Scientists of the Ural Federal University (UrFU) and the Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences have proposed a method for processing aluminum ore that allows extracting up to 98% of alumina and tripling the formation of solid waste – red sludge. This was reported to TASS by the press service of the university.
“Scientists of UrFU and the Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences have increased the efficiency of extraction of aluminum oxide (alumina) from bauxite (the main raw material for aluminum production). With the standard processing method, the maximum degree of alumina extraction was at the level of 80-85%. The modified technology will allow to extract up to 95-98% of the substance from bauxite,” the report says.
According to scientists, the new processing method will help make production sustainable and safe for the environment, as it will reduce the amount of by-product – red sludge. For each ton of bauxite, 0.7 to 1 ton of red sludge is formed during standard processing by the Bayer method.
“That is, how many tons of bauxite we process, almost the same amount of red sludge is stored in the sludge fields. Our method allows us to reduce the release of red sludge up to 300 kg per ton of bauxite,” explained Andrey Shoppert, Associate Professor of the Department of Metallurgy of Non-ferrous Metals at UrFU.
The university noted that the main danger of red sludge is its high alkalinity, the presence of heavy metals and other dangerous substances. “In the Sverdlovsk region, for example, there are two alumina plants. During their operation since the middle of the last century, more than 100 million tons of red sludge have been accumulated. It can be a source of man-made disasters – as, for example, it was in Hungary in 2010,” Shoppert added, adding that particles of dried red sludge can also be carried by the wind and pollute the environment.
To improve the method of extracting alumina from bauxite, scientists have applied the technology of electrolytic reduction of iron compounds. This increased the efficiency of leaching by opening stubborn minerals containing iron together with aluminum.
The university added that scientists will continue to work in this direction: the following experiments will be aimed at finalizing the process in order to achieve a complete absence of red sludge release.
A source: https://e-cis.info/news/569/112282/
