Rapid determination of hydrogen in lithium oxide by carbon monoxide carrier gas method

Abstract

The chemical form of hydrogen in lithium oxide is mainly lithium hydroxide, which is formed from the oxide and atmospheric moisture during its storage. The reaction of the hydroxide with carbon monoxide afford hydrogen gas and carbonate, so that hydrogen content in lithium oxide can be easily determined by the following method : lithium oxide sample (100 to 500 mg) is placed on a reaction tube (test-tube type, 15 mm i.d. × 200 mm, glassware). Then, carbon monoxide gas is passed through the tube at 80 ml/min and the tube is heated at 390 °C for 15 min. The hydrogen evolved from the sample is determined by using thermal conductivity detector. The evolution profile of hydrogen gas with the reaction of lithium hydroxide and carbon monoxide was influenced by physical property (density of powder) of sample rather than its hydrogen content. Carbonate in sample did not interfere with the determination of hydrogen. The lower limit of determination was 0.002 % for 500 mg of sample. The required time for analysis was about 20 min after the sample was weighed under a dried atmosphere in gloved box. The standard deviations for the determination of 0.028 %, 0.18%, and 0.70 % of hydrogen were 0.004 %, 0.01 %, and 0.05 %, respectively.