JPH11236608A - Treatment of molten blast furnace slag and treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treating method of a blast furnace slag which can separately produce crystallized slag grains or glassy slag grains from the molten blast furnace slag with an one apparatus. SOLUTION: In the treating method for producing the slag grains with a blasting granulation from the molten blast furnace slag, gas is blasted to the flowing down molten blast furnace slag at the inlet in an outer cooling rotary cylinder 1 to form the slag as granular drips. The granular drips are brought into contact with the inner surface of the rotary cylinder 1 and rapidly cooled to the temp. in the range from the re-fusion limit temp. or lower to the crystallizing lower limit temp. or higher at the vitrified cooling speed or more and discharged from the outer cooling rotary cylinder 1. In the case of producing the crystallized slag grains, the high temp. slag grains discharged from the outer cooling rotary cylinder 1 are slowly cooled, and in the case of producing the glassy slag grains, the high temp. slag grains discharged from the outer cooling rotary cylinder 1 are further rapidly cooled to the crystallized lower limit temp. or lower at the vitrified cooling speed by blasting the gas with a cooling speed adjusting gas blasting means 3 at the outlet of the outer cooling rotary cylinder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for processing molten blast furnace slag for producing glassy slag particles or crystalline slag particles from molten blast furnace slag produced as a by-product in a blast furnace.

[0002]

2. Description of the Related Art Slag particles are produced by subjecting a molten blast furnace slag in a molten state discharged from a blast furnace to a cooling treatment.
As a treatment method of the molten blast furnace slag, a treatment method by water granulation to produce slag particles by quenching the molten blast furnace slag with water,
There is a processing method based on air-blasting in which a gas such as air is blown onto a molten blast furnace slag that flows down to form droplets, and the droplets are cooled to produce slag particles.

[0003] In the treatment method by water granulation, the heat possessed by the molten blast furnace slag cannot be used effectively, whereas in the treatment method by wind granulation, heat is exchanged by gas from the molten blast furnace slag, and high-temperature gas is used. Heat can be recovered.

For example, Japanese Patent Publication No. 63-21110 discloses a cooling tank provided with a granulator for spraying jet air onto a falling blast furnace slag to form droplets, and a granulated blast furnace slag. The blast furnace slag after the granulation is introduced into the heat holding tank, and gradually cooled from the semi-molten state to 800 ° C. at a cooling rate of 100 ° C./min or less. A method is described in which a fluid gas is introduced into a granulator and exchanged with high-temperature slag particles, and crystalline slag particles are produced.

[0005]

When the molten blast furnace slag is cooled, the slag particles become crystalline slag particles or vitreous slag particles depending on the cooling rate. Crystalline slag grains are used in place of natural sand, and glassy slag grains are used as a raw material for cement because they have the effect of solidifying cement.

However, in the method of treating blast-furnace slag by blasting described in the above-mentioned publication, heat recovery can be performed effectively, but for this reason, it is a process of producing only crystalline slag particles and can be used as a raw material for cement. There is a disadvantage that vitreous slag granules cannot be produced.

Accordingly, the present invention provides a method and an apparatus for treating blast furnace slag that can produce two types of slag grains, either crystalline slag grains or vitreous slag grains, from a molten blast furnace slag with one apparatus. It is.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for treating molten blast furnace slag, comprising the steps of: A gas is sprayed on the molten blast furnace slag flowing down to form droplets, and the droplets are brought into contact with the inner surface of the externally cooled rotating cylinder to cool the vitrification at a cooling rate higher than the re-fusion limit temperature to the crystallization lower limit temperature or higher. Rapidly cooled to the temperature and discharged from the outer cooling rotary cylinder, and then, when producing crystalline slag grains, gradually cool the high-temperature slag grains from the outer cooling rotary cylinder to a heat exchanger on the downstream side, When manufacturing vitreous slag grains, it is necessary to further cool the high-temperature slag grains coming out of the outer cooling rotary cylinder by blowing a gas at the outlet of the outer cooling rotary cylinder to rapidly cool the glass at a temperature lower than the crystallization lower limit temperature and at the vitrification cooling rate. Features.

In the apparatus for treating molten blast furnace slag of the present invention, an outer cooling rotary cylinder whose outside is cooled by water is rotatably provided, and the molten blast furnace slag flowing down is blown off at the inlet of the outer cooling rotary cylinder. Of blast-furnace slag by blasting provided with a gas spraying means for blowing gas for forming droplets by cooling the hot-cooled slag particles discharged from the outer-cooled rotating cylinder at the outlet side of the outer-cooled rotating cylinder. To adjust the speed,
A cooling rate adjusting gas blowing means for blowing a cooling rate adjusting gas is provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall view of a slag grain production facility used in the treatment method of the present invention.

In the slag particle production facility, an external cooling rotary cylinder 1 whose outside is cooled by water is rotatably provided in order to form droplets of the molten blast furnace slag flowing down. The outer cooling rotary cylinder 1
The slag is inclined downwardly toward the outlet to move the hot slag particles by rotation from the inlet to the outlet.

At the inlet of the outer cooling rotary cylinder 1, gas blowing means 2 for blowing a gas such as air to blow off the molten blast furnace slag flowing down to form droplets is provided. The cold rotating cylinder 1 contacts the inner peripheral wall and is rapidly cooled. A cooling speed adjusting gas blowing means 3 for blowing a cooling speed adjusting gas such as air in order to adjust a cooling speed of the high-temperature slag particles discharged from the outer cooling rotary cylinder 1 is provided on an outlet side of the outer cooling rotary cylinder 1. The gas is blown to the hot slag particles.

A hopper 4 for receiving high-temperature slag particles discharged from the outer cooling rotary cylinder 1 is provided below the outer cooling rotary cylinder 1 on the outlet side.
Is provided below the hopper 4, and a cutting device 5 for cutting out high-temperature slag particles is provided.

A conveyor 6 is arranged below the cutting device 5 and supplies the cut high-temperature slag particles to a heat exchanger 7.

The heat exchanger 7 is blown with air for heat exchange and heat-exchanged with the high-temperature slag particles as in the conventional heat exchanger 7, and the heat-exchanged and high-temperature air is removed by a dust collector 8 such as a cyclone. Thereafter, steam is generated by the boiler 9, the turbine 10 is rotated, and power is generated by the power generator 11. The air that has left the boiler 9 is exhaust gas treatment equipment 1 equipped with a desulfurization device and the like.
2 and discharged from the chimney 13. Before the boiler 9, an additional cooker 14 for generating hot air may be provided.

FIG. 2 is a graph showing the cooling rate required for vitrification.

When vitrifying molten slag, about 145
Melting slag at 0 ° C to 1200 ° C at 21 ° C / sec or more
200 ° C to 1100 ° C, 6.4 ° C / sec or more, 1100 ° C
~ 1100 ° C over 3,6 ° C / sec, 1000-850 ° C
Can be vitrified by cooling at a cooling rate of 0.3 ° C./sec or more.

In the case of crystallization, the re-fusion limit temperature is about 95
After reaching 0 ° C., it is obtained by slow cooling at a cooling rate of less than 0.3 ° C./sec.

Next, a method of treating molten slag for producing crystalline slag particles or glassy slag particles will be described.

The molten slag discharged from the blast furnace is allowed to flow down directly or by a ladle to the inlet of the outer cooling rotary cylinder 1, and the molten slag flowing down is blown with compressed air by the gas blowing means 2 to form droplets. When it is brought into contact with the inner peripheral wall of the cylinder 1 and rapidly cooled from a temperature lower than the re-fusion limit temperature to a temperature within the range from the lower limit temperature of crystallization to the temperature higher than the cooling rate of vitrification, 950-11
It becomes high temperature slag particles of 50 ° C.

The high-temperature slag particles move from the entrance side to the exit side as the outer cooling rotary cylinder 1 rotates, and fall into the hopper 4.

When the high-temperature slag particles are discharged from the outlet of the rotary cylinder 1, when producing vitreous slag particles, the high-temperature slag particles are further blown with cold air by the cooling rate adjusting gas blowing means 3 to reduce the temperature below the crystallization lower limit temperature. Rapidly cools to about 850 ° C. or less and vitrifies.

In the case of producing a crystalline slag, similarly to the case of vitrification, compressed air is blown by gas blowing means 2 to form droplets, and the droplets are brought into contact with the inner peripheral wall of the outer cooling rotary cylinder 1 to vitrify. When the temperature is rapidly increased to a temperature within the range from the re-melting limit temperature or lower to the crystallization lower limit temperature or higher at the cooling rate or higher, the skin is cooled and the slag grain surface is cooled to a temperature at which the slag grain surface does not fuse. The high-temperature slag particles of 950 to 1150 ° C. discharged from the outlet of the outer cooling rotary cylinder 1 do not vitrify while being supplied from the conveyor 6 to the heat exchanger 7 without cooling at the outlet of the outer cooling rotary cylinder 1. It is slowly cooled at a cooling rate and crystallized. The high-temperature slag particles are supplied to the heat exchanger 7 by the conveyor 6 and exchanged with the air blown into the heat exchanger 7. The heat-exchanged and high-temperature air is dust-removed by the dust collector 8 and then steamed by the boiler 9. Is generated and the turbine 10 is rotated to generate electric power by the generator 11. The exhaust gas that has exited the boiler 9 is processed by the exhaust gas treatment equipment 12 and released from the chimney 13.

[0024]

According to the present invention, vitreous slag grains or crystalline slag grains can be produced depending on whether or not the cooling rate adjusting gas is cooled at the outlet of the outer cooling rotary cylinder. On the other hand, in the past, a dedicated processing device for each of glassy and crystalline materials was required, but since the present invention can be separately manufactured with a single air-crushing equipment, it is superior in terms of equipment layout, equipment cost, and conventional technology. ing.

[Brief description of the drawings]

FIG. 1 is an overall view of a slag grain production facility used in the treatment method of the present invention.

FIG. 2 is a graph showing a cooling rate required for vitrification.

[Explanation of symbols]

 1: Outer cooling rotary cylinder 2: Gas blowing means 3: Cooling rate adjusting gas blowing means 4: Hopper 5: Cutting device 6: Conveyor 7: Heat exchanger 8: Dust collector 9: Boiler 10: Turbine 11: Generator 12: Exhaust gas treatment equipment 13: Chimney 14: Reheating device

Claims (2)

[Claims] 1. A method for treating molten blast furnace slag in which slag particles are produced from the molten blast furnace slag by air-blasting, wherein a gas is blown to the molten blast furnace slag flowing down at the inlet of an externally cooled rotary cylinder cooled from the outside to form droplets. The droplets are brought into contact with the inner surface of the outer cooling rotary cylinder, quenched from a temperature lower than the refusion limit temperature to a temperature within the range from the lower limit of crystallization to the temperature equal to or higher than the lower limit of crystallization at a cooling rate of vitrification or higher, and discharged from the outer cooling rotary cylinder. When producing glassy slag particles, the high-temperature slag particles coming out of the outer cooling rotary cylinder are gradually cooled down to the heat exchanger on the downstream side, and when producing vitreous slag particles, the outer cooling rotary cylinder is used. The method further comprises subjecting the high-temperature slag particles discharged from the blast furnace to a gas at the outlet of the outer cooling rotary cylinder to rapidly cool the slag particles to a temperature lower than the crystallization lower limit temperature and at a vitrification cooling rate. 2. An outer cooling rotary cylinder whose outer side is cooled by water is rotatably provided, and a gas for blowing a gas for blowing down molten blast furnace slag flowing down to form droplets at an inlet of the outer cooling rotary cylinder. In the apparatus for treating molten blast furnace slag by means of air-blasting provided with spraying means, a cooling rate adjusting gas is provided on the outlet side of the outer cooling rotary cylinder in order to adjust the cooling rate of the high-temperature slag particles discharged from the outer cooling rotary cylinder. A processing device for molten blast furnace slag, comprising cooling rate adjusting gas blowing means for blowing blast furnace.