GB877510A - Improvements in method for preparing alkali metal hydrides - Google Patents

Abstract

<PICT:0877510/III/1> An alkali metal hydride is prepared by passing a liquor containing molten alkali metal, an inert liquid, and alkali metal hydride at a controlled rate upwardly in each of a plurality of series-connected vertical reactors, introducing H2 at the first reactor to maintain an atmosphere of H2 in each reactor under pressure, maintaining the liquor in each reactor at a temperature at which H2 reacts with the alkali metal, agitating the liquor in each reactor to form a dispersion of the metal and hydride in the inert liquid, introducing molten alkali metal and inert liquid into the first reactor in amounts to provide a liquor containing 10-40% alkali metal, and recovering alkali metal hydride dispersed in the inert liquid at the controlled rate from the last reactor. Each reactor is provided with at least one agitator and (1) the ratio of the internal diameter of the reactor to the outside agitator diameter is greater than 1 but less than 20, (2) the ratio of the volume occupied by liquid during the operation in each reactor in gallons to the cube of the outside agitator diameter in inches times the number of agitators is greater than 0 but not greater than 1.5, and (3) the agitator peripheral speed in feet/min. times the number of agitators is greater than 500 and less than 20,000. Molten Na is fed from melting tank 15 by inert gas pressure through filters 17, 19, weighing device 18 and pump 16 into the lower portion of reactor 10 at a controlled rate. Controlled amounts of inert high-boiling liquid, e.g. mineral hydrocarbon oil, are fed from tank 28 pump 30 meter 31 and mixing valve 32 to reactor 10. Tank 34 and heater 35 are provided for hot oil, which may also be fed to mixing valve 32 in response to temperature regulator 36. Reactor 10 is thus provided with a dispersion of Na, and the reactor has a hot oil jacket, motor driven agitator 12 working at 2,300 r.p.m. and baffles, while the temperature in 10 is 270 DEG C. rising to 350 DEG C. H2 from 21 passes through pressure regulators 23, 24 and meters 25, 26 into the lower portion of reactor 10 to establish a pressure 25-250 p.s.i.g. After the major portion of the Na has reacted, the resulting solution, including H2 to establish a constant pressure atmosphere thereabove, passes through 38 to the lower portion of reactor 11. Reactor 11 has agitator 12 and is jacketted with cooling oil. Product oil dispersion of NaH is withdrawn to tanks 41, 44, and may be withdrawn at 50. Agitators 43, 47 maintain solids in dispersion. KH and LiH may be produced in the same manner.