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:
Feb. 18, 2003
Filed:
Oct. 26, 2001
Hisahiro Matsunaga, Chiba, JP;
Masato Kumagai, Chiba, JP;
Hiroyuki Tobo, Chiba, JP;
Yasuo Kishimoto, Chiba, JP;
Toshikazu Sakuraya, Tokyo, JP;
Kawasaki Steel Corporation, Hyogo, JP;
Abstract
A method of rapidly reducing chromium oxide-containing slag and the like in large quantities, in a simplified manner and without requiring high temperatures. Chromium oxides are reduced with at least one of elementary sulfur and compounds of sulfur having a valence less than 6. For an aqueous solution of the sulfur component, desirably, its sulfur content is more than 0.03% by weight. As the sulfur source, preferred is blast furnace slag (e.g., non-aged, gradually-cooled blast furnace slag) that is discharged in large quantities in the iron industry. Cr in chromium oxides is reduced in one of the following ways: (a) Chromium oxide-containing substances are sprayed with or immersed in blast furnace slag-released water that has been used in cooling blast furnace slag. (b) Chromium oxide-containing substances are mixed with blast furnace slag, and then kept in an air atmosphere. Optionally, the mixture is sprayed with blast furnace slag-released water. (c) Chromium oxide-containing substances are mixed with blast furnace slag, and then steamed. (d) Prior to the reduction treatment, chromium oxide-containing substances are preferably steamed. 100 parts by weight of reduced chromium oxide-containing compounds are mixed with from 0.1 to 90 parts by weight of sulfur-containing slag, and used in various civil engineering works.