| 摘要 |
A high specific surface hydrargillite, well adopted as filler material or primer particulates in the production of finely divided aluminum trihydroxide by decomposition of Bayer process aluminate liquors, is readily prepared by (i) reacting an alkali metal aluminate with hydrofluoric acid at a temperature ranging from about 5 DEG to 95 DEG C., the amount of said hydrofluoric acid ranging from about 25% to 90% of that amount stoichiometrically required for complete neutralization of the alkalinity of said aluminate, (ii) optionally treating the hydrargillite precipitate which results at a temperature of from about 5 DEG to 95 DEG C. for from about one-half to 10 hours, and thence (iii) recovering said hydrargillite precipitate, preferably by filtering, washing and drying.
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