Method for reducing the plating of nickel on vessels, piping and cells in an alkali metal hydroxide manufacturing process
US6200455A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Mar 13, 2001 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01D1/42
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method to prevent cladding or plating of metals, such as nickel or iron in a continuous production of alkali metal hydroxides which involves several steps: electrolyzing an aqueous alkali metal salt solution forming hydrogen, chlorine and an at least 10% caustic solution at a temperature of from about 75 to about 100 F; and treating said at least 10% caustic solution to create a more concentrated caustic solution while continuously and magnetically removing up to 33% of the metals present in the solution from the at least 10% caustic solution using a first magnet prior to evaporation, flashing and cooling of the at least 10% caustic solution, and then magnetically removing an additional amount of metals from the resultant more concentrated caustic solution again with a second magnet prior to filtration of the more concentrated caustic solution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.