SU945206A1 - Method for preparing agglomeration batch for sintering - Google Patents

Description

one

This invention relates to the preparation of metallurgical | Rrgo raw materials for blast-furnace smelting and can be used in sinter production in the agglomeration of iron ores and concentrates.

There is a method of sintering ore with a high moisture content. In the mixing drum, the ore is mixed with fuel, fluxes and hot return, as a result of which the moisture content in it is reduced to 3-7% tl.

The disadvantage of the method is the destruction of the granules upon contact with the hot return, which is the reason for the decrease in the gas permeability of the agglomerated layer.

There is also known a method of preparing the mixture for sintering, which is based on the fact that, at the first stage of mixing, a large part of the ore load of the agglomerate without fuel and all the water necessary for

obtaining optimum moisture content of the agglomerate. As a result of mixing, a first- is formed in the first mixer; reuvlazny grains, which in the second stage of pelletizing roll fuel and the rest of the ore load C2.

The disadvantage of this method is that in the first stage, the pelletizing of the mixture is overwetted, the granules are oversized and do not contain fuel. Further, they are poorly baked and reduce the quality of the agglomerate.

The closest to the proposed by the Technical essence and the achieved result is the method of preparing the sinter blend to 20 seconds baking, including mixing,

moistening and pelletizing of 20-70% aglo-. a mixture consisting of all the components, mixing with the initial dry charge and final pelletizing 3. A disadvantage of the known method is that with a two-step pelletizing with constant humidity it is impossible to obtain a mixture of increased particle size with a simultaneous decrease in the optimal value. moisture granulation. This is due to the fact that for the growth of granules of an agglomerate with a limited flow of moisture from the outside, it is necessary to use the moisture present inside the granules. To do this, sequential repeated rolling of the fine component of the charge onto the pelletizing center, under the action of dynamic loads, flattening of small particles and, as a result, squeezing moisture to the periphery of the granule, is necessary. Such a mechanism of granule growth during the two-stage development does not receive the development of the same ones, which, with increasing particle size, has an increased humidity. The purpose of the invention is to improve the granometric composition of the pelleted sinter blend, reduce the moisture content of the granulation and increase the productivity of sinter machines. The goal is achieved by the method of preparing the sintering mixture for sintering, including mixing, moistening and multistage pelletizing, at each subsequent pelletizing stage, the pre-granulated mixture is added in an amount equal to 1030 rel., The amounts of preformed and raw materials are reduced, and the humidity of the mixture is reduced by 0.51, 5 abs.%. The method is carried out as follows. The total flow of material going to sintering is divided into several streams. The charge of the first stream is subjected to a one-step pelletizing: moistened and pelleted. In the second stage of granulation, the mixture of the first and second streams is mixed, moistened and pelleted. At the third stage of granulation, the mixture of the first, second and third streams is mixed, moistened and pelletized, etc. Calculation of material consumption by flows at each stage of pelletizing should be carried out from the last stage of granulation, where the amount of agglomerate per unit 64 times is added to the pre-pelletized mixture equal to 10-30 of the total consumption. The lower limit corresponds to the charge containing in the iron ore part more than 50% of the concentrate, the upper - less than 50% of the concentrate. This is due to the fact that the concentrate is the most fine material and contains a small amount of. comparing with ores of colloidal particles and for rolling on the overwetted granules, a smaller amount of a crumpled component is needed, which includes the entire concentrate. There are particles in the Bce ore that are centers of pelletizing. For example, the Dzerzhinsky mine administration sinter ore contains up to 50% of particles greater than 5 mm. At the last stage of pelletization in the aggregation of particles, they do not take part, since they do not have a surface waterlogging. At the previous last stage of granulation, the charge consumption is also equal to .10-30%, but from the rest of the last stage, i.e. from 70-90% of the total consumption, in a similar way, the calculation is performed for all stages | NM to the first. The drawing shows a scheme for the technical implementation of a multi-stage pelletizing sinter charge (three-stage. Technological line for preparing the sinter blend according to the proposed technology consists of loading hopper 1, belt feeders 2 and 3, a drum pelletizer k, a preliminary granulation, a drum pelletizer 5 final granulation. 1 agglomerate is discharged to belt feeders 2 and 3. 70% to 90% of the total material is fed to the feeder 2, and 10 to 30% of the total to the feeder 3 quantities of the charge. The discharge end of the feeder 2 is placed 1 / 3-1 / 2 the length of the intermediate drum, in the loading part of which 70-90% of the incoming charge is unloaded with scrapers, and the remaining 10-30% comes next in 1 / 3-1 / 2 length drum. In the loading part of the drum, the mixture is mixed, moistened and pelletized. After passing the charge 1/3 1/2 of the drum length, the pre-pelletized mixture is mixed with 10-30 feedstock from the feed feeder A. After mixing and the addition of water is completed the second stage is pelletizing of the agglomerate. From the drum, the charge is discharged to the belt feeder 3, in which 10–30% of the initial mixture moves from the hopper 1 of the sintering machine. In a drum pelletizer 5, the charge, after two pelletizing stages in pelletizer A and the initial feed through conveyor 3, is mixed, moistened and subjected; from the third granulation stage. The agglomeration mixture according to the granulation stages is calculated as follows. On the feeder 3 from the hopper 1 receives 10-30 of the entire charge, and in the drum pelletizer 70-90%. This mixture in the drum is divided into two parts: the total amount is removed by scrapers in the loading part, or the granulation rate of the mixture increases in the initial mixture of solid M pellets entering the drum. When 70–90% of the solid pelletizing centers in the mixture are mixed, solid part of the agglomerate is distributed between the solid nuclei of the granules in proportion to the surface area of the fraction. in the charging of the charge, which contains more than 50% of the concentrate in the iron ore part, there is a shortage of solid centers of work. Therefore, in the first stages, most of the mixture is pelletized (up to 90%). In the early stages of iron ore mixed with fuel and flux, smaller amounts of the charge (70%) are pelletized at the first stages, since the sinter ore contains up to 50% pieces of more than 3 mm, which are solid centers of pelletizing. The optimum moisture content of the granulation decreases with an increase in the proportion of concentrate in the charge. With an increase in the moisture content of the aglo-mixture by 0.1-2.5%, the particle size of the granules, and with it the gas permeability of the charge, increases. However, at the same time, the moisture content of the mixture increases, which slows down the process of fuel combustion in the agglomerated layer. Therefore, it is necessary, after the first granulation stage, to reduce the total moisture of the mixture by adding the initial dry batch at the subsequent stages. If, for example, in the first stage, water is added 1.5% higher than the optimum, then in a three-stage pelletizing in the second stage it must be reduced by 1.0% in the third by an additional 1, 0%. At the same time, the total moisture content of the granulation of the mixture will be below the optimum by 0.5%. In tab. 1 shows the dependence of the content of fractions +10 and -3 mm on the moisture content of the charge. In tab. 2 gives a comparative assessment of the indicators of the agglomeration charge pelletizing under two- and three-stage pelletizing. The mixture containing 30% of the ore and 70% of the concentrate in the iron ore part is granulated; the basicity of the agglomerate is 1.25. As can be seen from the table. 2, the gas filtration rate is maximum at a preliminary granulation of 10–30% of the charge at the second and third stages of granulation. The multi-stage pelletizing process of the sintering mixture allows, when the moisture content of the material is reduced by 0.5-1.5%, to change the particle size distribution of the charge in a wide range, to increase the size of the agglomerate to more than 50% in the amount of overwetting of the materials in the agglomeration. layer, increase the productivity of sintering machines by l-tjO and reduce fuel consumption by. The economic effect of using the proposed method of preparing the sinter charge for sintering at the plant will be Q50 thousand rubles. Parameters Humidity, Fractions - IOmm Fractions -3mm, - ---- - Parameters Layer height, mm Humidity,% 30.0 25, 21.8 20.3 20.0 15.0 13.6 18.2

500 500 500 500 0.5 0.58 0.63 0.5

20.3 16,

23.1

12.0 11, 15.3 500

500

500

0.65 0.72

0.55 | -, - ---.,. ..J ..... I..iLiLj ... L ± ... 6,06,57,0 7,5 8,08,59,09,5 7,07,07,0 1,0 18.2 2, Q, 0%, 2 52.0 51 „5 З, 0 18,3,5ОО -.-. - - -, - «.. - --- Two-stage (known) Three-stage Contents of the charge according to the stage Contents of the charge according to the stages of di, Po + Pz,% 50 + 50 70 + 3o 80 + 20 90-flO 25+ 25 + 5oU9-21 + 3o | 6i + l6t20J 81 + 10 + 9.0 300 300 300 300 300 300 300 zoosoo 7.5 7.5 7.5 7.5 7.5 7.0 7.0 7.5 Table Option Table 2 Pellet Technologists

Claims (3)

1. US patent If 3003864, cl. 75-5, 1.961. 2. Patent of England Vf 96700 4, cl. (C1A) C 22 V, 1962. 3. USSR author's certificate №, cl. From 22 to 1/14, 1375.