At a research centre devoted to non-ferrous metals, steels and special alloys involving the activities of pyrometallurgy (for the purpose of developing or improving metal production processes), 3 explosions occurred around 1 pm in conjunction with the spraying of molten metal at the time of casting molten metal into pockets during a ferromanganese pilot effort. Minor deflagrations arose on the first of the 3 pockets during the successive filling, following perforation of the casting hole with an oxygen nozzle. The responsible pocket was then punctured and its contents (metal and slag) spilled into the dedicated retention pit, causing the onset of fire on the furnace’s grounding cables and instrumentation wires present inside the pit. The electricity, gas and compressed air supply lines were all turned off, the smoke outlets were open and the casting hole was plugged once again in order to limit flow. Centre personnel had the fire under control using powder and CO2 extinguishers as well as sand before the arrival of public emergency response teams; the furnace was drained in the presence of fire-fighters. No injuries were reported and no environmental impacts detected. Property damage-related costs were estimated at €20,000. According to the operator, a contact between water (wet refractory material) and molten metal alongside the production of hydrogen was the cause of this accident; the first pocket had been dried for 48 hours, while the second for just 8 hours. Organisational and human errors were observed, especially the lack of procedures for refractory materials and the limited experience possessed by technicians.

Before conducting the next test campaign scheduled in June 2010, the operator planned to implement several remedial measures: a revamped refractory drying system and drafting of use procedures for this system; awareness building among technicians regarding the importance of transfer pockets (drying, refractory quality); and elimination or protection of cables located in the furnace retention pit.