EP1234889B1 - Apparatus for granulating of liquid slag - Google Patents

Abstract

Device for sputtering and granulating liquid slag comprises a spray head with a rotating spinner (9), and a cooling chamber (13) formed as an annular chamber concentrically surrounding the spinner and connected to the spinner. Preferred Features: The tundish outlet is connected with the spinner and the annular chamber via a heated connecting tube (5). Burners (6,7) open into the tube.

Description

The invention relates to a device for atomizing and granulating melts, especially liquid ones Slag, at which a Tundishauslauf a spray head with an impeller driven for rotation, whose axis of rotation towards the axis of the tundish spout emerging slag jet runs, as well as a cold room connected.

AT 407 247 B has already proposed a melt from a melt dentalis with fluid under pressure, in particular compressed gas, steam or pressurized water in Direction of slag exit pressed from the tundish has been. The Schlackentundishauslauf requires in such Training special measures to prevent the Freezing orifice and it has therefore been proposed a height-adjustable weir pipe in the area of the slag outlet to lower into the tundish to the each outflowing amount to regulate the propellant jet coaxial with Axle of the outlet opening was introduced and the Tundishauslauf immediately flows into the refrigerator. In such a Formation of the atomizer head as a nozzle, in which Coaxially the jet of a propellant gas lance, must in the Usually a highly superheated steam can be used to grow to prevent the opening, depending on the composition the melt and in particular at higher iron oxide content the melt also high demands on the refractory material be put. The same applies to training the height-adjustable weir tube, which in aggressive Melting is subject to high wear and therefore a complicated regulation for the correct adjustment of the Height of the weir pipe required. In addition to such Formation of the atomizer head as a discharge nozzle from a Schlackentundish are other training, for example, the AT 406 954 B, in which case the liquid slag in sucked in a negative pressure expansion chamber is transported and with a propulsion jet in the cooling zone becomes.

In AT 405 511 B is a method for granulation and crushing of molten material described in which liquid slag in freefall with pressurized water jets is applied, whereupon the solidified and granulated Slag together with the steam formed via a pneumatic Delivery line and a distributor is performed. That up this way distributed material can be directly in one Jet mill to be further crushed. The basic processes during granulation and comminution of molten Material by applying steam are also in EP 683 824 B1 already described, with a mixing chamber provided here is in which water, water vapor and / or air-water mixtures be injected, whereupon the evaporated water in common with the solidified material ejected through a diffuser becomes. The atomizer head is in such a configuration designed as a mixing chamber with subsequent diffuser, although in this case molten slag a corresponding storage vessel or a tundish supplied can be.

In AT 407 152 B, solid material is formed in a melting cyclone melted, being closed to the pressure-tight Melting cyclone directly connected to a refrigerator, which subsequently under lower pressure than the melting cyclone must be kept to the discharge of the material from the Enabling melting cyclone in the refrigerator. Because at one Such processes the required heat of fusion in Melting cyclone must be applied during combustion of fuels in the melting cyclone produces a large amount of gas, which subsequently requires a correspondingly expensive cleaning. A regulation of such a method is only in the extent possible, in which, as required, the corresponding Heat of fusion is provided, so that in particular a reduction in the amount of gas produced and a setting to the desired cooling conditions in such a Melting cyclones can not be achieved.

Common to all these known trainings is the fact that that for the emission of slag high amounts of propellant gases, in particular steam can be used, whereby steam in all Usually strongly overheated and propellant gases correspondingly highly preheated must be used. In addition to the high to be heated Gas quantity is a relative to the atomization high effort in the required cleaning of the used and gases formed, so that the equipment required for gas production and the gas purification is relatively high.

Classical granulation processes provide; that melting or Slags are easily introduced into cooling liquids, wherein naturally when using water as the cooling liquid the slags may contain only small amounts of iron in order to to ensure stable operation. In dry granulation the slag reaches cooling belts or cooling plates, for what usually relatively large-scale facilities required are.

The invention now aims to provide a device for atomizing melts, in which much smaller particle sizes than in conventional granulation can be achieved and in which the amount of gas generated in the process or required for the operation of the process can be kept low. To solve this problem, the device according to the invention of the type mentioned is essentially the fact that the cooling space is formed as the centrifugal concentrically surrounding annulus and connected with the interposition of a heated annular chamber to the impeller. Characterized in that, as known per se, the melt passes directly with the interposition of a conventional Schmelzenflußregelorganes, such as a feeder or Tundishstopfens on a blast wheel whose axis of rotation substantially coincides with the axis of Tundishauslaufes, a very small-scale device is provided in which the blast wheel correspondingly comminutes the melt flow as a function of the rotational speed, with corresponding coolants being installed in the radially adjoining space. The device is thus constructed as a substantially annular chamber, whereby only a small height is required and the manipulation of the melts is simplified accordingly, since the melt no longer, as in conventional Dampfzerstäuberdüsen must be raised accordingly to expelled into an underlying space become. The use of such a blast wheel with subsequent annular cooling chamber thus constructively represents a very small-scale device, in which nevertheless important process parameters which are relevant for the formation of suitable particle sizes can be adjusted within wide limits and with simple means. When using centrifugal wheels, for example, it was frequently observed in slag melts that they tend to form a thread, whereby further comminution was possible only with great effort. In the context of the device according to the invention, it is now possible in a simple manner to maintain the temperature of the slag during and immediately after crushing by the blast wheel to correspondingly high temperatures to ensure the formation of droplets, with appropriate heating of small sections, the desired temperatures and thus the desired surface tensions to form the corresponding droplets can be adjusted within wide limits. For this purpose, the inventive construction is advantageously made such that the Tundishauslauf is in communication with the impeller and the annular space via a heatable connecting pipe. Immediately after the tundish spout can hiebei with burners or hot gas and in particular at temperatures of 1400 ° to 1800 ° C still overheating of the slag are made so that the formation of fine droplets is ensured by the spinner. The impeller itself can have a corresponding controllable drive, for example, in the speed range from 3,000 to 20,000 min ^-1, to be operated. In order to achieve the appropriate slag overheating to hitting the corresponding baffles of the blast wheel for a short distance, the design is advantageously made so that open into the connecting tube burner.

Even after leaving the wheel it is for training according to fine droplets and preventing from Threading necessary to ensure that the slag or melt droplets have a correspondingly high temperature, so that due to the surface tension a Droplet formation is favored. Even after leaving to ensure a corresponding temperature control yet the training is inventively made so that the annulus formed as a cooling space with interposition a heated annular chamber connected to the impeller is.

The designed as an annular chamber cooling chamber can be in conventional Be cooled and it can be the training in particular be made for this purpose so that the radially extending walls of the refrigerator double-walled as Radiation cooling surfaces are formed at the cavity Lines for cooling medium are connected. The dimensions of a but such a cooling chamber can also be characterized further reduce when in the cooling chamber directly media be injected, which, for example, under high Decompose enthalpy consumption. An advantage is the training Therefore, made so that the designed as a cooling space annulus Connections for the injection of cooling agents, such as e.g. hydrocarbons, has in the annulus.

The invention will be described schematically with reference to the drawing illustrated embodiment of an inventive Means partly explained in detail in section.

In the drawing, 1 denotes a melting tundish, whose Schmelzeausflußregelorgan 2 is designed as a feeder and by lifting in the direction of the double arrow 3 a corresponding Regulation of the respective outflowing melt stream 4 allows.

Pressure-tight to this tundish 1, a connecting pipe 5 is connected, in which injected via ring nozzles 6 and 7 hot gas becomes. Alternatively or additionally, each burner open into the shaft formed by the transition pipe 5, so that the slag jet 4 corresponding to temperatures up can be overheated to 1800 ° C. At this connection pipe. 5 an annular chamber 8 is connected, which consists of several sections consists. In the first section of this annular chamber 8 is a blast wheel 9 rotatably mounted, wherein the axis of rotation 10 substantially with the axis 11 of the tundish spout flees. The melt or slag thus hits the rotating impeller 9 and is in the radial direction in the annular chamber 8 thrown outward. In a first to the Blower wheel subsequent section of the annular chamber, which is designated 12, there is a further heating to the Melt temperature according to the desired parameters for example, again to temperatures between 1400 ° and 1800 ° C, so that a fine droplet formation under Avoiding threading occurs. The outer area of the Ring chamber 8 is formed as an annular cooling chamber 13, whose walls are double-walled. In the between The cavity 14 enclosed by the walls can be corresponding Coolant can be introduced. In addition, nozzles 15 are provided, about which, for example, injected hydrocarbons which are the fine under strongly endothermic decomposition Hot melt droplets quickly withdraw heat and in this way ensure a safe solidification and cooling.

The microgranules formed leave the annular cooling chamber on the circumference of the same in particular with temperatures between 200 ° C and 500 ° C and can be collected outside the annulus become.

Claims (5)

1. A device for pulverizing and granulating melts, particularly liquid slags, in which are connected to a tundish downspout a spraying head including a whirl gate (9) capable of being driven to rotation and whose axis of rotation (9) extends in the direction of the axis of the slag jet (4) emerging from the tundish downspout as well as a cooling chamber, characterized in that the cooling chamber is designed as an annular space (13) concentrically surrounding the whirl gate (9) and connected to the whirl gate (9) with a heated annular chamber (12) being interposed.
2. A device according to claim 1, characterized in that the tundish downspout communicates with the whirl gate (9) and the annular space (8) via a heatable connection tube (5).
3. A device according to claim 2, characterized in that burners (6, 7) open into the connection tube.
4. A device according to any one of claims 1, 2 or 3, characterized in that the annular space (13) designed as a cooling chamber comprises connections (15) to nozzle into the annular space (13) cooling agents such as, e.g., hydrocarbons.
5. A device according to any one of claims 1 to 4, characterized in that the radially extending walls of the cooling chamber (13) are designed as double walls constituting radiation cooling surfaces, to whose cavities (14) ducts for cooling medium are connected.

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