JPS5855094B2 - Grain slag cooling recovery method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for cooling and recovering grain slag.

Methods for recycling metallurgical slag discharged from refining furnaces such as blast furnaces, converters, and electric furnaces include slow cooling to obtain crystalline slag, and quenching with water to obtain amorphous slag. There is also a method of obtaining semi-crystalline slag by spraying water vapor or the like.

Of these, slag was often disposed of as landfill material, but due to its dense and mechanically strong properties, it has recently been used for purposes such as roadbed materials and aggregate for concrete. It is increasing.

It is expected that this trend will become even stronger in the future from the standpoint of resource and energy conservation. The development of a treatment method is desired.

In order to meet such demands, in the case of blast furnace slag, etc., slag fields,
It is unsatisfactory to improve the conventional method of obtaining slag for the above-mentioned use by excavating the coagulated mass that has been cooled and solidified in a dry pit, etc., crushing it to an appropriate particle size, and classifying it.

Recently, various methods have been proposed to directly granulate crystalline slag from slag, in which the slag is supplied to a rotating body or compressed fluid, dispersed into droplets, and granulated into spherical particles by surface tension. However, it has not yet reached the stage of practical use as a method for obtaining spherical slag with a good yield and desired quality.

This is because no means has been established to efficiently collect the droplets dispersed by the method described above, cool them down to the solidification region with the same particle size, and recover them as slag.

In other words, the particle slag that has been dispersed and released into droplets by an appropriate method is still hot, so when it collides with an obstacle such as a wall, it deforms into a flat shape, and when the particles come into contact with each other, they immediately weld together and form a nodule. Although they are easy to elongate, once the surface temperature of the particles drops to the solidification range (non-welding temperature), such troubles no longer occur, and subsequent handling is relatively easy.

Therefore, in order to process metallurgical slag in a molten state and granulate it for uses such as aggregate for concrete, the technical point is to establish a cooling recovery method from the granulation temperature of the molten slag to the non-welding temperature.

From this point of view, the present invention provides droplets obtained by dispersing molten slag with an appropriate means such as a rotating body or compressed fluid, and
To provide a cooling recovery method and device for granule slag, which can be cooled and solidified while maintaining the original granulation shape up to a non-welding temperature range, and can be recovered at a good yield as granule slag that can be used as fine aggregate for concrete, etc. This was created with the aim of The molten slag is supplied into droplets to the upstream side of the duct, and the main body of the transport duct is vibrated to supply air flowing in opposite directions above and below the current plate, passing through the holes in the current plate from the lower duct to the upper duct. The blown air fluidizes the grain slag layer and moves it downstream,
This system is characterized by continuously collecting solidified slag from the downstream end of the upper duct.

Embodiments of the present invention will be described below with reference to the drawings.

The transport duct main body 3 is composed of an upper duct 6 and a lower duct 7, and is a horizontal duct that is slightly inclined with respect to a horizontal plane from the upstream side to the downstream side.

And upper duct 6 and lower duct 7 of transport duct main body 3
A porous rectifier plate 8 is installed between the flow path and the cross section of the flow path to be divided into upper and lower sections.

The current plate 8 needs to have sufficient strength and thermal durability and non-wetting properties against the slag due to the amount of slag to be fluidized and its high-temperature properties. For example, heat-resistant ceramic is used.

In addition, the porous holes are extremely small continuous through holes provided in the plate thickness direction in order to uniformly fluidize the grain slag without channeling or blow-through, and the unit area of the holes in the current plate 8 is The ventilation resistance per unit area is set to be greater than or equal to the ventilation resistance per unit area of the grain slag layer.

The width of the current plate 8, that is, the width of the transport duct body 3, must be greater than the width of the slag group to be supplied, and the cross-sectional distribution of the slag layer perpendicular to the movement direction of the slag is such that the slags are It is determined that the particles do not weld to each other during flow, and based on this condition, the transportation speed of the grain slag is determined with respect to the supply amount of the grain slag.

The length of the current plate 8, that is, the length of the duct, is determined from the product of the transportation speed of the slag and the residence time of the slag in the duct. The time required to cool and solidify to a certain hardness is determined based on the maximum grain size of the grain slag, since there is a difference in time until the non-welded region is reached depending on the grain size.

The upstream end 4 provided at the upstream end of the upper duct 6 is provided with an opening 37 for guiding the grain slag group 2 into the upper duct 6. End 5
A partition wall 43 for separating and sealing the upper duct 6 and the lower duct 7 is provided inside, and a cold air sealed channel 38 and a grain slag sealed channel 39 are formed.

The opening 37 is formed to have a sufficient width and height so that the particle slag group 2 obtained by dispersing the slag flow into droplets is collected in the flight direction without contacting the surrounding wall surface. .

A cold air header pipe 1 is installed at the upstream end 35 of the lower duct 7.
A plurality of cold air supply nozzles 10 fixed to the current plate 8
A plurality of air supply nozzles 15 are attached to the lower part of the rectifying plate 8 in parallel with the rectifying plate 8, and a plurality of air supply nozzles 15 fixed to the air header pipe 16 are attached to the downstream end 5 of the rectifying plate 8. The device is parallel to 8.

In addition, at the bottom of the cold air sealed channel 38 and the grain slag sealed channel 39,
A cyclone 20 is connected via a telescopic tube 21.

The cyclone 20 is provided with an exhaust pipe 22 at its upper part and a sludge discharge port 23 at its lower part.

Appropriate addition is applied to the iron skin of the transport duct main body 3 in order to prevent problems such as particles being supplied from the opening 37 and still at high temperature falling onto the rectifying plate 8 at the welding temperature, adhering to it and blocking the holes. A shaker (pie break) 31 is installed.

A cold air pipe 1 is connected to the cold air header pipe 11 via a telescopic pipe 40.
2 is connected, and the cold air pipe 12 is provided with a cold air regulating valve 13 for adjusting the flow rate and pressure of the cold air sent to the lower part of the rectifying plate 8 by the blower 14.

The air pipe 1 is connected to the air header pipe 16 via a telescopic pipe 41.
The air pipe 17 is provided with an air control valve 30 for adjusting the flow rate and pressure of the air sent to the upper part of the rectifying plate 8 by the blower 19, and an air control valve 30 for adjusting the temperature of the air supplied into the upper duct 6. A heat exchanger 18 is provided for this purpose.

An opening 3 is provided at the boundary between the upper duct 6 and the upstream end 4.
In order to prevent the adverse effect of the flow of the suction air flowing in from the air supply nozzle 15 into the upper duct 6, a partition plate 25 is fixed to the partition plate 25. A suction port 36 is provided for sucking in the supplied air flow.

The suction port 36 is connected to the suction pipe 2 via the telescopic pipe 42.
6 is connected, and a cyclone 27 is provided at the tip of the suction pipe 26.

An exhaust pipe 28 is connected to the upper part of the cyclone 27, and an exhaust fan 29 is provided at one end of the exhaust pipe 28.

- A slag discharge port 24 is provided at the lower end of the Kacyclone 27.

On the upstream side of the opening 37, there is disposed a rotating drum 1 which is rotated by a drive device (not shown) in the direction of the arrow, for example, in order to turn the slag into droplets. A slag hopper 32 is installed for dropping and supplying slag 34 to the rotating drum 1 through a nozzle 33.

Note that 9 in the figure is a grain slag layer.

Next, the operation of the present invention will be explained.

First, the blowers 14 and 19 and the exhaust fan 29 are driven, the vibrator 31 is vibrated, the rotating drum 1 is also rotated in the direction of the arrow, and the slag 34 is stored in the slag hopper 32 by appropriate means. By appropriately adjusting the nozzle 33, the liquid is dripped onto the rotating drum 1 and is caused to collide with and recoil by the surface of the rotating drum 1.

The slag that has left the rotating drum 1 is dispersed into droplets due to air resistance, becomes a slag group 2, and is supplied onto the rectifying plate 8 in the transport duct main body 3 through the opening 37.

The required amount of cold air sent from the blower 14 passes through the cold air pipe 12 at a predetermined pressure by operating the cold air regulating valve 13, and is evenly distributed to each cold air supply nozzle 10 by the cold air pipe 11. The air is fed into the lower duct 7 to form a cold air flow with a uniform velocity Vc along the lower surface of the rectifying plate 8.

Then, the grain slag that falls into the upper duct 6 and comes close to the top surface of the current plate 8 is supported by the air blown upward from the current plate 8 through the holes in the current plate 8, and hardly contacts the top surface of the current plate 8. It becomes a fluid state forming a grain slag layer 9 of a certain thickness, and is moved inside the upper duct 6 from the upstream side to the downstream side due to the air resistance due to the accompanying flow and the component force of gravity due to the tilting of the current plate 8 toward the downstream side. Start moving to the side.

When moving, the supply temperature of the granulated blast furnace slag is 1
In the case of 400°C, it is necessary that the particles maintain their spherical shape without welding or deforming due to contact with each other and the particles with the wall surface while cooling to the solidification temperature of 1250°C.

The requirements for this are a relatively coarse particle size distribution in which the slag does not come into contact with each other, and a uniform distribution in which the particles do not collide with each other during flow and can continue to be distributed as they are supplied into the duct. It is desirable to achieve a fluid state of the grain slag layer.

However, due to the difference in air resistance due to the difference in grain size of the supplied grain slag, collision between the grain slag is unavoidable. Therefore, it is important to quickly cool and solidify the flowing fine particles to minimize the above-mentioned troubles caused by mutual collisions.

There, the air sent from the blower 19 is transferred to the heat exchanger 18.
The flow rate and pressure are adjusted to a predetermined state using the air control valve 30, the air is evenly distributed to each air supply nozzle 15 by the air header pipe 16, and the temperature, flow rate, and pressure are adjusted from the air supply nozzle 15. A controlled air flow is supplied from the downstream side of the upper duct 6 to the upstream point 11, that is, in a direction opposite to the moving direction of the grain slag, thereby increasing the cooling effect of the grain slag, and at the same time, combined with the supply of cold air, the grain slag is Make the flow state as uniform as possible.

The flow and cooling state of the grain slag in this case will be explained in detail as follows.

That is, from the air supply nozzle 15 provided on the downstream side of the upper duct 6, an air flow (
When the flow velocity Va) is uniformly supplied along the rectifying plate 8, the influence of the main air flow on the flow of the grain slag layer 9 is
The flow rate of the cold air in the lower duct 7 is opposite to that of the cold air flow with the above-mentioned flow rate Vc supplied from the upstream side of the lower duct 7.
If the air flow velocity Va in the upper duct 6 is set higher than the air flow velocity Va in the upper duct 6, the cold air flow blown upward from the bottom of the baffle plate 8 will be apparently stronger than the air flow trying to pass downward through the holes in the baffle plate 8. By appropriately setting the velocity difference (Vc-Va) between the two flows, the flow of the slag layer is the same as when only cold air flow is used, and the slag layer is supported with a certain layer thickness, and the slags Stable fluidization is achieved by maintaining a certain distance from each other.

Since the current plate 8 is provided with a downward slope with respect to the horizontal plane, the fluidized granule layer 9 as described above is
It falls like a stream of water toward the downstream side in the upper duct 6 along the rectifying plate 8 under the force of gravity in the direction of inclination.

Furthermore, due to the speed difference (Vc-Va) caused by the air flow of the cold air flow, air resistance due to the accompanying flow blown up from the lower surface of the upper straightening plate 8 appears to cause the particle force to increase in addition to the above-mentioned component of gravity. Slag layer 9
, the movement speed of the grain slag layer 9 is accelerated accordingly.

On the other hand, in order for the granulated slag to crystallize as slag while falling along the straightening plate 8, each high-temperature slag is quickly cooled and assimilated by forced convection heat transfer by the air flow passing around it. In that case, the amount of heat transferred from the hot slag to the cold air stream per unit time is proportional to the relative velocity of the slag surface and the air stream.

When only a cold air flow parallel to the movement direction of the grain slag layer 9 is supplied along the lower surface of the current plate 8, the relative speed between the two cannot be set so high, and therefore the required cooling effect cannot be obtained.

On the other hand, in this device, which can supply an air flow whose temperature and air volume can be adjusted from the downstream end 5 of the upper duct 6 facing the direction of movement of the slag, the relative speed of the refrigerant flow to the slag is The sufficiently supplied air flow passes between the grain slags and removes heat uniformly from each grain slag, so when the grain slag is fluidized and cooled and solidified using only the cold air flow along the lower surface of the current plate 8. In comparison, the cooling performance has been significantly improved, and the cooling and solidification time for each grain slag to the non-welding temperature can be further shortened, thereby preventing troubles such as welding of grain slag to each other and deformation due to collision during the solidification region during flow. It can be prevented.

Moreover, the speed difference (Vc - Va) between the cold air flow with a flow velocity Vc and the air flow with a flow velocity Va is kept constant, and Va and Vc can be changed while the moving speed of the grain slag remains unchanged, or the temperature of the air flow can be adjusted. The cooling conditions can be arbitrarily adjusted according to the properties of the slag.

On the other hand, since the grain slag receives a mixed flow of cold air and air in opposite directions as described above on the upstream side of the current plate 8, the air flow is often disturbed due to the uneven distribution of the grain slag.
As a result, the flow toward the surface of each grain slag may change, causing the grain slag to roll, and the still hot grain slag supplied from the opening 37 of the father part duct 6 reaches the welding temperature on the current plate 8. The vibrator 31 is used to prevent problems such as falling and blocking the hole.
is being vibrated.

The vibration exciter 31 moves the transport duct body 3 within the inclined surface of the rectifying plate 8.
It can make the whole thing vibrate.

In addition, the vibration of the vibrator 31 not only prevents grain slag from adhering to the upper surface of the rectifier plate 8, but also adjusts the direction, amplitude, period, etc. of the vibration according to the properties of the grain slag.
The mixed flow of cold air and air can be made into a uniform flow, and as a result, the flow of the grain slag layer 9 can be maintained in a desired state.

As mentioned above, the movement of the grain slag in the upper duct 6 usually depends mainly on the action of the gravitational force due to the inclination of the rectifier plate 8, but in this method, the movement of the grain slag in the direction opposite to the direction of the moving force of the grain slag is Since the system uses a method of feeding air, the inclination angle of the rectifying plate 8 is adjusted for each equipment according to the speed resistance of the air flow in order to obtain the moving speed determined from the dense distribution of the grain slag layer. I will do it.

This angle of inclination can be larger than when this type of transport duct is used for normal powder transport.

The grain slag layer 9, which has moved from upstream to downstream within the transport duct main body 3 while being cooled and solidified along the straightening plate 8, is cooled and solidified to a non-welding temperature and is transferred to the downstream end 5 and the grain slag sealed channel 39. The cold air flow that continuously falls into the cyclone 20 through the telescopic pipe 21 and passes through the lower duct 7 along the lower surface of the rectifier plate 8 flows into the cyclone 20 via the cold air sealed flow path 38 and the telescopic pipe 21. do.

In the cyclone 20, the grain slag and the hot air, which is a high-temperature cold air stream, are separated, and the grain slag is discharged from the grain slag discharge port 23 and the warm air is discharged from the exhaust pipe 22 to the outside.

Since the extensible tube 21 is provided with a partition wall 43, the grain slag and the cold air flow do not mix inside the extensible tube 21.

Since the spherical solidified slag separated by the cyclone 20 still retains high-temperature heat, it is passed through an appropriate heat exchanger in the next process to recover the heat, and then undergoes secondary processing such as classification to obtain a predetermined quality. It is finally commercialized as aggregate in concrete.

- The air flow that flows from downstream to upstream facing the ten thousand grain slag layer 9 becomes high temperature and flows from the suction port 36 to the expansion pipe 42 and the suction pipe 26.
The air flows through the cyclone 27, where the entrained particles contained in the air flow are removed, and only the air flow reaches the exhaust pipe 28.
The air is discharged to the outside by the exhaust fan 29.

The influence of the vibration of the vibrator 31 is as follows:
1.42 is a provision, so it does not extend to other devices.

In the present invention, if the flow path of the transportation duct main body 3 is lengthened to increase the residence time of the granule in the duct, the granule can be processed without passing through the heat exchanger in the next step as described above.
It is possible to recover the sensible heat of the grain slag as hot gas from the exhaust pipe 22.28 of the cyclone 20.27, and even in the case of the above-mentioned example in which the grain slag is cooled to the non-welding temperature range, the grain slag is cooled to the non-welding temperature range. It goes without saying that the sensible heat possessed by the slag can be recovered, and that various other changes can be made without departing from the gist of the invention.

Since the granule dregs cooling recovery method and apparatus of the present invention have the above-described configuration, they can achieve various excellent effects as described below.

(I) Not only blast furnace slag, but also all metallurgical slag such as converter slag and electric furnace slag, regardless of the granulation method, the granulated molten slag is supplied and cooled to the required temperature. It becomes possible to collect and process.

(II) Since the process is carried out in a sealed container, no pollution is generated, and the sensible heat of the slag during the cooling and solidification process can be easily recovered as hot gas.

([D) Not only is it easy to adjust the equipment scale according to the processing amount, but it is also possible to
By adjusting the temperature, pressure, and flow rate of the air flow supplied to the chamber, variations in grain slag properties and throughput can be accommodated.

(IV) There are no driving parts in the duct through which the slag passes, so the structure is simple and handling and maintenance are easy.

(■ By lengthening the transport duct and installing a device to replenish the airflow along the way, it can also be used as a heat recovery device for slag from a high-temperature molten state to solidified slag at room temperature.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the method and apparatus for cooling and recovering grain slag according to the present invention, and FIG. 2 is a view taken along arrows 1--2 in FIG. 3 is a transportation duct main body, 6 is an upper duct, 7 is a lower duct, 8 is a rectifier plate, 9 is a grain slag layer, 10 is a cold air supply nozzle, 1
3 is a cold air control valve, 14.19 is a blower, 15 is an air supply nozzle, 18 is a heat exchanger, 20.27 is a cyclone, 2
9 is an exhaust fan, 30 is an air control valve, 31 is an exciter, 38 is a cold air sealed channel, and 39 is a slag sealed channel.

Claims (1)

[Claims] 1. A droplet of solution is placed on the upstream side of the upper duct of a transport duct main body whose flow path cross section is partitioned into upper and lower sections by a porous rectifier plate provided at a downward slope from upstream to downstream. At the same time as supplying the slag, the main body of the transport duct is vibrated to supply air flowing in opposite directions to the upper and lower surfaces of the rectifying plate, and the air blown from the lower duct to the upper duct through the holes in the rectifying plate flows through the granule slag layer. A method for cooling and collecting grain slag, characterized by continuously collecting the solidified grain slag from the downstream end of an upper duct. 2 A porous rectifying plate is installed on the main body of the transport duct with a downward slope from upstream to downstream to partition the cross section of the flow path into two upper and lower chambers, and a vibration exciter is attached. An opening is provided at the top to supply the molten slag into droplets, and a device is provided at the upstream and downstream ends of the rectifying plate to supply air in opposite directions to the upper and lower surfaces of the rectifying plate, respectively, and the slag is solidified at the downstream end of the upper duct. A cooling recovery device for grain slag, characterized in that it is equipped with a device for recovering the grain slag.