The chemicals and aids used in oil refining
Refining crude oil into a clear, stable, neutral product uses a sequence of processing chemicals and aids: degumming agents (water, phosphoric or citric acid) to remove gums and phospholipids; alkali (caustic soda) for neutralising free fatty acids; activated bleaching earth (and sometimes silica) for adsorbing colour, oxidation products and trace metals; and steam in deodorisation for final flavour and odour removal. Among these, activated bleaching earth is the key adsorbent for colour and purity.
Where activated bleaching earth fits
Bleaching sits after degumming and neutralisation and before deodorisation. The bleaching earth adsorbs chlorophyll and carotenoid pigments, peroxides and secondary oxidation products, residual soaps and phospholipids, and pro-oxidant trace metals such as iron and copper — producing a clean feed for the deodoriser and a stable final oil.
Bleach Master specifications
Our activated bleaching earth, Bleach Master, is engineered for high adsorption performance:
| Parameter | Bleach Master |
|---|---|
| Bleachability | ~75% |
| Surface area | 290–310 m²/g |
| Oil retention | ≤ 20% |
| Moisture | 5–8% |
| Bulk density | 0.55 g/cc |
| pH (2% suspension) | ~4.0 |
| Material | Acid-activated montmorillonite clay |
Citric acid and silica: complementary aids
Many refiners dose a little citric acid before bleaching to chelate calcium and magnesium and convert non-hydratable phospholipids into a removable form, and some use synthetic silica to strip soaps and phospholipids so the bleaching earth's capacity is reserved for colour. Used well, these complement — not replace — activated bleaching earth.
A reliable supplier of oil-refining adsorbents
Umiya Minerals is one of India's largest manufacturers of activated bleaching earth — India's second-largest plant — supplying refiners across India and exporting to the Middle East and East Africa. We provide technical support to help you optimise dosage and cost across your refining chemistry.
Frequently Asked Questions
What chemicals are used in oil refining?
Oil refining uses degumming agents (water, phosphoric or citric acid), alkali (caustic soda) for neutralisation, activated bleaching earth (and sometimes silica) for adsorption during bleaching, and steam during deodorisation. Activated bleaching earth is the main adsorbent for colour and purity.
Is activated bleaching earth a chemical or a processing aid?
It is a processing aid — an acid-activated clay adsorbent used during bleaching and then removed by filtration, so it does not remain in the finished oil.
What does bleaching earth remove during refining?
Chlorophyll and carotenoid colour pigments, peroxides and secondary oxidation products, residual soaps and phospholipids, and pro-oxidant trace metals such as iron and copper.
Where can I buy oil refining chemicals like bleaching earth in India?
Umiya Minerals manufactures and supplies Bleach Master activated bleaching earth from Bhuj, Gujarat — across India and for export to the Middle East and East Africa. Request a sample and quote.