EP1273863A1 - Process for cleaning hot surface for deposits of metal or slag - Google Patents

Abstract

Process for removing metal and slag residues from hot surfaces comprises spraying water onto the surface to be cleaned under a pressure of at least 2,000 bar from one or more nozzles in an amount sufficient so that the sprayed water is converted into vapor without leaving a residue. Preferably 15-20 liters per minute of water are sprayed onto the surface to be cleaned. The surface is made from refractory materials.

Description

When producing metals by melting or remelting processes, it is necessary liquid metal melts in transport containers or with the help of channels transport. These vessels and gutters are always lined with refractory materials, which are subject to considerable wear during operation. This Wear occurs through abrasion as a result of the relative movement between the melt and vessel or channel, furthermore by chemical reactions with the refractory material, especially in the melt / slag interface, favored by frequent temperature changes. The service life of the refractory material can be increased by applying suitable Repair material can be lengthened by spraying or pouring repair material on the vessel surfaces or channel surfaces.

When carrying out such repair work, however, the problem always arises that the Surface of the refractory material to be repaired with a layer of metal and / or slag is coated. These layers come from the previous one Use of the metallurgical vessel or the metallurgical transport trough.

If repair material is now applied to such metal and slag layers, so There is therefore no long-lasting repair effect, since the repair material layers applied have not found a cheap prison surface. Comes after Completion of the repair work, the repaired surface again with hot, molten material (metal and / or slag) in contact, so the applied Repair materials detached from their surface and washed away.

Such slag and metal layers are removed from refractory surfaces conventionally with the help of mechanical methods and essentially through Chiseling, milling or chain slaps.

Chisel blows uncontrollably damage the surface of the remaining material. The heavy blows wear down the remaining material until it is Fracture. Zones of premature wear at slag-air boundaries or metal-slag areas can hardly with the chisel due to their notch-shaped geometry can be cleaned without significant damage to the remaining material and thus causing wasteful refractory material to be wasted.

When using a milling machine, unnecessary surface wear is reduced. Also the geometry of the notches at the level boundaries can be achieved with less destruction of the residual material that is still suitable. However, there are high costs through the wear of the tools.

In both cases, an excavator-like vehicle serves as the tool carrier Radiant heat of the hot surface is largely exposed unprotected. in the In the event of a gutter cleaning, this vehicle runs on the gutter. Because of the dynamic The channel is subjected to high mechanical loads.

Cleaning with chain cleaning machines (EP 0 429 487 B1) initially requires an effort to bring the machine into the cleaning position. The environment must be cordoned off as there is a significant risk of accidents due to residual materials flying around and worn chain links.

DE 43 24 516 A1 describes a powder stream with oxygen and fuel particles Cleaning of refractory surfaces provided. However, this process is complex and prone to accidents.

The above-mentioned common mechanical procedures for removing Slag and metal layers are consequently cost-intensive or prone to accidents. The in Refractory residual heat contained in refractory material leads to working too roughly and a large part of the undamaged base material is destroyed or worn down becomes.

The invention has for its object a new method for removing Specify slag and metal residues from refractory surfaces with which Help refractory surfaces of transport containers, transport channels and the like residues of slag and metal can be removed gently and safely. In particular The aim of the new procedure is to ensure that the cleaning staff neither due to heat or flying particles, be it the removed slag and metal residues or the underlying refractory material. The new process is also intended to completely remove the metal and slag residues guarantee from the refractory surfaces.

This object is achieved by the method specified in claim 1.

The progress that can be achieved with the method results primarily from that with the help of the high-tension water jet a safe, the refractory surface gentle removal of the slag and metal layers to be removed guaranteed by the refractory surfaces. After the cleaning process the cleaned refractory surfaces offer a secure base for sticking on Repair material.

Preferred embodiments and advantageous configurations of the invention Cleaning procedures are specified in the subclaims.

For the successful implementation of the method according to the invention, the for amount of water that acts on the cleaning surfaces in terms of pressure and amount be chosen carefully. At present, water pressures of at least 2,000 bar preferred, with a water amount of about 15 to 20 l per minute in the form of a thin Sprayed onto the hot surface to be cleaned.

The water jet emerges from a nozzle, which at the end of a sufficiently long-dimensioned Tube sits around people or machines handling the said tube, Protect from harmful heat equipment.

The amount of water sprayed out of the nozzle in the unit of time is so small that An instant conversion of the water to superheated steam occurs when the water strikes the hot surface to be cleaned. Due to the large, sudden entry Volume change from liquid to gaseous (i.e. from water to water vapor) becomes a detonation of those to be removed adhering to the material to be cleaned Layers, which means that the slags to be removed and peel off metal residues from the underlying refractory material.

The high impact pressure of the spray water on the surface to be cleaned also exercises a mechanical removal effect on the surface layers to be removed and on the underlying, destroyed, near-surface refractory material.

So-called hydrogen explosions are known and feared among experts, which occur when water and molten metal meet. These explosions occur, for example, when a molten metal is placed in a vessel, on the bottom of which water has accumulated. Fearing the possibly The devastating effects of such explosions are rejected by experts against proposals to use water in areas where molten metal can reach.

Contrary to the fears of the professional world arise when performing the invention However, the process does not involve such explosions because of the high tension Water jet in the method according to the invention only in such an amount the surface to be cleaned is sprayed that the sprayed water immediately without Residue is converted into steam. This will prevent yourself from Water accumulates in the refractory masonry or its surroundings.

The application of the surface to be cleaned with the high-tension water jet is preferably continued until it is on the refractory base material Grooves have formed, which in turn is an excellent basis for adhesion to the applied Form repair material.

Claims (4)

Process for removing metal and slag residues from hot surfaces, characterized in that water is sprayed at a pressure of at least 2000 bar from one or more nozzles onto the surface to be cleaned in such a quantity that the sprayed water immediately leaves no residue in steam is converted. A method according to claim 1, characterized in that 15 to 20 l of water per minute are sprayed from a nozzle onto the surface to be cleaned. Method according to one of the preceding claims, characterized in that the surfaces of refractory materials are freed from adhering metal and / or slag layers. Method according to one of claims 1 to 3, characterized in that the application of the high-tension water jet to the surface to be cleaned is continued until striations have formed in the substrate freed from metal and / or slag.