Apparatus for carrying out chlorinating reactions

#The present invention relates to a device for carrying out chlorinating reactions in connection with the extraction of metals such as titanium, zirconium or the like when extracting uranium and thorium during the reprocessing of burned-off fuel and/or breeder elements for core reactors as well as when purifying coal and graphite. Such apparatus consists of a graphite shaft or blast furnace which is heated by a direct flow of current and while being coaxially surrounded by a mantle communicates through a connection or adapter piece with a subsequent condenser of graphite.

#A chlorinating reactor is known the main component of which is formed by a heated graphite tube. With this known reactor, this graphite tube is surrounded by a ceramic pipe forming the shell therefor and has a connecting or adapter piece through which the graphite tube forming the reaction vessel proper is rigidly and in a gas-tight manner connected to a condenser for the substances which volatize during the chlorinating process. If, as it is customary in practice, quartz material is employed as ceramic material for the shell, for which quartz material there is used for instance a material known under the trademark Rotosil, the necessary gas seal is obtained for the processing of highly radioactive substances. It is also advantageous that the expansion in length of the quartz material as it is caused by the changes in temperature is only minor and that at a temperature above 1000.degree. C., the plasticity of the quartz material is such that in the connecting piece between the furnace and the condenser no tension stresses will occur due to the heating up and cooling off. However, it has proved disadvantageous that the wall thickness of the adapter piece employed as connecting piece must be only relatively thin in order when being melted onto the condenser that a clean melting area will be obtained as it is required for the gas-tight connection. In view of the various mechanical stresses, the possibility of a break or crack cannot be fully excluded. A repair is, however, particularly difficult when radioactive substances are subjected to the intended reaction and thereby the device itself becomes highly radioactive.

#A further drawback of the heretofore known chlorinating devices consists in that due to the employment of a ceramic pipe the upper limit of the shell diameter must be approximately 40 centimeters. This limits the throughput. This is not of material importance for the working of fuel elements because the reaction vessel must for reason of criticality not have a greater diameter. If, however, the device is also to be used for other chlorinating reactions, for instance for making reactor graphites by chlorinating or for extracting non-fissionable volatile chlorides such as titanium chloride, zirconium chloride or the like from the corresponding ores or from deep sea sediments, devices for chlorinating of larger dimensions are necessary. This also holds true for the purification of pulverized graphite by removing impurities as volatile gaseous chlorides.

#These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing diagrammatically illustrating partially in longitudinal section an embodiment of the device according to the invention.

#The device according to the invention is characterized primarily in that the shell of the shaft or blast furnace and the adapter piece connecting the said furnace and the condenser are made of graphite while the shell of the furnace, the condenser, and the adapter piece which connects the shell to the condensers are arranged within a gas-tight steel casing or shell. Experience has proved that in this way a high temperature resistance or stability is realized and that if the shell is made of graphite rings or graphite bricks, at the same time a high life span can be realized. The temperature resistance may furthermore be increased by having the steel casing surrounding the shell of the furnace in spaced relationship so that an annular intermediate space or chamber is formed in which graphite wool is contained.

#It has proved expedient to design the adapter piece as a cantilever-shaped support at the free end of which the condenser is arranged. In this way, it will be realized that no stresses can occur between the structural elements which might otherwise result in disorders. However, if desired, the condenser could also be supported by spring elements arranged below a collecting container at the lower end of the condensers. An advantageous further development of the device according to the present invention is characterized in that bores with corrosion-resistant heating elements therein are provided in the adapter piece. In this way, also the adapter piece can be heated to the temperature prevailing in the reaction zone of the furnace. Thus, a desublimation of the chlorides in the adapter piece will be avoided. It is expedient to make the heating elements of graphite.

#Referring to the drawings, the apparatus consists of a shaft furnace 1 for carrying out of chlorine reactions and a condenser post-connected as to the shaft furnace; the condenser serves for separation of reaction products withdrawn from the shaft furnace 1 during simultaneous cleaning of the reaction gases. The shaft furnace 1 consists of a shaft of graphite arranged vertically in which the material to be chlorinated becomes supplied or introduced out of the storage container 14 by way of a worm 15. For supply of chlorine gas, the shaft furnace 1 is provided with a supply conduit in the upper area and a central tube 19 with a gas connection 20 projecting into the middle range or area of the shaft furnace. The central pipe or tube 19 consists in the upper part 21 thereof, of gas-tight graphite and provides a pipe part 22 in the middle range of the shaft furnace consisting of porous graphite so that at this location the central pipe distributes the chlorine gas uniformly entering into the reaction chamber of the shaft furnace 1. The shaft furnace 1 consists of porous graphite. The support construction 23 of the shaft furnace is connected with an electrical voltage source 24 so that the same may be heated as a resistance heater. The hottest zone 2 in the shaft furnace becomes formed where the shaft furnace provides a reduced wall thickness as is the case in the middle range of the shaft furnace in the sample embodiment. In the range of the hot zone 2 of the shaft furnace 1, the working temperature amounts to approximately 1700.degree. C.