The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 23, 1980
Filed:
May. 08, 1979
Joseph Cohen, Aix-en-Provence, FR;
Alain Adjemian, Aix-en-Provence, FR;
Michel Ferran, Aix-en-Provence, FR;
Aluminum Pechiney, Lyons, FR;
Abstract
A process for obtaining pure alumina comprising the combination of chlorosulphuric attack of calcined aluminous ores containing impurities, followed by concentration of the liquor obtained after the attack and separation of the sterile material, sulphuric acid treatment of the concentrated liquor followed by chlorination to precipitate almost all the hexahydrated aluminum chloride, separation of the precipitate of hexahydrated aluminum chloride and of the chlorosulphuric mother liquor charged with impurities, pyrohydrolysis of the precipitate to give the desired pure alumina with recycling of released hydrochloric acid, degassing of the chlorosulphuric liquor of impurities with recycling of the gaseous HCl for chlorination, yielding a sulphuric liquor of impurities, finally the elimination of the impurities present in this latter liquor in the form of a sulphuric precipitation by concentration in the presence of potassium ions.