STUDY OF SOLID PHASE PROCESSES UNDER SINTERING OF LIMESTONE-NEPHELINE MIXTURE WITH TECHNOGENOUS ADDITIVES

The PURPOSE of the paper is to study the thermochemical transformations occurring in limestone-nepheline mixture under sintering when technogenous additives are introduced. METHODS. Thermogravimetry, electron microscopy, mineralogical and x-ray diffractometric methods have been used in the study. RESULTS. It is proposed to introduce ferrotitanium slag in order to increase the content of alumina in limestone-nepheline mixture when sintering off-spec nepheline ore. It is shown that phase and chemical composition of ferrotitanium slag is not uniform since the slag is of technogenous genesis and contains many fine intergrowing mineral phases. The main minerals of the alumina containing slag are analcime (Na(Si₂Al)O₆×H₂O), montmorillonite (Al(OH)₂)_0.33Al₂(Si_3.67Al_0.33O₁₀)(OH)₂), hercynite (FeAl₂O₄) and iron replaced grossular (Ca₃Al₂(SiO₄)₂(OH)₄). It is noted that the behavior of minerals under limestone-nepheline mixture sintering differs significantly when ferrotitanium slag is introduced. It has been proved that slag minerals - analcime and montmorillonite - can be easily released in the process of caustic leaching. Grossular can be released in strong caustic condition only. Spinel hercynite (FeAl₂O₄) can not be broken down completely even in strong caustic conditions. Technological studies of limestone-nepheline mixture sintering with the addition of grounded ferrotitanium slag (100% -0.074 mm fraction) have shown the increase of alumina content in the sinter. CONCLUSION. Conducted thermochemical studies of ferrotitanium slag and its soda and limestone mixture calcination have shown that sintering temperature is about 1237°C. It is lower than the sintering temperature of limestone-nepheline mixture without slag additions. The results of technological tests of mixture sintering in the presence of ferrotitanium slag have confirmed the results of thermoanalitical studies. Addition of 5% of grounded ferrotitanium slag (100% -0.074 mm fraction) in limestone-nepheline mixture has increased the alumina content in sinter from 16 to 17.5-18.5%.

alumina production, ferrotitanium slag, nepheline ore, thermochemical transformations, limestone-nepheline mixture, technological studies

1. Сизяков В.М. 80 лет алюминиевой промышленности России (историко-аналитический обзор) // Цветные металлы. 2012. № 5. С. 76-84.

2. Matjie R H, Bunt J R, Van H. Extraction of Alumina from Coal Fly Ash Generated from a Selected Low Rank Bituminous South African Coal // Minerals Engineering. 2005. Vol. 18. Issue 3. P. 299-310.

3. Yao Z.T., Xia M.S., Sarker P.K. A review of the alumina recovery from coal fly ash, with a focus in China // Fuel. 2014. Vol. 120. P. 74-85.

4. Сизяков В.М. Современное состояние и проблемы развития алюминиевой промышленности России // Записки горного института. 2006. Т. 163. С. 163-170.

5. Roelof Den Hond, Iwan Hiralal, Ab Rijkeboer. Alumina Yield in the Bayer Process; Past, Present and Prospects // Light Metals. 2007. P. 3742-3758.

6. Шепелев И.И., Сахачев А.Ю., Александров А.В. и др. Альтернативные направления переработки некондиционного нефелинового сырья // Научные основы и практика переработки руд и техногенного сырья: материалы XXII Междунар. науч.-техн. конф. (Екатеринбург, 19-20 апреля 2017 г.). Екатеринбург: Изд-во ООО «Таилс КО», 2017. С. 244-249.

7. Ни Л.П., Райзман В.Л. Комбинированные способы переработки низкокачественного алюминиевого сырья. Алма-Ата: Наука, 1988. 255 с.

8. Loginova I.V., Kyrchikov A.V., Lebedev V.A., Ordon S.F. Investigation into the question of complex processing of bauxites of the Srednetimanskoe deposit // Russian Journal of Non-Ferrous Metals. 2013. Vol. 54. No. 2. P. 143-147.

9. Виноградов С.А. Технология совместной переработки нефелинов и бокситов // Записки Горного института, 2007. Т. 170. С. 153-156.

10. Ndlovu S., Simate G.S., Matinde E. Waste Production and Utilization in the Metal Extraction Industry. Boka Raton: Taylor & Francis, CRC Press, 2017. 511 p.

11. Zhang L., Zhang L.N., Wang M.Y., Li G.Q., Sui Z.T. Recovery of titanium compounds from molten Ti-bearing blast furnace slag under the dynamic oxidation condition // Minerals Engineering. 2007. Vol. 20. P. 684-693.

12. Holappa L, Xiao Y. Slags in ferroalloy production - review of present knowledge // Journal of the South African Institute of Mining and Metallurgy. 2004. Vol. 104. No. 7. P. 429-437.

13. Головных Н.В., Шепелев И.И., Пихтовников А.Г., Горбачев С.Н. Использование техногенных отходов в глиноземном производстве при переработке нефелинового сырья // Цветные металлы. 2012. № 5. С. 84-88.

14. Cherkasova M.V., Brichkin V.N., Kremcheeva D.A. Recovery of valuable components during co-processing of nepheline concentrates and urtite rocks from Khibini region of Russia // Scientific reports on resource. Issues 2015, Innovations in Mineral Resource Value Chains Freiberg (Germany): Medienzentrum der TU Bergakademie Freiberg, 2015. P. 178-182.

15. Перепелицын В.А., Рытвин В.М., Гильварг С.И. и др. Ферросплавные алюмотермические шлаки. Екатеринбург: Уральский рабочий. 2014. 368 с.

16. Шепелев И.И., Алгебраистова Н.К., Сахачев А.Ю., Жижаев А.М., Прокопьев И.В. Исследование измельчаемости нефелиновой руды и шлака ферротитанового производства для их переработки по спекательной технологии // Вестник ИрГТУ. 2017. Т. 21. № 11. С. 167-178. https://doi.org/10.21285/1814-3520-2017-11-167-178

17. Perepelitsyn V.A., Ponomarenko A.A., Gilvard S.I., Rytvin V.M. Titanium-Alumina Slag - Semifunctional Technogenic Resource of High-Alumina Composition. Part 1. Substance Composition and Titanium-Alumina Slag Properties // Refractories and Industrial Ceramics. 2017. Vol. 58. No. 2. P. 130-135. https://doi.org/10.1007/s11148-017-0070-7

18. Перепелицын В.А., Рытвин В.М., Коротеев В.А. Техногенное минеральное сырье Урала. Екатеринбург: РИО УрО РАН. 2013. 332 с.