St. Petersburg Mining University‘s research team has developed an effective technology for producing alumina by sintering kaolin ores with limestone and the addition of carbon-containing activating agents. Their solution may result in more uses for kaolin ores in the aluminium industry.
The scientists found the optimal content of additives, leading to an increase in alumina recovery of over 7%. The highest efficiency is seen with the carbon proportion in a furnace charge varying between 1.5% and 3%, depending on the type of carbonic material used.
The gradual depletion of high-quality bauxite deposits coupled with the increasing global demand for aluminium necessitates looking for alternative feedstocks. Nepheline formations, low-quality bauxites, clays, and kaolin ores can be the alternatives.
According to Mining University’s team, headed by Vyacheslav Brichkin, Doctor of Engineering Sciences, there is a potential for more extensive use of the ores in producing alumina.
The new technology’s significant benefit is that it reduces the costs of sintering the limestone-kaolin charge due to the self-dissipation effect. Alumina extraction with this technology reaches 93.5%. Moreover, the figure is only slightly affected by the chemical composition of the base kaolin ore.
Kaolin ores are especially relevant for countries lacking large reserves of bauxite and nepheline, such as Egypt. El Dib Amr Basyouni Saad, a postgraduate student at the Department of Metallurgy, representing Cairo-based Al-Azhar University, in also in the team.