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It is well known that an unstable composition of ore and auxiliary materials creates the need to manage material flows and their composition in order to ensure the required productivity and achieve the desired qualitative and quantitative characteristics of the final products. The above problem was decided to find a solution for through analysis and mathematical processing of the RUSAL Achinsk database containing data on the incoming nepheline ore and limestone. Thus, one could analyze variations in the ore composition and carry out a statistical analysis by calculating the root-mean-square (standard) deviation and the variation coefficient. A digital model of the alumina and soda product production process employed by RUSAL Achinsk was used as the main tool for calculating production indicators as a function of the raw material composition. The model was built by RUSAL ETC on the basis of lumped parameters modelling. It is shown that the chemical composition of the raw materials supplied to RUSAL Achinsk and their variability in the current operating conditions of the Kiya-Shaltyr nepheline mine and Mazoul limestone mine have a significant impact on the alumina and by-product production process and some adjustment of the process flows is required. It was estimated how the output and the consumption of soda-sulfate mixture and potash are likely to change depending on the concentration of Al2O3, K2O, Na2O and SO3 in the feed material. Based on the obtained results, one can identify the most innovative process solutions that would enable to raise the output of by-products while maintaining the output of alumina due to the introduction of appropriate corrective ingredients. In this case, the output of potassium sulfate is expected to rise from 1.22 to 5.78%, and that of soda ash — from 1.27 to 6.5%, which determines a significant increase in profit for these two products. This research study was funded by the Russian Science Foundation under the Grant Agreement No. 18-19-00577 dated 26th April 2018 on fundamental scien tific research and exploratory scientific research.

Deposits of bauxite ores near aluminum smelters often possess an excessively high percentage of silica. Development of such high-silica ores would be benefi cial to alumina producers. Therefore, unique industrial and operational experience in the fi eld of high-silica bauxite processing was gained at the R u s s i a n N a t i o n a l A l u m i n i u m -Magnesium Institute, St. Petersburg, pilot plant with the consecutive extraction of silica and alumina from low-grade ores. This article describes the chemistry, processing-unit operations, and results obtained from this process.

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