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LIGHT METALS, CARBON MATERIALS
ArticleName The activating effect of carbon during sintering the limestone-kaolin mixture
DOI 10.17580/tsm.2020.07.02
ArticleAuthor ElDeeb A. B., Brichkin V. N., Povarov V. G., Kurtenkov R. V.
ArticleAuthorData

Saint-Petersburg Mining University, Saint-Petersburg, Russia1 ; Mining and petroleum department, Faculty of Engineering, Al-Azhar University in Cairo, Egypt2:

A. B. ElDeeb, Post – Graduate student, Metallurgy Department1,2, e-mail: s175000@stud.spmi.ru

 

Saint-Petersburg Mining University, Saint-Petersburg, Russia:
V. N. Brichkin, Head of Metallurgy Department, Doctor of Technical Sciences, e-mail: Brichkin_VN@pers.spmi.ru
V. G. Povarov, Leading Researcher of the Center for Collective Use, Doctor of Chemistry Sciences, e-mail: povarov_vg@pers.spmi.ru
R. V. Kurtenkov, assistent, Metallurgy Department, Candidate of Technical Sciences, e-mail: Kurtenkov_RV@pers.spmi.ru

Abstract

The results of studying the activating effect of carbon on the sintering performance of two-component limestone-kaolin mixture and subsequent hydrometallurgical processing of sinter are presented. Samples of charcoal and used anodes from aluminum electrolysis plants were added to the kaolin-limestone mixture in the range of 1–4% carbon of the charge mass. Briquetted mixtures were sintered in the established technological mode, with a constant heating and cooling rate of materials at an isothermal holding temperature in the range of 1250–1360 °С. The temperature of phase transformations and the values of thermal effects were estimated by using thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The phase composition of the sinter was studied by X-ray diffraction analysis (XRD) and the particle size distribution of the sinter samples formed as a result of the self-disintegration process was studied by laser microanalysis. Sintered samples of the obtained particle size and without additional grinding were subjected to soda leaching under the same technological conditions in terms of temperature and process duration, initial concentration of solid in the pulp, composition and concentration of the solution. The sludges obtained from leaching the sinters were filtered and washed with distilled water then examined by (XRD) analysis to determine the phase composition and by X-ray fluorescence spectrometry (XRF) analysis to determine the chemical composition. Extraction of alumina into the solution was evaluated by the Al2O3 content in sinter and sludge. The results of experimental studies showed that the largest increase in the extraction of alumina from kaolin ore is more than 7% with a carbon content in the charge from 1.5 to 3.0%, depending on the nature of the carbon material. Further increase of the corresponding carbon additive in the charge causes a decrease in Al2O3 extraction, which is associated with the formation of hard-to-open mullite. At the same time, the activating role of the carbon additive has a thermodynamic energy and kinetic nature, which explains a more complete assimilation of lime with the formation of end products and a decrease in the metastable stability of the  β-form C2S. The latter causes its accelerated transition to a thermodynamically stable γ-modification of C2S, increased self-disintegration of sinter, and noticeable amorphization of sintering products.
Studies were conducted with the involvement of the laboratory base of the Center for Collective Use of the Mining University.
The work was carried out with the financial support of the Russian Science Foundation under the Agreement No. 18-19-00577 of April 26 2018 of grant for fundamental scientific research and exploratory scientific research.

keywords Kaolin ore, limestone-kaolin mixture, sintering, carbon addition, phase transformations, activation, self- disintegration, aluminum oxide recovery
References

1. Guo Y., Yan K., Cui L., Cheng F. Improved extraction of alumina from coal gangue by surface mechanically grinding modification. Powder Technol. 2016. No. 302. pp. 33–41.
2. Al-Zahrani A. A., Abdul-Majid M. H. Extraction of alumina from local clays by hydrochloric acid process. Journal of King Abdulaziz University: Eng. Sci. 2009. Vol. 20, Iss. 2. pp. 29–41.
3. ElDeeb A. B. S., Brichkin V. N. Egyptian aluminum containing ores and prospects for their use in the production of Aluminum. Int. J. Sci. Eng. Res. 2018. Vol. 9, Iss. 5. pp. 721–731.
4. Wu Y., Xu P., Chen J., Li L., Li M. Effect of temperature on phase and alumina extraction efficiency of the product from sintering coal fly ash with ammonium sulfate. Chin. J. Chem. Eng. 2014. Vol. 22, Iss. 11-12. pp. 1363–1367.
5. Samal S., Ray A. K., Bandopadhyay A. Characterization and microstructure observation of sintered red mud-fly ash mixtures at various elevated temperature. J. Clean. Prod. 2015. No. 101. pp. 368–376.
6. Tian Y., Pan X., Yu H., Han Y., Tu G., Bi S. An improved lime sinter process to produce Al2O3 from low-grade Al-containing resources. Ed. Williams E. Light Metals. 2016. pp. 5–9.
7. Brichkin V. N., Kurtenkov R. V., ElDeeb A. B., Bormotov I. S. State and development options for the raw material base of aluminum in non-bauxite regions. Obogashchenie Rud. 2019. No. 4. pp. 31–37. DOI: 10.17580/or.2019.04.06
8. Wang H., Feng Q., Liu K. The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process. Appl. Clay Sci. 2016. No. 132–133. pp. 273–280.
9. Al-Ajeel A. A., Abdullah S. Z., Muslim W. A., Abdulkhader M. Q., Al-Halbosy M. K., Al-Jumely F. A. Extraction of Alumina from Iraqi colored kaolin by lime-sinter process. Iraqi Bull. Geol. Min. 2014. Vol. 10, Iss. 3. pp. 109–117.
10. Toama H. Z., Al-Ajeel A. A., Jumaah A. H. Studying the efficiency of limesoda Sinter process to extract alumina from colored Kaolinite ores using factorial technique of design of experiments. Eng. Technol. J. 2018. Vol. 36, Iss. 5A. pp. 500–508.
11. Sizyakov V. M. Chemical and technological mechanisms of a alkaline aluminum silicates sintering and a hydrochemical sinter processing. Proceedings of the Mining Institute. 2016. Vol. 217. pp. 102–112.
12. Brichkin V. N., Vasilyev V. V., Nagornaya E. A., Gumenyuk A. M. Bauxite grade improvement through selective girding. Obogashchenie Rud. 2017. No. 3. pp. 3–9. DOI: 10.17580/or.2017.03.01
13. 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. P. 105–109.
14. 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. pp. 38–45. DOI: 10.17580/tsm.2018.03.06
15. Allegretta I., Pinto D., Eramo G. Effects of grain size on the reactivity of limestone temper in kaolinite clay. Appl. Clay Sci. 2016. No. 126. pp. 223–234.
16. Liu X., Liu X., Hu Y. Investigation of the thermal behavior and decomposition kinetics of kaolinite. Clay Miner. 2015. Vol. 50, Iss. 2. pp. 199–209.
17. Dubovikov O. A, Brichkin V. N., Ris A. D., Sundurov A. V. Thermochemical activation of hydrated aluminosilicates and its importance for alumina production. Non-ferrous Metals. 2018. No. 2. pp. 3–15. DOI: 10.17580/nfm.2018.02.02
18. Bai G., Teng W., Wang X., Qin J., Xu P., Li P. Alkali desilicated coal fly ash as substitute of bauxite in lime-soda sintering process for aluminum production. Trans. Nonferrous Met. Soc. China. 2010. Vol. 20, Iss. 1. pp. 169–175.
19. Sun H., Wang B., Zhang J., Zong S. Characterization and alumina leachability of 12CaO·7Al2O3 with different holding times. Adv. Mater. Sci. Eng. 2014. pp. 1–6.
20. ElDeeb A. B., Brichkin V. N., Kurtenkov R. V., Bormotov I. S. Extraction of alumina from kaolin by a combination of Pyro- and hydrometallurgical Processes. Appl. Clay Sci. 2019. No. 172. pp. 146–154.
21. Layner A. I., Eremin N. I., Layner Yu. A., Pevzner I. Z. Alumina Production. Мoscow : Metallurgiya, 1978. 344 p.
22. Guo Y., Yan K., Cui L., Cheng F., Lou H. H. Effect of Na2CO3 additive on the activation of coal gangue for alumina extraction. Int. J. Miner. Process. 2014. No. 131. pp. 51–57.
23. Tang A., Su L., Li C., Wei W. Effect of mechanical activation on acid-leaching of kaolin residue. Appl. Clay Sci. 2010. No. 48. pp. 296–299.
24. Kuang J., Yuan W., Li L., Hu J., XU L. Effects of Er(NO3)3, Nd(NO3)3 and Y(NO3)3 on kinetics of dehydroxylation of kaolinite. Powder Technol. 2016. No. 301. pp. 581–589.
25. Souri A., Golestani-Fard F., Naghizadeh R., Veiseh S. An investigation on pozzolanic activity of Iranian kaolins obtained by thermal treatment. Appl. Clay Sci. 2015. No. 103. pp. 34–39.
26. Qiao X. C., Si P., Yu J. G. A Systematic investigation into the extraction of aluminum from coal spoil through kaolinite. Environ. Sci. Technol. 2008. No. 42. pp. 8541–8546.
27. GOST 7657–84. Charcoal. Specifications. Introduced: 01.01.1986.
28. TU 1913-001-00200992–95. Calcined anode blocks type B and C for aluminium electrolyzers. Introduced: 01.01.1996.
29. Taylor H. F. W. Cement Chemistry. Мoscow : Мir, 1996. 560 p.
30. Khalifa A. A., Utkov V. A., Brichkin V. N. Red mud effect on dicalcium silicate polymorphism and sinter self-destruction prevention. Proceedings of Irkutsk State Technical University. 2020. Vol. 24. pp. 231–240.

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