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Potassium Ethyl Xanthate (PEX) CAS 140-89-6

Potassium ethyl xanthate, commonly known as PEX or KEX, is a high-efficiency xanthate collector with CAS number 140-89-6
  • aozun

  • 2930902000

  • PEX

  • White to pale yellow crystals or crystalline powders

  • 140-89-6

  • C3H5KOS2

  • 160

  • 205-439-3

  • Soluble in water

Availability:

Product Description

What Is Potassium Ethyl Xanthate?

Potassium Ethyl Xanthate, commonly abbreviated as PEX or KEX, is a water-soluble organosulfur compound primarily used as a collector in the froth flotation of selected sulfide minerals.

Its short ethyl group gives it lower collecting strength but potentially better selectivity than longer-chain xanthates. PEX is therefore particularly useful when concentrate grade and separation selectivity are more important than maximum collecting power.

Potassium Ethyl Xanthate does not guarantee recovery for every ore. Its performance depends on mineralogy, oxidation state, particle size, pH, activation, reagent sequence, conditioning and the other reagents used in the circuit.

AOZUN supplies industrial-grade PEX in powder or pellet form for mineral-processing applications and international distribution.

Potassium Ethyl Xanthate Quick Facts

Property

Information

Product name

Potassium Ethyl Xanthate

Abbreviations

PEX, KEX

CAS number

140-89-6

EC number

205-439-3

Molecular formula

C3H5KOS2

Linear formula

C2H5OCS2K

Molecular weight

160.30 g/mol

Chemical class

Alkali-metal xanthate

Appearance

Pale-yellow to yellow powder, crystals or pellets

Water solubility

Soluble

Main function

Selective sulfide-mineral flotation collector

Typical commercial grade

≥90% active xanthate

Common transport reference

UN 3342, Xanthates

Main handling risks

Flammable solid, irritating dust and possible carbon disulfide generation during decomposition

The approved AOZUN specification, current SDS and batch COA govern commercial acceptance and handling.

Potassium Ethyl Xanthate Specifications

The following specifications represent AOZUN’s standard industrial-grade supply profile. Confirm the applicable specification in the quotation and batch COA.

Test item

Standard specification

Appearance

Pale-yellow powder or pellets

Active ingredient

≥90.0%

Moisture and volatile matter

≤4.0%

Free alkali, calculated as KOH

≤0.2%

Insoluble matter

≤0.5%

CAS number

140-89-6

Form

Powder or pellet

Packaging

Confirm according to order and shipping route

Laboratory or synthesis grades may use a different assay method and should not be compared directly with mining-grade active-content specifications.

Why Do PEX Quality Indicators Matter?

Active Ingredient

The active-content result indicates how much usable xanthate is present in the product.

Variation in active content can change:

  • Effective collector dosage

  • Conditioning response

  • Flotation kinetics

  • Recovery

  • Concentrate grade

  • Reagent cost per tonne of ore

When comparing suppliers, use the same test method and calculation basis.

Moisture and Volatile Matter

Excess moisture can accelerate product degradation and reduce storage stability. It can also cause caking, poor flow and inconsistent dosing.

Moisture-sensitive storage is especially important in humid mining regions and partially used packaging.

Free Alkali

Free alkali is commonly calculated as KOH. It may influence product alkalinity, solution preparation and flotation-circuit chemistry.

A high free-alkali value can also indicate manufacturing inconsistency or affect reagent-balance calculations.

Insoluble Matter

Insoluble material may accumulate in:

  • Solution tanks

  • Screens

  • Pumps

  • Dosing lines

  • Valves

  • Spray systems

Controlling insoluble matter helps reduce blockage and improve dosing consistency.

Powder vs Pellet Form

Powder can dissolve rapidly but may create more dust during handling. Pellets generally provide better flow and lower dust generation but may require adequate agitation and conditioning time.

The preferred form depends on the mine’s solution system, occupational controls and feeding equipment.

How Does Potassium Ethyl Xanthate Work in Froth Flotation?

PEX contains a polar xanthate group and a short non-polar ethyl group.

Potassium Ethyl Xanthate collector used in sulfide ore froth flotation

The polar portion interacts with suitable mineral-surface metal sites, while the ethyl portion helps make the treated surface more hydrophobic. Hydrophobic particles can attach to air bubbles and rise into the froth phase.

The simplified process is:

  1. Ore is ground to liberate valuable minerals.

  2. The mineral slurry is conditioned at the required pH.

  3. Activators, depressants or other modifiers may be added.

  4. PEX is introduced as the collector.

  5. PEX interacts with suitable sulfide-mineral surfaces.

  6. Hydrophobic particles attach to air bubbles.

  7. The mineral-rich froth is collected as concentrate.

  8. Hydrophilic gangue remains mainly in the tailings.

Actual surface chemistry can involve chemisorption, metal-xanthate species and oxidation products such as dixanthogen. The dominant mechanism varies with the mineral and electrochemical conditions.

Is PEX a Strong or Selective Xanthate?

PEX is one of the shorter-chain commercial xanthates. It is generally considered relatively weak but selective.

As the hydrocarbon chain becomes longer, xanthate collecting power usually increases, while selectivity may decrease.

Xanthate

Alkyl chain

Relative collecting tendency

General positioning

Ethyl xanthate, including PEX

C2

Relatively weak

Higher selectivity for readily floatable or activated sulfides

Isopropyl xanthate

C3

Moderate

Balance of recovery and selectivity

Isobutyl xanthate

C4

Moderately strong

Broader sulfide collection

Amyl xanthate, including PAX

C5

Strong

Higher collecting power but generally lower selectivity

This comparison is a screening guide, not a guaranteed ranking for every ore.

Ore mineralogy, oxidation, liberation and water chemistry may be more important than alkyl-chain length alone.

Which Minerals Can Be Floated with PEX?

Lead Sulfide Ores

PEX is commonly evaluated for galena flotation because galena can be relatively easy to float under appropriate conditions.

Its selectivity may help improve lead-concentrate grade where excessive collection of unwanted sulfides is a concern.

Performance still depends on:

  • Galena surface oxidation

  • Liberation size

  • Zinc and iron sulfides

  • Depressants

  • pH

  • Water chemistry

  • Conditioning time

Zinc Sulfide Ores

Sphalerite often requires activation before it responds effectively to xanthate collectors. Copper sulfate is commonly used as an activator in many zinc circuits.

PEX may be selected when controlled collection and separation from other sulfides are required.

Activation conditions must be established through laboratory testing. Excess activator can reduce selectivity by activating unwanted minerals.

Copper Sulfide Ores

PEX can collect selected copper sulfides, but its relatively low collecting strength may result in slower flotation kinetics than longer-chain xanthates.

It may be considered when:

  • Copper sulfides are readily floatable

  • Selectivity against pyrite is important

  • Head grade is relatively low

  • The circuit provides sufficient conditioning and residence time

  • PEX is combined with another collector

It may not be the preferred single collector for highly oxidized, tarnished or difficult copper ores.

Nickel Sulfide Ores

PEX may be evaluated for activated or readily floatable nickel sulfide minerals such as pentlandite.

Nickel circuits commonly contain pyrrhotite, pyrite and magnesium-bearing gangue, so collector selection must consider both recovery and concentrate quality.

Gold- and Silver-Bearing Sulfide Ores

PEX may assist recovery when gold or silver is associated with floatable sulfide minerals.

PEX does not dissolve gold and is not a direct replacement for cyanide leaching. Its role is to help recover sulfide particles that may carry precious metals into a flotation concentrate.

Mineralogical testing should determine whether the valuable metal is:

  • Free

  • Locked in sulfides

  • Associated with pyrite

  • Associated with arsenopyrite

  • Present in oxidized material

  • Too finely disseminated for effective recovery

Oxidized and Tarnished Ores

PEX is not normally a strong direct collector for oxide minerals.

Some oxidized or tarnished mineral surfaces may respond after sulfidization or surface cleaning. However, reagent order and dosage become especially important, and over-sulfidization may depress flotation.

Use on oxide or mixed ores should be based on mineralogical analysis and staged flotation testing.

What Controls PEX Flotation Performance?

Ore Mineralogy

The names “copper ore,” “lead ore” or “zinc ore” are not sufficiently specific for reagent selection.

Important mineralogical information includes:

  • Valuable mineral species

  • Pyrite and pyrrhotite content

  • Degree of oxidation

  • Liberation size

  • Association with gangue

  • Clay and talc content

  • Presence of secondary copper minerals

  • Distribution of gold and silver

Particle Size

Coarse particles may detach from bubbles, while extremely fine particles may consume reagent, form slimes or reduce selectivity.

Collector selection should be evaluated together with grinding and classification performance.

pH

pH affects mineral-surface chemistry, xanthate adsorption, pyrite depression and collector stability.

Higher pH may help depress pyrite in selected copper and zinc circuits, but excessive alkalinity can also reduce the flotation of target minerals.

Low-pH conditions can accelerate xanthate decomposition. The correct pH must be established for the specific ore and reagent system.

Collector Dosage

Too little PEX can cause slow kinetics and lower recovery. Excess collector may:

  • Float unwanted sulfides

  • Reduce concentrate grade

  • Increase reagent cost

  • Increase residual xanthate in process water

  • Mask the effect of other reagents

Supplier dosage ranges are only starting points. Laboratory tests and controlled plant trials are required.

Conditioning Time

PEX needs sufficient contact with the target mineral surface. Inadequate conditioning can reduce recovery, while excessive conditioning may contribute to collector loss or undesirable interactions.

Activators and Depressants

Activators can make selected minerals more responsive to PEX. Depressants help prevent unwanted minerals from floating.

The addition sequence is critical. The same chemicals added in a different order can produce a different flotation result.

Frother Selection

PEX is a collector, not a frother. A separate frother is normally used to create a manageable bubble and froth structure.

Frother type and dosage influence:

  • Bubble size

  • Froth mobility

  • Entrainment

  • Concentrate drainage

  • Fine-particle recovery

  • Froth stability

Process Water

Dissolved ions, residual reagents, hardness, salinity and recycled-water contaminants can alter collector performance.

Bench testing should use representative plant water rather than distilled water whenever possible.

How Should PEX Solutions Be Prepared and Managed?

Potassium Ethyl Xanthate is normally delivered as a dry solid and prepared as a water solution for controlled dosing.

Preparation must follow the site procedure and current SDS.

Good practice includes:

  • Use clean, compatible equipment

  • Prevent contact with acids

  • Control dust during charging

  • Avoid excessive temperature

  • Prepare only the required quantity

  • Keep solution tanks covered and ventilated

  • Monitor solution age

  • Prevent contamination with oxidants

  • Clearly label tanks and lines

  • Avoid accumulation of residues and decomposition products

Xanthate solutions lose active strength over time. Decomposition generally becomes faster with higher temperature, lower pH and extended storage.

Concentrated solutions may not necessarily provide better stability. Solution strength, temperature and residence time should be validated at the site.

Freshly prepared solution and consistent preparation procedures improve flotation repeatability.

Why Do PEX Solutions Decompose?

Xanthates can decompose through hydrolysis, oxidation and other reactions.

Possible decomposition products include:

  • Carbon disulfide

  • Alcohol

  • Carbonate

  • Trithiocarbonate species

  • Dixanthogen and related oxidation products

Acid contact is particularly dangerous because it can accelerate decomposition and release toxic, highly flammable carbon disulfide vapor.

The rate of decomposition depends on:

  • pH

  • Temperature

  • Concentration

  • Oxygen exposure

  • Light

  • Metal contamination

  • Solution age

  • Water quality

There is no single universal shelf life for a prepared PEX solution.

Potassium Ethyl Xanthate vs Other Flotation Collectors

PEX vs PAX

PEX has a shorter ethyl chain and is generally more selective but less powerful.

PAX has a longer amyl chain and normally provides stronger collection but may recover more unwanted sulfide minerals.

PEX vs SIPX

Sodium isopropyl xanthate generally provides stronger collection than ethyl xanthate while retaining moderate selectivity.

SIPX may be considered when PEX kinetics are too slow but PAX is insufficiently selective.

PEX vs SIBX

SIBX is typically stronger and is widely used in copper and polymetallic sulfide flotation. PEX may offer an advantage where cleaner separation is more important than aggressive recovery.

PEX vs Dithiophosphates and Thionocarbamates

Specialty collectors may provide faster kinetics or better selectivity for particular copper, gold, nickel or polymetallic ores.

PEX may be used:

  • As the main collector

  • As a secondary collector

  • In a mixed-collector system

  • In cleaner or selective stages

  • As a comparison reagent during testing

The best collector cannot be selected from product literature alone.

How Should a Mine Evaluate PEX?

A useful laboratory program should compare:

  • Recovery

  • Concentrate grade

  • Selectivity index

  • Flotation kinetics

  • Mass pull

  • Water recovery

  • Froth characteristics

  • Collector consumption

  • Performance at different pH values

  • Interaction with activators and depressants

Tests should include untreated ore and relevant collector alternatives.

A plant trial should record:

  • Feed mineralogy and head grade

  • Grinding performance

  • Reagent dosage

  • Addition point

  • Conditioning time

  • pH

  • Frother dosage

  • Mass pull

  • Concentrate and tailings assays

  • Recovery by shift

  • Froth appearance

  • Process-water condition

One short trial may not distinguish reagent performance from normal plant variability.

Quality Control for Potassium Ethyl Xanthate

Active-Xanthate Analysis

Active content is commonly determined by titration. Buyers should confirm the analytical method and reporting basis.

Moisture and Volatile Matter

This test helps evaluate storage condition, degradation risk and the amount of usable dry product.

Free-Alkali Testing

Free alkali is typically expressed as KOH and supports manufacturing and batch-consistency control.

Insoluble-Matter Testing

Insoluble matter should be monitored when the product will be prepared in automated solution and dosing systems.

Appearance and Flowability

Color, odor, caking, broken packaging and flowability provide useful incoming-inspection information but do not replace chemical testing.

Why Choose AOZUN as Your PEX Supplier?

Application-Oriented Product Selection

AOZUN can review the buyer’s target mineral, ore type, current collector, required form and packaging before confirming the supply option.

Batch Documentation

Available documents may include:

  • Batch certificate of analysis

  • Safety data sheet

  • Technical data sheet

  • Packaging information

  • Transport documentation

  • Country-of-origin information

  • Regulatory statements where available

Powder and Pellet Options

Powder or pellet form may be selected according to dissolution equipment, dust controls and dosing requirements.

Availability should be confirmed when requesting a quotation.

Industrial Packaging

Packaging options may include bags, drums or bulk packages, subject to quantity, product classification and shipping route.

The approved packaging, net weight and dangerous-goods marks must be confirmed in the sales contract.

International Logistics Support

AOZUN can coordinate export documentation and shipping information with the buyer and logistics provider.

The importer remains responsible for confirming local registration, dangerous-goods storage and end-use compliance unless otherwise agreed.

Packaging and Storage

Store PEX in a cool, dry and well-ventilated warehouse.

Recommended controls include:

  • Keep containers tightly closed

  • Protect from moisture and rain

  • Protect from direct sunlight

  • Keep away from heat and ignition sources

  • Separate from acids

  • Separate from strong oxidizing agents

  • Prevent packaging damage

  • Control dust and static discharge

  • Use suitable secondary containment

  • Restrict access to trained personnel

Do not store PEX solutions for longer than the validated site holding time.

Shelf life depends on product form, packaging, temperature, humidity and storage history. Refer to the applicable AOZUN commercial documents.

Safety and Environmental Handling

Potassium Ethyl Xanthate may be classified as a flammable solid. It can be harmful if swallowed or inhaled and may irritate the skin, eyes and respiratory tract.

Decomposition can generate carbon disulfide, which is toxic and highly flammable.

Controls may include:

  • Enclosed charging and transfer

  • Effective ventilation

  • Dust collection

  • Grounded equipment

  • Chemical-resistant gloves

  • Protective clothing

  • Eye and face protection

  • Suitable respiratory protection where required

  • Emergency washing facilities

  • Fire and spill procedures based on the SDS

Never mix PEX with acids.

Prevent discharge into drains, soil and natural water. Residual xanthate and flotation-process water should be monitored and treated according to the site’s environmental permits.

Transport and Regulatory Considerations

Bulk commercial xanthates are frequently shipped under:

  • UN number: UN 3342

  • Proper shipping name: Xanthates

  • Hazard class: 4.2

Packing group and transport classification can vary with composition, form, packaging and jurisdiction. Some laboratory-product SDS documents may show a different transport status.

Always use the current AOZUN SDS and shipping documents for the actual product—not a generic online classification.

Buyers should confirm:

  • Import registration

  • Dangerous-goods permits

  • Approved storage conditions

  • Port restrictions

  • Packaging approval

  • Marine-shipping requirements

  • Workplace exposure controls

  • Environmental discharge requirements

Information to Include in Your PEX Inquiry

For a faster quotation, provide:

  • Product: Potassium Ethyl Xanthate

  • CAS number: 140-89-6

  • Required active content

  • Powder or pellet form

  • Required quantity

  • Packaging preference

  • Destination port

  • Target mineral

  • Current collector

  • Required documents

  • Delivery schedule

  • Sample or trial requirement

If available, include basic mineralogical and flotation information so the supply team can better understand the intended application.

Frequently Asked Questions

What is the CAS number of Potassium Ethyl Xanthate?

The CAS number is 140-89-6.

What do PEX and KEX mean?

Both abbreviations are commonly used for Potassium Ethyl Xanthate.

What is PEX mainly used for?

It is primarily used as a selective collector in the froth flotation of suitable sulfide minerals.

Is PEX a strong collector?

Compared with longer-chain xanthates, PEX is relatively weak but more selective. It is most useful for readily floatable or properly activated sulfide minerals.

Can PEX be used for copper flotation?

Yes, in selected copper-sulfide circuits. Its slower kinetics and lower collecting strength must be considered, especially with oxidized or difficult ores.

Can PEX float zinc minerals?

Sphalerite commonly requires activation before effective xanthate collection. The activator and collector program must be tested.

Can PEX recover gold?

PEX may help recover gold associated with floatable sulfides. It does not dissolve gold and is not a replacement for gold-leaching reagents.

Is PEX suitable for oxide ores?

Not usually as a direct collector. Some oxide or tarnished minerals may respond after sulfidization or surface treatment, but laboratory testing is essential.

What is the typical PEX dosage?

Published supplier ranges are often approximately 10–100 grams per tonne, but this is not a universal recommendation. The correct dosage must be established from ore-specific flotation tests.

Why should PEX solution be prepared fresh?

Xanthate solutions gradually lose active strength. Decomposition becomes faster under unsuitable pH, temperature and storage conditions.

Can PEX contact acid?

No. Acid contact may accelerate decomposition and release toxic, highly flammable carbon disulfide.

Should buyers choose powder or pellets?

Powder may dissolve faster but generate more dust. Pellets usually offer better flow and lower dust. The choice depends on the solution system and occupational controls.

What documents can AOZUN provide?

Available documents may include a batch COA, SDS, TDS, packaging data and transport documentation. Confirm the required documents before ordering.

Request a Potassium Ethyl Xanthate Quote

AOZUN supplies Potassium Ethyl Xanthate CAS 140-89-6 for sulfide-mineral flotation and international distribution.

Send us your required active content, product form, quantity, packaging, destination and target mineral. AOZUN will review product availability, documentation and shipping requirements before providing a quotation.

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