1412 (2022)

Synthesis and characterization of CZTSe nanoinks using polyetheramine as solvent

Chi-Jie Wang, Shih-Chang Shei, and Shoou-Jinn Chang
Opt. Mater. Express 4(8) 1593-1600 (2014)