About High Activity Bleaching Earth
High Activity Bleaching Earth is activated more intensively than our standard grade, giving a larger surface area and a higher density of acidic adsorption sites. It is intended for feedstocks that are hard to bleach: dark or oxidised palm crude, oils with high chlorophyll, and mineral oils, lubricating base oils and waxes that carry polar compounds, resins and colour bodies.
Mineral oil and wax refiners use this grade in contact treatment, where the clay is mixed into hot oil or molten wax and then filtered out. It helps remove oxidation products, sulphur- and nitrogen-bearing polar compounds and residual colour, improving the appearance and stability of base oils, transformer oils, paraffin and microcrystalline waxes. In edible oil refining it allows a lower dosage on difficult crude, which can cut both clay consumption and oil retained in the cake.
Higher activity also means higher acidity, so the grade is best used where free fatty acid rise and acid-catalysed reactions are not the main concern. Obsidian Minerals manufactures High Activity Bleaching Earth in Gujarat, tests surface area, acidity, moisture and particle size in an NABL-accredited laboratory and supplies each batch with a Technical Data Sheet and Certificate of Analysis. We recommend a side-by-side trial against your current clay before switching.
Typical specifications
| Parameter | Typical Value | Test Method |
|---|---|---|
| Specific surface area (BET) | 250–320 m²/g | BET, nitrogen adsorption |
| Free acidity | 2.0–6.0 mg KOH/g | Internal method |
| pH (10 % slurry) | 2.5–4.0 | Internal method |
| Moisture | ≤ 12 % | Loss on drying, 105 °C |
| Passing 75 µm | 75–90 % | Wet sieve |
| Bulk density | 0.50–0.70 g/cm³ | Internal method |
| Bleaching performance | Reported on customer feedstock | Lab bleaching test |
Typical values for guidance. Guaranteed limits are stated on the Technical Data Sheet and batch CoA. Results depend on feedstock and contact conditions.
Key features & benefits
Higher surface area
Intensive activation gives High Activity Bleaching Earth a larger surface area than standard grades, so more pigments and polar impurities are adsorbed per kilogram of clay added to the oil.
Built for mineral oils and waxes
The grade handles the higher contact temperatures and darker feedstocks found in base oil, transformer oil and wax refining, helping improve colour and remove oxidation and polar compounds.
Lower dosage on difficult crude
On dark or oxidised edible crudes, a more active clay can reach the colour target at a lower addition rate, reducing clay purchases, spent cake volume and oil losses.
Strong action on oxidation products
The activated surface is effective at adsorbing peroxides and their breakdown products, which supports flavour stability in edible oils and oxidation resistance in refined mineral oils.
Applications
Lubricating base oil finishing
Used in clay contact treatment of base oils and re-refined lubricants to improve colour, remove polar residues and lift oxidation stability before blending and packing.
Transformer oil reclamation
Applied to reclaim used insulating oils by removing acids, sludge precursors and other polar ageing products. Treated oil should be re-tested against the operator's applicable acceptance standard.
Paraffin and microcrystalline wax
Mixed into molten wax to remove colour and odour bodies, giving lighter wax for candles, packaging and industrial use. Dosage and temperature are set by trial on each feedstock.
Dark or oxidised palm crude
Supports refiners processing low-grade palm crude with high oxidation values, where a standard clay would need an uneconomic dosage to reach the colour and stability targets.
Usage & handling
- Edible oils: typically 0.5–1.5 % of oil weight on difficult crude, confirmed by laboratory trial.
- Mineral oils and waxes: typically 1–5 % by weight, at contact temperatures set by the refinery process.
- Provide good agitation and adequate contact time, then filter while the oil or wax is hot.
- Keep bags sealed and dry; handle with dust control and the PPE listed on the SDS.
Packaging & supply
- 25 kg or 50 kg HDPE or paper bags
- 1 MT or 1.2 MT jumbo (FIBC) bags
- Custom packaging on request
Frequently asked questions
When should I choose High Activity Bleaching Earth over the standard grade?
Choose it when your feedstock is hard to bleach, such as dark or oxidised palm crude, high-chlorophyll seed oils, mineral oils or waxes, or when a standard clay needs too high a dosage. If free fatty acid rise is your main concern, our Low Free Acid Grade may be more suitable.
Can it be used for transformer oil regeneration?
Yes. Acid-activated clay is used to remove acids, sludge precursors and other polar ageing products from used insulating oil. The treated oil should then be tested against the specification the operator works to, as results depend on the condition of the oil and the treatment process.
Does higher activity increase free fatty acids in edible oil?
More strongly activated clays carry more acidity, which can cause a small rise in free fatty acids in some oils. In physical refining this is usually removed during deodorisation. Refiners who are sensitive to this effect should compare the high-activity grade with our Low Free Acid Grade in a laboratory test.
What contact temperature is used for wax bleaching?
Wax is bleached in the molten state, so contact temperature is set by the melting range of the wax and the refinery's own process, not by the clay. Typical practice is to stir the clay into hot molten wax for a fixed time and filter hot. We recommend trials at your normal operating conditions.