Potassium Amyl Xanthate, Potassium Pentyl Xanthate, Potassium Amyl Dithiocarbonate, Potassium Amyl Xanthogenate, Potassium Pentyl Dithiocarbonate, PAX, KAX, 2720-73-2
POTASSIUM AMYL XANTHATE (PAX)
Product Name: Potassium Amyl Xanthate
Other Names: Potassium Pentyl Xanthate, Potassium Amyl Dithiocarbonate, Potassium Amyl Xanthogenate, Potassium Pentyl Dithiocarbonate, PAX, KAX
CAS Number: 2720-73-2 (Primary)
Other CAS: 140-93-2 (Alternative)
Chemical Formula: C₆H₁₁KOS₂
Molecular Weight: 202.38 g/mol
Chemical Class: Xanthate (Dithiocarbonate) – Flotation Reagent
SECTION 1: PRODUCT IDENTIFICATION AND DEFINITION
| Parameter |
Information |
| Product Name |
Potassium Amyl Xanthate |
| Other Names |
Potassium Pentyl Xanthate, Potassium Amyl Dithiocarbonate, Potassium Amyl Xanthogenate, Potassium Pentyl Dithiocarbonate, PAX, KAX, Potassium O-Amyl Dithiocarbonate, Amylxanthic Acid Potassium Salt, Potassium O-pentyl carbonodithioate |
| CAS Number |
2720-73-2 (primary); 140-93-2 (alternative) |
| EC Number (EINECS) |
220-329-5 |
| Chemical Formula |
C₆H₁₁KOS₂ |
| Molecular Weight |
202.38 g/mol |
| Physical Appearance |
Pale yellow powder, granules, crystals, or pellets |
| Odor |
Pungent, unpleasant (reminiscent of rotten cabbage or carbon disulfide) |
| Chemical Class |
Xanthate (Dithiocarbonate) – Flotation Reagent |
| Primary Function |
Strong, unselective collector for sulfide minerals in froth flotation |
| UN Number |
3342 |
| Hazard Class |
4.2 (Substances liable to spontaneous combustion) |
SECTION 2: CHEMICAL STRUCTURE AND PROPERTIES
2.1. Chemical Structure
| Parameter |
Information |
| Chemical Name |
Potassium O-pentyl dithiocarbonate |
| IUPAC Name |
Potassium pentoxymethanedithioate |
| SMILES |
CCCCCOC(=S)[S-].[K+] |
| InChI Key |
RKVMAMRYKCITAI-UHFFFAOYSA-N |
| Alkyl Group |
Amyl (pentyl) – C₅ (5-carbon chain) |
| Functional Group |
Dithiocarbonate (xanthate) – OCSS⁻ |
2.2. Physical Properties
| Property |
Value |
| Appearance |
Pale yellow powder, granules, or pellets |
| Odor |
Unpleasant, sulphurous |
| Molecular Weight |
202.38 g/mol |
| Melting Point |
19.5 – 21.5°C |
| Boiling Point |
190.7°C at 760 mmHg (decomposes) |
| Flash Point |
69.1°C |
| Density |
1.22 g/cm³ |
| Solubility |
Highly water-soluble; hygroscopic (absorbs moisture from air) |
| pH Stability |
Relatively stable between pH 8 and 13; maximum stability at pH 10 |
| Purity (Typical) |
90.0% – 97.0%+ |
2.3. Chemical Properties
| Property |
Description |
| pH Stability |
Stable in alkaline conditions; decomposes rapidly in acidic environments (pH < 7) |
| Reaction with Metal Ions |
Forms insoluble complexes with heavy metal ions |
| Hydrolysis |
Hydrolyzes to produce xanthic acid and alcohol; decomposes to carbon disulfide (CS₂) |
| Aqueous Stability |
First-order degradation rate constant: 7.05 × 10⁻⁴ h⁻¹ at 25°C |
SECTION 3: MECHANISM OF ACTION IN FLOTATION
3.1. Collector Mechanism
| Mechanism |
Description |
| Adsorption |
PAX adsorbs onto the surface of sulfide minerals through chemisorption (formation of metal-xanthate complexes) |
| Hydrophobicity |
The adsorbed PAX layer makes the mineral surface hydrophobic, allowing it to attach to air bubbles |
| Long Amyl Chain |
The 5-carbon amyl chain provides strong collecting power; highest binding energy among xanthate series |
| Flotation |
Hydrophobic mineral particles attach to air bubbles and rise to the surface for collection |
3.2. Xanthate Chain Length vs. Collecting Power
| Xanthate Type |
Alkyl Chain |
Collecting Power |
Selectivity |
Typical Plant Concentration % |
| Sodium Ethyl Xanthate (SEX) |
C₂ (2-carbon) |
Weakest |
Highest |
10-20% |
| Potassium Ethyl Xanthate (KEX) |
C₂ (2-carbon) |
Weak |
High |
- |
| Sodium Isopropyl Xanthate (SIPX) |
C₃ (3-carbon) |
Moderate |
Moderate-High |
10-20% |
| Sodium Isobutyl Xanthate (SIBX) |
C₄ (4-carbon) |
Strong |
Moderate |
10-20% |
| Potassium Amyl Xanthate (PAX) |
C₅ (5-carbon) |
Strongest |
Lowest |
15-25% |
| Sodium Hexyl Xanthate (SHX) |
C₆ (6-carbon) |
Very Strong |
Very Low |
- |
SECTION 4: DETAILED TECHNICAL COMPARISON WITH OTHER XANTHATES
| Parameter |
SEX (140-90-9) |
KEX (140-89-6) |
SIPX (140-93-2) |
SIBX (25306-75-6) |
PAX (2720-73-2) |
SHX (35042-31-6) |
| Alkyl Chain |
Ethyl (C₂) |
Ethyl (C₂) |
Isopropyl (C₃) |
Isobutyl (C₄) |
Amyl (C₅) |
Hexyl (C₆) |
| Collecting Power |
Weakest |
Weak |
Moderate |
Strong |
Strongest |
Very Strong |
| Selectivity |
Highest |
High |
Moderate-High |
Moderate |
Lowest |
Very Low |
| Binding Energy with Cu Ions |
Lowest |
- |
Moderate |
Higher |
Highest |
- |
| Degradation Rate (h⁻¹ at 25°C) |
4.07 × 10⁻⁴ |
- |
5.11 × 10⁻⁴ |
7.05 × 10⁻⁴ |
- |
- |
| Primary Application |
Cu, Pb, Zn sulfides |
Cu, Zn ores |
Au, Cu sulfides |
Pb, Zn sulfides |
Au, Cu, Ni, pyrite |
Refractory ores |
| Suitable Ores |
Selective flotation |
Selective flotation |
Wide range |
Balanced |
Difficult ores, pyrite, bulk flotation |
Very difficult ores |
| CAS Number |
140-90-9 |
140-89-6 |
140-93-2 |
25306-75-6 |
2720-73-2 |
35042-31-6 |
SECTION 5: APPLICATION AREAS
5.1. Mineral Processing (Flotation)
| Application |
Description |
| Gold Ores |
Flotation of gold-bearing sulfide minerals (pyrite, arsenopyrite); preferred for gold-bearing pyrite ahead of oxidative pre-treatment circuits |
| Copper Ores |
Flotation of chalcopyrite; achieves 78-83% copper recovery in primary sulfide flotation and >82% Cu recovery from tailings reprocessing |
| Nickel Ores |
Flotation of pentlandite and other nickel sulfide minerals |
| Lead/Silver Ores |
Maximum recoveries: Lead 89.2%, Silver 64.9% at optimal conditions |
| Pyrite |
Pyrite recovery (gold-bearing pyrite) |
| Refractory Ores |
Difficult ores requiring strong collector; effective at coarse grind sizes (P80 >170 µm) |
| Bulk Sulfide Flotation |
Bulk recovery of sulfide minerals |
| Oxide Mineral Flotation |
After sulfidization treatment; effective where shorter-chain xanthates fail |
| Scavenger Flotation Operations |
For recovery of residual valuable minerals |
5.2. Other Industrial Applications
| Application |
Description |
| Rubber Chemical |
Used as an intermediate and chemical additive |
| Surfactant |
Surface-active agent in various processes |
| Hydrometallurgy |
Pre-concentration of ores before leaching |
| Analytical Chemistry |
Reagent for metal ion detection and precipitation |
SECTION 6: PERFORMANCE DATA AND EVIDENCE
6.1. Copper Flotation Performance
| Metric |
PAX Performance |
| Copper Recovery (Primary Sulfide) |
78-83% |
| Copper Recovery (Tailings Reprocessing) |
>82% in single rougher stage |
| Effective Grind Size |
P80 >170 µm (coarse particles) |
6.2. Lead and Silver Flotation Performance
| Metal |
Optimal PAX Concentration |
Maximum Recovery |
| Lead |
200 g/t |
89.2% |
| Silver |
200 g/t |
64.9% |
6.3. Binding Energy Comparison
| Xanthate Type |
Binding Strength to Copper Ions |
| Amyl-xanthate (C₅) |
Highest |
| Isobutyl-xanthate (C₄) |
High |
| Ethyl-xanthate (C₂) |
Lowest |
SECTION 7: ADVANTAGES AND DISADVANTAGES
7.1. Advantages
| Advantage |
Description |
| Very Strong Collector |
Strongest collector in the alkyl xanthate series; effective in difficult and complex ore flotation |
| Versatile |
Widely used in gold, copper, nickel, lead, silver, and pyrite flotation |
| Coarse Particle Recovery |
Effective at coarse grind sizes (P80 >170 µm) where shorter-chain xanthates fail |
| Bulk Flotation |
Excellent for bulk sulfide flotation and scavenger operations |
| Compatibility |
Can be used with lime to provide a pH operating range of 9-12 |
| Cost-Effective |
Least expensive sulfide mineral collector; easy to manufacture |
| Available Forms |
Available in solid pellet form for easy handling; can be fed as 5-20% aqueous solution |
| Effective on Oxidized Ores |
Works on sulfidized oxide ores where shorter-chain xanthates fail |
7.2. Disadvantages
| Disadvantage |
Description |
| Low Selectivity |
Can collect non-target minerals (less selective than shorter-chain xanthates); results in lower concentrate grade |
| Environmental Risk |
Decomposition releases carbon disulfide (CS₂), which is toxic |
| Hazardous Material |
Self-heating; flammable; requires special safety measures for storage and handling |
| Decomposition |
Sensitive to heat, moisture, light, and acidic conditions |
| Limited Stability in Process Water |
Degrades ~1.7x faster than SIBX and ~4.8x faster than SEX at 25°C |
| Pungent Odor |
Strong, unpleasant odor during handling |
| Bio-Oxidation Inhibition |
May inhibit bacterial oxidation activity in bioleaching circuits at certain dosages |
SECTION 8: TYPICAL DOSAGE AND APPLICATION
8.1. Recommended Dosage
| Parameter |
Value |
| Typical Dosage Range |
50 – 250 g/t of ore (depending on ore type and conditions) |
| Optimal Dosage |
200 g/t for lead/silver flotation |
| Typical Plant Concentration |
15-25% of the ore |
| Solution Strength |
5-20% aqueous solution |
| Addition Point |
Added to the grinding circuit or conditioning tank |
8.2. Application Instructions
| Step |
Description |
| 1 |
Prepare PAX solution by dissolving in water (typically 5-10% solution) |
| 2 |
Add to the flotation circuit at the designated addition point |
| 3 |
Condition the pulp for optimal adsorption |
| 4 |
Adjust dosage based on ore characteristics and flotation response |
| 5 |
Use solutions within three days to prevent decomposition into carbon disulfide |
8.3. Recommendations for Different Ores
| Ore Type |
Recommended Xanthate |
Notes |
| Copper Sulfides |
SEX, KEX, SIPX |
Selective flotation preferred |
| Gold-Bearing Sulfides |
PAX, SIPX |
PAX is strongest for pyrite |
| Nickel Sulfides |
PAX, SIBX |
PAX for pentlandite |
| Lead/Silver Ores |
PAX |
Best recoveries: 89.2% Pb, 64.9% Ag |
| Refractory Ores |
PAX, SHX |
Strong collectors required |
| Bulk Sulfide Flotation |
PAX, SIBX |
Strong collecting power needed |
SECTION 9: QUALITY SPECIFICATIONS
| Parameter |
Specification |
| Appearance |
Pale yellow powder or granules |
| Purity (Active Content) |
≥ 90.0% – 97.0% |
| Moisture |
≤ 3 – 5% |
| Solubility |
≥ 95% soluble in water |
| pH (1% solution) |
8.0 – 10.0 |
| Hygroscopicity |
Hygroscopic (absorbs moisture from air) |
| HS Code |
2930902000 |
SECTION 10: PACKAGING OPTIONS
| Packaging Type |
Quantity |
Material |
| Plastic Drum |
100 – 200 kg |
HDPE |
| Fiber Drum |
100 – 150 kg |
HDPE + PE liner |
| Multi-layer Bag |
25 kg |
PE-lined kraft paper |
| Big-Bag |
500 – 1000 kg |
Polypropylene (with PE liner) |
SECTION 11: STORAGE AND SHELF LIFE
| Parameter |
Information |
| Storage Conditions |
Cool (<15°C), dry, well-ventilated area; avoid direct sunlight |
| Container Requirements |
Tightly closed, original packaging; maintain air gap between stacks/pallets |
| Protect From |
Heat, moisture, direct sunlight, acidic conditions, incompatible materials |
| Shelf Life |
6-12 months (unopened original packaging) |
| Stability Note |
Decomposes in acidic conditions; sensitive to heat and moisture; decomposes to carbon disulfide (CS₂); self-heating in large quantities |
SECTION 12: SAFETY AND HEALTH INFORMATION
12.1. Classification
| Parameter |
Information |
| GHS Classification |
Self-heating substances (Category 2), Acute Toxicity (Category 4), Skin Irritation (Category 2), Eye Irritation (Category 2A), Reproductive Toxicity (Category 2), Specific Target Organ Toxicity (Category 2/3) |
| Signal Word |
WARNING |
| WHMIS Classification |
B-6: Reactive Flammable Material; D-1B: Toxic (acute effects); D-2B: Toxic (skin and eye irritant) |
12.2. Hazard Statements
| Code |
Statement |
| H252 |
Self-heating in large quantities; may catch fire |
| H302+H312+H332 |
Harmful if swallowed, in contact with skin, or if inhaled |
| H315 |
Causes skin irritation |
| H319 |
Causes serious eye irritation |
| H335 |
May cause respiratory irritation |
| H361 |
Suspected of damaging fertility or the unborn child |
| H373 |
May cause damage to organs through prolonged or repeated exposure |
12.3. Precautionary Statements
| Code |
Statement |
| P201 |
Obtain special instructions before use |
| P235+P410 |
Keep cool. Protect from sunlight |
| P261 |
Avoid breathing dust |
| P280 |
Wear protective gloves, protective clothing, eye/face protection |
| P301+P312 |
IF SWALLOWED: Call a POISON CENTER/doctor if you feel unwell |
| P305+P351+P338 |
IF IN EYES: Rinse cautiously with water for several minutes |
| P308+P313 |
IF exposed or concerned: Get medical advice/attention |
| P403+P233 |
Store in a well-ventilated place. Keep container tightly closed |
| P405 |
Store locked up |
| P420 |
Store away from other materials |
12.4. Toxicological Information
| Parameter |
Value |
| Oral LD50 (Rat) |
Acute Oral Toxicity – Category 4 (Harmful if swallowed) |
| Dermal LD50 (Rabbit) |
Acute Dermal Toxicity – Category 4 (Harmful in contact with skin) |
| Skin Irritation |
Category 2 (Causes skin irritation) |
| Eye Irritation |
Category 2A (Causes serious eye irritation) |
| Inhalation |
May cause respiratory irritation; may cause damage to organs through prolonged exposure |
| Reproductive Toxicity |
Category 2 (Suspected of damaging fertility or unborn child) |
| Target Organ Toxicity |
Category 2 (May cause damage to organs through prolonged or repeated exposure) |
SECTION 13: ENVIRONMENTAL INFORMATION
| Parameter |
Information |
| Decomposition |
Decomposes to carbon disulfide (CS₂), which is toxic and environmentally hazardous |
| Aquatic Toxicity |
Toxic to aquatic organisms (Hazardous to the environment) |
| Persistence |
Degrades in the environment; may persist under certain conditions |
| Environmental Precautions |
Prevent entry into drains, soil, and surface waters |
SECTION 14: TRANSPORT INFORMATION
| Parameter |
Information |
| UN Number |
3342 |
| UN Proper Shipping Name |
XANTHATES (Potassium Amyl Xanthate) |
| Hazard Class |
4.2 (Substances liable to spontaneous combustion) |
| Packing Group |
II or III (depending on formulation) |
| ADR/RID |
Regulated |
| IMDG Code |
Regulated |
| IATA (Air) |
Regulated |
| Hazchem/Emergency Action Code |
1Y |
SECTION 15: REGULATORY STATUS
| Parameter |
Information |
| TSCA (USA) |
Yes |
| EINECS |
220-329-5 |
| RTECS Number |
FG1581900 |
| HS Code |
2930902000 |
SECTION 16: SUMMARY AND CRITICAL NOTES
Product Summary
| Parameter |
Value |
| Product |
Potassium Amyl Xanthate (PAX) |
| CAS Number |
2720-73-2 (primary) |
| Chemical Formula |
C₆H₁₁KOS₂ |
| Appearance |
Pale yellow powder, granules, or pellets |
| Primary Function |
Strong, unselective collector for sulfide minerals in froth flotation |
| Key Feature |
Strongest collecting power among common xanthates |
| Typical Purity |
90.0% – 97.0%+ |
Critical Notes
-
Strongest Common Xanthate: PAX has the longest commonly used alkyl chain (C₅), providing the strongest collecting power among the alkyl xanthate series.
-
Low Selectivity: Due to its strong collecting power, PAX has lower selectivity compared to shorter-chain xanthates (SEX, KEX, SIPX); results in lower concentrate grade but higher recovery.
-
Primary Applications: Gold-bearing sulfide ores, copper sulfides (78-83% recovery), nickel sulfides (pentlandite), lead/silver ores (89.2% Pb, 64.9% Ag), and pyrite flotation.
-
Refractory Ores: Preferred for difficult ores requiring strong collector power; effective at coarse grind sizes (P80 >170 µm).
-
Mechanism: PAX adsorbs onto sulfide mineral surfaces through chemisorption, forming hydrophobic layers that enable bubble attachment; binding strength increases with chain length (Amyl > Isobutyl > Ethyl).
-
Decomposition: Decomposes in acidic conditions (pH <7) to carbon disulfide (CS₂); must be stored in alkaline conditions (pH 8-13, max stability at pH 10).
-
Safety: Self-heating substance (Category 2); flammable; toxic; requires careful handling and storage; may cause skin/eye irritation and respiratory issues.
-
Environmental: Decomposition products (CS₂) are toxic to the environment; prevent entry into drains and waterways.
-
Industry Standard: One of the most widely used xanthates in the mining industry globally.
-
Chain Length Rule: As alkyl chain length increases, collecting power increases, but selectivity decreases; PAX is used when strength is prioritized over selectivity.
-
Aqueous Stability: PAX degrades ~1.7x faster than SIBX and ~4.8x faster than SEX at 25°C; solutions should be used within 3 days.
-
Oxidized Ores: Effective on sulfidized oxide ores where shorter-chain xanthates fail.
-
Bioleaching Inhibition: May inhibit A. ferrooxidans bacterial oxidation activity at certain dosages; effect is dosage-dependent.
-
Compatibility: Can be used with lime to provide pH operating range of 9-12; compatible with frothers and modifiers.
-
Flotation Performance: In copper flotation, PAX achieves 78-83% recovery; in lead/silver flotation, optimal recovery at 200 g/t with 89.2% Pb and 64.9% Ag recovery.
IMPORTANT DECLARATION: This Technical Data Sheet (TDS) is for informational purposes only and has been prepared based on available technical data. The user is responsible for determining the product's suitability for their specific application and for complying with all local, national, and international regulations. For complete safety, storage, use, transport, waste, and regulatory compliance information, refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier.
