What is bleaching earth?

Oil bleaching extraction plant

Bleaching Earth is manufactured from the best quality, selectively mined and scientifically blended montmorillonite clays under stringent process controls. While making Bleaching Earth special care is taken in maintaining the important properties like absorptive capacity, acid properties, catalytic properties, ion exchange capacity and particle size distribution.

Charcteristics of bleaching earth
1. Normally about 0.5% - 3% of earth is required for bleaching application of vacuum during process which results in less oxidation & improvement in oil colour.
2. Choice of Bleaching clay as per its characteristics.
3. The total acidity (titrable acidity) of clay is expressed as mg of KOH/g of clay on a hot water extract.
4. The Moisture content of Earth is vital as activity of clay depends on the evaporation of moisture from earth after its admixture with oil (15% max free moisture is desirable)
5. The Particle size of Earth affects filtration & oils retention as per type of earth used & determines losses during bleaching process.
6. Operations & maintenance of filters is very important during process.
7. Treatment with Acid Activated Bleaching Earth in post-bleaching step removes traces of Nickel from hydrogenated oils (0.25-0.5% of earth used).

Refinery plant, workshop using bleaching earth