Dithiophosphate Promoter (Aerofloat) Storage & Tank Compatibility

Storing Dithiophosphate Promoter (Aerofloat)? Start Here

Dithiophosphate “promoters” — historically sold under the Aerofloat name — are sulfide-mineral flotation collectors built around dialkyl or diaryl (dicresyl) dithiophosphoric acid and its sodium or ammonium salts. They are used to recover copper, lead, zinc, nickel, and precious-metal sulfides, frequently alongside xanthates, and the diaryl “promoter” grades also add frothing character. Acid-form grades are dark, oily, cresylic liquids; some grades are amine- (aniline-) stabilized, and water-solution grades are the corresponding salts.

Material of construction matters because the as-supplied concentrate is an oily organic reagent — carrying cresol/cresylic acid and, in many grades, a flash point — not a simple aqueous salt. The dominant compatibility driver is therefore organic/cresol absorption and flammability, with a secondary corrosion concern: acidic dithiophosphate solutions can degrade over time and liberate hydrogen sulfide. Picking the wrong tank risks swelling, stress cracking, and a flammable or odorous release.

Polyethylene (HDPE / XLPE) Compatibility with Dithiophosphate (Aerofloat) Promoter

Verdict: Unsuitable (U) for the as-supplied concentrate. Polyethylene is not recommended for oily, cresylic acid-form Aerofloat reagents. The active chemistry is carried in cresol/cresylic acid and exists as an organic dithiophosphoric ester/acid — and published polyethylene resistance data rate cresols as only marginal on HDPE, satisfactory near ambient but subject to attack at elevated temperature. Organic and cresylic media are absorbed into the polyethylene matrix, which swells, softens, and becomes prone to environmental stress cracking; flammable cresylic grades also sit outside the intended service of tank-grade poly.

The dilute sodium-salt water solution used at the mill is much milder on plastics, but the bulk product as delivered is the concentrate, so tank selection must follow the concentrate. Use 316 stainless or a solvent/cresol-resistant FRP for the reagent, line bare steel against acidic attack, and pair with Viton (FKM) seals. Always confirm the specific grade against its SDS Section 7 (Handling & Storage) before committing to a tank material.

Material compatibility at a glance

Store concentrated dithiophosphate (Aerofloat) promoter in 316 stainless or a solvent/cresol-resistant FRP — not in polyethylene. The as-supplied reagent is an oily, cresylic, often flammable organic blend that polyethylene absorbs and swells, so HDPE/XLPE is unsuitable for the concentrate. Acidic grades are also corrosive to bare steel and can liberate hydrogen sulfide on decomposition; line steel and provide ventilation. Pair with Viton seals and avoid EPDM. Dilute sodium-salt make-down solutions are milder, but tank selection should follow the as-supplied concentrate.

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

• Flammable / combustible (acid-cresylic grades): H226 — vapors can form ignitable mixtures; keep away from heat, sparks, and open flame; bond and ground during transfer.
• Hydrogen sulfide risk: acidic dithiophosphate solutions can decompose over time and liberate toxic H₂S — keep storage alkaline-stabilized per supplier guidance, ventilate, and monitor confined spaces.
• Irritant: H315, H319, and H335 — causes skin and serious eye irritation and may irritate the respiratory tract; wear chemical goggles, gloves, and use local ventilation.
• Harmful if swallowed / organ effects: H302 and H373 — the cresol and aniline content can damage organs on prolonged or repeated exposure; minimize contact and inhalation.
• Environmental hazard: H411 — toxic to aquatic life with long-lasting effects; provide secondary containment and prevent releases to soil and water.
• Storage: Keep cool, ventilated, and away from acids, oxidizers, and ignition sources; use compatible (stainless/FRP) containment with proper venting and spill control.

Common questions

Can I store dithiophosphate (Aerofloat) promoter in a polyethylene (HDPE or XLPE) tank?

Not for the as-supplied concentrate. The reagent is an oily, cresylic, often flammable organic blend, and cresol/organic media are absorbed by polyethylene — resistance charts rate cresols only marginally on HDPE and note attack at elevated temperature. That leads to swelling, softening, and stress cracking, and flammable grades sit outside poly's intended service. Use 316 stainless or a solvent/cresol-resistant FRP and confirm against the SDS.

What tank material should I use for an Aerofloat-type collector?

For the concentrated reagent, 316 stainless steel or an FRP built with a solvent/cresol-resistant resin is the safe choice. Bare carbon steel can be used for some grades but should be lined and given a corrosion allowance because acidic dithiophosphate solutions can be corrosive over time. Pair with Viton (FKM) seals and avoid EPDM.

Why is hydrogen sulfide a concern with dithiophosphate reagents?

Salts of dialkyl dithiophosphate become unstable when the solution turns acidic (around pH 6 or below): over time they can polymerize and decompose, releasing hydrogen sulfide and other byproducts. Keep storage alkaline-stabilized per the supplier, ventilate, and treat tanks and headspace as potential H2S environments.

Is the diluted mill solution different from the bulk product for tank selection?

Yes — the dilute sodium-salt water solution used at the flotation circuit is much milder on plastics than the oily concentrate. But the product you receive and store in bulk is the concentrate, so tank material must be chosen for the concentrate (stainless or cresol-resistant FRP), not the diluted working solution.