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Samadov Alisher Usmonovich, doctor of Technical Sciences, Almalyk branch of Tashkent state technical university E-mail: alishersamadov@yandex.ru Xoliqulov Doniyor Baxtiyorovich, candidate of technical sciences, Almalyk branch of Tashkent state technical university, E-mail: doniyor_xb@mail.ru Matkarimov Sohibjon Turdalievich, senior teacher of chair"Metallurgy" Tashkent state technical university
EXTRACTION IRON AND ITS COMPOUNDS FROM SLAGS BY USING GRAVITATION METHODS
Abstract: The article considers the issues of additional extraction of iron and its oxidized compounds from steel-making slags SC "Uzbeksteel". It is shown that after the separation of the magnetic components in the dump slags a significant amount of iron remains, the concentration of which is comparable to the poor iron ores of Uzbekistan.
Keywords: slags, iron extraction, steel-smelting slags, additional extraction, magnetic components, gravitational precipitation.
For years of independence the Republic of Uzbekistan has turned into dynamically developing state which is moving ahead on the way of technological progress. Problems of rational use of natural resources and environmental protection are under constant attention of the leadership of the Republic of Uzbekistan [1]. The basic concepts of waste-free and low-waste technology are so far formulated; the main objectives and the directions of their development are planned. Features are revealed and the main directions of development waste-free and low-waste technologies of mining and metallurgical productions which consist in development of essentially new directions, nonconventional ways and improvement of the existing production technologies, for reduction at all his stages of harmful emissions of complexity of use of raw materials and full use of the formed waste are planned. It directly concerns also the only enterprise of ferrous metallurgy in the Republic, SC "Uzbeksteel".
When melting ferriferous raw materials, at the expense of the proceeding physical and chemical changes steel-smelting slags are formed. The maintenance of Fet al in the formed slags makes the considerable size (50-70%), and pure iron of 10-12%. Now on Uzbeksteel these slags for extraction of ferriferous components and pure iron are exposed to crushing, crushing and magnetic separation. After processing slags contain 15-25% of the sum of Fe2O3 and FeO and also 2-4% of Femet. These slags aren't processed and stored now in special dumps while when melting steel in the martin and arc steel-smelting furnace as oxidizers apply Fe2O3, FeO, iron ore, scale,
agglomerate, iron ore briquettes and other materials abroad, for currency. At the same time the plant incurs substantial damages on the organization and operation of slag dumps. Today reserves of slags make 1-1,5 million tons, the annual gain makes 60-80 thousand tons [2].
When carrying out approximate calculations it is possible to see that the quantity of Fe2O3 which is contained in the saved-up steel-smelting slags is 100-150 thousand tons, and the amount of pure iron is 20-40 thousand tons. As a result of extraction of iron and its connections from steel-smelting slag the volume of the oxidizer delivered from abroad will be reduced by 6,0-10,0 thousand tons when processing 60,0-80,0 thousand tons of steel-smelting slags in a year. Besides, it will have also considerable social effect since the ecological situation around the plant improves. As a result of the research works which are carried out at departmentof Metallurgy it has been established that for extraction of iron and its compounds from the processed steel-smelting slags application of methods of gravitational enrichment is possible. The fact that about 90% of iron and manganese ores are enriched with gravitational methods also demonstrates to it and also individual share of gravitational methods in processing of the oxidized iron ores annually increases [3].
For definition of an optimum way of extraction of iron and its connections the following methods of gravitational enrichment have been used: jigging; enrichment on a screw separator; enrichment on a concentration table. Chemical consists steelmaking slag SC "Uzbeksteel",%: Fe 1.5-1.6; FeO 7.4-9.8;
Fe2O3 15.4-17.5; CaO 22.0-26.0; SiO2 24.0-28.0; Al2O3 5.8-7.0; MnO 7.9-10.2; MgO 7.61-10.7; P2O5 0.2-0.13; SO3 0.2-0.26; others 2.8-5.1.
100 %T 75
50
25
-0
Optical properties of Fe2O3 sample were determined through UV-spectrum. The optical absorption spectra was recorded by using SHIMADZU IRAffinity - 1 (Figure 1).
4500 4250 4000 17,01,2018 Sohib 1pr
3500 3250 3000 2750
Figure 1. UV-spectrum of steel smelting slag SC "Uzbeksteel"
The UV spectrum of iron oxide manifests prominent absorption band located at 398.32.434.00 and 507.37 cm-1.
o ID CO ro" --3,038
.......................................................... 00 in CN ........ 2,890 2,797
r- CN O o~ r-H UD p-? OD r- £ O | J^IW UD ÎN l'en AM in m ro ! ij1 S s N LT5 g "S r-_ 2 CO 1 CM Mi CO CD Ï-H r-T r- f £ ° Av/^ CN LT> U- W^vA^ r-- co 1,257
3000-
2000-
1000-
10
30
40
60
70
Ttieta-2Theta fdeqj
Figure 2. XRD pattern of steel smelting slag SC "Uzbeksteel"
The structural features of minerals are explored from XRD date (Figure 2). They are: anortit with sodium feldspar - 4.265; 3.343; 1.813; 1.539 Â; mullite - 2.855; 2.452 Â; hematite - 2.696; 2.518; 1.834; 1.688 Â; enstatit - 3.157 Â; magnetite 2.541; 1.612 Â. On the structure steel-smelt-
ing slags are self-breaking up and low-active. The maintenance of Fe in slags fluctuates within 50-70%, pure iron -10-12%.
Table 2.- Particle size distribution of the processed steel-smelting slag
Class, mm Mass, kg Out put, % Total «+», %
+3.0 0.859 17.18 17.18
-3.0+2.5 0.280 5.6 22.78
-2.5+2.0 0.320 6.4 29.18
-2.0+1.5 0.470 9.4 38.58
-1.5+1.2 0.243 4.86 43.44
-1.2 2.828 56.56 56.56
Total 5.0 100 100
Extraction of iron and its connections from the processed steel-smelting slags is based by method of a jigging on a difference of speeds of a motion of grains in the pulsing environment [4]. The jigging was carried out in the laboratory two chamber jigger. At a jigging initial material is exposed to division into the layers differing on density and fineness which are formed on a jigger sieve in a result of periodic action of the ascending and descending streams of the dividing environment, the driving mechanism caused by work. In the lower layers the heavy product, and in the top-easy concentrates. The hinge plate of the processed steel-smelting slags weighing 5,0 kg was exposed
to a research. Average values of results of 5-6 pilot studies are presented in tab. 2. In experiments tails of the first jigging loaded again into the jigger therefore received two concentrates.
At enrichment on a screw separator the uniformity of food was maintained. An amount of water in food it was set at the rate of receiving a pulp with a density of 20-30% of firm. The consumption of flushing water is regulated visually and averages 0.05-0.2 p/a. Results of distribution of valuable components of the processed steel-smelting slags at enrichment on a screw separator are given in (tab. 3).
Table 2.- Qualitatively - a quantitative index of division of valuable components of the processed steel-smelting slag at a jigging
Products Out put, % Content, % Extraction, %
kg % FeO+Fe2O3 Fe FeO+Fe2O3 Fe
Original 5.0 100 17.6 3.8 100 100
Concentrate 1 2.45 49 15.2 2.21 42.3 28.6
Concentrate 2 1.05 21 16.8 2.3 20.0 12.8
Tails 1.5 30 34.4 7.4 37.7 58.6
Table 3.- Qualitatively - a quantitative index of division of valuable components of the processed steel-smelting slag on a screw separator
Products Out put, % Content, % Extraction, %
kg % FeO+Fe2O3 Fe FeO+Fe2O3 Fe
Original 5.0 100 17.6 3.8 100 100
Concentrate 1 2.10 42.0 15.42 2.96 38.6 32.7
Concentrate 2 1.75 35.0 9.35 2.32 18.6 21.4
Tails 1.15 23.0 35.12 7.58 42.8 45.9
Analysis of data of tab. 3. shows that losses with tails make considerable size that significantly reduces indicators of process and can hardly be an effective method of processing of the fulfilled steel-smelting slags. At extraction of iron and its connections on a concentration table division of materials of slag comes from the processed steel-smelting slags in thin water flow, (sound board) flowing on a low-bevel flat surface of a table [5]. The sound board makes asymmetric returnable step the movements in the horizontal plane.
Pilot studies were conducted on a laboratory single-tier concentration table of LKS - 1Ya. The table is intended for material enrichment by fineness - 3 mm, productivity of a table of 15-20 kg/h; the size of the course of a sound board is regulated in repartitions of 8-16 mm; number of the courses in a minute 275-325; inclination of a sound board from 0 to 100; water 0,5 consumption of m3/h. After establishment of technical indicators of a table began performance of pilot study. At first water in the quantity sufficient for a covering was pumped
by a thin layer of all surface of a table. The processed steel- Qualitative quantitative indices of enrichment of the
smelting slag moved in a loading box of a table in the form of crushed processed steel-smelting slags on a concentration the pulp received after crushing with L: S relation = 2:1. table are given in (tab. 4).
Table 4.- Average values qualitatively - quantitative indices of division of valuable components of the processed steel-smelting slag on a concentration table
Products Out put, % Content, % Extraction, %
kg % FeO+Fe2O3 kg % FeO+Fe2O3
Original 5.0 100 17.6 3.8 100 100
Concentrate 1 1.46 29.3 37.9 10.2 63.0 78.2
Concentrate 2 1.2 24.0 16.8 1.73 22.8 11.2
Tails 2.34 46.7 5.3 0.9 14.2 10.6
By results of the conducted researches it is visible that at enrichment of the processed steel-smelting slags on a concentration table extraction of valuable components makes,%: a concentrate 1 - FeO+Fe2O3-63.0; Fe-78.2; a concentrate 2 - FeO+Fe2O3-22.8; Fe-11.2. The comparative analysis of indicators of extraction of FeO, Fe2O3 has been made for the choice of an optimum way of gravita-
tional enrichment of the processed steel-smelting slags (tab. 5).
As a result of the carried-out comparison of results of enrichment of the processed steel-smelting slags, it is established that an optimum method at which the maximum extraction of FeO, Fe2O3, Fe is reached is enrichment of the processed steel-smelting slags on a concentration table.
Table 5 - The comparative analysis of extraction of useful components from the processed steel-smelting slags by method of gravitational enrichment
Method extraction Extractivevaluable compounds Extraction, %
Concentration-1 Concentration-2 Tails
Jigger FeO + Fe2O3 42.3 20.0 37.7
Fe 28.6 12.8 58.6
Screw-separator FeO + Fe2O3 38.6 18.6 42.8
Fe 32.7 21.4 45.9
Concentration table FeO + Fe2O3 63.0 22.8 14.2
Fe 78.2 11.2 10.6
It is established that for processing of these slags by the cal and mining operations and to pass to low-waste technol-
most acceptable use of gravitational enrichment is. Use of this ogy. At the same time waste slag can be actually eliminated
development in the industry will allow to expand a source of that will favorably affect an ecological situation around iron
raw materials of plant without capital expenditure for geologi- and steel works.
References:
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2. Yusupkhodjayev A. A., Valiyev X. R., Khudoyarov S. R., Matkarimov S. T. Increase in efficiency of steel-smelting production by additional recovery of valuable components from the utilized slags.- M.: Magazine of "Ferrous metals", 2015.- No. 1. - P. 19-22.
3. Matkarimov S. T. and others, Studing methods of extraction iron and its compounds from steel-smelting slags //Proceedings of the international conference on integrated innovative development of Zarafshan region: achievements, challenges and prospects, - Navai, 26-27. - october 2017 y.- P. 182-184.
4. Yusupkhodjayev A. A. Theory waste free technology on the ferrous metallurgy.- Tashkent: TSTU, 2017.- 4. p.
5. Matkarimov S. T. and others, Researching of an optimum way of extraction of iron and its compounds from the steel-smelting slags / Proceedings of the international conference "Scientific-technical progress as factor of improving modern civilizations", - Magnitagorsk, - 14. - November, 2017 y.- P. 77-81.
