Potassium Amyl Xanthate (PAX) Storage & Tank Compatibility

Storing Potassium Amyl Xanthate (PAX)? Start Here

Potassium amyl xanthate, widely known by the trade abbreviation PAX, is one of the most important sulfhydryl collectors in sulfide-mineral froth flotation. With the formula _C6H11KOS2 it is the potassium salt of O-pentyl dithiocarbonic acid, supplied as a pale-yellow powder, pellet or flake that dissolves readily in water to give a mildly alkaline reagent solution. In the flotation circuit the xanthate anion chemisorbs onto copper, lead, zinc, nickel and precious-metal sulfides, rendering them hydrophobic so they report to the froth. The dissolved reagent is the form that contacts storage and dosing equipment, and it is well-matched to polyethylene. The solid, however, demands respect: it is a flammable, self-heating material that decomposes on exposure to moisture, heat or acid to release flammable and toxic carbon disulfide. Sound storage design keeps the product cool, dry and isolated from acids and oxidizers until it is dissolved for use.

Is Polyethylene (HDPE / XLPE) Compatible With Potassium Amyl Xanthate?

Yes - for the aqueous reagent solution, high-density polyethylene (HDPE) and cross-linked polyethylene (XLPE) are the recommended tank materials, and they are the resins flotation plants actually use for bulk PAX storage and mixing. Polyethylene is chemically inert toward the alkaline xanthate salt and its dilute solutions, so it will not corrode, scale or contaminate the reagent the way carbon steel does. The important caveats are about the chemistry of the product itself, not the resin. First, store the solid dry: xanthates are self-heating, flammable solids that liberate carbon disulfide on contact with moisture, heat or acid, so a polyethylene mixing or day tank should be vented, kept cool, and protected from acid carryover. Second, keep oxidizers and strong acids out of the tank and bund. Third, choose chemically appropriate ancillaries - EPDM gaskets, polypropylene or PVC/CPVC piping - and confirm any fluoroelastomer (FKM) seals against the sulfur chemistry before service. Used this way, a polyethylene tank gives long, trouble-free life on aqueous potassium amyl xanthate.

Material compatibility at a glance

Aqueous potassium amyl xanthate solutions are mildly alkaline organosulfur salts, and high-density and cross-linked polyethylene handle them very well. HDPE and XLPE tanks are the standard choice for bulk reagent storage and day tanks at flotation plants. Keep the product dry until it is dissolved: solid PAX is a self-heating, flammable solid that liberates flammable, toxic carbon disulfide on contact with moisture, heat or acid. Pair the polyethylene tank with EPDM seals, PP or PVC/CPVC dosing lines, vented and bunded layout, and keep all incompatible acids, oxidizers and ignition sources well away.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Carbon disulfide hazard: Contact with moisture, heat or acid decomposes xanthates to flammable, toxic carbon disulfide. Keep the solid dry, store away from acids, and ensure storage and mixing areas are well ventilated.
• Flammable, self-heating solid (H228): Keep away from heat, sparks, open flame and other ignition sources; avoid dust accumulation and confined hot storage that can promote self-heating.
• Corrosive and irritant (H314 / H318): Causes severe skin and eye damage. Wear chemical-resistant gloves, goggles or face shield, and protective clothing; provide emergency eyewash and shower.
• Skin absorption and sensitization (H311 / H317): Toxic in contact with skin and may cause an allergic skin reaction; prevent all skin contact and practice strict hygiene.
• Aquatic toxicity (H411 / H412): Toxic to aquatic life with long-lasting effects. Bund tanks, prevent releases to drains and waterways, and manage spills as hazardous waste.
• Storage discipline: Keep containers tightly closed, cool and dry; segregate from oxidizers and acids; follow the product-specific SDS for ventilation, grounding and incompatible-material lists.

Common questions

Can I store potassium amyl xanthate solution in an HDPE or XLPE tank?

Yes. For the aqueous reagent solution, HDPE and XLPE are the recommended and industry-standard tank materials. Polyethylene resists the mildly alkaline xanthate salt solution and will not corrode like steel. Keep the solution from picking up acid, pair the tank with EPDM seals and PP or PVC/CPVC piping, and vent the tank.

Why is potassium amyl xanthate considered hazardous if the solution is compatible with plastic?

The compatibility rating is about the storage material; the hazard is about the chemistry of the product. Solid PAX is a flammable, self-heating solid that decomposes on contact with moisture, heat or acid to release flammable, toxic carbon disulfide. It is also corrosive and an aquatic toxin. Polyethylene handles the solution well, but you still need ventilation, acid segregation and full PPE.

What materials should I avoid with potassium amyl xanthate?

Avoid carbon steel for wet contact, since aqueous xanthate and liberated carbon disulfide drive corrosion and sulfide attack. Treat stainless steel and fluoroelastomer (FKM/Viton) seals as conditional and verify them against the sulfur chemistry. Above all, keep the product away from acids and oxidizers, which trigger decomposition.

What is potassium amyl xanthate used for?

It is a sulfhydryl collector used in sulfide-mineral froth flotation. Dissolved in water and dosed into the flotation circuit, the xanthate adsorbs onto copper, lead, zinc, nickel and precious-metal sulfides, making them water-repellent so they attach to air bubbles and report to the froth concentrate.