DE2759205A1 - DEVICE FOR COOLING SLAG - Google Patents

Description

18 304 40 / kr

Applicant: Ishikawajiaa-Harima Jukogyo Kabushiki Kaieha

No. 2-1, 2-choae, Ote-machi, Chiyoda-ku. Tokyo-to / Japan

When various metals such as iron are refined, slag comes out of the furnace and is at a high temperature. If this slag is properly converted into a particular pore, it can be used as an aggregate for concrete, which is very advantageous from a commercial point of view. However, the slag coming out of the furnace has a very high temperature, so that it has to be cooled ''

Various methods are used to cool slag that is at a high temperature, if it is in a particular one Form is transferred. A first method is to drop the slag in water. A second procedure exists in that the slag is dropped into a liquid at a high temperature. In a third procedure, a Related to air cushions. Finally, in a fourth method, the slag is left in a container filled with solid particles fall. The first method is advantageous in that the water acts as a cushion so that the slag is not subjected to mechanical shock. On the other hand, however, it is obviously also disadvantageous because the slag quickly reaches a temperature

809828/0762

door is cooled below 100 G, so that it becomes powdery due to the thermal shock and thus loses its commercial value. The second method, which is an application of tempering and lightening, as it happens in the manufacture of steel, uses a heated oil or a molten salt at a high temperature. This method is therefore not only disadvantageous from an economic point of view, but also requires post-treatment in order to remove the oil or salt adhering to the slag accumulation and thus avoid environmental pollution. In addition, temperature control is difficult due to the poor heat conduction between the cooling gas and the dross. In particular, a large volume of cooling must be brought into contact with the slag because the heat capacity of the cooling gas is significantly reduced is lower than the heat capacity of the slag, and, since the thermal conductivity between the gas and the surface of the slag particles is low, the slag particles - to prevent sticking or agglomeration - must be cooled down very quickly when! they are at a high temperature (around 1200 C in the case of the slag produced in iron production), whereas they have to be cooled down relatively slowly as soon as they are at a lower temperature (around 1000 ^° C in the case of the slag produced in iron production) because then the slag is susceptible to thermal shocks. In practice, however, it is extremely difficult to meet both conditions at the same time. According to the fourth method, the solid particles act as a cushion to prevent mechanical shock. After the heat of the slag has been absorbed by the solid particles, both are discharged together and separated from each other in a separator. However, the solid particles work

809828/0762

Particles as thermal insulation, so that the temperature in the The vicinity of the slag particles increases so that the slag particles and the solid particles melt and consequently combine with each other. In addition, the slag particles containing solid particles are not discharged evenly. Part of the mixture is always held back. In general is It is extremely difficult to drain a mixture of particles of different sizes evenly into a kettle.

The invention is therefore based on the object of a device for cooling slag which has already been converted into a special, specially granular form, in such a way that the above-mentioned problems as well as others with the known devices occurring problems are essentially avoided.

This object is achieved with the device according to claim 1. The subclaims specify advantageous configurations of this device.

Further advantages, features and details of the invention result can be derived from the following description of an exemplary embodiment based on a single enclosed figure. ;

Reference is now made to this figure. A rotating drum 2, which is located directly below the funnel opening of a funnel 1 is driven by a suitable main drive motor in the with the direction indicated by the arrow, so that the slag grains generated on the drum surface 2 can be discharged into 'a cooling device 3 of the fluidized bed type through its opening adjacent to the circumference of the rotary drum 2. A perforated gas distributor 15 is inclined from the side adjacent to the rotary drum 2 to a sorting pipe 8 progressively by an angle between approximately 5 and 10 degrees. A heat exchange pipe 4 is arranged within the cooling device 3 and above the gas distributor, so that the heat exchange between a through the

809828/0762

Viärmeaus caii ^ -hrohr H flowing cooling medium and a fluidized bed - *. ·. .stai, t! 'in icii, which consists of semi-molten slag grains, pulverized solid particles such as silica sand, graphite, aluminum oxide, limestone and the like input from the rotary drum 2, and the gas described below.

The cooling device 3 is through the sorting pipe 8 with a heat exchanger 9 of the moving bed type with an inverted conical Gas distributor 16 connected. The heat exchanger 9 is Connected via a discharge tube 10 for the slag grains with a memory 11 for receiving the slag grains. A blower 5, (is arranged below the cooling device 3 via a line 17 to the cooling device 'for supplying gas connected to the fluidized bed ^ a. Above the cooling device 3 is a cyclone separator 13 for separating the slag grains and the Silicanands ν ·> η dem from the cooling device 3 via a line 1 ') released gas, the slag particles and the silica sand after separation via a return line 20 into the cooling device 3 can be returned. The cyclone separator 13 is Via a line 21 with a heat exchanger 12 for recovering waste heat connected, which in turn is connected to a fan 14 via a line 22.

A fan 6 is arranged below the heat exchanger 9 and connected to this via a line 18 for supplying gas to the moving bed in the heat exchanger 9. The upper zone of the Heat exchanger 9 is via a bypass line 7 niit the line 19 in connection.

Next, the operation will be described. Molten slag in the hopper 1 is discharged through the hopper opening and bounces onto the rotary drum 2, being granulated when it bounces back from the drum surface, and then is dispersed

809828/0762

BATH ORIGINAL

and fed through the opening of the cooling device 3 to the fluidized bed 3a. That on line 1? supplied gas from the blower 5 flows through the perforations of the gas distributor 17 into the fluidized bed 3 a 'so that the bed is kept in the fluid state will. The gas absorbs the heat from the fluidized bed 3a, which in turn absorbs the heat from the slag particles so that the gas is heated to a temperature almost equal to the temperature of the fluidized bed 3a is.

The slag grains fall into the fluidized bed '3a without any mechanical shocks occur and are quickly caused by the gas and pulverized solid particles of the fluidized bed 3a cooled to a temperature almost equal to the temperature of the pulverized solid particles.

The slag grains and other particles are removed from the cooler 3 gas discharged via the line 19 is carried into the cyclone separator 13. They are in the cyclone separator 13 of the Gas separated and returned via line 20 to the cooling device 3, while the gas via line 21 from the cyclone separator 13 flows into the heat exchanger 12. The gas cooled in the heat exchanger 12 is then passed through the line 22 and the ' Fan 14 released to the outside air.

The slag grains move along the inclined gas distributor 15 to the sorting pipe 8, with the solid particles of the fluidized bed 3a can be mixed.

The gas introduced by the blower 6 via the line 18 and the gas distributor into the moving bed in the heat exchanger 9 flows through the slag grains up into the sorting pipe 8 'and then into the cooling device 3 · Tm Bortierrohr 8, the gas flows faster than the gas in the fluidized bed 3a, and the particle size of the solid particles in the bed is uv about half the size of the grain

808828/0762

JAHiOlRO QA8

size of the slag. Therefore, at the inlet of the sorting pipe 8 is a aerodynamic sorting made to the slag grains and to separate the solid particles from one another, so that only the slack grains continue through the sorting pipe 8 into the heat exchanger 9 fall, being cooled by the gas flow coming from the heat exchanger 9 and flowing upwards. The on this Slag grains that have been cooled in this manner are discharged into the reservoir 11 via the discharge tube 10. The setting of the particle size sorting The slag grains are carried out by the opening dimension of a damper (not shown), "the one in the bypass line 7 is arranged, is adjusted so that the flow rate of the gas passed through the line 7 is suitable can be adjusted.

The temperature of the fluidized bed 3 & can be varied by a variety of Värmeaur.taur.chrohren 4, the volume of the pipe 7 auo removed from the heat exchanger 9 and passed to the line 19 Gas and by the volume of the fan 5 to the cooling device 3 released gas can be controlled. Therefore, the slag grains can be prevented from being caused by thermal Shocks break and merge into clusters.

In the fluidized bed 3a, the heat exchanger 9 via the ßortierrohr 8 gas discharged into the cooling device 3, mixed with the gas supplied by the fan 5 of the cooling device 3, flows then via the line 19 into the cyclone separator 13 »is in it separated from the slag grains and the other particles and then flows to the heat exchanger 12 where it is cooled and finally via line 22 and fan 14 in that described above Way is released to the outside air. That through the bypass line 7 led gas is treated in the same way.

According to the preferred embodiment of the invention, the rotary drum 2 used to granulate the molten slag, each

809828/0762

but it goes without saying that instead of the rotary drum any other suitable facility can be used. That also applies to further changes to the other components.

The advantages of the device according to the invention for cooling Slag particles can be summarized as follows:

1) When converting slag that is at a high temperature into a usable granulate form in which the slag can be used advantageously as an aggregate, the heat is recovered in a very effective manner. Therefore energy can be saved to a considerable extent with the device according to the invention.

2) The cooling gas can be chosen depending on the properties of the slag to be treated, and even recirculation of the cooling gas is possible. Therefore, the amount of exhaust gas discharged can be reduced to a considerable extent, so that environmental pollution can be avoided at the same time.

3) The fluidized bed prevents the slag particles from being exposed to mechanical shocks and, since the heat capacity! of a fluidized bed is several hundred times as large as the heat capacity of the slag particles or the cooling gas, the Temperature change i »fluidized bed as a result of a change in the supply of slag particles and cooling gas is minimized and through the fluidized bed continuously maintained at a suitably selected constant temperature causes the slag grains to be broken up prevented as a result of the thermal shock.

4) As the effective thermal conductivity of the slag particles within the fluidized bed is on the order of several hundred Kcal / m hr ° C, even if the slag particles melted or half-melted are added to the fluidized bed

• 01828/0782

den, their surfaces solidify quickly so that mutual agglomeration is prevented.

5) Due to the active movements of the particles in the fluidized bed, an almost uniform temperature can be maintained through the entire fluidized bed , in particular an optimal mean temperature with which the two apparently contradicting conditions can be met at the same time, namely to avoid thermal shocks , and on the other hand, to obtain rapid solidification of the surfaces of the slag particles.

809828/0762

Claims (4)

PATFNT / .: Dr. rtr. imL THE iL il I. ^. 9 7 S 9 2 O 5 DipL-Phys. CLAUS F ÜHL / x * '** * "Dt ^ L-lnf. FRANZ LCl · .Τ.ΣΝΤΖ NORNBER (/ KESSLCRPLATZ 1 18 304 40 / kr Applicant: Ishkawajima-Harima Jukogyo Kabushiki Eaisha No. 2-1, 2- chome, Ote-machi, Chiyoda-ku «Tokyo-to / Japan 1. Device for cooling slag, characterized by a Device (2) for converting the molten slag into a granulate form, a cooling device (3) with a fluidized bed (3a) made of solid particles through which gas flows, a heat exchanger (9) which is connected to the bottom of the cooling device (3) and has a moving bed of slag grains through which the gas flows and through a the cooling device (3) with the heat exchanger (9) connecting the sorting pipe (8) for sorting out the slag grains from t the solid particles of the fluidized bed (3a). 2. Apparatus according to claim 1, characterized in that the The device for converting the molten slag into a granulate form is a rotary drum (2). 3. Apparatus according to claim 1 or 2, characterized in that a heat exchange pipe (4) through which a heat exchange medium flows within the fluidized bed (3a) in the cooling device (3) is arranged. 4. Device according to one of the preceding claims, characterized in that 809828/0782 indicates that da.3 a cyclone separator (13) for separating the slag grains and other loose particles carried by the gas discharged from the cooling device (3) and for returning the slag grains and other solid particles to the cooling device and a heat exchange device (12 ) are provided for recovering the heat from the gas given off by the cyclone separator (13). 809828/0762