JPS5919533A - Granulation of molten substance - Google Patents

Abstract

PURPOSE:To uniformize a heat exchange amount, by a method wherein the flow amounts of gases injected from upper and lower nozzles are alternately varied while a molten substance is flowed downwardly between both nozzles to vary the flight pattern of comminuted particles to eliminate the excessive accumulation of semi-solidified particles. CONSTITUTION:A molten substance 1 such as shaft furnace molten slag is flowed downwardly between gas jet nozzles 2, 3 having mutually independent gas supply systems and comminuted by gases injected from the nozzles 2, 3. In this atomizing method, only the amount of a gas injected from either one of the gas nozzles is varied with the elapse of time or the amounts of gases injected from both gas nozzles are alternately varied to change the scattered distribution formed in a comminuted state. As the result, the excessive accumulation of semi- solidified particles is eliminated while a welding and lump forming phenomenon is avoided and a heat exchange amount at each part is uniformized and the uniform cooling of particles and the level-up of a gas temp. can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for completely controlling the distribution of fine particles in the gas atomization method. Attempts have been made to use a gas atomization method to atomize substances that solidify as the temperature decreases, obtain them as granular solids, and at the same time recover the heat held by the substances. Generally, in the gas atomization method, a supplied bath melt is blown off and atomized by high-speed gas ejected from a snorzzle. The fine and granular material is cooled while flying through nitrogen, becomes semi-solid particles as the cooling progresses, and eventually becomes solid. If the melt discharged at high temperature has a low freezing point or if the particle size after atomization is large, it is difficult to solidify, and if you try to cool and solidify it in the air, you will have to take a total of 7.1n free time. So, in order to solidify, do we have to increase the falling distance or use a large amount of gas to blow all the particles far away? However, no matter which method is used, the equipment becomes large-scale and cannot be said to be very efficient when considering heat recovery.

For this reason, it is necessary to devise a method for collecting semi-solidified bithermal particles that makes the equipment compact and allows for sufficient heat recovery. Semi-solidified particles collect the appropriate amount,
If the cooling is not carried out quickly, the particles will re-fuse with each other and become agglomerated, and not only will it be impossible to obtain the desired particles, but also the heat recovery will not be satisfactory.

FIG. 1 shows an example of nozzle arrangement in the gas atomization method. In the conventional gas atomization method, the ratio between the melt supply lid and the amount of gas varies slightly;
is kept more or less constant.

Therefore, if the amount of melted material is constant, the amount of gas ejected from the gas nozzle will also be constant as shown in Figure 2, and as a result, the flight of fine particles (9 turns) will be constant,
The deposition density after falling is approximately as shown in FIG. In the case of this uniform 9 turns, there was a problem that particles often adhered to each other near the peak value, and the operation had to be stopped.

Also, in areas with low density, the amount of heat exchange is small, and the gas temperature does not rise much.

The present invention was provided as a method for simultaneously solving the problems in the conventional method, and its gist is that the entire melt flows between gas injection nozzles having mutually independent gas supply controls, and the gas nozzles In the gas atomization method, which atomizes the molten material by using a jet of gas from
By varying the amount of gas injected from the gas nozzle of either piece 11111 over time, or by varying the amount of gas injected from both gas nozzles,
e. A method for granulating a melt, which is characterized in that the scattering distribution of the formed particles is reduced to kf.

Hereinafter, the present invention will be explained in more detail based on the drawings.

FIG. 1 shows an example of the nozzle arrangement and gas control system in the gas atomization method.

For example, in the case of molten slag, -C is not supplied by gutter 1,
It is made finer by the gas nozzles 2 and 3 placed above and below,
It becomes particulate matter 4 and flies. The gas supplied to the gas nozzles 2, 3 is controlled by independent supply piping and control valves 5.6.

The controller 7 that controls the valves 5 and 6 is equipped with an e-control so that the amount of air supplied to the nozzles 2 and 3 can be correlated, so that the amount of air can be appropriately distributed to the amount of slag. In the example of the present invention, the distribution of the amount of air supplied to the upper and lower nozzles is given a time-varying dead charge, and as shown in FIG. changes as shown in Fig. 5. For example, by continuously decreasing the air amount of the lower nozzle from (1) to (2), and prompting this to increase the upper nozzle air amount from (2) to As the ability is secured, the center of the particle flight and plane continuously changes from (E) to (
), and then continue to increase the air volume of the lower nozzle from (B) to (G), and then decrease the nozzle air volume from (B) to (G), thereby reducing the center of the particle flight and turn. changes continuously from (f) to (e) to make the deposition density distribution uniform. As a result, there is no excessive accumulation of semi-solidified particles υ, the phenomenon of fusion and agglomeration is eliminated, and the amount of heat exchanged at each part is made uniform, thereby achieving uniform cooling of the particles and leveling of the gas temperature.

As described above, the present invention will be explained using an example in which the flight pattern of fine particles is varied by alternating the injection gas flow rate of both nozzles while causing the bath melt to flow between the upper and lower nozzles. However, as an embodiment of the present invention, there are other nozzles in the left and right horizontal directions. There is a method of arranging the nozzles to vary the gas flow rate of both nozzles to 1tt - 1i, and a method of arranging upper and lower nozzles or left and right e nozzles and varying the gas flow rate of one nozzle over time. Flying! Turns can be varied.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the air control flow and the granulation section. Figure 2 is a diagram showing the control flow of the air amount supplied to the upper and lower nozzles using the conventional method. Figure 3 is a diagram showing the control of the flow rate of air supplied to the upper and lower nozzles using the conventional method. A diagram showing the subsequent particle accumulation density 45, FIG. 4 is a diagram showing nine turns of gas supply control to the upper and lower nozzles according to the present invention, and FIG. 5 is a diagram according to the present invention! FIG. 7 is a diagram showing the instantaneous deposition density pattern of flying particles at the farthest point and the closest point from the r nozzle when all lt control is performed. l: liquid supply gutter, 2: lower gas nozzle, 3: upper gas nozzle,
4. Flying particles, 5, 6: control valve, 7: control device.

Claims (1)

[Claims] In a gas atomization method in which a bath melt flows down between gas injection nozzles having mutually independent gas supply systems and the melt is atomized by the injection gas from the gas nozzles, injecting from the gas nozzle on either side. By varying only the amount of gas over time or by alternatingly varying the amount of gas injected from both gas nozzles, it is possible to change the scattering distribution of particles formed by atomization. A method of granulating a melt.