This work presents the results of smelting ferromanganese from high-silica iron-manganese ores with 36 % manganese content by the flux method. The Shubarkol deposit coal and metallurgical coke as reducing agents were used. The fluxing material was solid slag from the smelting of medium-carbon ferromanganese. The technological modes of the smelting process are established. The optimal composition of the charge was determined. As a result of the theoretical and experimental studies, the tasks have been solved completely - the smelting technology of high-silicon ferromanganese was developed and tested using a substandard raw materials, such as iron-manganese ores and flux

A. Baisanov

A. Isagulov

N. Smagulova

V. Yudakova

Zh. Maishina

English

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89METALURGIJA 60 (2021) 1-2, 89-92A. BAISANOV, ZH. MAISHINA, А. ISAGULOV, N. SMAGULOVA, V. YUDAKOVAEXPERIMENTAL MELTING OF HIGH-SILICON FERROMANGANESE WITH THE USE OF FERROMANGANESIAN ORE AND MANGANESE SLAGReceived – Primljeno: 2020-08-25Accepted – Prihvaceno: 2020-10-30Preliminary Note – Prethodono priopćenjeA. Baisanov (alibekbaisanov-chmi@mail.ru), Chemical and metal-lurgical institute named after J. Abishev, Karaganda, Kazakhstan. Zh. Maishina, А. Isagulov, N. Smagulova, V. Yudakova Karaganda Techni-cal University, Karaganda, KazakhstanThis work presents the results of smelting ferromanganese from high-silica iron-manganese ores with 36 % manga-nese content by the flux method. The Shubarkol deposit coal and metallurgical coke as reducing agents were used.The fluxing material was solid slag from the smelting of medium-carbon ferromanganese. The technological modes of the smelting process are established. The optimal composition of the charge was determined. As a result of the theoretical and experimental studies, the tasks have been solved completely - the smelting technology of high-sili-con ferromanganese was developed and tested using a substandard raw materials, such as iron-manganese ores and flux.Keywords: ferroalloys, high-silicon ferromanganese, ore-thermal smelting, substandard raw materials, chemical compositionINTRODUCTIONThe steady growth of world steel production observed in recent decades is associated with the inherently grow-ing demand of the metallurgical industry for ferroalloys. The most used today are manganese-containing ferroal-loys (high- and low-carbon ferromanganese, ferrosilicon manganese, metallic manganese, etc) [1].Today, it is interesting and relevant to obtain high-silicon ferromanganese using non-traditional ferroman-ganese ores and manganese slag for this process. Inter-est arose in connection with the steady depletion of re-serves and the high cost of manganese-containing raw materials.It is known that for the carbon ferromanganese FeMn75 and FeMn78 grade production requires high-quality concentrates with at least 43 and 50 % manga-nese content, respectively. The Mn/Fe ratio must be at least 8 [2-4].Standard carbon ferromanganese, according to GOST 4755-91 must contain no more than 2 % of sili-con. Therefore, the ratio of SiO2/Mn in manganese-ore raw materials should be equal to 0,3 and 0,2 for the smelting of carbon ferromanganese, respectively, grades FeMn75 and FeMn78. Manganese ores with SiO2/Mn ratio greater than 0,4 are not applicable [5-6].The study of the process of obtaining ferromanga-nese with a high silicon content (6-8 %) is particularly relevant today. This alloy can be used for deoxidation of ISSN 0543-5846METABK 60(1-2) 89-92 (2021)UDC – UDK 669.168:669.15.782.74:621.745:66.014 = 111quiet steel, where the presence of silicon facilitates the deoxidation process. The production of ferromanganese from iron-manganese ores with a ratio of silicon to manganese greater than 0,4 is appropriate due to its cost-effectiveness due to the use of cheap substandard raw materials. Thus, the purpose of this work is to re-search using of iron-manganese ores and slag from the medium-carbon iron-manganese smelting of instead of standard expensive raw materials for ferromanganese smelting.RESEARCH METHODOLOGYIn real industrial conditions, refined ferromanganese is obtained from manganese ore, low-phosphorous manganese slag or silicomanganese withlime, where lime binds silica to calcium silicates [7]. In this paper, tests for ferromanganese smelting were carried out us-ing iron-manganese ores with a high content of silicon from the Bogach and Yessymzhal deposits.Chemical composition of Bogach and Yessymzhal ore deposits, which were used for experimental tests are presented in Table 1 and Table 2, respectively.Metallurgical coke and long – flame gas coal of the Shubarkol deposit as a reducing agent were used. Tech-nical analysis of Shubarkol deposit coal and metallurgi-cal coke is shown in Table 3.Chemical composition of coal ash / %: SiO2 – 60 - 64, Al2O3 – 30 - 35. Specific heat of coal burning is 7 500 – 8 000 thousand kcal/kg. Specific consumption of high-ash coal per 1 ton of fer-roalloy was 2,72 t.The fluxing material was solid slag from of the me-dium-carbon ferromanganese smelting with 22 – 24 % 90A.BAISANOV et al.: EXPERIMENTAL MELTING OF HIGH-SILICON FERROMANGANESE WITH THE USE OF... METALURGIJA 60 (2021) 1-2, 89-92the discharge of an arc of a graphite electrode with 200 mm diameter.The furnace was heated for 8 hours using a coke pil-low as an electric current conductor. At the end of the heating period, the bath was completely cleared of the remains of the coke pillow. Electric mode of the heating period: voltage 49 V, load on the electrodes 100 - 200 A.After the initial heating period and the formation of a garnissage on the walls of the furnace, the formation of the crucible shifted slightly towards the right elec-trode because the main arc burning occurred under it The current load was stable at 380 - 430 A. The charge collapsed by self-propelled, which indicates the pres-ence of a gas cavity under the grate, which also contrib-uted to the easy cutting of the pilot hole.The melting process was periodic with an average duration of 1 - 1,5 hours, i.e. the charge is loaded after the release and set of current load. The charge settled by itself as it was melted, forming a slag bath in the center of the furnace. During melting, the current load was kept evenly (I = 150 – 250 A), and no emissions were observed on the grate. The slag was liquid and active. After melting the charge, the slag and metal were re-leased from the pilot hole (Figure 1). The metal and slag were separated well after cooling.During operation, no serious deviations from the normal course were observed. The landing of the elec-trode was quite deep and stable, no sintering of the grate was observed. Metal and slag came out actively, which confirmed the hot course of the process as a whole.The alloy was produced in cast-iron mills, the average weight of the alloy piece is 11-15 kg, the alloy does not crumble. To average the alloy, grinding was performed on a jaw crusher, where the formation of fines (fractions less than 10 mm) is no more than 10 % of the total mass.Table 1  Chemical compositioniron-manganese ore with a high content of silicon from the Bogach deposit№ Name of the sampleContent / %Mntotal Fеtotal SiO2 Mn/Fe SiО2/Мn1 Sample of Mn ore 1 30,11 8,35 18,72 3,61 0,622 Sample of Mn ore2 33,8 4,97 23,0 6,80 0,683 Sample of Mn ore3 26,53 6,87 17,52 3,86 0,664 Sample of Mn ore 4 35,51 5,98 14,13 5,94 0,40MnO content and a basicity of 1,3 – 1,5. Additional charging by other materials was not done.Tests on the smelting of high-silicon ferromanga-nese were carried out at the experimental site of the Chemical and metallurgical Institute named after J. Abi-shev on an ore-thermal furnace, which is equipped with a two-phase step-down furnace with 0,2 MVA trans-former capacity. The secondary voltage varies between 18 - 50 V (six steps), the current on the high side reach-es 789 A.Lining the inner surface of the furnace with fireclay and magnesite refractory bricks, with filling the seams with fireclay powder, coking the pilot block, pre-paring the electrode holder, graphite electrodes and nip-ples was part of the preparation of the ore-thermal fur-nace for melting.Prepared a flying hole at the bottom at the level of the bottom for the release of metal. The filling of the furnace bottom is carried out at a slight angle in the di-rection of the pilot hole, which provides an easier exit of the melt from the recovery zone. The temperature in the reaction zone reaches 2 500 – 4 500 °C is provided by Table 2  Chemical composition iron-manganese ore with a high content of silicon from the Yessymzhal deposit№ Name of the sampleContent / %Mntotal Fеtotal SiO2 Mn/Fe SiО2/Мn1 Sample of Mn ore 5 39,30 6,52 18,53 6,03 0,472 Sample of Mn ore 6 28,17 19,32 16,87 1,46 0,603 Sample of Mn ore 7 34,11 7,64 15,64 4,46 0,464 Sample of Mn ore 8 29,23 4,50 19,61 6,50 0,67Table 3 Technical analysis of the Shubarkol deposit coal and metallurgical cokeMaterialTechnical analysis / %W(moisture)A(ash)V(volatile matter yield)Cs(solid carbon)Shubarkol deposit coal 1,78 29 12 46Metallurgi-cal coke 1,28 12,18 2,0 84,92Figure1 Release of ferromanganese from the 0,3 MVA furnace91A.BAISANOV et al.: EXPERIMENTAL MELTING OF HIGH-SILICON FERROMANGANESE WITH THE USE OF...METALURGIJA 60 (2021) 1-2, 89-92After cooling, the molten metal was subjected to rapid analysis using a portable Niton X-ray-fluores-cence analyzer to monitor the melting process and charge composition.RESULTS RESEARCHSelectively, individual samples were submitted for a full chemical analysis of the main elements. The results of chemical analysis of experimental samples of slag and metal are presented in Table 4 and Table 5, respec-tively.According to the results of experimental work on the smelting of high-silicon ferromanganese, the following was established:− the multiplicity of slag is 2,1 - 2,3;− manganese extraction rate 79 - 81 %−  the degree of silicon recoveryis 18 - 22 %.In the process of smelting high-silicon ferromanga-nese using iron-manganese ore and manganese slag, the furnace operation was characterized by a stable current load. The landing of the electrode was sufficiently deep and stable, and the top was not sintered. Metal and slag came out actively, which confirmed the hot course of the process as a whole.Thus, as a result of experimental melting, an experi-mental batch of ferromanganese alloy with a high con-Table 4  Chemical composition of metal samples obtained from experimental smelting of high-silicon ferromanganese№ Content / %Mn Fе Si S P1 75,1 11,71 5,91 0,0039 0,1312 76,0 11,77 4,57 0,0032 0,1003 75,0 10,37 4,88 0,0039 0,0964 74,8 11,04 5,60 0,0032 0,0925 75,1 10,76 5,98 0,0039 0,0816 74,3 10,71 9,09 0,0039 0,0737 72,8 12,32 7,34 0,0038 0,0928 74,1 10,48 9,02 0,0032 0,0819 74,3 10,04 8,98 0,0038 0,09210 75,0 10,48 5,71 0,0026 0,112Table 5  Chemical composition of slag obtained as a result of experimental smelting of high-silicon ferromanganese№ Content / %MnО Fеtotal SiO2 Аl2O3 CаO MgO S C1 7,9 0,38 36,47 7,32 42,26 0,15 0,095 0,0782 16,3 - 35,36 5,19 43,82 - 0,115 0,2303 3,7 0,27 27,90 4,45 57,91 - 0,217 5,3174 7,0 1,26 21,55 4,17 54,78 0,08 0,231 4,2835 3,4 0,44 27,21 6,35 54,78 0,01 0,134 3,1506 3,8 0,27 29,00 6,01 52,43 0,06 0,117 3,3087 3,3 0,055 29,97 7,31 56,34 0,01 0,141 1,7768 3,7 0,27 27,90 4,45 57,91 - 0,217 5,3179 4,0 1,26 21,55 4,17 54,78 0,08 0,231 4,28310 5,4 0,49 25,14 5,95 54,65 - 0,186 4,311tent of silicon was developed. The alloy which was ob-tained by the experimental melting in ore-thermal fur-nace is characterized by the following chemical compo-sition / %: Mn - 73 - 76, Si - 5,7 - 9,09, P - 0,07-0,131; S - 0,0026 - 0,0039; C - 2,2.Also, possibili ty of achieving the minimum content of 3,3 - 3,4 % MnO in waste slags was shown.CONCLUSIONThus, as a result of experimental melting, an experi-mental batch of ferromanganese alloy with a high con-tent of silicon was developed. The experimental alloy was obtained using substandard materials as the charge. Such materials as iron-manganese ores of Bogach and Yesymzhal deposits were used. The slag from the smelt-ing of medium-carbon ferromanganese as fluxing mate-rials was used. Metallurgical coke and long-flame gas coal from the Shubarkol deposit were used as reducing agents.The tests have shown that for the smelting of high-silicon ferromanganese corresponding to the FeMn75 grade for manganese, it is possible to use manganese ores with a Mn/Fe ratio of less than 8 and SiO2/Mn ratio of more than 0,4, which significantly reduces the re-quirements for the quality of the initial manganese raw materials.Experiments on smelting were carried out in an ore-thermal furnace with a transformer capacity of 0,3 MVA. This study has shown the possibility of smelting carbon ferromanganese, standard for the main element, from high-silica ferromanganese ores with a content of less than 36% of manganese by the flux method. At the same time, as a fluxing and low-iron manganese addi-tive, it is possible to use a solid slag from the smelting of medium-carbon ferromanganese with a content of 22 - 24 % MnO and a basicity of 1,3 - 1,5.Engaging for ferromanganese smelting substandard raw materials allows to exclude traditionally used sili-comanganese brand SiMn17 and SiMn26. In this rough comparative economic evaluation of traditional and devel-oped technology shows that the cost of 1 t of ferromanga-nese in the studied technology will be significantly lower than traditional.The data obtained by us give grounds to make a ten-tative conclusion about the possible economic and tech-nological feasibility of obtaining ferromanganese with a high content of silicon from high-silica ferromanga-nese ores and manganese slags.To establish the economic and technological effi-ciency of this alloy, it is necessary to conduct further research and implement it in real production conditions as a deoxidizer and modifier of steel.The obtained data will further allow us to develop a comprehensive and resource-saving technology for smelting a new type of manganese-containing Ferroal-loy, which can be used in the steel industry, in particular for deoxidizing steel and other types of steel.92A.BAISANOV et al.: EXPERIMENTAL MELTING OF HIGH-SILICON FERROMANGANESE WITH THE USE OF... METALURGIJA 60 (2021) 1-2, 89-92REFERENCES[1] Tekhnologiya margancevyh ferrosplavov. CH. 2. Nizkou-glerodistye splavy / V. I. ZHuchkov, L. A. Smirnov, V. P. Zajko, YU. I.  Voronov. – Ekaterinburg: UroRAN, 2008. – 442 s (Russian)[2] Gabdullin T. G., Takenov T. D., Baisanov S. O., Buketov E.A. Fiziko-himicheskie svojstva margancevyh shlakov. – Alma-Ata:Nauka, 1984. – 92 (Russian)[3] Gasik M. I. Marganec. – M.: Metallurgiya, 1992. - 608 s. (Russian)[4] Gasik M.I. Elektrotermiya marganca. Kiev, Tekhnika, 1979. (Russian)[5] W. Zhang, Ch. Y. Cheng. Manganese metallurgy review. Part I: Leaching of ores/secondary materials and recovery of electrolytic/chemical manganese dioxide. Hydrometal-lurgy 89 (2007) 137–159.[6] Zhukov, D. Y., Averina, Y. M. Development of a pyrome-tallurgical technology for processing synthetic pyrolusite and chemisorption manganese oxide concentrate into me-tallic manganese and low-carbon ferroalloys. CIS Iron and Steel Review (2019)17, 25-29.[7] A. Issagulov, N. 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Experimental melting of high-silicon ferromanganese with the use of ferromanganesian ore and manganese slag

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