Charge for Producing Iron-Ore Pellets (Variants)

Abstract

The invention relates to the field of producing iron-ore pellets for blast-furnace smelting. In a first variant, a charge contains iron-ore concentrate and manganese limestone as a binding agent and flux, the ratio of charge components in wt % being as follows: 1.0-5.0 manganese limestone; and the balance iron-ore concentrate. In a second variant, the charge contains iron-ore concentrate, bauxite as a modifying agent, and manganese limestone as a binding agent and flux, the ratio of charge components in wt % being as follows: 1.0-3.5 manganese limestone; 1.2-1.5 modifying additive; and the balance iron-ore concentrate. The invention increases the strength of green and sintered pellets while preserving a high iron content, reduces the softening-melting interval of the pellets in a blast furnace, and simplifies the production of iron-ore pellets.

Claims

1. A charge for producing iron-ore pellets, the charge comprising an iron-ore concentrate, a flux and a binder, the charge comprising manganese limestone serving as the binder and the flux, wherein a ratio of components of the charge is, wt %: manganese limestone(1.0-5.0); iron-ore concentratethe rest.

2. The charge of claim 1, wherein a manganese content in the manganese limestone is at least 6%.

3. A charge for producing iron-ore pellets, the charge comprising an iron ore concentrate, a flux and a binder, the charge comprising a bauxite serving as a modifying additive, and manganese limestone serving as the binder and the flux, wherein a ratio of components of the charge is, wt %: manganese limestone(1.0-3.5); modifying additive(1.2-1.5); iron-ore concentratethe rest.

4. The charge of claim 3, wherein a manganese content in the manganese limestone is at least 6%.

Description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] The test charge for iron-ore pellets was performed in laboratory conditions. The iron-ore concentrate was used as the iron-ore material, the chemical composition of which is given in table. 1. There are also compositions of fluxes and bauxite given there. Bentonite, fluxes and bauxite were ground in a ball mill to a particle size of less than 0.072 mm, injected into the concentrate in a predetermined amount, mixed, moistened, and then the pellets were produced in a drum granulator with a particle size of 10-15 mm Raw pellets were tested for strength by dropping from a height of 30 cm. The sintering was performed in a muffle furnace with a programmable heat treatment mode at a maximum temperature of 1300 C. After firing and cooling, the pellets were tested for crushing strength according to GOST 24765-81, the chemical composition and softening-melting temperatures were determined according to GOST 26517-85.

[0036] For comparison, the tests were conducted on the charge of the prototypes, respectively, according to the first and second variant. The test results are presented in Table 2.

[0037] Analysis of the obtained results shows that the claimed charge for producing iron-ore pellets in both variants ensures the achievement of the stated goal of increasing the strength of raw and sintered pellets while maintaining a high iron content and reducing the softening-melting interval in the blast furnace.

[0038] The charge in both variants for obtaining iron-ore pellets compared to the corresponding prototypes increases the strength of raw pellets from 2.2 to 3.5-5.0 drops, the strength of sintered pellets from 250 to 313-510 kg/pellet, reduces the softening-melting temperature range from 320 to 240-290 C., retains a high iron content in the pellets.

[0039] The claimed technique can be implemented in industry with the achievement of the stated technical result.

[0040] Simplification of the charge is due to the fact that manganese limestone is intended for use as a flux and binder (i.e., such a component of the charge as a binder is not required separately).

[0041] As manganese limestone use natural raw materials (manganese ore), characterized by a manganese content of at least 6%.

TABLE-US-00001 TABLE 1 The chemical composition of the charge components, % Components Fe FeO Fe.sub.2O3 CaO MgO SiO.sub.2 AL.sub.2O3 MnO LOI Iron-ore concentrate 67.49 28.70 64.52 0.22 0.51 5.50 0.19 0.03 0.27 Bentonite 1.50 1.00 0.50 60.00 36.90 Manganese limestone 0.84 1.20 40.50 0.77 8.70 3.10 9.91 35.75 Bauxite 14.04 20.06 0.79 0.75 8.70 40.87 24.90 Chalky marl 1.12 1.60 44.40 0.70 14.50 3.50 35.40 Limestone 0.18 0.26 54.2 0.71 1.28 0.34 0.01 42.50 LOIloss on ignition

TABLE-US-00002 TABLE 2 Test Results The strength of The content in the charge, % raw pellets - The iron Crush strength of Softening-melting Experiment Manganese the number of content in sintered pellets, temperature # Concentrate Bentonite limestone Bauxite drops, times the pellets, % kg/pellet range, C. 1- 95.0 Chalky marl 2.2 64.95 250 320 according 5.0 to the USSR IC No. 800200 2 99.2 0.8 2.7 66.69 265 310 3 99.0 1.0 3.5 66.60 313 275 4 97.0 3.0 4.0 65.78 402 260 5 95.0 5.0 5.0 64.95 366 240 6 94.5 5.5 6.5 64.75 350 255 7- 97.9 0.6 Limestone 1.1 3.0 66.12 260 390 according 0.4 to patent No. 2,202,632 8 98.1 0.8 1.1 2.8 66.33 275 340 9 97.8 1.0 1.2 3.9 66.21 360 290 10 96.7 2.0 1.3 4.2 65.77 450 270 11 95.0 3.5 1.5 4.5 65.08 510 265 12 94.4 4.0 1.6 4.9 65.84 335 280