| 摘要 |
Precipitated silica with the following physical-chemical characteristics: - BET surface: DIN 66131 100-130 m2/g - DBP absorption DIN 53601 >/=275 g/100 g - (anhydrous) ASTM D 2414 - Loss on drying DIN ISO 787/II - (2 h/105 DEG C.) ASTM D 280 3.5-5.5 wt. % - JIS K 5101/21 - Oversize with - ALPINE air-jet sieve: - >63 mu m </=10.0 wt. % - >150 mu m </=0.1 wt. % - >250 mu m </=0.01 wt. % - Chloride content: </=100 ppm - is prepared by introducing water into a precipitation vessel, adding water glass until an alkali value of 5-15 is reached, then adding further water glass and sulfuric acid simultaneously, interrupting the precipitated silica suspension with sulfuric acid to a pH-value of 8.5, with stirring, then continuing acidification with concentrated sulfuric acid to a pH-value of 4, then separating and washing the precipitated silica which has a solids content in the suspension of approx. 88 g/l, liquefying the filter cake obtained, drying it with a spray drier and grinding it. The precipitated silica may be used for the production of battery separators.
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