Abstract: A rotary kiln assembly comprising an inlet arrangement, a rotary kiln and an outlet arrangement. A seal arrangement is provided between the inlet arrangement and the rotary kiln and a seal arrangement is provided between the rotary kiln and the outlet arrangement. It is a problem with rotary kiln assemblies to remove the seals without relative movement of the rotary kiln or the inlet or outlet arrangements. At least one of the seal arrangements is made retractable in telescopic manner and the kiln assembly includes detachable spacing means such that the retractable seal arrangement can be removed from the kiln assembly as a unit without fouling or movement of the kiln or the inlet or outlet arrangements and hence without disturbing their alignment. The spacer means may be detachable only after retraction of the sealing arrangement and may be integral with a part of the sealing arrangement.

Abstract: A problem that can occur with a large rotary kiln assembly is that it can move out of position or seals can become defective, making an escape of materials possible. The present invention provides transducers (10, 15) for detecting movement of the rotary kiln itself or part of a seal assembly secured thereto relative to an inlet/outlet arrangement of the kiln assembly or a part of a seal arrangement secured thereto and also means whereby the condition of the seals can be monitored by following changes in the pressure or flow rate of a purge gas. If the rotary kiln (2) should move out of alignment, then corrective action can be taken. If the seals should leak, then they are changed. A record of kiln movement is provided and if movement is excessive, an alarm (20) is sounded.

Abstract: A boiler for vaporizing liquid hydrogen fluoride has a heat transfer surface arranged to be covered increasingly by the liquid as the liquid level rises so that the heat supplied to the boiler can be adjusted to maintain a constant level of liquid in the boiler and thereby equate the feed rate of liquid hydrogen fluoride to that vaporized. Thus by metering and controlling the feed rate of the liquid the feed rate of the vapor can be metered and controlled.

Abstract: In a process for the conversion of uranium hexafluoride to an uranium oxide by injecting uranium hexafluoride and dry steam into a first region of a vessel so as to form a plume of particles of uranyl fluoride and reacting the uranyl fluoride in a second region of the vessel with a countercurrent flow of steam and/or hydrogen the operation of the process is such that a major proportion of the uranyl fluoride is caused to circulate within the first region so that the original uranyl fluoride particles are able to grow and agglomerate in a dendritic manner.

Abstract: A boiler for vaporizing liquid hydrogen fluoride has a heat transfer surface arranged to be covered increasingly by the liquid as the liquid level rises so that the heat supplied to the boiler can be adjusted to maintain a constant level of liquid in the boiler and thereby equate the feed rate of liquid hydrogen fluoride to that vaporized. Thus by metering and controlling the feed rate of the liquid the feed rate of the vapor can be metered and controlled.