The rapid Si-furnace excavation - an unique chance to investigate the interior of the furnace

The paper presents procedures, observations and data obtained during so-called rapid excavation of a 33 MW Si-furnace performed within 4 days. Excavation started one day after the furnace was stopped. The nature of the zones and the characterization of samples taken from different areas in the furnace are described, despite the challenging "dig out" conditions caused by the extremely hot interior of the furnace. Accumulation of a 1.5m thick slag layer around the wall of the furnace seems to be a significant zone in the furnace. Thus, it limits the space for the "active zone", for example hindering the flow of the charge material but also can cause the problems with the tapping of the furnace. Below the loose charge, the material that consists mostly of particles of SiC mixed with melted quartz and white slag, was located. The described method including equipment, sampling and observation technique, for rapid excavation can successfully be used.