SU1717654A1 - Method of agglomeration of iron ore materials - Google Patents

Abstract

The invention relates to the agglomeration of iron ore materials. The aim of the invention is to increase the productivity and quality of the sinter. To do this, additionally, for every 10 mm increase in the height of the agglomerated layer, the ratio of the length of the primary throttling zone to the length of the secondary throttle zone is reduced. solos on 0,1-0,25 at a constant total length. 1 tab.

Description

The invention relates to the sintering of iron ore materials and can be used in the agglomeration production of ferrous metallurgy.

The aim of the invention is to increase the productivity of sintering machines and improve the quality of the agglomerate.

The essence of the method is the following. over

The grates of sintering carts ag. Pelletized mixture contains an increased amount of large granules (10–15 mm) in the ground-cutting machines, and fine particles (3–0 mm) are concentrated in the upper part of the agglomerated layer. This distribution of the pelleted charge fractions over the bed height also contributes to the distribution of solid fuel characteristic of agglomeration: the upper part of the bed concentrates more of it than the bottom, which favorably affects the distribution of heat over the height of the bed - there is more fuel where there is less heat recovery.

The aerodynamic resistance of the agglomerated layer changes during the sintering process. In the initial period, the total resistance of the layer increases, which is associated with the formation of the main zones of agglomerate formation: waterlogging, drying, heating, burning, melting and cooling. In the next, main period, the geometrical dimensions of the zones of drying, burning, melting change insignificantly. This reduces the height of the overwetting zone and increases the thickness of the agglomerate layer with the highest gas permeability from all agglomeration zones. In this connection, the total gas dynamic resistance of the agglomerated layer drops and the rate of air entrainment into the layer along the length of the sintering belt increases to the unloading part of the machine. The amount of air per unit area on the last vacuum chambers, where most of the layer is represented by agglomerate, grows especially strongly by 4-6 times.

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Reducing the rate of air filtration through the layer, starting from the last row of burners in the hearth, reduces the cooling rate of the upper layers of the agglospace, which contributes to the high mechanical strength of this part of the agglomerate. Throttling of the vacuum chambers, which reduces the rate of air filtration through the layer, starts from the last row of incendiary burners — the primary burner — covers the last vacuum chambers — the secondary. The ratio of the length of the primary throttling zone to the length of the secondary throttling zone is reduced by 0.1-0.25 for every mm of the height of the agglomerated layer, starting from 200 mm.

In the upper part of the agglomerated layer, heat recovery has a rudimentary development and, therefore, the filtration rate of gases is set at a minimum of 0.1 m / s, which is achieved by throttling vacuum chambers.

The number of vacuum chambers of the primary throttling zone, at which the rate of air filtration through the bed is reduced, is determined by the formula:

, 05- vn / Vcn i.

where 0.05. - thickness of the upper sintered layer of agglomerate, m;

vn — sintering speed, m / min;

VCD - sintering rate of agglomerate, m / min;

I is the length of one vacuum chamber, m

The thickness of the upper horizon, equal to 50 mm, is chosen from the calculation that during the motion of the layer under the mountain the mixture heats up to a depth of 10-20 mm, which ensures slow cooling of the top of the spec. total depth 60-70 mm.

A decrease in the ratio of the length of the primary throttling zone to the length of the secondary throttling zone by an amount of 0.1-0.25 is carried out for each

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10 mm layer height, starting from 200 mm. The lower limit corresponds to a layer height of 200 mm, the upper one - to a layer height of 600 mm. The depth of the throttling of the last vacuum chambers is set to provide a gas filtration rate of 4 m / s. This is due to the fact that in the lower layers of the layer the thickness of the high temperature zone reaches 100-150 mm and more, which allows increasing the sintering rate without reducing the quality of the agglomerate. At a higher sintering rate, the productivity of sintering machines is reduced by reducing the rate of gas filtration in the upper part of the agglomerated layer.

The total number of throttled vacuum chambers is constant and equal to half of their number, counting from the last row of incendiary burner burners. With more throttled vacuum chambers, the productivity of sintering machines decreases, while with less, the amount of agglomerate decreases.

The table presents the sintering results of the agglomerate at different layer heights and the length of the primary and secondary throttling zones obtained on the hot model of the agglomeration process.

Invention Formula

The method of agglomeration of iron ore materials, including laying the charge on a conveyor belt, high-temperature heating, filtering gases through the layer, primary throttling of the vacuum chambers behind the incendiary mountain, secondary throttling of the vacuum chambers in the discharge part of the sintering belt, characterized in that, in order to improve performance and quality agglomerate, in addition, from every 10 mm increase in layer height, starting from 200 mm, the ratio of the length of the primary throttling zone to the length of the secondary throttling zone decreases 0.1-0.25 .posto at constant total length of the orifice areas.

Claims (1)

Claim A method of agglomeration of iron ore materials, including laying the charge on a conveyor belt, high-temperature heating, filtering gases through a layer, primary throttling of the vacuum chambers behind the incendiary furnace, secondary throttling of the vacuum chambers in the discharge part of the sinter, characterized in that, in order to increase productivity and quality sinter, in addition to every 10 mm increase in layer height, starting from 200 mm, the ratio of the length of the primary throttling zone to the length of the secondary throttling zone is reduced by 0.1 -0.25 with a constant total length of the throttling zones. h Layer height mm The number of covered vacuum chambers Specific productivity, t / m ^g · h Yield,% Primary throttle zone Secondary throttling zone 200 5 1 1,5 65,4 300 4 . 2 1.45 66.5 400 3 3 1.4 69,4 500 2 4 1.42 70,4 600 1 5 1.35 75.5 P RO TO TI P 350 4 2 1.33 58.5