Sodium butyl xanthate (SBX) and sodium isobutyl xanthate (SIBX) are the two most widely used xanthate collectors in sulfide ore flotation. As short-chain xanthates, they combine strong collecting power with good selectivity, making them the default choice for copper, lead, zinc and pyrite circuits around the world. This guide explains what they are, how they differ, and how to select the right one for your concentrator.
What Are Sodium Butyl Xanthate and Sodium Isobutyl Xanthate?
Both products belong to the xanthate family of flotation collectors. Sodium butyl xanthate (formula C4H9OCSSNa, CAS 141-33-2) is produced from butanol, carbon disulfide and caustic soda, while sodium isobutyl xanthate is made from isobutanol. Both are supplied as yellowish powder or pellets with a pungent odour, soluble in water and alcohol, and packed in woven bags with PE liners for export.
Key Specifications (YS/T 269-2008)
| Item | Sodium Butyl Xanthate | Sodium Isobutyl Xanthate |
|---|---|---|
| Molecular formula | C4H9OCSSNa | (CH3)2CHCH2OCSSNa |
| Active content (pellet) | ≥ 90.0% | ≥ 90.0% |
| Free alkali | ≤ 0.2% | ≤ 0.2% |
| Moisture & volatiles | ≤ 7.0% | ≤ 7.0% |
Values per Shanghai Minglan Chemical product data sheet (YS/T 269-2008).
SBX vs SIBX: Which Xanthate Should You Use?
Collecting power. Sodium isobutyl xanthate is generally regarded as a slightly stronger collector at the same dosage because the branched isobutyl chain adsorbs more effectively on chalcopyrite and sphalerite surfaces. This makes SIBX popular for difficult ores and for circuits where recovery is prioritised over concentrate grade.
Selectivity. Sodium butyl xanthate offers a good balance of recovery and selectivity in bulk copper circuits and is preferred when gangue depression is critical. In many plants the two are used interchangeably, with dosage adjusted for the difference in collecting strength.
Practical guidance. For copper circuits, start at 20-80 g/t depending on head grade and pulp conditions; for lead-zinc circuits, use lower dosages with a depressant such as zinc sulfate or sodium sulfite. Always run a laboratory flotation test on your own ore before committing to a reagent regime.
Applications in Sulfide Ore Flotation
- Copper ores: chalcopyrite, bornite and chalcocite float efficiently with butyl and isobutyl xanthate in alkaline circuits (pH 9-11.5).
- Lead-zinc ores: used for selective flotation of galena and sphalerite, often with cyanide-free depressant combinations.
- Auriferous pyrite: xanthates collect pyrite where gold is associated with sulfide, enabling precious metal recovery.
Buying Xanthate: What to Check
When sourcing from a flotation reagent manufacturer, verify the active content certificate against YS/T 269, check free alkali and moisture, and request a COA for every batch. Shanghai Minglan Chemical supplies SBX and SIBX in pellet and powder forms with stable quality, export packaging and dosage optimisation support.
For samples, technical data sheets or pricing, contact Minglan Chemical at info@minglanchem.com.