SU34574A1 - Chess multi-chamber furnace for the direct reduction of iron and steel from ore - Google Patents

Description

In the proposed multi-chamber shaft furnace, the iron ore crushed to the size of a pea passes from top to bottom between two louver-shaped machines, through which reducing gases are blown either from one side or from the other, at a temperature of 850-950 ° C, but below the sintering temperature of the ore. The recovered ore is discharged from below and separated from the waste rock on magnetic separators. .

In FIG. 1 depicts a multi-chamber shaft furnace in cross section; FIG. 2 - the same) in longitudinal section; FIG. 3-4 installation diagrams in two versions, and FIG. 5-7-louver construction.

In the proposed multi-chamber shaft furnace for direct reduction of iron and steel from ore, the iron ore crushed to approximately the size of a pea by the conveyor 7 through trays 2 is evenly distributed through the bunkers 5; Further, the ore passes from top to bottom into the working chambers 30, formed by two louvered walls of 4 gas chambers 57. Walls 4 are reinforced in the slots of vertical posts 5. Blinds are separate grate bars (Fig. 6) made from melted basalt or other refractory material (360). The slopes are inclined so that the gases between the individual grate bars penetrate freely and the ore can be poured onto the can. The distance between the walls 4 below is wider than the top, which prevents the caking of the ore and causes some mixing while lowering. From the bottom, the recovered ore is loaded automatically and continuously with feeders 6 and removed for magnetic separation by the screw 7.

To reduce the ore, it is heated to the reduction temperature. Heating of the ore can be carried out in two ways - either waste reducing gases or hot flue gases containing excess oxygen. In the latter case, simultaneously with heating, the ore is burned, which is important for ores containing sulfur. The flue gases at a temperature of approximately 900-1000 flow through the hog 8 and through the windows 9 pass between two louvre-like chambers filled with ore. The flue gases then go around the partition JO, the passage across the layer through the louver 4 twice and leaving through windows 7 / into the burs 72. The amount of gases is regulated by the valve 75. As the ore is unloaded by the feeders 6, the ore is heated to the second zone-zone

in the middle (part of the furnace. Reducing gases flow through the windows J4, pass through the ore layer between the louvers, skirt the partition 15 on both sides and, passing from the other side through the ore layer, go to the windows / b, also mixing the reducing gases gases entering through windows 9 are prevented from solid partitions 17, and gas is thrown through the vertical ore into the louvers between windows 9 and 76 due to a small difference in gas pressure and a large thickness of the layer. Yelnia gases below the sintering temperature of the ore by oxidation of parts contained in the gases of CO to CO2.

The amount of reducing gases in each part of the furnace is regulated by the valves / 5 in front of the exhaust gases 7P. In the event that the ore is heated by the heat of the spent reducing gases, the gases from the gas duct / transfer to the borax and exit through the borax / 2.

If the ore needs to be cooled after reduction, this is done either by blowing cooling gases through the layer of ore, or in a surface cooler 24 bathed in outside air with cold air.

Perhaps the final reduction of ore with hydrogen coming through the windows 22, 20 n of the valve 23, in general, this creates a significant complexity of the installation; therefore, it is better to work without it, increasing the residence time of the ore in the furnace.

The reducing gas is produced in the gas generator 25 by incomplete oxidation of the fuel. A burner 28 serves to burn the pulverized fuel entering through pipe 26. Hot combustion air is supplied through pipe 27. To reduce fuel consumption, a certain generator of exhaust generator gas is fed into pipe generator 29 through pipe 29. , according to the equation СОЗ - | - С 2СО. The quantitative ratio between fuel, air and gas should be such as to obtain a reducing gas that does not contain CO, with a temperature of t ° 850 -

950 °, but not higher than the sintering temperature

Rudy.

FIG. 3 shows a setup diagram, in which in the first zone of the furnace the ore is fired in an excess of oxygen at a gas temperature of 850-950. The ore is crushed in a crushing plant 33 and conveyor 34 is sent to a louvered furnace 55. The output of the reduced iron is from below, from where the conveyor 36 ore is sent to a magnetic separator. The fuel is pulverized to a pulverized state, neither in the mill 37 and the conveyor 58 is introduced into the gas generator 39, where it burns with a lack of air in CO. Generator gas passes through the ore in furnaces 55 and spent (with a CO2 content) leaves through pipe 40 to heat exchanger 4J, where it is cooled and fan 42 is injected for use to the following users: 1) through pipe 43 to furnace 44, where it burns in excess air and hot gases at a temperature (not lower than the sintering temperature of the ore) through pipe 5 are directed to a louver-shaped furnace 55 for heating and firing the ore in the first zone; 2) part of the exhaust gas through the pipe 46 passes into the gas generator 39; the remaining gases through pipe 47 are used for other plant needs. The air is blown by the fan 48 to the heat exchanger 4J, where 6N is heated by the heat of the exhaust generating gases and is directed through the pipe 50 to the furnace 44 and the gas generator 39.

FIG. 4 shows a diagram of a reduction plant, in which in the first zone of the heating of the furnace the ore is heated by means of heat-reducing reducing gases.

The ore is crushed to the size of a pea in a crushing plant 55 and conveyor 34 is sent to a louvered furnace 55. The output of the reduced iron is from the bottom, from where the conveyor 36 ore is sent to separate the iron to a magnetic separator.

The fuel is pulverized to a pulverized state at mill 57 and conveyor 38 is introduced into the gas generator, where it is burnt, with a lack of air in the CO. Hot generator gas passes through ore in louvered furnaces 55

and the exhausted (with a CO2 content) cooled while passing through a layer of cold, freshly loaded ore, is discharged into the upper part of the furnace through pipe 40. Then, this gas is blown through fan 41 through dust cleaners 42, and the purified gas is separated: part through pipe 5 / valve the torus 52 is passed through the cowper 55, from where the heated gas

pipe 54 is directed to gas generator 39, another part of gas is consumed through pipe 55 for heating cowper 55 and 56 and for the rest of the plant needs. Air for the gas generator 39 is pumped by the fan 57 through the cowper 56 and hot air.

Trub.e 58 passes into the gas generator.

If the ore is reduced by natural gases, they are heated in the cowers according to the scheme of FIG. four.

Fig. 5 shows a vertical stand 60 for installing individual inclined grid-irons forming a chamber wall; 61-inks (blinds). FIG. B-7 shows the inclined wall 61 of the grate (louver), preventing the ore from falling out; 62 tides for placing the grate bars (louvers) on top of each other, entering the grooves of the uprights.

This furnace is suitable for reducing ores that are not sintered at the reduction temperature. Its advantages over the shaft furnace are, according to the inventor, in the uniform passage of gases through the ore layer, since there are no dead zones, and in the possibility of restoring finely chopped and

silt ores (mixed with lumpy), as the pressure loss during the passage of gases through a thin layer of ore (--- 100 - 200 mm) at low velocity gases (about 0.03 to 0.05 m / s), The large surface of the louvered walls 4 (Figs. 1 and 2) is very small and does not exceed 60-80 mm of water column. The distance between the louvered walls at the bottom of the retort is 2-3 times more than at the top, which ensures the mixing of the ore particles when lowering it in the furnace, and, consequently, creates a homogeneous process of restoring the entire ore.

The subject matter of the invention.

Claims (2)

1. A multi-chamber furnace for direct reduction of iron and steel from ore, the chambers of which have louvre shaped walls, characterized in that narrow working chambers 50 which extend downwards and fed from bunkers 5 are formed by louvered walls of gas chambers 31, which the feeds to chambers 30 on different horizons of gases of different composition are divided by horizontal partitions 75, / 7, Yu into parts, alternately equipped with inlets 22, 14, 9 and output 16, 11 for gas windows. 2. In the furnace of claim 1, use of a conveyor device mounted above the chambers 30 of the furnace and intended to direct the reduced iron, with the aim of enriching it, to a magnetic separator. m -6}