To improve reactor throughput and raw material utilization, the direct synthesis process for producing sodium aluminum tetrahydride is conducted in a semi-continuous manner whereby in at least one run (and preferably in each of a plurality of successive runs) the reaction is conducted (and preferably the respective reactions are conducted) to a stage at or before which the reaction rate would begin to significantly decrease due to consumption of the sodium. At that stage at least a portion of the liquid reaction solution is separated from the unreacted aluminum and sodium to leave a highly active sodium- and aluminum-containing heel for use In initiating the ensuing run. Preferablythe aluminum used in at least some of the runs contains a reaction-promoting amount of another metal such as titanium. Use of an ether reaction medium (which need not be pre-treated to remove small amounts of alcohols and/or water) is also preferred. Sodium aluminum tetrahydride is a well-known chemical reducing agent.
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