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. 25, 1979
Filed:
Jan. 03, 1978
Applicant:
Inventors:
Assignee:
Nippon Electric Co., Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C02B / ; C02C / ;
U.S. Cl.
CPC ...
210 49 ; 75109 ; 210 52 ; 210 56 ; 210D / ; 423142 ; 423594 ;
Abstract
A method is provided for treating waste water containing solids of difficultly-soluble compounds of at least one heavy metal, the method comprising the steps of adding an amount of ferrous ions to said waste water corresponding on a molar basis to about 2 to 100 times the total molar amount of heavy metal present in said waste water, adding an alkaline substance to said waste water in an amount corresponding to about 0.9 to 1.2 equivalent of free acid present in said waste water, and stirring the waste water without aeration at a temperature of at least about 40.degree. C., whereby insoluble ferrite crystals are precipitated having said heavy metal incorporated therein.