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. 08, 2000
Filed:
Feb. 17, 1999
Keisuke Nakahara, Chigasaki, JP;
Yasushi Hoshino, Machida, JP;
Satoshi Matsui, Yachiyo, JP;
Takuya Shinagawa, Kawasaki, JP;
NKK Corporation, Tokyo, JP;
Abstract
A method for recovering phosphorus from organic sludge includes the steps of producing incinerated ash from organic sludge, mixing the incinerated ash with a carbon source, vaporizing phosphorus from phosphorus compounds in the incinerated ash by heating the incinerated ash mixed with the carbon source in a non-oxidizing atmosphere, preferably, at 1,000 to 1,250.degree. C., and recovering phosphorus by bringing the vaporized phosphorus into contact with water to condense the vaporized phosphorus. Alternatively, the vaporized phosphorus is oxidized to phosphorus pentoxide, and phosphorus is recovered as phosphoric acid by bringing the phosphorus pentoxide into contact with water. Instead of the steps of producing incinerated ash from organic sludge and mixing a carbon source with the incinerated ash, by dehydrating and drying organic sludge and carbonizing organic substances in the organic sludge, preferably, at 400 to 700.degree. C., similar effects can be obtained.