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:
Oct. 17, 1995
Filed:
Aug. 18, 1993
Materials-Concepts-Research Limited, Don Mills, CA;
Abstract
A process for producing hydrogen and/or hemihydrate calcium sulphate from calcium sulphite. Waste solid containing calcium sulphite and other calcium salts is treated by the addition of aqueous sulphur dioxide solution or sulphuric acid solution to produce a liquid phase product. The liquid phase product may be separated from any remaining solid phase material and then subjected to the addition of sulphuric acid in a second step, wherein calcium sulphate hemihydrate is produced. The addition of sulphuric acid to the liquid phase results in the evolution of sulphur dioxide which may be used as such or in sulphur dioxide electrolysis cells in order to produce hydrogen and sulphuric acid. An especially unique feature of the process is that the sulphuric acid produced in generating hydrogen can be recycled to the step where the calcium sulphate crystals are produced.