| 摘要 |
The invention relates to a process for preparing aluminium oxide by hydrochloric acid digestion of clays or alumina-containing minerals. The aim of the invention is an environmentally friendly process for preparing alumina with low losses of Al2O3. It is an object of the invention to provide a process in which an alumina suitable for use in melt electrolysis (dry electrolysis) is prepared with utilisation of the initial K2O content of the raw clay, and the remaining alkali metal and alkaline earth metal chlorides are converted into a solid product. According to the invention, this object is achieved by cooling the barren liquor from the crystallisation stage, with the addition of < 10% of water or vapour condensate, to a temperature </= 30@C, working up the crystallisate thus formed in a known manner to give KCl- or K2SO4-containing fertilisers, feeding the main amount of the mother liquor to the crystallisation stage, evaporating a sub-stream amount of the mother liquor to about 23-30 % by mass of CaCl2, converting the AlCl3.6H2O crystallisate thus formed, by addition of water or vapour condensate, into a mother liquor which is a precursor to the crystallisation stage, converting the CaCl2-rich residual solution, in a known manner with addition of sulphuric acid, into gypsum sludge.
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| 申请人 |
VEB MANSFELD-KOMBINAT WILHELM PIECK |
发明人 |
ZIEGENBALG,SIEGFRIED,PROF.DIPL.-CHEM.DR.;FISCHER,GERHARD,DIPL.-ING.DR.;STOELZEL,WOLFGANG,DIPL.-ING.;HAUPT,FRANK,DIPL.-ING.DR.;HOCHSTEIN,REINHARD,DIPL.-CHEM.;ERDMANN,HILMAR,DIPL.-CHEM.;RUESTER,MANFRED,DIPL.-ING.;GEILER,GUNTER,DIPL.-CHEM.;SCHOENHERR,JOACHIM,DIPL.-ING. |
