A smelting vessel includes a plurality of heat pipes (21) positioned in a refractory lining of at least a part of the hearth (9) for cooling at least a part of the refractory lining. At least one of the heat pipes includes (a) a liquid phase of a heat transfer fluid, typically water, in a lower section of the heat pipe and (b) a vapor phase of the heat transfer fluid, typically steam, in an upper section of the heat pipe. The heat pipe also includes a vent to allow vapour phase to escape from the heat pipe to reduce the pressure or the temperature within the heat pipe when the vapour pressure or the temperature in the heat pipe exceeds a predetermined threshold pressure or temperature.

One embodiment provides an article, comprising: an inner container having a cavity, the inner container comprising a ceramic; and an outer container, the outer container comprising a susceptor; wherein at least a portion of an outer surface of the inner container is in contact with an inner surface of the outer container, and wherein the inner container is removable from the mold. Methods of melting using the present article are also provided.

A hold down mechanism for releasably securing a refractory lining to a furnace. The hold down mechanism can comprise plate segments that form a composite plate. The plate segments can comprise a first plate segment structured to articulate relative to a second plate segment. Furthermore, a gap in the hold down mechanism can be structured to adjust in response to a thermal condition of the composite plate, such as thermal expansion or thermal contraction of at least one plate segment. The composite plate can also comprise an articulation plate pivotally coupled to at least one of the first plate segment and the second plate segment via a pivot and/or a slot and pin engagement. The composite plate can further comprise a third plate segment and a second articulation plate pivotally coupled to at least one of the second plate segment and the third plate segment.

A crucible used for forming ceramic particles from metal oxide gel particles includes a tubular graphite housing having an open end, an inner surface, and a seat in the inner surface near the open end. A sleeve lines the inner surface of the tubular housing. The sleeve has at an open end and is formed from a metal which is chemically inert to the metal oxide gel particles. A graphite outer cap removably covers the open end of the tubular housing. An inner cap formed from the chemically inert metal fits into the seat in the inner surface of the tubular housing, and is pressed into the seat against the open end of the sleeve by the outer cap. The crucible may be used for forming ceramic particles from uranium oxide gel particles, and the sleeve and the inner cap may be formed from molybdenum, tungsten, or an alloy thereof.

An apparatus for containment of a molten substance using non-wetting materials comprising a crucible, and a layer of a non-wetting material deposited onto the crucible, wherein said layer of non-wetting material is deposited near the rim of the crucible and wherein the non-wetting material is deposited onto the crucible by one selected from the group consisting of RF magnetron sputtering, chemical vapor deposition, thermal spray, thermal evaporation, dip coating of precursors followed by thermal treatment, and spray coating of precursors followed by thermal treatment.

The melting induction furnace comprises, together with a casing (7) to which a lower sole plate (11) is added to form the central part of the structure, a removable inner crucible (1) composed of an internal layer (4) resisting heat and aggressiveness of the molten bath (20), an external layer (6) delimiting the crucible and an insulating intermediate layer (5). The crucible (1) is a disposable crucible and can be stored with its charge in an appropriate container. Heat losses are low, even when the casing (7) is cooled. Stresses due to differential thermal expansions are also very much reduced.

The invention relates to a shaped body comprising a substrate with a firmly adhering separating layer, wherein the separating layer comprises 92-98 wt. % silicon nitride (Si.sub.3N.sub.4) and 2-8 wt. % silicon dioxide (SiO.sub.2) and wherein the separating layer has a total oxygen content of 8 wt. % and a hardness of at least 10 HB 2.5/3 according to DIN EN ISO 6506-1.

An ingot mold for curing fused and melted material is provided. The ingot mold includes a steel box, a foamed carbon layer, and a graphite block layer. The foamed carbon layer is formed inside the steel box. The graphite block layer is formed inside the steel box.