| 摘要 |
A process for beneficiating a poor grade crude kaloinitic clay mineral to produce a clay filler for use in papermaking to improve the brightness of the paper product. The crude kaolin clay is blunged with water containing a dispersing agent to form a high solids fluid aqueous clay suspension. This clay suspension is then screened and fractionated to reduce the particle size thereof to 92-95% finer than 2 microns. The fractionated clay suspension is treated with an alkaline leaching solution containing a reducing agent effective in converting ferric ions to ferrous ions and, preferably, a water-soluble anionic phosphate. The leached clay suspension, which has a solids content of at least 55%, is then treated with an oxidizing agent to oxidize unreacted leaching agent and byproducts formed during the leaching process. |
