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:
Oct. 12, 1976
Filed:
Jun. 26, 1975
Applicant:
Inventors:
Helmut Reinhardt, Rodenkirchen, DT;
Karl Trebinger, Wesseling, DT;
Gottfried Kallrath, Wesseling, DT;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09C / ;
U.S. Cl.
CPC ...
106304 ; 423367 ;
Abstract
Berlin blue is produced by converting (a) calcium ferrocyanide, sodium ferrocyanide or magnesium ferrocyanide with (b) an iron II salt at a pH below 7 to an acidic iron II salt of ferrocyanic acid FeH.sub.2 [Fe(CN).sub.6 ]. The calcium or sodium ions can be washed out of the precipitate of the ferrocyanic salt. The precipitate is treated with (c) an inorganic or organic potassium salt to form Berlin white and then oxidized to Berlin blue. Alternatively, (a), (b) and (c) can be reacted together at a temperature of 20.degree. to 60.degree.C. to form Berlin white directly.