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ArticleName Understanding the regularities of aluminum chloride hexahydrate crystallization from hydrochloric acid solutions. Part 2. Parameters of aluminum chloride hexahydrate crystallization
DOI 10.17580/tsm.2020.02.03
ArticleAuthor Pak V. I., Kirov S. S., Mamzurina O. I., Nalivaiyko A. Yu.

National University of Science and Technology MISiS, Moscow, Russia:

V. I. Pak, Postgraduate Student, Department of Non-Ferrous Metals and Gold, e-mail:
S. S. Kirov, Associate Professor, Department of Non-Ferrous Metals and Gold, Candidate of Technical Sciences, e-mail:

O. I. Mamzurina, Senior Lecturer, Department of Non-Ferrous Metals Science, e-mail:
A. Yu. Nalivaiko, Senior Lecturer, Department of Non-Ferrous Metals and Gold, Candidate of Technical Sciences, e-mail:


This paper examines how temperature, the concentration of AlCl3 in the initial solution and the consumption rate of gaseous HCl impacts the degree of AlCl3·6H2O crystallization from aluminium chloride solutions resultant from leaching of Russian kaolin clays. The experiments involved introduction in the solution of return gaseous hydrogen chloride. This technique is based on decreasing the solubility of aluminium chloride while increasing the concentration of HCl in the system. The effect of impurity iron on the crystallization parameters has been studied. The initial solutions used in the experiments had the concentrations of iron chloride of 8.5 and 16.7 g/l. It was found that impurity iron does not produce any significant impact on the crystallization process. At the same time, a double increase of [Fe3+] in the initial solution leads to a 1.5-time increase in the iron concentration in aluminum chloride hexahydrate crystals. The findings show that the impurities contained in AlCl3·6H2O crystals mainly include residual mother solution on the particle surface. The effect of temperature has been established on the physical and chemical properties of deposited crystals. The average size of crystals produced during high-temperature AlCl3·6H2O crystallization was 500 μm, and it was 250 μm following low-temperature crystallization. The authors found that during high-temperature crystallization the AlCl3·6H2O particles form coarser agglomerates making crystal filtering and washing more efficient. Studies have been conducted with AlCl3·6H2O crystals produced in different crystallization regimes. The effect of using concentrated hydrochloric acid to wash AlCl3·6H2O crystals has been studied. It was found that due to crystal washing the amount of impurities carried away with the solution can be reduced by 70–80 %.

keywords Hydrochloric acid, crystallization, aluminium chloride, iron chloride, kaolin clay, aluminium chloride solution, hydrogen chloride, agglomeration of crystals, crystallization rate, crystallization degree

1. Poylov V. Z. Regularities of mass polythermal crystallization of potassium chloride. Vestnik Permskogo natsionalnogo issledovatelskogo politekhnicheskogo universiteta. Khimicheskaya tekhnologiya i biotekhnologiya. 2016. No. 2. pp. 106–119.
2. Matusevich L. N. Crystallization from solutions in the chemical industry. Moscow : Khimiya, 1968. 340 p.
3. Brichkin V. N., Sizyakov V. M., Oblova I. S., Fedoseev D. V. Industrial synthesis of finely-dispersed aluminum hydroxide in processing of aluminic raw materials. Tsvetnye Metally. 2018. No. 10. pp. 45–51.
4. Khamskiy E. V. Crystallization in the chemical industry. Moscow : Khimiya, 1979. 343 p.
5. Larichev T. A., Titov F. V., Serkachev B. A., Sotnikova L. V. Mass crystallization and determining the dispersion characteristics of silver halide microcrystals : Learner’s guide. Kemerovo State University. 2nd revised edition. Kemerovo : Kuzbassvuzizdat, 2004. 88 p.
6. Brichkin V. N., Kurtenkov R. V., Fedoseev D. V. Kinetic regularities of hydrometallurgical processes involving a gas phase and how they influence the choice of the production regime. Vestnik Irkutskogo gosudarstvennogo tekhnicheskogo universiteta. 2016. No. 3. pp. 97–104.
7. Guo Y., Yang X., Cui H., Cheng F., Yang F. Crystallization behavior of AlCl3·6H2O in hydrochloric system. Huagong Xuebao/CIESC Journal. 2014. Vol. 65, Iss. 10. pp. 3960–3967.
8. Layner Yu. A. Comprehensive processing of aluminium-containing materials with acids. Moscow : Nauka, 1982. 208 p.
9. Guo Y., Lv H., Yang X., Cheng F. AlCl3·6H2O recovery from the acid leaching liquor of coal gangue by using concentrated hydrochloric inpouring. Separation and Purification Technology. 2015. Vol. 151. pp. 177–183.
10. Yuan M., Qiao X., Yu J. Phase equilibria of AlCl3 + FeCl3 + H2O, AlCl3 + CaCl2 + H2O and FeCl3 + CaCl2 + H2O at 298.15 K. Journal of Chemical and Engineering Data. 2016. Vol. 61, Iss. 5. pp. 1749–1755.
11. Wang J., Petit C., Zhang X., Cui S. Phase equilibrium study of the AlCl3 + CaCl2 + H2O system for the production of aluminum chloride hexahydrate from Ca-Rich Flue Ash. Journal of Chemical and Engineering Data. 2016. Vol. 61, Iss. 1. pp. 359–369.
12. Nesmeyanov A. N., Baranov V. I., Zaborenko K. B., Rudenko N. P., Priselkov Yu. A. A guide to practical radiochemistry. Moscow : Gosudarstvennoe nauchno-tekhnicheskoe izdatelstvo khimicheskoy literatury, 1956. 398 p.
13. Ajemba R. O., Onukwuli O. D. Kinetic Model for Ukpor Clay Dissolution in Hydrochlorlc Acid Solution. Journal of Emerging Trends in Engineering and Applied Sciences (JETEAS). Scholarlink Research Institute Journals. 2012. No. 3. pp. 448–454.
14. Lima P. A., Angélica R., Neves R. Dissolution kinetics of Amazonian metakaolin in hydrochloric acid. Clay Minerals. 2017. No. 1. pp. 75–82.
15. Cheng H., Zhang J., Lv H., Guo Y., Cheng W. et al. Separating NaCl and AlCl3·6H2O crystals from acidic solution assisted by the non-equilibrium phase diagram of AlCl3 – NaCl – H2O(–HCl) salt-water system at 353.15 K. Crystals. 2017. Vol. 7, Iss. 8. p. 244.
16. Suss A. G., Damaskin A. A., Senyuta A. S., Panov A. V., Smirnov A. A. The influence of the mineral composition of low-grade aluminum ores on aluminium extraction by acid leaching. Light Metals. 2014. pp. 105–109.
17. Al-Zahrani A. A., Abdul-Majid M. H. Extraction of Alumina from Local Clays by Hydrochloric Acid Process. Journal of King Saud University – Engineering Sciences. 2009. Vol. 20, No. 2. pp. 29–41.
18. Balmaev B. G., Kirov S. S., Pak V. I., Ivanov M. A. Kinetics of hightemperature hydrochloric leaching of kaolin clays of east-siberian deposits in laboratory conditions and pilot plant tests. Tsvetnye Metally. 2018. No. 3. p. 38–45.
19. Balmaev B. G., Tuzhilin A. S., Kirov S. S., Shebalkova A. Yu. Mathematical modelling and optimization of aluminium hydroxychloride obtaining process. Tsvetnye Metally. 2017. No. 3. pp. 57–62. DOI: 10.17580/tsm.2017.03.09
20. Pak V. I., Kirov S. S., Mamzurina O. I., Nalivayko A. Yu. Understan ding the Regularities of Aluminum Chloride Hexahydrate Crystallization from Hydrochloric Acid Solutions. Part 1. Process Kinetics. Tsvetnye Metally. 2020. No. 1. pp. 47–53. DOI: 10.17580/tsm.2020.01.07.
21. Kogan V. B., Fridman V. M., Kafarov V. V. A handbook of solubility. Moscow – Leningrad : Izdatelstvo Akademii nauk SSSR, 1962. 1961 p.
22. Balmaev B. G., Kirov S. S., Ivanov M. A., Pak V. I. Filtration process modeling for aluminium-bearing hydrochloric acid pulp. Tsvetnye Metally. 2017. No. 10. pp. 63–68. DOI: 10.17580/tsm.2017.10.07.

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