| 摘要 |
Finished grade pigments are prepared from crude pigment precursors by conversion to aggregated low crystallinity pigment followed by milling the aggregated low crystallinity pigment in water having a pH of from 7 to 14 and from 5 to 25% based on pigment of a separate phase comprising an organic liquid which is effective in growing and improving the crystallinity of the pigment particles. The resulting material is extracted in dilute acid, washed free of acid and dried to produce the final finished grade pigment.
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