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:
Sep. 05, 2000
Filed:
Mar. 13, 1998
Dieter Schlafer, Ludwigshafen, DE;
Michael Mauss, Neustadt, DE;
Matthias Rauls, Limburgerhof, DE;
Dieter Baumann, Frankenthal, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
In a process for preparing crystalline NaOH.3.5H.sub.2 O, NaOH.3.5H.sub.2 O is allowed to crystallize from an aqueous sodium hydroxide solution which contains sodium chloride and is saturated in respect of NaOH.3.5H.sub.2 O and the crystals formed are separated from the solution using a mechanical solid/liquid separation apparatus, wherein the solid/liquid separation is carried out under conditions under which the crystalline NaOH.3.5H.sub.2 O is freed sufficiently of residual solution adhering to the surface for the sodium chloride content of the crystalline NaOH.3.5H.sub.2 O obtained to be less than 100 mg per kg. The crystalline NaOH.3.5H.sub.2 O is subjected to an additional purification step, which may include the at least superficial melting or the at least superficial dissolution of the crystals, in combination with a solid/liquid separation step. The additional purification step. The additional purification step comprises washing the crystalline NaOH.3.5H.sub.2 O separated off.