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Figure 9:
Overview of zones in Si furnaces: a) Wacker furnace no.1, b) Elkem Thamshavn, c)
Wacker furnace no.4
An overview of the zones found in Si furnaces is shown in figure 9. On the top of the
furnaces raw materials were loosely packed. Due to its loose structure this layer is
always removed firs as dig out progresses That can lead to misinterpretation about
findings for example of unreacted quartz particles in the bottom part of the furnace.
Below the loose charge layer, reacted charge, held together with smelted
quartz/condensates was observed. In Elkem Thanshavn and Wacker furnace 1, the
reacted charge looks relatively similar, which can be seen in figure 10. However in
furnace no. 4 in Wacker this area of furnace consist mostly of particle of SiC mixed
with melted quartz and white slag. Samples collected from this area are presented in
figure 11. This layer was soft and easy to dig out of the furnace. Loose SiC with
quartz and slag was tightly surrounding all three electrodes without any empty space
between electrodes and charge.
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