| 摘要 |
<p>A xanthan concentrate obtained by the removal of a precipitant in a vapor saturated atmosphere from a pre-concentrate obtained by precipitation of an aqueous xanthan fermentate with a water miscible solvent as precipitant does not produce aggregates by dilution with water or sea water. This, or the pre-concentrate - optionally supplemented with biocide - is thus useful subsequent to dilution as viscosifier for enhanced oil recovery in oil wells. The preparation of the xanthan concentrate is disclosed.</p> |
