摘要 |
Process for manufacturing alumina trihydrate by alkaline attack of bauxite, following the general steps of the Bayer process, and during which, after settling and before decomposition, the aluminate liquor undergoes a filtration, known as security filtration, so that at the end of the filtration it contains less than 10 mg/l of insoluble particles, characterized in that, during said security filtration, a filtration device is used that comprises a zone in which the liquor is subjected, after passing through said filtration media, to a pressure greater than 2 bar, preferably greater than 3 bar. Preferably, this device also comprises a zone in which the liquor is subjected, before passing through the filtration media, to a pressure greater than 5 bar, preferably greater than 6, typically in the vicinity of 7 bar. In this way, the aluminate liquor can be kept at a high temperature during the security filtration, typically greater than 130°C, preferably greater than 140°C, and be brought to a high degree of supersaturation Rp, typically greater than 1.25, without risk of reversion. |
申请人 |
ALCAN INTERNATIONAL LIMITED;FORTIN, LUC;FORTE, GUY;THOMAS, HENRI;BASSAM, EL KADI |
发明人 |
FORTIN, LUC;FORTE, GUY;THOMAS, HENRI;BASSAM, EL KADI |