Furnaces for silicon: Medium-frequency coreless induction furnaces
There is no doubt that global energy supply will be dominated by the increasing use of regenerative energy sources. In this connection, the demand for high-power solar cells is expected to increase considerably. Since solar cells are mainly made up of high-purity polycristalline silicon, the demand for this material will increase accordingly.
A wide range of processes is used for producing solar silicon. The most important processes are the refining of metallurgic silicon and the production of pure silicon by carbothermal reduction using high-purity raw material.
Most of the processes currently considered relevant are characterized by the fact that in certain process stages the use of coreless induction furnaces is required for process technology reasons.
OTTO JUNKER have developed a suitable, innovative melting furnace technology for producing high-purity silicon. Special requirements result from the required purity of the silicon, the electrical characteristics of the material, the very high energy consumption required for melting (four times as high as for cast iron or aluminium) and from the necessity to incorporate the furnace into overall plants which can be very complex. In particular, the fact that the semi-conductor silicon is non-conductive in solid state but provides a good electric conductivity when liquid requires very specific detail solutions. The inductive melting technology is ideally suited for this application due to its flexibility and its process technological advantages.
Technical and economical features
- „ Ideally suited for high-purity silicon due to the direct heating principle (induction)
- „ Furnace designs: Gas-tight and vacuum induction technology
- „ Close power application control by means of IGBT converter technology
- „ Furnaces equipped with special tilting geometry, lifting and moving devices