Microfiltration of zeolites
US5919721A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 25, 1995 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | May 25, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10G35/095
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Processes for washing zeolites, preferably less than about 0.5 micron in size, with a microfiltration system employing a washing liquid, such as an aqueous solution or water (preferably deionized water), to produce zeolite crystals having a zeolite pH in the pH range of 9.4 to 10.0 are provided. The zeolite pH is determined by a special procedure. The preferred washing processes include slurring the zeolite crystals with water (or an appropriate wash solution), initially concentrating the slurry with a microfilter to a preselected initial concentration, washing the crystals by adding make-up water at the same rate as the fluid loss due to permeate flow until the permeate pH is below a preselected value, then stopping the make-up flow and concentrating the slurry to a preselected maximum final concentration. A sample of the zeolite is dried and tested for its pH and if within the desired range, the batch of maximally concentrated slurry is dried. These processes are employed to produce zeolite crystals having a zeolite pH of about 9.4 to 10.0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.