About Standard Bleaching Earth
Standard Bleaching Earth is our general-purpose activated clay for edible oil refineries. It is designed for the daily bleaching of soybean, sunflower, palm and rice bran oils, where a refiner needs reliable colour reduction at a moderate dosage, and a spent cake that filters cleanly without holding back too much oil.
The grade is activated with sulphuric acid to develop surface area and adsorption sites, then washed, dried and milled to a particle size chosen for good contact in the bleacher and good release on leaf or plate filters. It removes chlorophyll, carotenoid pigments, soap traces, residual phospholipids and metal ions, preparing the oil for deodorisation. Consistent activity between batches means operators can hold dosage settings steady rather than adjusting for each delivery.
This grade suits both chemical and physical refining lines. For heavily pigmented crude, oxidised oils or mineral oil applications, the High Activity Grade may give a better result per kilogram of clay. Obsidian Minerals manufactures Standard Bleaching Earth in Gujarat and tests activity, acidity, moisture and particle size on every batch in an NABL-accredited laboratory. Refiners should verify suitability against the food regulations in their market, and we can run a bleaching trial on a sample of their crude oil before supply.
Typical specifications
| Parameter | Typical Value | Test Method |
|---|---|---|
| Specific surface area (BET) | 200–250 m²/g | BET, nitrogen adsorption |
| Free acidity | ≤ 3.0 mg KOH/g | Internal method |
| pH (10 % slurry) | 3.0–4.5 | Internal method |
| Moisture | ≤ 12 % | Loss on drying, 105 °C |
| Passing 75 µm | 70–85 % | Wet sieve |
| Bulk density | 0.55–0.75 g/cm³ | Internal method |
| Bleaching performance | Reported on customer crude oil | Lab bleaching test |
Typical values for guidance. Guaranteed limits are stated on the Technical Data Sheet and batch CoA. Bleaching results depend on crude oil quality and process conditions.
Key features & benefits
Reliable colour reduction
Standard Bleaching Earth removes chlorophyll and carotenoid pigments at moderate dosage, giving refiners predictable Lovibond colour after bleaching and a sound, repeatable base for deodorisation.
Good filtration behaviour
Particle size is controlled so that the spent clay forms a permeable cake on leaf and plate filters, helping keep filter cycles and pressure build-up within the normal operating window.
Controlled oil retention
The grade is milled to limit very fine particles that trap oil in the cake. Lower oil retention reduces product loss and the amount of oil sent out with spent clay.
Removes more than colour
Alongside pigments, the activated surface adsorbs soap traces, residual phospholipids, metal ions and primary oxidation products that would otherwise affect flavour, stability and shelf life.
Batch-to-batch consistency
Activity, acidity, moisture and particle size are checked on every lot, so refinery operators can keep clay dosage settings stable from one delivery to the next.
Applications
Soybean and sunflower oil
Used to reduce chlorophyll, soap and phospholipid traces after degumming and neutralisation, giving light-coloured, low-soap oil ready for deodorisation in chemical or physical refining lines.
Palm oil and palm fractions
Applied in the bleaching of crude palm oil, palm olein and stearin to support carotenoid breakdown and remove oxidation products and trace metals ahead of high-temperature deodorisation.
Rice bran and other seed oils
Suitable for rice bran, cottonseed, groundnut and mustard oils where routine colour correction is needed. Darker or more difficult crudes may call for trials with the High Activity Grade.
Usage & handling
- Typical dosage: 0.5–2.0 % of oil weight, set by laboratory bleaching trials on the crude oil.
- Typical conditions: 90–110 °C under vacuum, with 20–40 minutes of contact time and good agitation.
- Add the clay to dried, pre-treated oil and filter promptly after the contact period.
- Store bags off the floor in a dry area; absorbed moisture can change activity and filtration.
Packaging & supply
- 25 kg or 50 kg HDPE or paper bags
- 1 MT or 1.2 MT jumbo (FIBC) bags
- Private-label packaging on request
Frequently asked questions
What dosage of Standard Bleaching Earth is typical for soybean oil?
Soybean oil refiners often work in the range of about 0.5–1.0 % of oil weight with a standard activated clay, depending on chlorophyll level and colour target. The best figure for your plant comes from a laboratory bleaching test on your crude, which we can carry out if you send us a sample.
Can Standard Bleaching Earth be used for palm oil?
Yes. It is used for crude palm oil and its fractions. Palm oil generally needs a higher dosage than seed oils, and refiners processing low-quality or highly oxidised crude may get better results per kilogram from our High Activity Grade. A side-by-side trial is the simplest way to decide.
How does this grade affect oil losses?
Some oil always remains in the spent filter cake. Standard Bleaching Earth is milled to limit excess fines, which helps keep oil retention under control. Using the lowest effective dosage, maintaining good filtration and steaming or blowing the cake where your equipment allows all reduce losses further.
What documents are supplied with each shipment?
Every shipment of Standard Bleaching Earth carries an SDS, Technical Data Sheet and a batch Certificate of Analysis covering activity-related properties, acidity, moisture and particle size. Additional documentation for food regulatory review can be discussed on request, and further batch test data can be provided where a refinery audit needs it.