SU863644A1 - Method of cooling sulfur-containing iron-ore lumped materials - Google Patents

Description

(54) COOLING METHOD FOR SERO-CONTAINING IRON PIECES OF MATERIALS

1, v. This invention relates to the preparation of metallurgical raw materials in ferrous metallurgy.

Methods are known for removing sulfur from sulfur-containing iron ore materials, such as pellets, on conveyor-type calcining machines, including a two-stage purge of the calcined materials with an oxygen-cooling agent. In these methods, sulfur from the pellets is removed in the high-temperature zones.

However, these methods are characterized by insufficiently effective removal of sulfur from the oximate, especially fluxed (the sulfur content in the finished product, as a rule, does not fall below 0.1%, which significantly degrades the quality of the metal during the blast furnace), an increase in the length of the high-temperature zones and, as a result, reduced performance of the roaster unit.

The closest to the invention in its technical essence is a method for cooling iron-containing lump material, which produces a two-stage blowing of materials with a cooling agent with the presence of water vapor in the first stage of the cooling zone. According to this method, the pellets are supported in the zone of maximum temperatures.

-3-10 min with oxygen content in

gas phase 2-15% 1,

The disadvantages of this method are: the inefficiency of its use in the firing of fluxed okatia, since the sulfur content in finished products exceeds 0.08%; There is no sufficiently high sulfur recovery from sulfur-containing iron ore materials, an increase in the length and temperature range of the zones and, consequently, a decrease in production of the roasting machine; meeting the requirements for the gas phase in the zone, which significantly complicates the gas flow scheme.

The purpose of the invention is to increase the degree of removal of syngene {ml from lump materials and improve the quality of the finished product.

The goal is achieved by the fact that in the recirculation gas stream

25 with the oxygen content of 16–20% and a temperature of 350–450 seconds water is added well. emulsion 10-16 kg / m, while the final temperature of the cooling agent in the first stage of the cooling zone is set within 280-320 ° C,

30, the filtration rate of the cooling agent at the first stage is 1.3-2.0 times lower than the second. Iron ore deposits after the completion of strengthening calcination in high-temperature zones of the calcining conveyor machine undergoes cooling. However, the sulfur content in the calcined oxaite before the cooling zone exceeds, as a rule, 0.1 Therefore, it is necessary to complete the process of sulfur removal and directly in the cooling zone. It was established that the removal of sulfur from pellets during their cooling is possible at a temperature of a cooling agent of 280–320 ° C and a water vapor content of 10–16 K / m of gas and oxygen in it is 16–20%. Under these conditions, sulfur is oxidized to SOj and hydrogen sulfide is formed). Obrazvdies sulnist compounds are removed from the layer of pellets with waste gases. As a result, the sulfur content in finished products is reduced to admissible limits (0.04-0.05% and lower). The oxygen content in the cooling agent (recycle gas stream) should be 16-20%. With a lower oxygen content (less than 16% slows down the process of sulfur oxidation to SOj and increases the sulfur content in the finished product. A higher oxygen content in the cooling agent (more than 20%) is impractical because it doesn’t improve the desulfurization process and requires additional oxygen in the stream recirculation gases. The required amount of water vapor in the cooling agent is obtained by supplying water emulsion to the hot recirculation gas stream. The amount of water emulsion should be 1016 kg / m. With a smaller amount of emulsion (less than 10 KG / N, the process of hydrogen sulfide formation slows down significantly and the sulfur content in the finished product increases. With more water emulsion (more than 16 kg / ky, temperature of the cooling agent the process of sulfur oxidation to SOf slows down and the quality of the finished product decreases. The temperature of the recirculated gases before the supply of the water emulsion should be 350-450 ° C. At less than (less) water per emulsion, evaporate cools the gas to temperatures below 280 ° C, which , as shown above, is unacceptable. Higher temperature (more) undesirable according to the conditions of operation of liquid ingot equipment. The temperature of the cooling agent at the inlet to the first stage of the cooling zone should be 280-320. At temperatures below, the process of sulfur oxidation slows down to SO and the quality of the finished product falls. The temperature of the cooling agent above is undesirable, since it leads to a decrease in the cooling efficiency of the layer with pellet. Increasing the temperature of the coolant in the first stage of the cooling zone to 280-320 ° C also contributes to the elimination of the heat shock (reduction of the temperature difference between the pellets and the cooling agent), which is the main cause of destruction of the pellets in the cooling zone. The elimination of heat shock leads to a significant reduction in class trifles - 5 nl in finished products. In order to intensify the process of cooling pellets, the filtration rate of the cooling agent at the second cooling stage should be set 1.3-2.0 times more than at the first stage of the cooling zone. As a result, the efficiency of the cooling of pellets, and consequently, the productivity of the zone of cooling, increases significantly. Moreover, the filtration rate of the cooler at the second stage should not be less than 1.3 of the filtration rate at the first stage, since otherwise the cooling efficiency of the pellets and, consequently, the productivity of the frying machine will decrease. A higher filtration rate of the cooler in the second stage (more than 2.0 of the filtration rate in the first stage) is also undesirable, since it leads to an excessive increase in the power and size of one-year equipment. In order to intensify the removal of sulfur in the middle and lower layers of the layer, it is advisable to add solid fuel of 0.1-0.5% to the mixture of pellets. At the same time, the temperature is pelleted on the middle and lower layers of the layer and the desulfurization process is noticeably activated. An additive of solid fuel of less than 0.1% is undesirable because it does not improve the desulfurization process. The addition of topLive more than 0.5% does not increase the degree of sulfur removal from the deposit. The invention consists in cooling the pellets at first with respect to the hot cooling agent with a significant content of water vapor therein and in preparing such an agent directly on the recirculation gas path. Example. Iron ore pellets, such as the Sokolovsko-Sarbaysk deposit, with an iron content of 63% and sulfur of 0.35%, fall on a kiln of a conveyor type. As the roasting progresses, pellets are consistently dried.

gas coolant at 320 ° C, heated pr ", high-temperature roasting at 1300 ° C, recovery and cooling. In the flow of gases, which are supplied from the second stage of the cooling zone, the oxygen content is set at 20% and the temperature. J;: the oxygen content is controlled by the no-j means of the gate of the organized cold air podss (installed on a special cold air suction nozzle) and controlled according to the degree of opening of this gate and on the gas analysis for oxygen produced in the first standard stationary instrumentation (I & C). The gas temperature in front of the equipment of 350 ° C is controlled by the amount of cold air supplied to the path and is controlled by stationary flow meters and instrumentation thermocouples. -

After a liquid installation, a water emulsion is injected into the cooling agent stream, injected with water nozzles with nozzles of the type, for example, B-10. At the same time, the amount of water emulsion is set equal to 16 kg per m of cooling agent. The specific flow rate of the cooling agent (air) is maintained at 1800 m5 / t. Then, at the load of the roasting machine 120.t / h (for raw pellets), the flow rate of the water emulsion is set at 2800. The flow rate of the cooling agent is measured by stationary flow meters. The flow of water in front of the nozzles is controlled by valves and valves and controlled by a stationary water flow meter.

The temperature of the cooling agent supplied to the first stage of the cooling zone is set equal and controlled by varying the amount of water emulsion supplied. Temperature is controlled by stationary thermocouples.

The cooling agent prepared in the manner described is fed to the first stage of the cooling zone, sucked through a layer of pellets and discharged into the recirculation gas path.

When a cooling agent is drawn through, indicating the parameters through the LAYER of the calcined pellets, the process of sulfur incorporation into the gaseous medium occurs in them and the degree of desulfurization of the finished product increases markedly.

To intensify the cooling process, the filtration rate of the cooling agent on the second cfTyneHH is maintained 1.3 times higher than on the first, i.e. Wl j 1,3 Wy,, where Wj and W are the cooling agent velocity at the second and first 5 stages of the cooling zone, respectively. The speed of the cooling agent at both stages is set according to its consumption by means of adjusting gates and controlled by means of stationary displacement meters.

The burned pellets pass through the cooling zones, are cooled to a temperature below 100 ° C, additional desulfurization, and flow into the finished product path.

5 The application of the proposed method provides a reduction in the sulfur content in the finished product to 0.035% and below, a decrease in the content of fines of the class - 5 mm in baked oats,

0 an increase in the productivity of the cooling zone and the preparation of a cooling agent on existing equipment.

The implementation of the method at the SSGOK and the Kostamukshsky GOK makes it possible to obtain

5 economic effect (expected) over 115 thousand rubles. in year.

Claims (2)

1.Bratchikoy S.G. et al. Thermal engineering of the agglomeration of iron ore raw materials, 1970. 2. Authors certificate of the USSR 403793, cl. From 21 to 1/20, 1974.