Chemical Compatibility

Diaphragm Valve — Caustics/Bases

Moderate evidence

Named chemicals

lime slurry / calcium hydroxide (Ca(OH)2)sodium hydroxide 50%caustic soda 70%aqueous ammonia 19%

What LibertyCES's vendor documentation shows

The isolation-valve half of the lime slurry story the pump-only cell leaves open: the Type-14's weir design is specifically stated to seal bubble-tight even with slurries and suspended particles, which is the requirement in a lime feed line where a ball valve's seat pocket packs with hardened Ca(OH)2. Moderate because no vendor names lime slurry for a diaphragm valve directly — the caustics pairing data is real and concentration-specific, the lime application is corpus-level inference. Netafim's ALD70 caustic ratings are the only concentration-AND-temperature-resolved caustic diaphragm data in the corpus and show a genuinely non-monotonic pattern.

Materials documented for this service

EPDM diaphragm (Asahi's stated pairing for NaOH 50% and aqueous ammonia 19%)
3-layer EPDM/PVDF/PTFE diaphragm
PVC and PP body per ASTM D1784 CC 12454-A and D4101 CC PP0210B67272
Netafim ALD70 on caustic soda: Limit 15-50% @70°C, Limit 70% @38°C, Good 5% @50°C, Good 50% @100°C, Good 70% @50°C and @100°C

Products cited for this service

Asahi/America Type-14 Flanged Diaphragm Valve (weir design; bubble-tight sealing even with slurries and suspended particles; built-in travel stop prevents diaphragm overtightening; bayonet compressor-to-diaphragm connection)Asahi/America Type-14 True Union Diaphragm Valve (PVC/EPDM pairing for 50% NaOH and 19% aqueous ammonia per the Advanced PE chart)

Sourced to

data/vendor-sources/asahi-america-metal-replacement-valves.md
data/vendor-sources/asahi-america-advanced-pe-piping.md
data/vendor-sources/netafim-mining-heap-leaching.md
data/case-studies/solotech-lime-slurry.md

Every material and product claim on this page traces to the vendor documentation listed above. Chemical compatibility depends on exact concentration, temperature, and duty cycle — confirm current specifications with the manufacturer and request a spec review before final specification.

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