SU739120A1 - Method of producing metallized product - Google Patents

Description

The invention relates to ferrous metallurgy and can be used in metallurgical plants in the production of metallized iron ore for blast-furnace and steelmaking. Methods are known for producing a metallized product in shaft furnaces using hot converted gas produced in special conversion apparatuses or gas-oxygen burners 1. However, for reducing iron ore raw materials, hot reduction gas is fed into the furnaces, the production of which is layered, capital-intensive and expensive technological process. There is also known a method of obtaining a metallized product from iron ore materials by gas reduction in two stages successively with gases with different reduction potential in a fluidized bed furnace, including recirculation of the reducing gas 2. The disadvantage of this method is the need to obtain reducing gases with a high reduction potential in special devices that worsens the technician about the economic performance of the process of obtaining metallized raw materials. The purpose of the invention is to create a method for producing meta-product in a shaft furnace from lump ore, or pellets with high technical and economic indicators, using simple and reliable equipment without special conversion facilities for producing a converted gas with high reduction potential. The goal is achieved by the fact that heating and reduction of iron ore raw materials to the extent of reduction of 40-60% lead to incomplete combustion of natural gas with a 0.3-0.5, and the final recovery is further heated to a mixture of hydrogen and 600-800 ° C. natural gas, simultaneously with the decomposition of natural gas in the same furnace when the material is cooled from 900-1000 ° C to 700 ° C. FIG. 1 shows a scheme for deep metallization (up to 95%) of rich pellets (Pepper 373 66.98%) for further processing in steelmaking; in fig. 2 - a variant of metallization of the regular ones. pellets, such as Lisakovskogo GOK (54.73%), for the subsequent blast furnace processing. The installation includes a shaft furnace 1, burner 2, cyclones 3, wet gas cleaning devices 4, gas blower 5, recuperator 6 for heating the air, blower 7, recuperator 8 for heating the hydrogen. The technological process proceeds in the following sequence (Fig. 1). Heating up to 900-1000 ° C and pre-reduction of the pellets to a reduction rate of 45-50% is carried out in the upper part of the mine recovery zone 1 with natural gas combustion products with an air flow ratio of 0.40-0.45. The air before being fed into the burner 2 is preheated to 500-600 ° C in the heat exchanger 6. The heating and reduction process in the upper part is carried out in a countercurrent of gas and material. The flue gas is removed from the furnace, gas cleaning devices 3 and 4 pass through and gas blower 5 is fed to the heating of the heat exchangers 6 and 8. The remaining gas is discharged to outside consumers. The final reduction of pellets to 90-95% is carried out in the lower part of the reduction zone heated with hydrogen in a recuperator up to 700-800 ° C with hydrogen in a stream. To cover the deficit of hydrogen that is consumed during the reduction process, natural gas is introduced into the lower part of the reduction zone. HYDROGEN with moisture vapor is removed from nec at 500-600 ° C and together with the gas, coming from the cooling zone, passes into the equipment 3 and 4 oshk and gas drying and then is recycled into the cooling and reduction of the shaft furnace. The product is cooled in countercurrent with cold hydrogen circulating in a closed loop. The process of heating and reducing the pellets in the upper part of the mine is not limited by the products of natural gas burning, 40-0.45. The incremental reduction of pellets in the lower zone is carried out in a countercurrent of gas and material by hydrogen circulating in a closed loop. The lack of hydrogen is covered by the decomposition of natural gas. Hydrogen mixed with natural gas is supplied to the cooling zone of the mine nec. After the cooling zone, a part of the gas is removed from the foot, the rest of the hydrogen mixed with the natural gas enters the reduction zone, where the processes of decomposition of natural gas and the recovery of iron ore raw materials take place. Heat consumption for endothermic reactions of decomposition of natural gas and reduction of pellets, as well as heating of gas is covered by physical heat of the material heated in the upper zone to 900-1000 ° C. The gas is removed from the recovery and cooling zone, mixed and sent to the apparatus 3 and 4, cleaning and drying the gas and the recycle gas blower 5 is supplied again to the bottom of the shaft furnace. The expenditure indicators and process parameters obtained as a result of calculations of the process of metallization or pellets of the Lebedinsky and Lisakovsky GOKs are summarized in table. 1 and 2. Table 1

Temperature in the heat exchanger, C 600 Coefficient of air flow to the conversion burner, a0.44 0.42 Temperature of products of incomplete combustion of natural gas at the entrance to the furnace, ° С1000-1050 Specific consumption of products of incomplete combustion of natural gas, nm / tm.nr.1250 heating the material / and in the upper zone of the preliminary recovery, ° С950 600 0.44 0.420.98 - 1 1000-10501100-1200 12502160 9801000-1100

Consumption of dried flue gas,. for heating the heat exchanger for hydrogen heating

for heating the heat exchanger

for air heating

unauthorized consumer

common

Calorific ability

drained flue gas,

kcal / nm

Heat consumption per 1 ton is pelletized overall; Kcal / tm.pr.

Minus the heat of gas given off

outsiders,

kcal / tm.pr.

The degree of reduction P /% in the upper part of the furnace is final.

The composition of the metalized product P9

Fe Fe

general

not

Feo

Continued table. one

2 - 10

2 ten

20

48

80

80

56.75

65.7

39.85

48.2 21.78

22.5

Natural gas consumption,.

for conversion to conversion

burner

by mixing with hydrogen into the recycling cycle

for heating the heat exchanger for hydrogen heating

Total consumption,.

Air flow to the conversion burner. The application of the method will provide better metallic raw materials on a large scale with high technical and economic indicators, since this eliminates the need for special capital-intensive and expensive conversion plants for producing reducing gas and gas purification units for COj. Preheating and restoration of iron ore material will allow for the process of reducing iron oxide, which limits the whole metallization process, with optimal parameters; The moisture content in hydrogen will not exceed 2.5–3%, the temperature in the lazy zone will be 1000–700 ° C, high speed and ivianb specific hydrogen consumption. Recovery at high temperatures will provide a non-pyrophoric metallized product. The presence of black carbon in the final product in the range of 1.5-4.0% and the result of the decomposition of natural gas will allow for smelting metallized pellets in electric furnaces to remove residual iron oxides and carbonize the metal to the extent necessary, and to reduce the consumption of metallized raw materials in blast furnace production coke.

205

120

56 101

14,235

261

802

Claims (2)

1160 Claim method A method of producing a metallized product with a reduction rate of 80-95% in a shaft furnace from lump ore or pellets, including two-stage gas reduction of iron from its oxides, recirculation of reducing gas, in order to simplify the process and improve technical and economic indicators, the heating of iron ore raw materials and its restoration to the degree of 40-60% are the products of incomplete combustion of natural gas with a 0.30-0.50, and finally the restoration was carried out are heated to 600-800 ° C with a mixture of hydrogen and natural gas, simultaneously with the decomposition of natural gas in the same furnace when the material is cooled from 900-1000 ° C to 700 ° G. Sources of information taken into account during the examination 1.Kn pharynx VF, et al. Beskox's Iron Metallurgists, M., Metallurgists, 1972, p. 64-79, 2. Patent of FREDA N 1268487, class, C 21 V, 1960. "Si