Characterization of Lithium-Aluminate Powders in J.O. 909 and J.O. 911

摘要

It is concluded from the combined data that all powders of low bulk density were made from unusual aluminum oxide powder, with smaller particle size and somewhat different impurity content. Microstructure of the low bulk density powders reveal agglomerates having a spongy appearance. High bulk density powders have solid particles. Fisher Subsieve analysis confirms the open porosity of the low bulk density powder agglomerates. Low bulk density powders are essentially pure gamma -LiAlO sub 2 with about 10 percent free alumina. High bulk density powders had a variable alpha -LiAlO sub 2 content and somewhat lower free alumina contents. There was a rough correlation between raw powder bulk density and alpha -LiAlO sub 2 content. Total carbon content ran from 173 to 1363 ppM lower than the 3000 ppM level of the PT-66 powders. Batch weights varied between 330 and 562 pounds, with no visible correlation to powder characteristics. Total Li content was generally held to within 0.3 percent of 10.0. An overall average vendor performance was 9.99 percent Li (21 powder batches, analyses from vendor and Battelle averaged). Vendors loss on ignition figure was low, less than 0.3 percent in all cases but three. This probably represents a little better job of calcining and/or prompt analysis of the powder before moisture pickup becomes appreciable. Vendor sieve analyses reported 6 to 21 percent larger than 100 mesh (149) micron opening). Microscopic examination confirmed that the apparent particle size distribution does not vary perceptibly from batch to batch. No deliquescent particles were found. These variations make it very difficult to predict the processing behavior of powders in different batches, especially with the low bulk density powders. Recommendations are given for remedying this. (ERA citation 02:027141)