This article summarizes the results of a systematic review of the literature in one particular application area – the extraction of valuable elements (Fe, Al, Na, Ti) from red mud. The analysis showed that depending on the composition of the bauxite being processed and the instrumentaltechnological scheme for producing alumina, the content of iron oxide (Fe2O3) varies from 7 to 70 % by weight, aluminum oxide (Al2O3) – from 2 to 33 % by weight, titanium oxide (TiO2) from 2.2 to 25 % wt., sodium oxide (Na2O) up to 12.5 % wt. The achieved maximum percentage of iron extraction is 97.5 %, aluminum – 89.7 %, sodium – 96.4 %, titanium – 97 %. It was noted that all practical studies were carried out in laboratory conditions only. As the most effective, technological proposals have been allocated for complex processing of red mud, including processes of smelting reduction, magnetic separation, leaching with mineral (HCl, H2SO4, HNO3) and organic (H2C2O4) acids. In modern studies, it is proposed to use microwave, ultrasound, or plasma technologies in recycling. As a result of the work, a systematic table was proposed on methods for extracting Fe, Al, Na, Ti from red mud. Suggestions are made on the criteria of technology that would have environmental, energy and economic benefits.
Value adding red mud waste: High performance iron oxide adsorbent for removal of fluoride
