RU2061056C1 - Equipment to melt metal scrap and for off-the furnace processing of molten metal by blow of gases - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: invention relates to metal scrap remelting and refining of pig iron into steel. Equipment has vessel in the form of lined laddle suspended from hollow half-axles. Side walls of ladle have ducts in the form of even number of multistart spirales. Each pair of ducts has common outlet into lower part of vessel. One of ducts of pair is connected to source of combustible gas, the other one - to source of air or oxygen. Gas is fed into spiral ducts through hollow half-axles. EFFECT: simplified design, improved operational efficiency of equipment. 2 dwg

Description

 The invention relates to metallurgy, in particular, can be used in metallurgical plants, which produce remelting of scrap metal and redistribution of molten iron into steel. It can also be used in foundries and workshops.

 A device [1] is known for processing liquid metals by gas purging, containing a lined tank in the form of a bucket with a channel for supplying gas through a porous plug in the bottom of the tank.

 The disadvantages of this device is the inability to remelting scrap metal; low temperature of the gas entering the melt and large heat losses through the walls of the vessel, which reduces the temperature of the melt, as a result of this, a higher initial temperature of the melt is required and therefore a greater energy consumption.

 Closest to the proposed one is the device [2] adopted as a prototype for converting cast iron into steel in the form of a traditional converter, in the lining of the side walls of which a spiral pipe-pipe is laid, through which air, oxygen or at the final stage of redistribution are inert gas, which through the tuyeres at the bottom of the converter enter liquid metal. Passing through a spiral pipeline, the injected gases warm up, the heat lost through the side walls partially returns with the gases to the melt, as a result of which heat losses are reduced and it is possible to increase the amount of scrap metal loaded into the converter when cast iron is converted to steel.

 The disadvantages of this device are the impossibility of remelting only scrap metal; the presence of only one spiral channel in the side walls of the lining, which allows only one gas to be blown through the metal at a time, which limits the capabilities of the device.

 The aim of the invention is to provide a device in which it is possible to re-cast iron and steel scrap without pouring molten iron and then, after melting, to perform out-of-furnace treatment of molten metal by blowing with various gases.

 This is achieved due to the fact that the device for melting scrap metal and for out-of-furnace treatment of molten metal by gas purging contains a container in the form of a lined bucket suspended on the hollow half shafts, in the side lined walls of which there are spiral channels, the gas is supplied through the hollow half shafts, the spiral channels are multi-start, and their number is even, with distribution in pairs, each of which has a common outlet in the lower part of the tank, while one of the channels of the pair is connected to a hot gas burner, and the other with a source of air or oxygen.

 The invention consists in the following.

 Combustible gas (for example, natural) is supplied to one of the spiral channels of each pair, and air or oxygen to the other. At a common outlet, playing the role of a gas burner, the gas is ignited, which is melted into the charge loaded into the ladle with slag-forming additives. After melting, the metal is purged with gases and the after-furnace treatment of the metal with inert gases is performed.

 In FIG. 1 shows the proposed device, a longitudinal section; in FIG. 2 is one of the options for a common output for a pair of spiral channels into the bucket capacity.

 The device consists of a steel casing of the bucket 1, inside of which a lining 2 of refractory material is made. Inside the lining in the side walls of the bucket are spiral multi-start channels 3, the number of which must be even. Each pair of channels has a common outlet 4 into the bucket capacity, into which scrap and slag-forming additives are loaded. After melting in the bucket contains molten metal 5, covered with a layer of slag 6.

 Spiral channels can be made of ceramic or metal pipes.

 The overall output of the channel pair can be made as shown in FIG. 1, or in the form of a gas burner, for which a ceramic or metal refractory pipe 7 is inserted into one of the channels, and a refractory diaphragm 8 can be installed at the outlet, as shown in FIG. 2.

 For convenience, gases can be fed into the spiral channels along the hollow axles 9, on which the bucket is suspended. The half shafts are inserted into the supports 10.

 The proposed device operates in two versions.

In the first embodiment, the device is used initially for melting scrap metal, and then the liquid metal is purged with gases, as in devices [1, 2]
In a second additional embodiment, a crucible is installed inside the bucket, the device turns into a high-temperature crucible furnace, in which the combustible gas and air or oxygen are heated by the exhaust gaseous products of combustion.

 In the first embodiment, the operation of the device is as follows. Air or oxygen is let into one of the channels of each pair, and gas is ignited by a torch into the second combustible gas (for example, natural) and at a common outlet 4. Then they load metal scrap of ferrous metals (steel, cast iron, iron) or scrap of non-ferrous metals and the corresponding slag-forming additives. Gaseous products of gas combustion warm the mixture. As the charge is heated due to the heat leaving the side walls of the bucket, the gases in the spiral channels warm up and the temperature of the gases formed during combustion rises rapidly, as a result of which the charge quickly melts in an energy-saving mode.

 After the lower part of the charge is melted, the liquid metal closes the exit of 4 gases, but the combustion of gas continues at exit 4 and in bubbles of gases rising in the molten metal. The pressure of the gases as the level of molten metal rises can be increased, and the melting process will continue until complete.

 After the charge is completely melted, the supply of combustible gas to the channels can be stopped and gases can be blown, which are usually used for out-of-furnace treatment of liquid metal, for example, steel [1-3] by gas purging. For example, air or oxygen is purged to remove excess carbon or silicon from steel. In this mode, the operation of the device is similar to the operation of the converter. To remove harmful dissolved gases from the metal, the metal is purged with an inert gas (e.g. argon).

 If initially molten iron is poured into the ladle, then in this mode the device operates as a converter for redistributing cast iron into steel.

 After completing the purge in order to obtain the desired chemical composition, without stopping the purge, for example, with an inert gas, the ladle is tilted, the slag is initially drained, and then the finished metal is poured onto the molds. After that, the bucket can be loaded for subsequent metal processing.

 In the second embodiment of the proposed device, a crucible is initially installed inside the bucket, the charge is loaded into the crucible, the gas is ignited and the charge is melted. After melting, the crucible is removed and the molten metal is poured into the molds.

 The first option is intended for large metallurgical plants, the second for small casting in workshops.

 The advantage of the proposed device is the simplicity of design. For the manufacture of the device does not require large investments. It can be made at any metallurgical plant and even in a workshop.

 The proposed device can compete with open-hearth furnaces used for the smelting of ferrous metal scrap and the conversion of cast iron into steel and with converters used for the same purpose. In addition, the device will find wide application in foundries and repair shops for the repair and manufacture of spare parts from ferrous and non-ferrous metals.

Claims (1)

 A device for melting scrap metal and for out-of-furnace treatment of molten metal by gas purging, containing a container in the form of a lined ladle suspended on hollow half shafts, in whose lateral walls are spiral channels made, gas is supplied through hollow half shafts, characterized in that it is spiral the channels are multi-start, and their number is even with the distribution in pairs, each of which has a common outlet in the lower part of the tank, while one of the channels of the pair is connected to the source yuchego gas and another with a source of air or oxygen.

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