Method for removing an alkaline earth metal sulfate scale
US5093020A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 3, 1989 |
| Grant date | Mar 3, 1992 |
| Priority date | — |
| Expiry date | Apr 3, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/927
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A method and composition for removing barium and strontium sulfate scale deposits. The composition comprises an aqueous solution having a pH of about 8 to about 14, an EDTA or DTPA chelant, and a catalyst or synergist. Preferred chelants comprise diethylenetriaminepentaacetic acid (DTPA) or ethylenediaminetetraacetic acid (EDTA) or alkali salts thereof. Anions of organic and inorganic acids comprise the catalyst. Catalysts which can be used include Fluoride, oxalate, persulfate, dithionate, hypochlorite and formate anions also thio, amino, and hydroxy acetate anions. When the solution containing the composition is contacted with a surface containing a scale deposit, the deposit dissolves substantially more scale quicker than heretofore possible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.