Ald Diaphragm Chlorine Nitric Acid Limits Heap Leaching

Direct answer: Netafim's Mining Products catalog publishes a real chemical resistance chart for ALD70, the diaphragm material used across its 75/90/100 Series valves in heap-leaching service (the 'MIN' mining configuration). Several named chemicals rate flatly 'Not Good' regardless of concentration or temperature: nitric acid (not good even at 10%), chlorine dioxide, and chlorine gas. Sulfuric acid - the primary heap-leaching lixiviant for copper/uranium/nickel extraction per this same catalog's own process diagram (Cu2O3 + H2SO4 -> Cu2(SO4)3 + H2O) - is rated only to 38C max, a notably more restrictive limit than this project's existing sulfuric acid guidance which centers on PVDF/PTFE/FEP/PFA tank and pipe materials surviving to much higher temperatures at high concentration. This is a real, actionable reminder that a valve's diaphragm elastomer can be the limiting material in a system even when the body/liner material handles the chemical fine at higher temperature - relevant to any heap-leaching, gold/silver cyanide, or chlorine-based quote using this valve family. Netafim's own catalog identifies the fix: components can be ordered in Hastelloy instead, explicitly because Hastelloy 'is resistant against chlorine gas, hypochlorite and chlorine dioxide solutions' and has 'excellent resistance against concentrated solutions of oxidizing salts (such as iron III and copper chloride).'