SU1733480A1 - Method of preparing change, based on limonite ores with siderite content 4-17% for roasting in stepped fluidized-bed furnace - Google Patents

Abstract

The invention relates to the preparation of raw materials in ferrous metallurgy. Purpose - intensification of the burning process and reduction of fuel and energy costs. The method of preparation based on iron ore containing 4-17% siderite for burning involves mixing ore containing 4-17% siderite with solid carbon-containing fuel moreover, when the content of siderite in the ore is 4-6%, the ratio of the average size of fuel and ore is set equal to 3.5-4.0, and with an increase in the content of siderite from 6% for each 3%, this ratio increases from 4.0 to 0.3 -0.5 units For example, iron ore with a content of 10% siderite and an average particle size of 0.5 mm is mixed with coal. The average coal size is set to 4.535 average ore size, i.e. equal to 2.27 mm. The raw mixture is loaded into the furnace and subjected to drying, heating, partial and final recovery. SO with

Description

This invention relates to methods for preparing iron ore in ferrous metallurgy, in particular to the magnetising roasting of iron ores.

The purpose of the invention is to intensify the burning process and reduce fuel and energy costs.

The furnace stepped layer (SHS) works as follows.

The raw mixture (ore and solid fuel) is loaded into the furnace and is successively moved from stage to stage under the influence of high-speed gas-air jets to the re-recovery chamber.

potential temperature, the mixture successively passes through the zones of drying, heating, and partial recovery, and is loaded onto the batch mirror of the recovery chamber. The coolant transfers heat to the iron ore charge, when rotated above the re-reduction chamber, it gives up particles of material falling out of the gas suspension and is discharged to the furnace head. The completion of the restoration is carried out in a descending dense layer - in the restoring chamber. The solid fuel (coal) that is included in the raw mixture is a source of heat in the volume of an SHS furnace and a substitute for a part of natural gas, and, in addition, particles of solid carbon heated to 800–950 ° C are a reducing agent for iron oxides in XI

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remediation. Changing the amount of carbonate compounds (siderite) in the mixture requires adjusting the size of the fuel, which is partially burned in the furnace volume. The enlarged fuel particles provide both the supply of increased amount of heat into the volume of the SHS furnace and the supply of the prepared reductant to the re-recovery chamber. For this, at 4–6% content of siderite in the ore, the ratio of the average size of the fuel to the ore is set in the range of 3.5–4.0 units. With a smaller ratio of fuel and ore size due to the insufficient content of solid reducing agent in the after-treatment chamber, the productivity of the unit decreases. With a larger ratio of fuel and ore size due to an increase in the chemical underburning of solid fuels, fuel costs for redistribution increase.

The ratio of the size of the fuel and ore, equal to 3.5-4.0, on the SVS furnaces is maintained with the content of siderite in the ore up to 6%. Exceeding this value in order to supply a sufficient amount of the prepared reducing agent to the re-recovery chamber requires an adjustment of the charge composition.

An increase in the content of siderite in the ore from 6% for every 3% is accompanied by an increase in the ratio of the size of fuel and ore from 4.0 to 0.3-0.5 units. By increasing the ratio of fuel size and ore by

less than 0.3 units For every 3% increment of the content of siderite in the ore, due to the lack of a solid reducing agent in the dense layer, the intensity of the restoration roasting is reduced. With an increase in the ratio of fuel size and ore by an amount greater than 0.5 units. For every 3% increment of the content of siderite in the ore, due to the chemical underburning of solid fuels, fuel and energy costs for redistribution increase.

The application of the invention provides an increase in the degree of reduction of the burned ore, the degree of extraction of iron from the ore, and a decrease in the iron content in the tails during enrichment.

Claims (1)

The invention The method of preparing the charge on the basis of brown iron ores with a content of 4-17% siderite for roasting in a furnace of a step-weighted layer, including mixing ore with solid fuel, characterized in that, in order to intensify the process of roasting and reduce fuel and energy cost, when the content of siderite in the ore is 4-6%, the ratio of the average fuel size to the ore is set equal to 3.5-4.0, and with an increase in the content of siderite in the ore from 6% for every 3% 4.0 0.3-0.5 d.