Method for removal of nickel and iron from alkali metal hydroxide manufacturing process requiring the use of sodium borohydride
US6080299A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1999 |
| Grant date | Jun 27, 2000 |
| Priority date | — |
| Expiry date | Oct 14, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01D1/28
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
The method involves the steps of: exposing a cell liquor containing metal to a first magnet, magnetically removing up to about one third of said metal present in the cell liquor, evaporating a significant amount of water out of that fluid, and raising the temperature of that fluid to above 220 Fahrenheit and adding a small amount of sodium borohydride (NaBH.sup.4) to suppress the reaction of the caustic solution with metal in the manufacturing process, evaporating and flashing off more water from the caustic solution, cooling the solution after evaporation and then flowing it through and around a second magnet to magnetically removing an additional amount of metal the solution, filtering the solution and then magnetically removing an additional amount of metal from said solution forming a final caustic solution having 40-55% by weight caustic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.