Rotary Oxy-Combustion Melting Furnaces for Cast Iron
Sogemi has over twenty years of experience in the construction of cast iron melting rotary furnaces, developed with the aim of reducing running costs and in order to improve environmental impact, thereby reducing the levels of pollution arising from the melting process with a cupola furnace. Sogemi has thereby tackled these issues, in collaboration with the Air-Liquide Group, and has developed technology to ensure that rotary furnaces having a leading role to play in the foundry.
Sogemi has so far been responsible for the installation of over 100 plants worldwide, which cover all possible applications, from the smaller sized furnaces to the larger furnaces for mass production.
Sogemi furnaces distinguish themselves by virtue of the following:
- Excellent heat transfer: flame at 2800°C, with a high degree of radiation and thermal exchange by the refractory material for conveyance thanks to the rotary motion.
- Controlled melting in oxidizing or reducing environments, with rapid temperature increase (over 6°C a minute).
- Rapid automatic loading and slag removal thanks to the possibility of inclining the furnace until it is in vertical position.
Furnace for large sized castings
One of the most typical applications of the rotary furnace is that of cast iron melting for large sized casting. In such cases it is possible to note how the rotary furnace may be used to pour the molten cast iron directly into the ladle, which is then used to transfer the metal into flasks.
This makes it the ideal solution for those producing large sized castings: in fact the rotary furnace ensures the availability of molten metal in short time, rapid pouring into the ladle, the possibility of making any metallurgic adjustments that may be necessary.
Furnace for automatic molding lines
In this second application the furnace usually supplies a holding furnace, from which it takes the iron to then pour it into the molds/flasks of the molding line that comes after the melting system. In this case, at the end of the melting process, the molten metal is conveyed to the holding furnace through a special pouring channel, of either fixed or mobile type, connected to the rotary furnace.
In this type of application know as Duplex, it is possible to exploit the flexibility of the rotary furnace, which can be used to prepare the molten cast iron and then switched off without any problem.
The furnace after to the rotary furnace may be of electric melting type such as Press-Pour.
Dual loading options
Sogemi furnaces have a top loading function, thanks to a hydraulic system which permits the 40° inclination of the furnace itself to facilitate the loading operations. In order to meet varied customer needs, Sogemi has envisaged two different loading options:
- skip loading with mobile vibrating channel
- by means of metal shutter conveyor of Apron type
Simplicity, flexibility, savings
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High quality metallurgy:
- Grey iron and nodular/ductile iron. As well as iron alloys (Ni Hard, Ni Resist, Ferritic).
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Environment friendly:
- Reduced dust emission (no coke);
- Incredible reduction in fume volumes (no air);
- Minimum S02 content in the fumes (no coke);
- Reduction in N0x emission levels (no air);
- Cleaner foundry working environment.
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Competitive costing:
- Low initial investment requirement: simple technology;
- Low running costs: no electricity;
- Reduced labour requirements: a single operator for two furnaces.
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Process flexibility:
- PLC controlled system to ensure complete reproductive capacity;
- Excellent repetitive potential of the chemical analysis of the metal;
- Possibility of load alteration: production flexibility;
- Melting and holding: in the same furnace.
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Minimum maintenance:
- Mechanical and electrical maintenance: minimal;
- Refractory material: one hour each week together with a small quantity of repair material; complete reparation once a year.
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Wide range of solutions:
- Furnace capacityof between 2 and 30 ton
Operational cycle:
| Rotary furnace capacity | 3 tons | 5 tons | 8 tons | 15 tons | 20 tons | 30 tons |
|---|---|---|---|---|---|---|
| Preliminary operations [1] | 15 min | 15 min | 15 min | 15 min | 15 min | 15 min |
| Loading | 10 min | 10 min | 12 min | 15 min | 20 min | 25 min |
| Melting time with ALJET cycle [2] | 60 min | 75 min | 90 min | 110 min | 120 min | 135 min |
| Cast iron tapping | 10 min | 10 min | 10 min | 10 min | 15 min | 20 min |
| Slagging | 5 min | 5 min | 5 min | 10 min | 10 min | 15 min |
| Total cycle time | 100 min | 115 min | 132 min | 160 min | 180 min | 210 min |
| Cast iron production | 1,8 t/hour | 2,61 t/hour | 3,64 t/hour | 5,62 t/hour | 6,67 t/hour | 8,57 t/hour |
[1] Opening and closure of the pouring hole, opening and closure of the furnace loading hole etc...
[2] Cast iron at 1450 °C, second daily melting
Casting consumption rates with oxygen nozzle
| Furnace | Melting Time (min) | Gas Oil (kg/t) | Methane (Nm3/t) | Propane (Nm3/t) | Oxygen (Nm3/t) | Temperature (°C) |
|---|---|---|---|---|---|---|
| 3 ton | 60 | 34-39 | 39-44 | 15-17 | 130-150 | 1450 |
| 5 ton | 75 | 34-39 | 39-44 | 15-17 | 130-150 | 1450 |
| 8 ton | 90 | 34-39 | 39-44 | 15-17 | 130-150 | 1450 |
| 15 ton | 110 | 32-37 | 37-42 | 14-16 | 125-140 | 1450 |
| 20 ton | 120 | 32-37 | 37-42 | 14-16 | 125-140 | 1450 |
| 30 ton | 135 | 32-37 | 37-42 | 14-16 | 125-140 | 1450 |
PCI methane : 10 kWh/Nm3; PCI propane : 25.4 kWh/Nm3; PCI gas oil : 11.6 kWh/kg, with ρ = 0.89-0.93 kg/l at 15°C.
