| 摘要 |
<p>The invention relates to a method for producing precipitated silicas, comprising: (i) forming a starter having an alkali metal silicate M concentration of less than 20 g/L; (ii) adding acid thereto until at least 50% of the quantity of M2O is neutralised; (iii) adding silicate and acid simultaneously, such that the consolidation rate is greater than 4 and at most 100; (iv) adding acid until the pH measures between 2.5 and 5.5. According to the invention, the acid used in at least one of the steps is a concentrated acid, preferably selected from the group containing sulphuric acid having a concentration of at least 80 wt.-%, in particular at least 90 wt.-%, acetic acid or formic acid having a concentration of at least 90 wt.-%, nitric acid having a concentration of at least 60 wt.-%, phosphoric acid having a concentration of at least 75 wt.-%, hydrochloric acid having a concentration of at least 30 wt.-%.</p> |
