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:
Aug. 06, 1996
Filed:
Apr. 12, 1994
Heikki Tuovinen, Ulvila, FI;
Jorma Saari, Ulvila, FI;
Antti Roine, Vanha-Ulvila, FI;
Hannu Holma, Jarvenpaa, FI;
Matti Kalliokoski, Porvoo, FI;
Other;
Abstract
A method for treatment of process waste obtained from the synthesis of thiophene or its derivatives, which method produces phosphorus pentasulfide of sufficiently high purity for recycling in said synthesis process, as well as a residue material suited for use as a raw material for fertilizers. In the treatment method, the process waste is subjected to vacuum evaporation in a combination heating/evaporation reactor at 500.degree.-700.degree. C. and under a partial vacuum of 0.01-0.2 atm. To improve the yield of the evaporating phosphorus pentasulfide, sulfur is added to the process waste. The evaporating phosphorus pentasulfide is condensed, and when desired, pulverized. The usable, phosphorus- and potassium-containing evaporation residue is removed from the reactor and cooled for further use.