Evrazruda (Russia):

Ganzhenko I. M., Chief Specialist, pashkova_ns@nkmk.ru 
Zarshchikova G. G., Head of Laboratory, zarshhikova_gg@nkmk.ru 
Kamalova T. B., Head of Section, kamalova_tb@nkmk.ru
Alekseeva L. A., Leading Engineer, alekseeva_la@nkmk.ru
Shestak Ye. M., Deputy Shop Superintendent, shestak_em@nkmk.ru

Institute of Physics, Siberian Branch of the Russian Academy of Sciences (Russia):

Yakubailik E. K., Senior Reseacher, Ph. D. in Physical and Mathematical Sciences, churilov@iph.krasn.ru

Strong-magnetic iron ores classification efficiency, as well as efficiency of related process of strong-magnetic iron ores grinding in wet magnetic concentration, depend, in addition to water regime, on ore material magnetic properties: residual magnetization (σ_r), coercitive force (Н_с), saturation magnetization (σ_s). The mentioned properties cause concentrated material particles flocculation, which significantly hinders material sizing in classification and worsens grinding process results. The article presents the results of the investigations performed with a view to determine a degree of demagnetization effect, taking place ahead of secondary grinding stage hydrocyclones, upon the processing results at the OAO Evrazruda Abagursky operation. Preliminary studies were performed at the SB RAS Institute of Physics on magnetic properties of the Abagursky operation feed ores and their concentration products, also, concentrated material particles flocculation and deflocculation in demagnetization were studied. Magnetic strength of the field, required for Abagursky ores material deflocculation, was determined. Commercial-scale testing was performed on secondary grinding stage section, that included MShTs 2700×3600 mill, GTs-360 hydrocyclones, Eriez DRW9 demagnetizing apparatus and 8Gr8 360/40 pump. It was established, that application of demagnetization improves hydrocyclones' overflow parameters and leads to increase in size fractions coarser than 71 microns recovery into sands by 8.9 % (up to 86.6 %). As a result, mill circulating load was increased by 82 %, and mill specific throughput — by 13.7 %.

1. Lomovtsev L. A., Nesterova N. A., Drobchenko L. A. Magnitnoye obogashcheniye silnomagnitnykh rud (Magnetic beneficiation of strong-magnetic ores). Moscow, Nedra, 1979.
2. Volgay V. F., Karmazin V. I., Yurov P. P. K voprosu ob issledovanii namagnichivaniya i razmagnichivaniya magnetitovykh i vosstanovlennykh zheleznykh rud (To the question of research of magnetite and reduced iron ores magnetization and demagnetization). Obogashcheniye poleznykh iskopayemykh. Nauchno-tekhnicheskiy sbornik (Minerals processing, Scientific-technical collected book), Iss. 3, Kiev, Tekhnika, 1968, p. 19.
3. Spravochnik po obogashcheniyu poleznykh iskopayemykh (Minerals processing reference book). Vol. 1. Podgotovitelnyye protsessy (Preparative processes). Moscow, Nedra, p. 270, 299.
4. Ibidem, p. 282.