SU1388442A1 - Method of roasting ore-fuel pellets - Google Patents

Abstract

The invention is intended for the firing of ore-toplivny okrashey with air supply through a layer of pellets. The aim of the invention is to increase the content of residual carbon in oxidized oxides. The goal is achieved by the fact that the supply of air through the layer of the glass is carried out at a speed of 1.4-2.5 m / s. 2 tab.

Description

The invention relates to the burning of ore-coal okiptsey and can be used in metallurgy in the preparation of raw materials for metallurgical processing.

The purpose of the invention is to increase the content of residual carbon in oxidized pellets.

The method was tested in laboratory conditions. Under identical conditions, a comparative analysis of the quality of pellets obtained by the proposed method and prototype was carried out.

The chemical composition of the charge materials is given in tlbl. one.,

Anthracite contains,%: C 76.8; V 5.67; S 1.23; A.16,3.

The carbon content in the charge varied within: (3: 5) - (21-25)%.

Raw pellets were obtained on a granulator with diameters of 1 m, which were roasted in a bowl with an absorption area of 0.05 m. The gases were removed from the bed with a centrifugal fan with a capacity of 30 and a negative pressure of 1000 mm of water, Art. the limits of filtration rates,

Comparative analysis data are given in Table. 2. From table. 2, it follows that at filtration rates of 0.002-0.008 m / s and carbon content from 3-5 to 21-25%, sintering coal is formed when roasting coal-ore pellets. With an increase in filtration rate of up to 1.0-1.3 m / s and a carbon content of 3-5%, druses of oakshay are formed in the lower part of the layer, and with an increase in the carbon content of up to 8-25%, ore-fuel pellets form melted agglomerates. ratovichny spec. When the carbon content in ore-fuel oaks is 8–10% and the air filtration rate is 1.65–1.75 m / s, you get oaks containing 3-4% residual carbon and strength 190–200 kg / oK, t, e, strength satisfying the requirements of blast furnace smelting. With an increase in the carbon content in the ore-fuel pellets from 15 to 25% and an air filtration rate of 1.65-1.75 m / s, melted spec. With an increase in the filtration rate to 1.90-2.5 m / s and a carbon content of 1520% of the original ore-fuel openings, burned pellets are obtained.

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containing 8-10% residual carbon and strength 80-100 kg / approx. The strength of these oaks is not sufficient for use in a blast furnace. A further increase in the carbon content in the original ore-fuel cells to 21–25% and an increase in the air filtration rate to 2.6–3.0 m / s leads to a sharp decrease in the strength of the calcined pellets, which does not meet the requirements of blast furnace smelting.

Comparison of the quality of burned eyes, produced from ore-fuel charges according to the proposed method and according to the prototype method, shows that during the burning of ore-coal okshgey with sucking air at a speed of,. Filtration of 1.4-2.5 m / s is obtained that contain 2-3 times more residual carbon than pellets produced by the prototype method. At the same time, the quality of pellets satisfies the requirements of blast furnace smelting. According to the prototype method, an agglomerated melted specimen is formed.

Thus, the results of a comparative analysis of the proposed method show that the method of burning ore-fuel oats allows one to obtain oats with a higher content of residual carbon and physical and mechanical properties that satisfy the requirements of blast-furnace smelting.

The use of these oaks in blast furnace smelting reduces coke consumption due to the close contact between iron oxides and residual carbon particles in okshahg. The processes of iron reduction in oka- Tbmiax in the presence of solid carbon occur three times faster and at lower temperatures, which reduces the coke consumption.

The method is carried out in the following manner.

Raw fluxed ore fuel. Pellets with a diameter of 8-20 mm are laid with a layer of 100-300 mm on the grate of the sintering or firing machine. Raw materials are dried — by sucking or blowing through a layer of coolant gas with a temperature of 200–400 ° C and a filtration rate of 1.4–1.6 m / s, heated at 650–700 ° C, lower than

ignition temperature of solid fuel; burning with combustion products of gaseous or liquid fuel at 900-1300 ° C with an air excess factor of 1.2-1.4. The firing time, depending on the layer height, the temperature of the coolant, the excess air ratio, the carbon content in the charge and the degree of fluxing, varies within 1-6 minutes, during which the solid fuel contained in okatr is ignited in the upper part of the layer. Then, through the ignited layer of pellets, air is sucked from top to bottom for 4 to 7 minutes, resulting in the combustion of solid fuel contained in the pellets. The air filtration rate varies from 1.4 to 2.5 m / s, depending on the carbon content of the pellets, which can vary from 3 to 20%. At the same time, temperatures of 1180-1220 C develop on the surface of the pellets, at which the sintering of the pellets with each other does not occur, and the firing process proceeds at a rate that ensures incomplete burning of the fuel. In the laboratory

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Pellets containing 3–4% carbon were obtained in the upper and lower layers in a sintering area of 0.05 m. Strength. Crushing amounted to 190-200 kg / ok, and productivity

installations of 1.1 t / m h.

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Thus, the proposed method of burning ore-fuel cells allows to obtain pellets containing no higher amount of solid carbon and suitable for their physical and mechanical characteristics for smelting in blast furnaces.

Claims (1)

Invention Formula The method of burning ore-fuel pellets, which includes drying, heating, burning with the combustion products of liquid or gaseous fuel, supplying air through the layer and cooling, is due to the fact that in order to increase the content of residual carbon in the oxidized pellets The layer of the layer is carried out with a filtration rate of 1.4-2.5 m / s. Table 1 Materials Chemical composition, %  FeO | SiO. CaO MgO Influence of air filtration rate and carbon dioxide content in oaks on the physical state of the product, its strength and residual carbon content Known 0.002-0.008 Proposed 1 , 0-1.3 0.35-0.45 3.0-4.0 5.0-6.0 Speck 475-575 Speck Note: in the numerator is the physical state of the spec and strength pellets, kg / ok; in the denominator - the content of residual carbon in the pellets (%) after firing.