PHYSICO-CHEMICAL PROCESSES IN IRON ORE CONCENTRATE, PREVENTED BY LIME

Technological and mineralogical studies of the iron ore concentrate of wet magnetic separation were performed before, during and after prophylaxis with calcined limestone. It is shown that the water in the composition of the prophylactic concentrate has a complex heterogeneous solution in which Ca²⁺, (OH)^–, H⁺ ions are present, as well as colloidal dispersed particles of CaO, Ca(OH)₂, Fe₂O₄ and other minerals. It has been established that the mineral particles of the prophylactic concentrate form locally oriented aggregates among themselves, and the water becomes structured during prophylaxis. Differential thermal analyses of wet magnetic separation concentrate with the addition of different amounts of lime (from 4 to 14 %). It has been established that the evaporation of water in the concentrate begins from the twenty-fourth minute after the addition of lime and is accompanied by a large amount of heat. At the same time, the speed and temperature of the water evaporation process depends on the amount of lime introduced into the wet concentrate. The conducted studies allowed us to establish that during the prophylaxis of the concentrate, moisture evaporation proceeds more intensively in the first four hours and, depending on the mass of the burnt limestone added, the moisture content of the concentrate decreases by 0.3 – 1.0 %. It was found that a further decrease in moisture in the concentrate occurs due to the latent heat of crystallization and mineral formation. It has been experimentally established that the complete natural drying of the concentrate in the warm season lasts about 160 ‒ 250 hours (at a temperature of 20 °C).

1. Bersenev I.S., Klein V.I., Zarshchikov P.I., Osokin N.A., Shcheglov V.N. Production no-tified to agglomeration machine Mak-90. Stal'. 2013;4:2‒5. (In Russ.).

2. Prokhorovich V.A., Zaostrovsky A.I. Increas-ing the moisture capacity of iron ore concen-trates. Bulletin of the Kuzbass State Technical University. 2007;4:58-59. (In Russ.).

3. Bazilevich S.V., Vegman E.F. Agglomeration. Moscow: Metallurgiya, 1967:367. (In Russ.).

4. Berezhnoi H.H., Bulychev B.V., Kostin A.I. Manufacture of iron equipment in the district of Okat. Moscow: Nedra, 1977:240. (In Russ.).

5. Napol'skikh S.A., Gel'bing R.A., Sukharev A.G. Method sushki toncommelable Iron Horse-Center. Pat. 2425155 RF; opubl. 27.07.2011. (In Russ.).

6. Gelbing R.A., Ryabov N.I., Rybakin D.V., Mamonov A.L., Volkov D.N. A method for preventing freezing of wet iron ore concentrate. Pat. 2743951 of the RF; publ. 01.03.2021. (In Russ.).

7. Wang S., Guo K., Qi S., Lu L. Effect of fric-tional grinding on ore characteristics and se-lectivity of magnetic separation. Minerals En-gineering. 2018;122:251–257.

8. Sivrikaya O., Arol A.I. Use of Colemanite as an Addi-tive in Iron Ore Pelletizing. Proceeding of 11th. Inter-national Mineral Processing Symposium IMPS, Belek. Antalya. 2008:1121–1127.

9. Hong C., Xing Y., Si Y.X. et al. Lime-Mediated Sewage Sludge and Gas Ash use as Metallurgy Sin-tering Ingredients. Advanced Materials Research. 2013;779-780(9):1623‒1628.

10. Gen-Sheng Feng, Sheng-Li Wu, Hong-Liang Han et al. Sintering characteristics of fluxes and their structure optimization. International Journal of Minerals, Metallurgy and Materials. 2011:18(6):270‒276.

11. Jeong D., Kim K., Min D. W., Choi W. Freezing-Enhanced Dissolution of Iron Oxides: Effects of Inor-ganic Acid Anions. Environmental Science & Technol-ogy. 2015;49(21):12816–12822.

12. Chen H., Yi X., Yan X.S., Wang Z., Guang W.Y., Chang S.Y., Yang L., Xing Q.T., Fan Z., Ana A. Lime-Mediated Sewage Sludge and Gas Ash use as Metallurgy Sintering Ingredients. Ad-vanced Materials Research. 2013;779–780(9):1623‒1628. http://dx.doi.org/10.4028/www.scientific.net/AMR.779-780.1623

13. Feng G., Wu S., Han H., Ma L., Jiang W., Liu X. Sintering characteristics of fluxes and their structure optimization. International Journal of Minerals, Met-allurgy and Materials. 2011:18(6):270‒276. http://dx.doi.org/10.1007/s12613-011-0433-x

14. Loo C.E., Ellis B.G. Changing Bed Bulk Den sity and other Process Conditions during Iron Ore Sinter-ing. ISIJ International. 2014;54(1):19‒28. https://doi.org/10.2355/isijinternational.54.19

15. Cores A., Verdeja L.F., Ferreira S., Ruiz-Bustinza I., Mochon S. Sinterizacion de Min-eralesde Hierro. Parte 1. Teoria y Practica dee proceso. Dyna. August 2019:152‒171.

16. Permyakov A.A., Kuvshinnikova N.I., Kalinogorskii A.N., Butov P.Yu., Ganzhenko I.M., Osokin N.A. Technological-mineralogical and investigated Kinet-ics process in the Prevention of concentrate produced by Abagur branch OAO"EURASRUDA". In: Metal-lurgy: techno-Logies, management, innovation, quali-ty. All-Russian Scientific and practical conferences, 8-11 October 2013. Novokuznetsk: ITs SibGIU. EDN: RUPOET. 2013:12‒17. (In Russ.).

17. Glinka N.L. General chemistry. Leningrad: Khimiya, 1979:688.10.

18. Eisenberg D., Kautsman V. Structure and properties of water. Translated from English. Leningrad: Hydrometeoizdat. 1975:280.

19. Wells A. Structural inorganic Chemistry. Vol. 2. Translated from English. Moscow: Mir. 1987:696.

20. Filatov S.V., Kurunov I.F., Semenov O.A., Mansurova N.R., Koshelev V.A. Optimization of lime consumption when entering the sinter in order to improve the quality of the sinter. Steel. 2010;10:7‒9. (In Russ.).

21. Khristoforov V.P. Optimization of lime consumption in the production of agglomerate in the conditions of JSC Ural Steel. Science and production of the Urals. 2015;11:16‒19. (In Russ.).