RUSAL ETC (LLC), Saint Petersburg, Russia:

D. G. Chistyakov, Lead Engineer at the Department of Mathematical Modelling, Candidate of Technical Sciences, e-mail: Dmitriy.Chistiakov@rusal.com
V. O. Golubev, Head of the Mathematical Modelling Department, Candidate of Technical Sciences, e-mail: Vladimir.Golubev2@rusal.com

Saint Petersburg Mining University, Saint Petersburg, Russia:
V. M. Sizyakov, Professor at the Department of Metallurgy, Doctor of Technical Sciences, Professor, e-mail: Sizyakov_VM@pers.spmi.ru
V. N. Brichkin, Head of the Metallurgy Department, Doctor of Technical Sciences, Professor, e-mail: Brichkin_VN@pers.spmi.ru

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.

1. On the status and utilization of mineral resources of the Russian Federation in 2018 : State report. Ed. by E. A. Kiselev. Ministry of Natural Resources and Ecology of the Russian Federation. Moscow, 2019. 424 p.
2. McLemore V. T. Nepheline Syenite. Industrial Minerals and Rocks, 7^th edition. 2009. pp. 653–670.
3. Azof F. I., Yang Y., Panias D., Kolbeinsen L. et al. Leaching characteristics and mechanism of the synthetic calcium-aluminate slags for alumina recovery. Hydrometallurgy. 2019. Vol. 185. pp. 273–290.
4. Cohen J., Mercier H. Recovery of alumina from Non-Bauxite aluminumbearing raw materials. Ed. Donaldson D., Raahauge B. E. Light Metals. 2016. pp. 1057–1064.
5. Al-Ajeel A. A., Abdullah S. Z., Muslim W. A., Abdulkhader M. Q. et al. Extraction of alumina from Iraqi colored kaolin by lime-sinter process. Iraqi Bulletin of Geology and Mining. 2014. Vol. 10, No. 3. pp. 109–117.
6. Wu Y., Li L., Li M. Effect of pressure on alumina extraction from lowgrade bauxite by acid-leaching method. Light Metals. 2014. pp. 121–123.
7. Yao Z. T., Xia M. S., Sarker P. K., Chen T. A review of the alumina recovery from coal fly ash, with a focus in China. Fuel. 2014. Vol. 120. pp. 74–85.
8. Miao L., Ji G., Gao G., Li G. et al. Extraction of alumina powders from the oil shale ash by hydrometallurgical technology. Powder Technology. 2011. Vol. 207. pp. 343–347.
9. Kitler I. N., Layner Yu. A. Nephelines as a multicomponent raw material for aluminium industry. Moscow : Metallurgizdat, 1962. 237 p.
10. Layner A. I., Eremin N. I., Layner Yu. A., Pevzner I. Z. Alumina production. Moscow : Metallurgiya, 1978. 344 p.
11. Abramov V. Ya., Alekseev A. I., Badaliants Kh. A. Comprehensive processing of apatite-nepheline ore. Moscow : Metallurgiya, 1990. 392 p.
12. Sizyakov V. M., Brichkin V. N. On the role of calcium hydrocarboaluminates in achieving optimized processing of nephelines. Zapiski Gornogo instituta. 2018. Vol. 231. pp. 292–298.
13. Finin D. V., Kuranov A. V., Kovtun O. N., Kolmakova L. P. The practice of using brown coal for rotary kiln sintering of nepheline-lime-soda burden at “RUSAL Achinsk” JSC. Tsvetnye Metally. 2019. No. 9. pp. 36–41.
14. Brichkin V. N., Gumenyuk A. M., Panov A. V., Suss A. G. Determination of the Optimal Technological Conditions of Processing of the Alkali Alumosilicate. Proceedings of the Scientific-Practical Conference “Research and Development”. 2016. pp. 639–647. DOI: 10.1007/978-3-319-62870-7_67.
15. Shepelev I. I., Bochkov N. N., Golovnykh N. V., Sakhachev A. Yu. The chemical characteristics of resource-saving solid metallurgical waste disposal processes. Izvestiya vuzov. Khimiya i khimicheskaya tekhnologiya. 2015. Vol. 58, Iss. 1. pp. 81–86.
16. Sizyakov V. M., Utkov V. А., Brichkin V. N., Gumenyuk A. M. Limestonenepheline mix composition conditioning by using alkali-free feed additives. Obogashchenie Rud. 2017. No. 1. pp. 51–55. DOI: 10.17580/or.2017.01.10.
17. Sizyakov V. M. Sintering of alkaline alumosilicates and hydrochemical processing of cakes: Chemical regularities of the processes. Zapiski Gornogo instituta. 2016. Vol. 217. pp. 102–112.
18. Bazhin V. Y., Brichkin V. N., Sizyakov V. M., Cherkasova M. V. Pyro metallurgical treatment of a nepheline charge using additives of natural and technogenic origin. Metallurgist. 2017. Vol. 61, Iss. 1–2. pp. 147–154.
19. Abramov V. Ya., Nikolaev I. V., Stelmakova G. D. Comprehensive processing of aluminium ores: The physical and chemical basis. Learner’s guide. Moscow : Metallurgiya, 1985. 288 p.
20. Shmorgunenko N. S., Korneev V. I. Comprehensive processing and utilization of dumped alumina sludges. Moscow : Metallurgiya, 1982. 129 p.
21. Vinogradov S. A., Sizyakov V. M. Influence of iron compounds on baking technology of nepheline ores and concentrates. Tsvetnye Metally. 2010. No. 9. pp. 45–48.