Mining Institute, Kola Science Center, Russian Academy of Sciences, Apatity, Russia:

A. S. Opalev, Deputy Director of Scientific Work, Candidate of Engineering Sciences
M. S. Khokhulya, Leading Researcher, Candidate of Engineering Sciences, mike@goi.kolasc.net.ru
A. V. Fomin, Junior Researcher
I. V. Karpov, Leading Technologist

The authors review the available domestic technologies of iron processing with concentrate production at the final stage of dressing. These technologies fail to ensure the required quality of the concentrate by the iron mass fraction. Hematite concentrate production with jigging at processing plant of Olkon is discussed, and proposals are put forward for increased recovery of hematite from tailings of rougher magnetic separation by gravity concentration in thin flows (helical separation, table concentration). The paper describes the results of industrial tests on development of a technology for producing high-quality magnetite concentrates with content of Fetot. 69.5–70.5% at the dressing plants of Olkon and Karelsky Okatysh. It is shown that Olkon can obtain high-quality concentrates after the first grinding stage by the magnetic–gravity separation (MG-separation) from the undersize product of fine vibrating screening containing 45–52% Fetotal. Karelsky Okatysh applies MG-separation as a finishing operation of the prepared concentrate, as an alternative to the flotation re-concentration process, which makes it possible to obtain high-quality concentrates from refractory ore grades of the Kostomuksha deposit. To achieve the objectives, a pilot sample of a magnetic gravity separator MGS-0.5 was used. Based on the results of industrial tests, the authors propose an energy-saving processing technology ferruginous quartzites at Olkon and a process circuit for refractory ore at Karelsky Okatysh. In the gravitational cycle of hematite concentration at the processing plant of Olkon, it is recommended to replace inefficient jigging operation by the two-stage helical separation circuit, including tailings, rougher rough hematite concentrate, final table concentration and and high-intensity magnetic separation. Produced by the developed technology, the hematite concentrate contains about 57% of the mass fraction of hematite iron at recovery of 55% of Fetotal and 75% Fehem, which is 20–55% higher than concentration with jigging.

1. Chanturia V. A. Innovation-based processes of integrated and high-level processing of natural and technogenic minerals. Gornyi Zhurnal. 2015. No. 7. pp. 29–37. DOI: 10.17580/gzh.2015.07.05
2. Yushina T. I., Krylov I. O., Valavin V. S., Toan V. V. Old iron-bearing waste treatment technology. Eurasian Mining. 2018. No. 1. pp. 16–21. DOI: 10.17580/em.2018.01.04
3. Pirogov B. I. Technological mineralogy and iron ore. Leningrad : Nauka, 1988. 304 p.

4. Yushina T. I., Krylov I. O., Valavin V. S., Dunaeva V. N. Material constitution and features of low-grade and rebellious iron ore in processing and preparation for ROMELT direct iron ore smelting reduction process. Gornyi Zhurnal. 2015. No. 12. pp. 14–20. DOI: 10.17580/gzh.2015.12.03
5. Khokhulya M. S., Opalev A. S., Rukhlenko E. D., Fomin A. V. Production of magnetite-hematite concentrate from ferruginous quartzites and warehoused tailings based on mineralogy and technology studies. GIAB. 2017. No. 4. pp. 259–271.
6. Poperechnikova O. Yu., Shumskaya E. N., Nagaeva S. P. Semi-industrial researches of flotation technology of hematite concentrate obtaining from oxidized ferruginous quartzites. Gornyi Zhurnal. 2014. No. 11. pp. 40–43.
7. Lu Liming. Iron Ore: Mineralogy, Processing and Environmental Sustainability. Cambridge : Woodhead Publishing, 2015. 641 p.
8. Sadeghi M., Bazin C., Devin P.-O., Lavoie F., Hodouin D., Renaud M. Control of spiral concentrators for the concentration of iron ore. Proceedings of the XXVIII International Mineral Processing Congress. Quebec, 2016. Vol. 7. pp. 4534–4545.
9. Wanzhong Yin, Jizhen Wang, Longhua Xu. N Reagents in the Reverse Flotation of Carbonate-Containing Iron Ores. Proceedings of the 11^th International Congress for Applied Mineralogy. Cham : Springer International Publishing, 2015. pp. 459–470.
10. Buro Y. A., Schadrac Ibrango, Cassoff J., Bélanger L., Giroux É. et al. NI 43–101. Technical report on the feasibility study on labmag taconite project : final report. New Millennium Iron Corp., 2014. Available at: http://www.nmliron.com/data/document/en-CA/2013–007-NI-43–101-LabMag-FINAL.pdf (accessed: 19.04.2019).
11. Prokopyev S. A., Pelevin A. E., Napolskikh S. A., Gelbing R. A. Staged screw separation of magnetite concentrate. Obogashchenie Rud. 2018. No. 4. pp. 28–33. DOI: 10.17580/or.2018.04.06
12. Opalev A. S., Khokhulya M. S., Kucher E. V., Shcherbakov A. V. Upgrading of processing technology for ore and iron-containing waste towards complete extraction of valuable components and higher quality production. Modern Innovative Technologies in Mineral Mining and Processing : International Scientific–Practical Conference Proceedings. Moscow, 2018. pp. 187–194.
13. Patkovskaya N. А., Tasina Т. I. The Russia North-West Region iron-containing ores processing technology improvement. Obogashchenie Rud. 2011. No. 1. pp. 6–10.