RU2412257C1 - Procedure for agglomerate charge pelletising - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: agglomerate charge consisting of crumbled ore or concentrates, flux additives and solid fuel is pelletised producing two-layer pellets. At the end of pelletising part of fuel is supplied into the external layer of pellets. Also, as fuel, brown-coal coke is supplied into the external layer of pellets; optimal amount of coke should reach from 40 to 50 % of total consumption of solid fuel during agglomeration.

EFFECT: reduced consumption of heat in ignition hearth of agglo-machine, raised output of finished product of agglo-machine and increased rate of agglomerate sintering.

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Description

The invention relates to the field of sinter production and can be used to obtain sinter charge with high consumer properties.

A known method of pelletizing (see RU, AS No. 2005127296, class C22B 1/16, 2007), which consists in dividing the fuel (usually coke breeze) into two parts to obtain two-layer granules, where the first part of the fuel is introduced directly into charge and then pelletized, and the second part is applied to the pelletized pellet, forming the outer layer. The disadvantage of this method is that coke breeze, having a high ignition temperature and low reactivity, cannot provide a significant increase in the sintering speed of the charge and increase the productivity of the sinter plant as a whole.

The closest in technical essence and the achieved result is a method of pelletizing an agglomeration charge (see SU, AS No. 1770361, class C22B 1/14, 1992), consisting of crushed ores or their concentrates, as well as solid fuel, in which [in the method] highly reactive fuel, for example brown coal semicoke (BOD), is used as solid fuel. The disadvantage of this prototype is that highly reactive fuel is evenly distributed in the composition of the granules, i.e. the granule is single-layered, which does not give significant advantages in terms of reducing heat consumption in the incendiary furnace of the sinter machine.

The objective of the invention is to remedy these disadvantages of the prototype due to:

- reduce heat consumption in the incendiary furnace of the sinter machine;

- increase the sintering speed of the sinter mixture;

- increase productivity sinter machine on the finished product.

The inventive method of pelletizing an agglomeration charge, consisting of crushed ores or their concentrates, fluxing additives, as well as solid fuel (usually coke breeze), comprising obtaining two-layer granules by supplying part of the fuel to the outer layer of granules at the end of pelletization, while achieving of the above advantages, it is proposed that coke breeze applied to the outer layer of granules be completely replaced by a highly reactive BOD.

Comparative characteristics of the influence of coke breeze and BOD on the performance of the agglomeration process are shown in tables 1, 2, 3, 4.

Description of the method: preparation of ores (or their concentrates), fluxing additives and fuel for agglomeration, dosing of charge components, mixing and primary moistening of ores (or their concentrates), fluxing additives and part of the fuel (coke breeze) included in the granules in a mixer , pelletizing the mixture in a drum pelletizer, applying the second part of the fuel to the pelletized pellet, loading the mixture onto the sinter machine, igniting the sinter mixture in the furnace, sintering process, crushing the sintered agglomerate in crushers, screening the sinter stationary screens, cooling the agglomerate in the cooler, secondary screening of the cooled agglomerate on stationary screens, the issuance of agglomerate in railway hopper cars. As experiments have shown, the optimal amount of highly reactive fuel - BOD, applied to the outer layer of granules instead of coke breeze, should be from 40 to 50% of the total consumption of solid fuel in the sintering process. This is confirmed by the results of experiments (see table 3).

Table 1 Agglomeration process indicators The granule is single layer. Coke breeze is used as fuel The vertical sintering speed of the charge V, mm / min 13.1 The specific productivity of the sinter machine q, t / (m ² · h) 0.80 The mechanical strength of the agglomerate,% 13

table 2 Agglomeration process indicators The granule is two-layer. The amount of coke breeze in the outer layer of granules,% of total fuel consumption twenty 40 60 The vertical sintering speed of the charge V, mm / min 14.1 14.5 16,2 The specific productivity of the sinter machine q, t / (m ² · h) 0.81 0.87 0.82 The mechanical strength of the agglomerate,% fourteen 16.5 17.5

Table 3 Agglomeration process indicators The granule is two-layer. The number of BOD in the outer layer of granules,% of total fuel consumption twenty 40 60 The vertical sintering speed of the charge V, mm / min 15.1 15,5 17,2 The specific productivity of the sinter machine q, t / (m ² · h) 0.82 0.88 0.83 The mechanical strength of the agglomerate,% fifteen 17.5 18.5

Table 4 Pellet characterization Total fuel consumption for agglomeration The granule is single layer. Coke breeze is used as fuel 8.0 The granule is two-layer. Coke breeze is used as fuel (in the outer layer it is 50%) 7.7 The granule is two-layer. Coke breeze is used as fuel in the inner layer, BOD in the outer layer (50%) 7.2

Thus, the task is solved by using highly reactive fuels, such as brown coal semicoke, and two-stage pelletizing to obtain two-layer granules.

Claims (1)

A method of pelletizing an agglomeration charge consisting of crushed ores or their concentrates, fluxing additives, and solid fuel, including the production of two-layer granules by feeding part of the fuel to the outer layer of granules at the end of pelletizing, characterized in that to the outer layer of granules when pelletizing as fuel lignite semi-coke is introduced, the optimum amount of which is from 40 to 50% of the total solid fuel consumption in the sintering process.