GB2143311A - Metal/metal alloy melting furnace equipment - Google Patents

Abstract

Furnace equipment for melting charges of metallic material, such as aluminium and aluminium-containing scrap and/or alloys, iron, steel, copper, etc., or alloys thereof, comprises two chambers (1, 2) communicating by way of at least one channel inductor heater (7). One (1) of the chambers receives a charge from a feeding device (12) operating from above, and melt is arranged to be taken from the other chamber (2). <IMAGE>

Description

SPECIFICATION Metal/metal alloy melting furnace equipment The present invention relates to furnace equipment for melting metallic material such as aluminium and aluminium-containing scrap and/or alloys, iron, steel, copper etc., or alloys thereof.

Furnace equipment of the kind to which this invention relates is known from Swedish patent application 8205898-3, which describes equipment for melting and holding the melt of, for example aluminium. This equipment comprises an inductor, fixed to a furnace vessel, with a primary winding and a secondary circuit surrounding one leg of an iron core, the secondary circuit including at least one melt-containing channel. In addition, a heat source for holding melt at temperature, for example an electric resistor element, is mounted above the free surface of the melt, for example in a cover of the furnace vessel.

One problem in connection with the use of furnace equipment of the above-mentioned kind is to be able to charge it in a simple manner, and more particular liy to charge it with shredded scrap. It would be useful, when required, to be able to perform, in the furnace equipment, fluxing and chlorination of alu minium scrap, for example scrap derived from beer cans. It is also desirable to construct such furnace equipment for continuous operation.

The invention aims to provide a solution to the above-mentioned problem and to meet the abovenoted desiderata. What constitutes furnace equip ment according to the invention is set out in the following claim 1.

With a feeding device of the kind required in furnace equipment according to the invention, for example a stoker feeding device based on a conveying screw, it is possible to press finely-divided scrap down into the melt at a rate whose maximum value corresponds to the maximum melting capacity of the inductor so that the throughput of the furnace equipment can be up to 100% of the rated maximum capacity.

In a preferred embodiment, scrap containing alu minium, for example empty beer cans after fragmentation, is used as raw material and a charging device for fusing agent can suitably be connected to the feeding device, which makes the equipment as a whole suitable for processing scrap of the kind mentioned.

Chlorine gas can advantageously be supplied to the melt through an injector tube, immediately prior to the point where melt is run off from the second chamber of the furnace equipment.

A preferred form of furnace equipment in accordance with the invention will now be described with reference to the accompanying drawings, in which Figure 1 shows the furnace equipment partially sectioned in side elevation, and Figure 2 shows,, on an enlargeed scale, a section on the line ll-ll in Figure 1.

Figure 1 shows two furnace chambers 1 and 2, suitably mutually identical and arranged back-toback with an inductor bridge piece 7 disposed therebetween. The first chamber 1 is provided with a cover 3 with a heating source 4 (which may be built in or attached to the cover 3). The source 4 may, for example, be of the electric resistance type and is used for keeping the melt hot when the inductor heater in the bridge 7 is not operating. When the cover 3 is lifted, slag and the like can be withdrawn from the melt in the first furnace chamber 1 for collection in a container or car 5.

The bridge piece 7 which connects the chamber 1 to the chamber 2 contains two melt passages 19 and a vertically extending channel 20 which passes through the bridge 7 between the melt passages 19.

A transformer or inductor iron core 8 has a leg 21 extending vertically through the vertical channel 20 of the bridge 7, and this leg is surrounded by a single- or multi-phase primary winding or coil 23.

The balance of the core 8 extends around the outside of one side of the bridge 7, as shown in Figure 2, and it as well as all the outside surfaces of the bridge 7 are encased by a refractory thermal insulation layer 24. This layer 24 retards the escape of heat from the bridge 7. During melt heat retaining periods, when the inductor is unpowered or shut down,this thermal insulation assists in maintaining molten the melt in the inductor's channels. When the coil 23 is supplied with single-phase or multi-phase current melt is made to flow through the passages 19 and is heated by induction in the bridge piece 7. The second chamber 2 (the run off chamber) is provided with a cover 9 and resistance heaters 10, and run off to a ladle or a holding furnace may be performed from the chamber 2 at 11.

Afeeding device 12, for example a charging stoker, is mounted adjacent to the cover 3 to the first chamber 1 so that charge 16 for the furnace equipment is fed into the chamber 1. The feeding device 12 is mechanically driven (suitably motor-driven at 13) and arranged inside a cowl 14 with an exhaust duct 15. As charge material 16 there may suitably be used fragmented (finely-divided) aluminium, such as spent aluminium beer cans, which is fed down continuously, or at intervals, by means of the device 12 into the chamber 1. Fusing agent may be supplied at 17 to be fed in with the charge 16. The charging of the scrap may take place at a speed whose maximum value corresponds to the maximum melting capacity of the induction heater in the bridge piece 7 (up to 100%). The scrap may be so-called shredded scrap.

The fusing agent is also suitably fed in by means of a stoker control, and the mixture of scrap and fusing agent can be readily adjusted to the desired proportion.

Chlorination of an aluminium melt can take place by feeding in chlorine gas through an injectortube 18 immediately upstream of the run off outlet 11 from the second chamber 2.

It is to be understood that the furnace equipment can also be utilized for example, for scrap containing copper, steel or iron.

The bridge 7 can be removed, for example replaced, in a simple manner.

The equipment illustrated and described above may be varied in many ways within the scope of the following claims. Thus, for example, the charging device 12 can be arranged at other locations above the first chamber 1.

Claims (8)

1. Furnace equipmentfor melting metallic material, which comprises two chambers communicating via at least one channel-type inductor heater, one of which chambers is arranged to receive charge to be melted directly from a feeding device operating from above, and the other of which chambers is arranged so that melt can be fed out therefrom.

2. Equipment according to claim 1, in which the feeding device is included in a cowl to which charge material for the said one chamber can be fed.

3. Equipment according to claim 1 or claim 2, in which the feeding device consists of a mechanically driven feed means.

4. Equipment according to claim 2 or claim 3, in which the feeding device includes a charging device for fusing agent.

5. Equipment according to any preceding claim, in which means is provided to supply chlorine gas to melt in the said other chamber.

6. Equipment according to any preceding claim, in which each chamber has a cover that incorporates a heating means to heat melt in the chambers when the inductor heater is not energised.

7. Equipment according to any preceding claim, in which the inductor heater is incorporated in a bridge piece removably located between the two chambers.

8. Furnace equipment substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.