Ferric Chloride
The real challenge isn't chemical resistance — it's separation, settling, and elevated delivery temperature.
Ferric chloride is mainly a separation, settling and temperature problem, not a chemical-resistance problem. It is often delivered hot, so the tank must accommodate that structurally, and settled material makes pumping difficult without active mixing. A tank that is chemically compatible but lacks heat and mixing provisions will still fail operationally.
Ferric Chloride: identifiers
| CAS Registry Number | 7705-08-0 |
|---|---|
| Molecular formula | Cl3Fe (Hill notation) |
| Molecular weight | 162.20 g/mol |
| PubChem record | CID 24380: Iron chloride (FeCl3) |
What Ferric Chloride Storage Actually Needs
Heat pads and insulation
Reduces separation/settling. Ferric chloride is often delivered at elevated temperature, which means storage needs to account for tank expansion/contraction from that delivery temperature, not just ambient conditions.
Mixing system
Prevents separation — ferric chloride, like alums and polymer coagulants, presents a real settling/coagulation issue. Settling causes real pumping difficulty downstream if not actively prevented in storage.
Scrubber (if venting outdoors)
Protects surrounding vegetation from ferric fumes — this is a real, documented hazard, not a theoretical concern. Outdoor tank venting without scrubbing can defoliate nearby foliage.
XLPE (crosslinked polyethylene) tolerates the expansion/contraction from elevated delivery temperature better than standard polyethylene. A true-bottom-drain design (like Poly Processing's IMFO tank line) aids sludge control and cleaning — addressing the settling issue directly, not just containing the chemical.
Frequently Asked Questions
What makes ferric chloride storage different from a simple corrosive-chemical tank?
The real challenge isn't just chemical resistance — it's separation and settling. Ferric chloride (like alums and polymer coagulants) presents coagulation/settling issues compounded by temperature variation. A tank that's chemically compatible but lacks heat/mixing provisions will still have real pumping difficulty from settled material.
Why does ferric chloride need heated storage?
It's often delivered at elevated temperature, and the storage tank needs to accommodate the resulting expansion/contraction, not just store the chemical at ambient temperature. Heat pads and insulation also reduce separation/settling, which is a real operational issue independent of the chemical-compatibility question.
Can ferric chloride tank vents be a real hazard?
Yes — ferric fumes can defoliate surrounding vegetation, a documented real hazard for outdoor-vented tanks. A scrubber is required specifically when venting outdoors, not a generic best-practice suggestion.
What tank material and configuration is recommended for ferric chloride?
XLPE (crosslinked polyethylene), which tolerates the expansion/contraction from elevated delivery temperatures better than standard polyethylene. A true-bottom-drain tank design (like Poly Processing's IMFO line) aids sludge control and cleaning, addressing the settling issue directly rather than just containing the chemical.
Ferric chloride pump: keeping metal out of the wetted path
Ferric chloride attacks most metals, so a non-metallic pump keeps metal out of the wetted path. For bulk unloading and day-tank fill, the FTI Air FT30P puts polypropylene housings, plastic seats and a choice of eight diaphragms in contact with the fluid, and moves up to 300 gpm at 120 psi air.
Ferric is dense (check the SDS for SG) and stains everything, so plan exhaust piping and diaphragm-failure detection. We confirm materials for your grade and temperature in spec review. Size it first with the diaphragm pump sizing calculator.
Specifying a ferric chloride storage/dosing system?
Send LibertyCES your delivery temperature, storage volume, and venting configuration — we'll help avoid the settling and fume issues before they happen.
Ready to buy or need a fast answer? Call, text, or email James directly — (559) 395-5500 · [email protected].
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Reviewed by James Riggins, 30+ years specifying water and chemical process equipment · Updated