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:
May. 03, 2016
Filed:
Dec. 14, 2012
Sumitomo Metal Mining Co., Ltd., Tokyo, JP;
Yoshitomo Ozaki, Ehime, JP;
Jun-ichi Takahashi, Ehime, JP;
Yu Yamashita, Ehime, JP;
Hideki Ohara, Ehime, JP;
SUMITOMO METAL MINING CO., LTD., Tokyo, JP;
Abstract
It is an object to provide a method for producing magnesium oxide by which magnesium oxide being high in purity and low in impurity content can be produced simply and efficiently from a sulfuric acid solution containing magnesium and calcium such as waste water. In the present invention, calcium is precipitated as calcium sulfate and separated by concentrating a sulfuric acid solution containing magnesium and calcium, and magnesium is precipitated as magnesium sulfate and separated by further concentrating the solution resulting from the separation of calcium. The separated magnesium sulfate is roasted together with a reductant, so that magnesium oxide and sulfur dioxide are obtained. The resulting magnesium oxide is washed to produce magnesium oxide with high purity.