JPS5919531A - Granulation of molten substance - Google Patents

Abstract

PURPOSE:To reduce the generation of fibrous product resulting in the trouble of operation, by a method wherein a columnar liquid stream such as shaft furnace molten slag supplied downwardly is converted to a granulated substance and an intermittent stream by a mechanical force and the latter is comminuted by high flow speed air. CONSTITUTION:A rotor having at least one protrusion (hereinafter mentioned as a slicer 5) is provided to the periphery of a rotary disc or a cone shaped rotor having a shaft in the vertical direction and a gas jet nozzle 8 is arranged below the slicer 5. In the next step, a molten liquid 2 such as shaft furnace molten slag is flowed down onto the slicer 5 from above and converted to flying particles 6 and intermittent stream pieces 7 by rotating the slicer 5 while the intermittent stream pieces 7 are comminuted by the jet air stream from an air nozzle 8 to form flying particles 9. By this method, the generation of the fibrous product resulting in the trouble of operation is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of granulating a molten material by refining it to reduce the generation of fibrous products that are likely to occur when refining a molten material such as blast furnace molten slag.

For example, slag produced as a by-product from a blast furnace has a temperature of 1,500℃ to 16
It is discharged in a molten state at a high temperature of 00°C. In order to efficiently recover the heat retained in this slag, the slag is pulverized and granulated, and then the heat is recovered. Air atomization is often used as a means for this pulverization. However, in the case of blast furnace slag, etc., when the air flow rate and air volume are increased in an attempt to strengthen the refinement, a large amount of fibrous material (hereinafter referred to as wool) is generated. Excessive production of wool can block the outlet of particles after micronization, and the wool deposited between particles can act as a heat insulator, inhibiting the cooling of particles, and causing particles to re-fuse together. This causes operational problems such as large clumps.

The present invention provides a method for granulating a molten liquid to reduce the generation of wool that causes such operational failures. This produces granulated material and intermittent flow, and the intermittent flow is made fine by high flow rate air.

Hereinafter, the present invention will be explained with reference to the drawings.

FIG. 1 shows a granulation apparatus for carrying out the present invention. For example, in the case of blast furnace slag, the slag is fed into the wind tunnel 3 by a slag trough 1. The supplied slag is pulverized by a slicer 5 which is rotated on a horizontal plane by a drive device 4 installed outside the wind tunnel, and part of it is pulverized and flies into the wind tunnel 3 as flying particles 6. As shown in FIG. 3, it is cut into thin pieces to form the intermittent flow piece 7.

The intermittent flow pieces 7 collide with high-velocity gas ejected from an air nozzle 8 disposed below the rotating slicer 5, are atomized, become flying particles 9, and fly within the wind tunnel.

It is well known that liquids are generally atomized by applying an external force that overcomes the surface tension of the liquid. In the conventional air atomization method, the energy of the air is used as the external force for atomization, but if the energy is not distributed appropriately, the energy is used to generate wool, resulting in a large amount of wool. turn into. On the other hand, the amount of slag supplied varies depending on the operating conditions of the blast furnace that is the supply source. Therefore, the amount of air is changed accordingly, but in order to prevent the particles from becoming coarser, the amount of air is inevitably controlled to be slightly excessive, which promotes the formation of wool. Further, if it is desired to obtain particles with even smaller particle diameters, it is necessary to apply a large amount of air energy, but in this case as well, an increase in the amount of wool produced is unavoidable.

In this regard, in the present invention, the dependence on air energy is reduced by introducing mechanical force into the external force for atomization. In other words, if the slag flow is shredded in advance by a rotary slicer, it becomes easier to atomize the slag using air, and the amount of input energy is reduced.Therefore, the amount that contributes to wool production is also small, and as a result, , wool production decreases. In addition, in response to fluctuations in the amount of slag, the shredding length can be made constant by increasing or decreasing the number of rotations of the slicer, making it possible to keep the air amount close to the appropriate amount. be.

As shown in FIG. 4, the slicer used in the present invention has an angle α between the collision surface 10 of the slicer with the molten slag and the tangent to the slicer rotation locus circle at the collision point of 120~120.
It is best to keep it in the range of 1500. By setting within this angle, the direction of the flying particles 6 can be stably directed forward. Furthermore, since the slicer is heated to a high temperature due to collision with the molten slag, it is desirable to cool it directly with a water spray device 11 installed outside the wind tunnel as shown in FIG. Coating the slicer surface with a water film through direct water cooling is also effective in preventing slag adhesion.

Figure 5 shows the relationship between the amount of air for atomization and the wool generation rate. In the figure, curve (a) is the wool generation rate according to the conventional method without intermittent flow, and curve (b) is the wool generation rate according to the conventional method without intermittent flow. This is an example of the wool generation rate in the flowing down granulation method.

According to the present invention, the remarkable effect that the wool generation rate is reduced by about half compared to the conventional method is achieved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a granulation device used in carrying out the present invention, FIG. 2 is a plan view showing the shape of a rotary slicer,
Fig. 3 is an explanatory diagram showing the intermittent flow of the liquid column cut by the slicer, Fig. 4 is an explanatory diagram showing the collision surface angle between the liquid column and the slicer, and Fig. 5 is a comparison of the wool generation rate between the conventional method and the present invention. FIG. ■... Slag supply gutter, 2... Molten slag, 3...
Wind tunnel, 4... Slicer drive device, 5... Rotating slicer, 6... Flying particles by slicer, 7... Intermittent flow, 8... Air nozzle, 9... Flying particles by air nozzle, 10. ...Slicer collision surface, 11...Water spray device. Figure 7 $2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A rotating disk or a cone-shaped rotating body having an axis in the vertical direction, a rotating body having at least one protrusion (hereinafter referred to as a slicer) around the periphery, and a gas injection nozzle arranged at the bottom of the slicer, one slicer. A melting method characterized in that the molten liquid is made to flow down from the upper part, the falling liquid is made into an intermittent flow by rotating the slicer, and then the falling liquid is made into fine particles and blown away by an air jet from a gas nozzle. A method of granulating things.