SU846974A1 - Electric salt furnace - Google Patents

Description

(54) ELECTRIC SALT OVEN

I

The invention relates to metallurgical equipment, in particular, to the design of an electric salt furnace intended for the smelting of scrap and non-ferrous metal wastes, mainly chips of aluminum and copper alloys.

A known electric salt furnace for melting non-ferrous metals, for example, aluminum alloys, including a melting chamber, a metal digger, heating electrodes made in the form of a metal rod, placed in special cells with the possibility of contact with molten salt (coolant), perforated basket for the original raw materials with the mechanism of its movement and the lid 1.

However, due to the direct contact of the electrodes with the molten salt at elevated temperatures, there is a rapid deterioration of the electrodes. In addition, the electrodes themselves are due. limited cross section and elevated temperature, consume a significant amount of own electricity.

An electric salt furnace is also known, comprising a melting chamber, a metal digger, heating electrodes, a perforated basket and a device for changing the level of the molten salt in the melting chamber 2.

An electric salt furnace is also known, which includes a salt bath located in a housing, heating electrodes dipped in a salt melt 3.

A common disadvantage of these furnaces is the rapid deterioration of the electrodes in direct contact with the molten salt,

d having a high temperature.

Closest to the invention in terms of the effect achieved is a salt bath furnace for copper regeneration, including a melting chamber filled with salt melt, electrodes immersed in

tS salt melt to heat the latter, and an additional electrode in the form of a hollow tube installed in the bottom of the furnace — a pool of liquid metal, and used to heat the metal 4.

However, due to the direct contact of the electrodes with the salt melt, which has a high temperature and is an aggressive medium, there is an intense deterioration of the electrodes, which leads to their relatively quick change and just the furnace during the period of the change of electrodes. In addition, heating the electrodes to the temperature of the melt leads to a loss of energy to the electrodes due to their increased resistance.

The purpose of the invention is to eliminate the contact of the electrodes with the salt melt in order to ensure a longer service life and to reduce the stoppage downtime.

The goal is achieved by the fact that the furnace is additionally equipped with a chip compaction mechanism, including a pipe, to the lower end of which the bars - electrodes are hinged, the return-flow drive is driven, the pipe is curved, the electrode rotation mechanism around the hinges consisting of a pipe coaxially mounted in the pipe the chip compaction mechanism with reciprocating mixing, t g, pivotally connected at the ends with the tube of the turning mechanism and the bars with microelectrodes, and the tube mixing drive. In addition, each electrode is provided with an individual current lead in order to eliminate the arc effect in the upper electrode.

FIG. 1 shows schematically the proposed furnace, a longitudinal section; in fig. 2 is a section A-A in FIG. one.

The electric salt furnace comprises a metal body 1, a refractory lining 2 of the furnace, a lower (bottom) electrode 3, an upper electrode 4, a chip sealing mechanism, a rotation mechanism of the upper electrodes, and a cover 5. The refractory lining 2 is laid out of resistant salt melt and liquid metal refractory material inside the enclosure. 1. The body 1 and the lining 2 may preferably have a cylindrical shape. The lower electrode 3 is made in the form of a flat disk of a material resistant to the action of a molten metal, such as graphite, and is connected to a current lead 6. In lining 2, a metal collector 7 is formed in its lower part with a bore hole 8 for discharging liquid metal with molten salt coolant, chip compaction chamber 10 and chip loading chamber 11. The upper electrode 4 is made in the form of beams, radially mounted and pivotally connected to the chip compaction mechanism. It is possible to manufacture the electrodes 4 with side and bottom protrusions (not shown) to increase the contact surface with the chips. The chip compaction mechanism includes a pipe 12, to which in the lower part a bar-electrodes 4 are hingedly attached, and a drive 13 for reciprocating movement of the system electrodes - a pipe. Pipe 12 is installed in the lining of 2 furnaces. The electrode rotation mechanism contains a pipe 14 located inside the pipe 12 with the possibility of reciprocating movement, rods 15 pivotally connected at the ends with the pipe 14 and electrodes 4 (in Fig. 1), and a drive 16. Each electrode 4 has an individual flexible current lead 17 installed inside the pipe 14. Electrodes 4

made of metal with good electrical conductivity. The diameter of the electrode 3 and the diameter of the conditional circle formed by the electrodes 4 in their horizontal position are commensurate. An annular opening is provided in the furnace lid 5 for loading the starting material into the loading chamber 11. The proposed oven works as follows.

A flux (a mixture of salts) is placed in a dried oven, melted by known techniques. A layer of chips is placed above the molten salt while the system 12 is in the raised position — the electrodes 4, while the electrodes occupy a position close to vertical. The actuator 16 of the turning mechanism is turned on and the electrodes 4 are set in a horizontal position (and left in this position until the end of the cycle). After that, the chip compaction mechanism is turned on, when the pipe 12 with horizontal electrodes 4 is downward, the crumpling occurs

chip compaction. Voltage is applied to electrodes 3 and 4. Electric current passes from electrodes 4 through compacted chips, molten salts, metal layer to electrode 3 (or vice versa). In this case, with the passage of current through the salt melt

0 heat is released to increase the temperature of the molten salt and slightly the temperature of the liquid metal. Due to the heat released, the chip layer wetted by the molten salt is melted and the liquid metal passes through the flux layer and is directed to the metal container 7. The pressure of the electrodes 4 on the chip is constantly controlled by the drive control system 13. Simultaneously with the chip melting, the next batch of chips is loaded into the loading chamber 11. Upon completion of melting, most of the chips located under the electrodes 4 begin to lift the pipe 12 and simultaneously rotate the electrodes 4 to a position close to the vertical one. In this case, the chips accumulated with above the electrodes 4 (in their horizontal position) are lowered onto the molten salt and the cycle repeats.

The proposed furnace has the following advantages: there is no direct contact of the electrodes with the molten salt, which eliminates wear due to the interaction with the molten salt; the electrodes 4 are not heated to the temperature of the salt melts, due to which there is no loss of electricity to the electrodes; the presence of a sealing mechanism

chips (due to the back pressure due to the difference between the specific weights of the molten salt and aluminum chips and the drive pressure) ensures the forced layer-by-layer contact of the aluminum chips with the coolant, a salt melt, thereby providing more efficient chip melting.

Claims (4)

1. An electric salt furnace is preferable for melting metal chips, including a lined body, a salt bath, bottom and top heating electrodes, a metal collector and a lid, characterized in that, in order to increase the service life of the upper electrode by eliminating its contact with the molten salt at at the same time reducing energy losses for heating the upper electrode, it is equipped with a chip compaction mechanism that includes a pipe, to the lower end of which the bars - electrodes are hingedly attached, the drive will return ceiling elements moving pipe turning mechanism around the hinge electrodes consisting of truf .2. / , coaxially installed in the pipe of the sealing mechanism with the possibility of reciprocating movement, t g, pivotally connected at the ends with the pipe of the turning mechanism and the bar with mye-electrodes, and driving the movement of the pipe of the turning mechanism of the electrodes. 2. Furnace according to claim 1, characterized in that each electrode is provided with an individual flexible current lead. 3.Pech on PP. 1 and 2, characterized in that they are connected to the upper end of the electrodes. Sources of information taken into account in the examination 1. USSR author's certificate number 335498, cl. F 27 B 7/14, 1970. 2. USSR author's certificate number 466372, cl. F 27 B 17/00, 1972. 3. Patent Polish No. 83857, cl. H 05 B 3/30, 1974. 4. US patent number 3666370, cl. 13-23, 1972. 17 P 1 17