| 摘要 |
<p>Aq. solns. of the reactants are simultaneously and continuously added in equiv. quantities or with a slight, defined excess of one component, with intensive stirring, so as to maintain either no excess or a msall defined excess of either component in the ppt. suspn. The rate of addn. of at least one ingredient is controlled pref. in accordance wiht the pH of the suspn., pptn. taking place pref. at pH 6-8, esp. 7. Pigments and extenders eith suitable particle size and size distribution for direct use, without subsequent processes to increase particle size, are obtd.</p> |
