RU2568797C2 - Fuel and metallurgical granules, and method of their production and metal coating - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: fuel and metallurgical granules contain iron containing component, carbon containing component and fluxing addition - in form of lime, limestone, dolomite, chalkstone. As iron containing component the ironstone goethite-hydrogoethite oolites dehydrated at 320-380°C are used, and as carbon containing component the fine-grained semicoke of brown coal and/or peat in form of gel/sol with removed mineral part (ash of semicoking) is used. At that the charge components are mixed until homogeneous composition, heated and fed to the grainer of extruder type to produce granules in form of cylinders with diameter and height 8-16 mm.

EFFECT: production of qualitative raw material from irreducible iron ore and low carbonized fuel-recovery raw material suitable to produce several purpose concentrates and metallurgical treatment products.

8 cl, 1 ex

Description

The invention relates to ferrous metallurgy, to the fields of obtaining fuel raw materials and metallurgical raw materials for pyrometallurgy.

With the depletion of reserves of rich iron ores and coking coal, more and more attention is being paid to obtaining fuel and smelting materials from poorer raw materials available in sufficient quantities (Leontyev L.I., Yusfin Yu.S., Malyshev T.Ya. et al. Raw and fuel base of ferrous metallurgy. - M.: IKC Akademkniga, 2007. - 304 p.). In order to obtain a high-quality melting charge, fuel-melting materials are pelletized, producing various forms of compact raw materials in the form of moldings, briquettes, pellets, pellets, pellets (see, for example, Lurie L.A. Briquetting in ferrous and non-ferrous metallurgy. - M .: Metallurgy, 1963. - 324 pp .; Ravvich B.L. Briquetting in the ferrous and non-ferrous metallurgy.- M .: Metallurgy, 1975. - 232 pp .; Kozhevnikov Yu.N., Ravvich B.L. - M.: Metallurgy, 1991, - 303 p. And others).

A retrospective acquaintance only with domestic patented technical solutions for sintering poor fuel and metallurgical raw materials revealed a significant number of them, for example, RU 2095436; RU 2198340; RU 2202633; RU 2317341; RU 2356952 and others.

Of particular interest was the invention of F. Semyachkov. (1932) on thermal briquetting of ores and brown coals with the simultaneous semi-coking of carbon-containing material (SU 29179), which was developed in a number of subsequent works by other authors, for example, Smolyaninov S.I. The integrated use of peat in a chemical and metallurgical process based on Bakcharsky ores // Sat .: Results of research in chemistry over 50 years. - Tomsk: TPI, 1973; Smolyaninov S.I., Maslov S.G. Thermal briquetting of peat. - Tomsk: TSU, 1975; Smolyaninov S.I., Arkhipov B.C., Krinitsyn G.G. Testing peat fuel and smelting materials in a laboratory blast furnace // Bulletin of TPI, 1977. - T. 214 - S. 19-22; A method of obtaining a briquetted or granular iron coke according to patent SU 164619 and others

The main technical idea of these analog solutions is to obtain high-quality metallurgical raw materials from low-quality compacted ingredients (refractory iron ore, peat, brown coal).

In the case of semi-coking of carbon-containing material in the composition of the briquette / pellet, a common drawback of analog solutions is the introduction of harmful impurities contained in the semi-coking ash of peat and brown coal into the smelting mixture.

Close in technical essence, the analogue is also a solution for AS USSR No. 252365. According to this solution, for the purpose of producing sponge iron with a high degree of reduction of iron oxides (up to 98%), high-grade steel or iron ingots, high-grade milled peat with a low ash content and not containing fusible metals and other ashes is used as the carbon-containing ingredient of the briquette / pellet harmful impurities (for example, sulfur and phosphorus in amounts of less than 0.1 ÷ 0.5%). The resulting peat briquettes contained 44 ÷ 50% iron and 15 ÷ 20% carbon and were characterized by the following indicators: strength 180-290 kg / cm ² ; crumbling up to 8%; abrasion up to 10 s / o; bulk density of 1.8-2.3 kg / cm ³ .

The disadvantages of this method are the need to prepare for the compaction process and directly briquetting relatively large volumes of raw materials with a low degree of coalification to achieve the required carbon content in the composition of the peat briquette material, as well as the need for relatively large quantities of calcium-containing melting fluxes (limestone / lime).

As the closest analogue, we select granules and the method for their preparation, disclosed in A.S. SU 164619 A, publ. 07/19/1964. The raw material for the production of granules is a mixture of coal (gas or coke fat) of 50-70% fraction of 3-1 mm, hard-to-recover iron ore (or ore concentrate) 25-45% of the fraction of 1-0 mm, slaked lime Ca (OH) ₂ 5- 10% in grinding with a residue on a sieve of 900 holes / cm ² not more than 5%. Finished iron-coke granules are obtained by coking raw lime-coated granules in a shaft ring or coke oven.

The disadvantage of the invention is the use of carbon-containing raw materials with a high degree of coalification, which makes the resulting fuel and metallurgical granules more expensive.

The task is to obtain fuel and metallurgical granules from refractory iron ore and low-carbonaceous carbon-containing fuel-reduction raw materials suitable for producing several target products of enrichment and metallurgical processing.

The problem is solved as follows.

1. Fuel and metallurgical granules containing an iron-containing component, a carbon-containing component and a fluxing additive - in the form of lime, limestone, dolomite, chalk, characterized in that brown iron-containing goeth-hydrogetite dehydrated oolites are used as an iron-containing component, and high-carbon components are used semi-coke of brown coal and / or peat in the form of a gel / sol, from the composition of which the mineral part is removed - semi-coking ash.

2. Fuel and metallurgical granules according to claim 1, characterized in that the oolites are dehydrated at a temperature of 320-380 ° C.

3. Fuel and metallurgical granules according to claim 1 or 2, characterized in that the oolites are part of the granules in an amount not less than the amount of semi-coking ash removed from the semicoke.

4. The method of producing fuel and metallurgical granules according to any one of paragraphs. 1-3, including the selection of the components of the mixture containing iron, carbon and fluxes, preparation of the components for batching, mixing the prepared components to a homogeneous composition of the mixture, heating and granulating the mixture, and the iron-containing component of the mixture is prepared for batching by dehydration heating at a temperature of 320-380 ° C with the disclosure of iron and flux-containing concentric layers, and the carbon-containing component is prepared for blending by semi-coking, followed by separation of the mineral part - s carbonization as a first desired product, and obtaining carbonization gel / sol, whereupon all components are mixed, the batch is heated and fed into the extruder-type granulator to obtain a compact fuel pellets in a steel cylinder with a diameter and a height of 8-16 mm.

5. The method of producing fuel and metallurgical granules according to any one of paragraphs. 1-3, including the selection of the components of the mixture containing iron, carbon and fluxes, preparation of the components for batching, mixing the prepared components to a homogeneous composition of the mixture, heating and granulating the mixture, and the iron-containing component of the mixture is prepared for batching by dehydration heating at a temperature of 320-380 ° C with the disclosure of iron and flux-containing concentric layers, and the carbon-containing component is prepared for blending by semi-coking, followed by separation of the mineral part - semi-coking as the first target product, and obtaining a semi-coke gel / sol, after which all components are mixed, the mixture is heated and fed into a granulator, for example, of an extruder type to obtain compact fuel and metallurgical granules in the form of cylinders with a diameter and a height of 8-16 mm , the obtained granules are subjected to heat treatment in ore-reducing furnaces or in a fluidized bed of furnaces of hot-water or steam boilers of thermal power plants / combined heat and power plants by heating at temperatures of 850-1150 ° C with recovery up to 67% of iron from oxidized oolitic ore.

6. The use of fuel and metallurgical granules according to any one of paragraphs. 1-3 as an ingredient in the melting mixture of electric steel and blast furnaces.

7. The use of semi-coking ash obtained as the first target product in the method according to claim 4, as a raw material for hydrometallurgical processing of rare metals.

8. The use of semi-coking ash obtained as the first target product in the method according to claim 5, as a raw material for hydrometallurgical processing of rare metals.

A more detailed consideration of the invention, it is advisable to conduct a specific example of its possible implementation.

DESCRIPTION OF THE EMBODIMENT OF THE INVENTION

Currently, experts are considering fundamental approaches to the development of two deposits in the Tomsk Region of the Russian Federation that have billions of raw materials - the Bakcharsky brown iron ore deposit with an oolitic structure (BZHRM) and the Talovsky brown coal deposit (TBUM). The quality of Bakcharsky iron ore raw materials is such that the Novokuznetsk steel mills - KMK and ZSMK - closest to the deposit can consume unenriched ore in quantities not exceeding 10-14% of the total iron ore needs (which in absolute terms is about 1 million tons / year ) At the same time, the open-pit mining method of the Bakcharskoye deposit becomes profitable with an annual ore production of 10-12 million tons / year (the options for ore mining by a dry bore mine of 30, 60 or 120 million tons / year are considered optimal). Transportation of non-enriched Bakchar iron ore over distances of more than 500 km (to steel mills located in the central and western parts of Russia) is not economically feasible. Therefore, it is important to obtain enriched raw materials in a compact form intended for melting charges in a blast furnace (about 80% of the total volume of TMG) and outside the blast furnace (about 20% of the total volume of TMG).

Local reserves of carbon-containing raw materials for the production of TMG from ore in volumes of 30-120 million tons / year are enough with a multiple excess - these reserves are represented by Talovskiy brown coals, Bakchar brown coal in overburden rocks of the dry-sand pit and peats of the world's largest Vasyugan bog, overlapping BZHRM. Mined in 2007-2008 a large-volume (1.7 thousand tons) technological sample of Bakchar ore by 2/3 is represented by hydrogetitic oolites with a fineness class of 0.5 + 0.25 mm, usually of a concentric-zonal structure. The concentric zonation of the oolites is due to the alternation of dark (circular in cross section) zones of goethite-hydrogetite composition with light ring zones with varying degrees of saturation of the carbonate or clay component. In general, oolite size was in the size range from 0.045 to 1.00 mm; the iron content ranged from 35-46%, the content of flux-forming components exceeded 10%, and phosphorus reached 0.46%.

The results of a study of the core material of Talovsk brown coal (obtained in 1997-2000) established that the ash content of coal is - 25-40%; low heat of combustion - 3000-4000 kcal / kg; mass fraction of sulfur - 0.38-0.63%, phosphorus 0.005-0.0054%; the yield of volatile substances - 58.3-61.7%, humic acids - 47.9-53.4%, bitumen - 2.7-3.8%, resins - 14.56-20.43%. Coal pyrolysis provides a semi-coke yield in the amount of 45% of the mass of the feedstock 10% moisture (with a maximum moisture capacity of coal in the reservoir equal to 31-38%), caloric value 5500 kcal / kg. When processing Talov coal in mineral sediment, ash and dust of flue gases, an increased content of scandium, cobalt, rare earth elements and yttrium will be concentrated.

The use of Bakchar oolites as an iron-containing component of TMG is accompanied by the following features:

- light layers in the oolites are represented by flux-forming material necessary for the smelting of iron;

- derivatographic and thermosonic studies of oolites showed that in the temperature range 320-340 ° C on the DTA = f (T ° C) curve there is a significantly pronounced endoeffect - a “hydrogetite dehydrated well”, during the recording of which intense acoustic signals of decrepitation of the oolite structure are recorded;

- hydrogetite as a solid solution of water in goethite (α-FeOOH * nH ₂ O, where n = 1.2 ÷ 1.5), contains 10.1 ÷ 14.4% of intra-crystallization water, requiring an additional heat consumption for evaporation in the metallurgical process ;

- at relatively high heating rates of oolites, the dispersion of dehydration fractures caused by the explosive pressure of the vapor of crystallization water of hydrogetites is characterized by the size of oolite fragments of 0.01-0.02 mm;

- if necessary, excess phosphorus can be leached from oolite fragments;

- in the case of a sufficient amount of a reducing agent, for example, solid carbon of semi-coke of Talovan brown coals, the iron from the oxide form in the goethite and hydrogetite minerals is reduced, forming TMG with 67% Fe;

- the dense structure of TMG on the basis of dehydrated oolites during the burnout of semicoke in the temperature range of 850-1150 ° C forms sponge iron.

The use of Talov lignite as a reducing agent for iron and fuel in TMG is characterized by the following:

- semi-coking of coal and its anesthesia significantly increase the specific solid carbon content in TMG, minimizing the molding volume (instead of a briquette, a granule is formed);

- semi-coke ash is used as a raw material for hydrometallurgical redistribution into scandium, cobalt, rare earth elements and yttrium;

- during the restoration of TMG in the furnaces of TPPs / TPPs, oolites are included in the granules in an amount equal to the amount of removed semi-coking ash;

- the dispersion of semicoke reaches micro- and nanoscale grinding fineness;

- harmful impurities - sulfur and phosphorus - are mainly removed from the composition of TMG with semi-coking ash, the remaining part is removed together with harmful impurities in oolites during pyrometallurgical redistribution during duplex smelting with the removal of phosphorous slag.

The direct molding process of TMG has been sufficiently developed in various versions, it seems appropriate to use extruder granulators as the most productive (such are used at the Tomsk Petrochemical Plant located on board the Talovskoye field).

The restoration and metallization of TMG is carried out in accordance with the developed theory by known methods (Rostovtsev S.T. Theory of metallurgical processes. - M.: Metallurgizdat, 1956. - 515 p .; West Siberian iron ore basin. / Ed. By F.N. Shakhov . - Novosibirsk: Publishing House of the Siberian Branch of the Academy of Sciences of the USSR, 1964. - 448 p.).

Thus, the technical result is achieved, which consists in obtaining high-quality metallurgical raw materials from reduced TMG in the form of sponge and / or hot briquetted iron by including in the economic turnover huge reserves of brown-colored mineral raw materials of Western Siberia - brown iron ore and brown coal / peat. The resulting raw materials can replace a significant amount of the iron-containing part of the blast furnace charge of the nearby Siberian metallurgical plants - ZSMK and KMK, bringing ore over several thousand kilometers. The production and use of semi-coking ash increases the economic and environmental feasibility of using the proposed technical solution.

Claims (8)

1. Fuel and metallurgical granules containing an iron-containing component, a carbon-containing component and a fluxing additive - in the form of lime, limestone, dolomite, chalk, characterized in that brown iron-containing goeth-hydrogetite dehydrated oolites are used as an iron-containing component, and high-carbon components are used semi-coke of brown coal and / or peat in the form of a gel / sol, from the composition of which the mineral part is removed - semi-coking ash. 2. Fuel and metallurgical granules according to claim 1, characterized in that the oolites are dehydrated at a temperature of 320-380 ° C. 3. Fuel and metallurgical granules according to claim 1 or 2, characterized in that the oolites are part of the granules in an amount not less than the amount of semi-coking ash removed from the semicoke. 4. The method of producing fuel and metallurgical granules according to any one of paragraphs. 1-3, including the selection of the components of the mixture containing iron, carbon and fluxes, preparation of the components for batching, mixing the prepared components to a homogeneous composition of the mixture, heating and granulating the mixture, and the iron-containing component of the mixture is prepared for batching by dehydration heating at a temperature of 320-380 ° With the disclosure of iron-containing and flux-containing concentric layers, the carbon-containing component is prepared for burdening by semi-coking, followed by separation of the mineral part in de carbonization ash as a first desired product, and obtaining carbonization gel / sol, whereupon all components are mixed, the batch is heated and fed into the extruder-type granulator to obtain a compact fuel pellets in a steel cylinder with a diameter and a height of 8-16 mm. 5. The method of producing fuel and metallurgical granules according to any one of paragraphs. 1-3, including the selection of the components of the mixture containing iron, carbon and fluxes, preparing the components for batching, mixing the prepared components to a homogeneous composition of the mixture, heating and granulating the mixture, and the iron-containing component of the mixture is prepared for batching by dehydration heating at a temperature of 320-380 ° With the disclosure of iron-containing and flux-containing concentric layers, the carbon-containing component is prepared for burdening by semi-coking, followed by separation of the mineral part in of semi-coking ash as the first target product, and obtaining a semi-coke gel / sol, after which all components are mixed, the mixture is heated and fed into a granulator, for example, of an extruder type to obtain compact fuel and metallurgical granules in the form of cylinders with a diameter and height of 8-16 mm, the obtained granules are subjected to heat treatment in ore reduction furnaces or in a fluidized bed of furnaces of hot-water or steam boilers of thermal power plants / combined heat and power plants by heating at temperatures of 850-1150 ° С with reduction up to 67% of iron from oxidized oolitic ore. 6. The use of fuel and metallurgical granules according to any one of paragraphs. 1-3 as an ingredient in the melting mixture of electric steel and blast furnaces. 7. The use of semi-coking ash obtained as the first target product in the method according to claim 4, as a raw material for hydrometallurgical processing of rare metals. 8. The use of semi-coking ash obtained as the first target product in the method according to claim 5, as a raw material for hydrometallurgical processing of rare metals.