SU1086024A1 - Method of agglomerating iron ore materials - Google Patents

Abstract

A METHOD FOR AGGLOMERATION OF IRON ORE MATERIALS containing oily scale, includes loading oily scale onto a layer of agglomerate and air through the layer of agglomerate characterized in that, in order to increase plant performance, improve the quality of the sinter, set, and get to work. 10 mm.

Description

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4: The invention relates to the preparation and agglomeration of iron ore materials and can be used during agglomeration. In the rolling shops of metallurgical plants, a significant amount of oily scale (rolled to secondary shrinkage tanks) is formed, which does not find application. At metallurgical plants of the USSR of 750 thousand tons. rolling sludge containing an increased amount of oil (Ro 15%), more than AGO thousand. t. is transported to the ore, which dramatically worsens the ecological state of the environment. In this case, the metal is irretrievably lost, since the scale contains up to 72% of iron. The oil content in the rolling slurry depends on the state of the rolling and dewatering equipment, as well as on the load on the secondary settling tanks. In order to use rolling sludge in the agglomerate, the content of oils in it should not exceed 0.2%. The known method of using npo sludge in the sintering stock with preliminary burning out of oils from it. However, the technological scheme of burning out oils is very complex in instrumental performance, and the gas cleaning equipment of exhaust gases is unstable, therefore this method is not economically feasible. A known method for the sintering of iron ore materials with the addition of pre-mixed sludge with burnt lime 2 is added to the mixture. This technology allows to increase the productivity of the sintering plant, improve the quality of sinter and slightly improve the condition of oil burnout during sintering. The disadvantage of this technology of using oily scale in the agglomerate is the sublimation of oils during the sintering process, since the temperature in the layer of sintered agglomerate increases and gradually reaches a maximum (l400-155Q ° C) in the burning zone of solid fuel. By that time, almost all the oils are sublimated and removed together with the exhaust gases. At the same time, they are again condensed in gas ducts and running means, which leads to premature exit from the exhaust rotor of the exhauster. When the consumption of scale with an increased oil content of 4% in the ducts, oil accumulates above the maximum permissible amount, which can lead to explosions. For this reason, a significant amount of oily scale is dumped into dumps. For example, at the Krivorozhstal metallurgical plant, over 100 thousand tons / year of such scale was removed by slag trucks to the dump, which dramatically worsens the state of the environment. In addition, sublimated olives of increased calorific value are not used in the thermal sintering process. When sintering agglomerates according to the usual technology, in the upper part of the layer there is a lack of heat and in the lower part there is an excess of it. In this case, the scale affects the thermal sintering process in the same way as solid fuel, since 16% of the scale in the sintering mix is equivalent to 1% of solid fuel. With this sintering technology, the strength of the agglomerate at the top of the VnHpora is the smallest, which ultimately reduces the performance of the sintering plant. These drawbacks require the development of a rational technology for the sintering of iron ore materials with the field utilization of oily scale. The closest to the invention to the technical essence and the achieved result is a method of sintering iron ore materials containing oily scale by the method of sucking air through a layer of sludge mixture, including loading oily scale on the surface of sintering material behind an incendiary mountain, but before the burners for additional heating of the sintering method, sublimation of oil is eliminated from dross and deposited on gas flues, tons of liquid fuel and gas cleaning facilities. The disadvantage of this method is that the deposition of scale on the formed upper sinter of the agglomerate slows down the processes of fuel burning in the underlying layers of the charge due to the reduced gas permeability of the layer and the lack of oxygen. This is associated with a decrease in sintering speed and sintering machine productivity. The aim of the invention is to increase the productivity of the plant and improve the quality of the agglomerate. The goal is achieved by the method of agglomeration of iron ore materials containing oily scale, which includes loading oily scale on a layer of sludge mixture and air through the layer of sludge mixture, laying oily scale in front of a burning layer of 1-10 mm. In the incendiary furnaces of the sintering machine, the temperature reaches 1250–1350 ° C; therefore, oils from scale, laid on the surface of the agglomerate with a layer of 1–10 mm, ignite and burn, bringing additional heat to the upper layer of the agglomerate. Since the ignition of agloshikts usually occurs when a vacuum chamber is 0.5-0.8 from thinning during sintering, the unheated oil vapors in the initial ignition period do not penetrate into the agglomerate layer with waste gases .. In this technology, during the ignition process its sintering hardens the upper layer of the sinter cake, which improves the quality of the entire mass of sinter and improves the productivity of the sintering unit. Experiments show that an increase in the layer of oily scale above 10 mm leads to a deterioration in the gas permeability of the layer, and also increases the influx of heat, thereby melting and slagging the upper part of the cake, which is undesirable according to the conditions of agglomeration. With a layer of 1 mm, the required amount of heat is not obtained. The method was tested under laboratory conditions by sintering agglomerate containing,%: Iron sinter 10.1 Manganese sinter lime 5, 8 Iron ore concentrate Koloshnikov Dust Coke breeze Known to Pest Oily Scale Scale Experiments are carried out in a shaker with a diameter of 190 mm and mixing and moistening. in a cylindrical drum with a diameter of 820 and a length of 300 mm. The mixture is mixed for 2 minutes and then moistened and pelleted also for 2 minutes. The bed height is 300 mm, the bed weight is 0.4 kg. In the conventional agglomeration method, oily dross is introduced together with scrapping materials, and, according to the proposed method, on the upper layer of the agglomerate. Ignition for 1.5 minutes at a vacuum of 600 mm of water. It is produced with a mixture of coke (0.3 kg sawdust (0.15 kg) and kerosene (0.2 l). Sintering is carried out according to the generally accepted method with a dilution of 1200 mm of water. With carbon consumption D and a return of 30%. On exit fractions of +10 mm after a single drop of agglomerate on a steel plate with a height of 2 m determine the output and productivity of the sintering unit. The pieces of 25 mm sinter are tested for strength in a drum with a diameter of 700 and a length of 300 mm for 4 minutes at a speed of 25 rpm. 5 mm estimate the mechanical strength of the agglomerate. To detect steam condensation In oils in gas ducts, a water-cooled glass insert with a diameter equal to the diameter of a metal gas duct is installed in a metal duct. In addition to the experiments shown, three sintering is performed with laying oily scale on the ignited charge with an oil content of 10 and a moisture content of 20% thick IO mm at the beginning of the 3rd minute after the start of the experiment, i.e. after stopping the ignition. At that moment the vacuum is 1200 mm of water. instead of 600 mm of water. at the beginning of the ignition. The top layer of the cake is 15-20 mm thick and cracked to 900-1000 ° C at the end of ignition. After placing the dross, the ignition (heating) is continued at 900 ° C again. At the moment of laying the scale, there is a sharp evaporation of moisture and cooling of the upper layer of the cake, and the particles of the scale are sharply drawn into the pores of the agglomerate and reach the sintering zone. In this case, the gas permeability of the layer is reduced, due to which the vacuum spontaneously increases to 1250 mm water column. The results of the sintering of the charge limestone and the proposed methods are presented in the table.

Way of laying okavt charge After zalina zhigani

Layer thickness ok10

Productivity, t / m-h

Also, %

Iinna sintering speed, mm / min

The output of sinter 1 + 10 mm1,%

Drum sample (-5 mm),%

Air consumption for sintering, m / min; on the 5th min of spe0, 81

0.88 Cani 1.08 1.05

at the end of the experience

Presence of condensation Detected Traces of oil vapors

Before ignition

13

 ten

0.93 0.98 1.17 1.26

Not found

Research results indicate that, due to stacking of oily scale with a layer of up to 10 mm on the surface of the sinter charge, the productivity of the sintering unit increases, mainly due to 40-fold increase in the yield of suitable sinter. However, no oil deposits are observed on the ducts.

Claims (1)

METHOD FOR AGROMERATION OF IRON-ORE MATERIALS containing oily scale, including loading oily scale on the sinter charge layer and air suction through the sinter charge layer, characterized in that, in order to increase the productivity of the installation, improve the quality of the sinter, the oily scale is laid in front of an incendiary mountain layer of 1-10 mm .