Chemical compatibility chart for dosing pumps
Key: A = recommended, B = acceptable with limits, C = limited / short-term, X = not recommended. Ratings are a general guide at ambient temperature (about 20–30 °C). Temperature, concentration and impurities change results, so always confirm with us before ordering.
| Chemical | SS316 | PP | PVDF | PTFE | Alloy 20 | Hastelloy C | Note |
|---|---|---|---|---|---|---|---|
| Sodium hypochlorite 10–15% | X | A | A | A | X | B | Use PVDF/PP liquid end with PTFE diaphragm; avoid metals. |
| Hydrochloric acid 30–33% | X | A | A | A | X | B | PP or PVDF diaphragm pump preferred. |
| Sulphuric acid 10–50% | X | A | A | A | A | A | Dilute acid is more corrosive to SS316 than concentrated. |
| Sulphuric acid 98% | B | X | A | A | A | A | Alloy 20 or PVDF/PTFE; keep water out. |
| Nitric acid up to 30% | A | B | A | A | A | B | SS316 is suitable for dilute nitric acid. |
| Phosphoric acid 85% | B | A | A | A | A | A | Alloy 20 for hot or contaminated acid. |
| Hydrofluoric acid 40% | X | B | A | A | X | B | PVDF/PTFE only; special safety precautions. |
| Acetic acid (glacial) | A | B | A | A | A | A | |
| Caustic soda (NaOH) 50% | A | A | C | A | A | A | PVDF not recommended for strong caustic. |
| Ammonia solution 25% | A | A | A | A | A | A | |
| Hydrogen peroxide 35–50% | A | B | A | A | A | B | Use degassing valve; SS316 must be passivated. |
| Ferric chloride | X | A | A | A | X | B | Highly corrosive to stainless steel. |
| Alum (aluminium sulphate) | B | A | A | A | A | A | |
| Poly aluminium chloride (PAC) | X | A | A | A | B | A | Chlorides attack SS316. |
| Polyelectrolyte (polymer) | A | A | A | A | A | A | Viscous: size suction line generously. |
| Chlorine dioxide solution | X | B | A | A | X | C | PVDF/PTFE preferred. |
| Sodium bisulphite / metabisulphite | B | A | A | A | A | A | |
| Lime slurry | A | A | A | A | A | A | Abrasive: use ball valves and flushing. |
| Antiscalant / scale inhibitor | A | A | A | A | A | A | Check the product datasheet. |
| Corrosion inhibitor | A | B | A | A | A | A | Many are solvent-based: confirm PP compatibility. |
| Methanol | A | A | A | A | A | A | Flammable: use flameproof motor. |
| Toluene / aromatic solvents | A | X | A | A | A | A | Avoid PP and EPDM seals. |
| Diesel / fuel oil additives | A | B | A | A | A | A | |
| Sodium silicate | A | A | A | A | A | A | |
| Biocide (glutaraldehyde / isothiazolinone) | A | A | A | A | A | A |
Choosing the liquid end
The liquid end is everything that touches the chemical: pump head, check valves, balls, seats and diaphragm or plunger. Diaphragms are usually PTFE-faced. Elastomer seals (Viton, EPDM) must also suit the chemical. Tell us the chemical, concentration and temperature and we will specify every wetted part.
Questions
Which pump material is best for sodium hypochlorite?
PVDF or PP liquid end with a PTFE diaphragm and ceramic or PTFE balls. Stainless steel and Alloy 20 are not recommended for hypochlorite.
Can SS316 pumps handle hydrochloric acid?
No. Hydrochloric acid attacks SS316. Use PP, PVDF or PTFE; Hastelloy C is an option for metal construction.
Which material suits concentrated sulphuric acid?
Alloy 20, PVDF or PTFE are commonly used for 98% sulphuric acid. PP is not recommended for concentrated sulphuric acid.
Is PVDF good for caustic soda?
PVDF is not recommended for strong caustic soda. Use SS316, PP or PTFE for sodium hydroxide.
Not sure which material?
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