| 摘要 |
A solid granular propping agent is disclosed having a Krumbein number of greater than 0.8, and containing granules between 0.2 and 1.7 mm in diameter, said granules being made from an unblended clay containing from 16 to 19% of silica, less than 0.35% alkali and alkaline earth metal oxides, and being fired at a time and temperature whereby the product contains a major mullite phase and a minor alpha alumina phase.
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