Heating Methods for Aluminum Hydride Production

Abstract

Disclosed herein are systems and methods for heating alane etherate compositions for producing microcrystalline alpha alane. An exemplary heating method comprises introducing a preheated solvent into the alane etherate composition and rapidly stirring to effectuate rapid heating of the composition without the need to heat the reactor walls. In this way, the alane etherate composition can be heated while also reducing the risk of decomposition. In further embodiments, a two-stage reactor can be employed for producing alpha alane, wherein the heating occurs in the second stage.

What is claimed is: 
     
         1 . A process for heating alane etherate slurry for conversion to alpha alane, the process comprising:
 providing an alane etherate slurry in a reactor at approximately room temperature;   introducing a heated solvent into the alane etherate slurry in the reactor; and   stirring contents of the reactor until the reactor contents are at a substantially uniform temperature above room temperature, to facilitate conversion of the reactor contents to alpha alane.   
     
     
         2 . The process of  claim 1 , wherein the stirring of the reactor contents occurs rapidly and facilitates heating of the reactor contents in an outward direction until the reactor contents are at the substantially uniform temperature above room temperature. 
     
     
         3 . The process of  claim 1 , wherein the introducing the heated solvent into the alane etherate slurry in the reactor occurs by introducing the heated solvent into a bulk of the reactor contents. 
     
     
         4 . The process of  claim 1 , wherein the introducing the heated solvent into the alane etherate slurry in the reactor further comprises introducing vapor bubbles of the heated solvent into the alane etherate slurry such that condensation from the heated solvent provides additional heating of the reactor contents. 
     
     
         5 . The process of  claim 1 , wherein the alane etherate slurry comprises alane etherate, lithium aluminum hydride, lithium borohydride, ether and toluene. 
     
     
         6 . The process of  claim 1 , wherein the heated solvent is in gaseous form. 
     
     
         7 . The process of  claim 1 , wherein the heated solvent is in liquid form. 
     
     
         8 . The process of  claim 1 , wherein the heated solvent is an aromatic solvent. 
     
     
         9 . The process of  claim 1 , wherein the heated solvent is a toluene solution. 
     
     
         10 . The process of  claim 1 , wherein the heated solvent is introduced at a temperature of approximately 85° C. 
     
     
         11 . The process of  claim 1 , wherein the heated solvent comprises toluene vapor and an inert gas. 
     
     
         12 . The process of  claim 1 , wherein the heated solvent comprises toluene and ether. 
     
     
         13 . The process of  claim 1 , wherein the reactor contents are heated at a rate of approximately 10 minutes per liter of reactor contents to rapidly raise the reactor contents from approximately room temperature to approximately 68-82° C. 
     
     
         14 . The process of  claim 1 , wherein the uniform temperature of the reactor contents is within a range of 65-82° C. 
     
     
         15 . The process of  claim 1 , further comprising removing the heated solvent from the reactor contents via filtration. 
     
     
         16 . The process of  claim 1 , wherein the alpha alane is microcrystalline alpha alane. 
     
     
         17 . The process of  claim 1 , further comprising rinsing resulting solid materials with an ether to dissolve excess lithium aluminum hydride and lithium borohydride. 
     
     
         18 . The process of  claim 1 , further comprising stabilizing the alpha alane with a stabilization solvent to prevent decomposition of the alpha alane. 
     
     
         19 . The process of  claim 14 , wherein the stabilization solvent comprises diethyl ether or toluene. 
     
     
         20 . The process of  claim 1 , further comprising passivating surfaces of microcrystals of the alpha alane by creating an aluminum oxide coating on the surface of the microcrystals of the alpha alane.