RU2016099C1 - Method of making iron ore agglomerate - Google Patents

Abstract

FIELD: production of iron ore agglomerate from a charge with high content of fine iron ore concentrate. SUBSTANCE: method comprises steps of separating red oxide of iron before introducing it to a sintering machine by fractions (1 ± 63) micrometers; introducing the fractions (1+63) micrometers and (1-63) micrometers to the charge with mass ratio (0.15-0.45). EFFECT: enhanced quality of agglomerate. 1 cl, 3 tbl

Description

 The invention relates to ferrous metallurgy, in particular to a technique for producing iron ore sinter, their mixture with a high content of fine iron ore concentrate.

 There are a number of inventions that propose the use of alumina production waste - red mud as a component of the sinter charge. So in the patent of Czechoslovakia N 129262.

 A method is proposed for granulating iron ores with a high content of slag-forming components (Pat. Czechoslovakia N 129262), with the fact that red sludge is added to the sinter mixture in an amount of 0.5-5 wt.%.

 The known method (ed. St. N 346341), in which, in order to prevent the polymorphic conversion of beta into the gamma of dicalcium silicate, stabilizers of cationic and anionic groups are introduced into the sintering mixture in an amount of 0.05-0.1% per 1% dicalcium silicate in the agglomerate . As a stabilizing additive, red mud is introduced into the mixture in a mixture with flux.

The closest in technical essence and the achieved result is a method of preparing for sintering of fine concentrates, including the introduction of red mud; mixing and pelletizing, with the fact that, in order to increase the productivity of sintering machines and the strength of the algomerate, the red mud is mixed with fine concentrates in an amount corresponding to concentrates with a specific surface of 1000-1500 cm ² / g 3-8%, 1500-2000 cm ² / g - 1.5-3.0% and more than 2000 cm ² / g - 1-1.5% by weight of the concentrate, respectively.

 The disadvantages of the preparation method for sintering fine concentrates include: a low coefficient of effect on increasing the performance of sintering machines and the strength of the sinter, as well as a decrease in the quality of the sinter due to a decrease in the iron content associated with the introduction of red mud.

 The purpose of the invention is to increase the productivity of the process of agglomeration of the quality of the agglomerate.

 The goal is achieved in that in a method for the production of iron ore sinter, including dosing of fine iron ore concentrates, fluxing additives, solid fuel and red mud, mixing, pelletizing the mixture and sintering on an agglomeration belt, according to the invention, the red mud is introduced into fractions ± 63 before being introduced into the charge μm, while the obtained fractions (+63) μm and (-63) μm are introduced into the mixture in a mass ratio of 0.15-0.45.

 Classification of red mud into a mud fraction (-0.063 mm) and sand fraction (+0.063 mm) and the introduction of both fractions into the sinter mixture based on thin iron ore concentrates in a mass ratio of sand to mud fraction in the range 0.15-0.45 provides: obtaining in the process of pelletizing a uniform grain composition and high strength of raw granules; during sintering, the stability of the structure of the granules in the drying and waterlogging zone, the uniformity of sintering in the entire volume, and as a result, an increase in the productivity of sinter machines and the production of high-quality sinter.

 The pelletization process is reduced to the following model: a thin iron ore concentrate is rolled onto sand particles of red mud, which are the centers of granule formation, which binds into a solid granule with a clay fraction of red mud, which has good astringent properties due to its highly developed surface and a significant amount of alkaline active cations in its composition metals. When both fractions of red mud are introduced into the sintering mixture in a weight ratio of less than 0.15, the process of overgrowing of the mixture is observed at the pelletizing stage, i.e. rolling individual grains into granules larger than +5 mm. Such granules have high strength, but in the process of sintering on the sinter strip they do not have time to acquire the final structure of the sinter - they do not sinter and the sinter is of poor quality, the yield of sinter is reduced, and dust removal increases.

 When both fractions of red mud are introduced into the sintering mixture in a mass ratio of more than 0.45, the process of undergrowing of the mixture is observed at the pelletizing stage, i.e. granule size is mainly (-1 mm). Raw granules have low strength. In the drying zone, such granules are destroyed, which leads to a decrease in the gas permeability of the charge layer and, ultimately, to a loss in the productivity of the agglomeration process and a deterioration in the quality of the agglomerate.

 A search in the scientific, technical and patent literature showed that it is known to use red mud as a component for the preparation of sinter batch, but a preliminary classification of red mud with the allocation of sand and silt fractions with the subsequent introduction of both into the sinter mixture in a mass ratio of sand to mud in the range of 0 15-0.45 provides an improvement in the pelletizing process of thin iron ore concentrates, an increase in the productivity of sintering machines, strength of the sinter and improvement of its quality and is High quality effect.

 The above allows us to conclude that the claimed solution meets the criterion of "significant differences".

 Examples of specific implementation.

 Separation of red mud into sand and silt fractions was carried out on a hydrocyclone. In the agglomeration studies, the following were used: sand fraction of red mud (+ 0.063 mm) (PCS); mud fraction of red mud (-0.063 mm) (ICS); source red mud (KS).

 The chemical composition of the original KS and its components are presented in table. 1.

 Obtained by the classification of PCS and ECS were introduced into the sinter mixture, including numerous components, the chemical composition of which is presented in table. 2.

 Mixing and pelletizing of the charge was carried out in a drum mixer-pelletizer with a diameter of 0.8 m and a length of 0.5 m. The amount of sinter return in all experiments was 20%. The fuel consumption of binders based on KS and the moisture content of the sinter mixture in each case were experimentally selected optimal. The interval in the weight ratio PKSh / IKSh was 0.05. Sintering was carried out on a laboratory sinter plant with a bowl with a diameter of 0.35 m and a height of 0.6 m. The quality tests of the sinter were carried out using standard equipment according to GOST 15137-77. The test results are presented in table. 3.

 Enhanced laboratory studies have shown that the classification of red mud into sand and silt fraction and their introduction into the sinter mixture in a mass ratio of 0.15-0.45 increases the productivity of the sintering process by an average of 12-25 rel.% And the strength of the sinter by an average of 3 -8 rel.%.

 As can be seen from the table. 3, an increase in the iron content in the agglomerate due to the introduction of a binder additive richer in iron (by 0.8-3.7%) further improves the quality of the agglomerate and positively affects the performance of the domain process.

Claims (1)

 METHOD FOR PRODUCING IRON AGRICOMET, including dosing of fine iron ore concentrates, fluxing additives, fuel and red mud, mixing, pelletizing and sintering on an agglomeration machine, characterized in that, in order to increase the productivity of the agglomeration process and the quality of the pellets, the red mud is divided into fractions before mixing + 63 μm and -63 μm and introduced into the mixture in a mass ratio of 0.15 - 0.45.

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