Chrome Reduction / Cyanide Destruction Control System — Metal Plating & Photographic Process Solutions
Named chemicals
What LibertyCES's vendor documentation shows
Regulatorily load-bearing setpoints that belong in gated synthesized content rather than an open spec table. Chrome reduction: lower pH to ~2.5 then add a reducing agent (sulfur dioxide, sodium sulfite or sodium metabisulfite); optimum pH 2.0-2.5 because the reaction slows significantly by pH 3.0 and is very slow at pH 4.0; minimum detention 15 minutes; ORP setpoint -300mV (-400mV max) generally adequate at pH 2.0; explicit vendor warning that lowering pH further than needed risks releasing hazardous sulfur dioxide gas. Cyanide destruction batch: raise pH to 11.5 with NaOH, add chlorine until ORP reaches +450mV, hold pH 11.5, then neutralize with acid plus a small amount of chlorine to convert cyanate to carbonate — with acid injection manually locked out to prevent pH dropping below 11. Two-step: stage 1 pH must be adjusted rapidly to avoid releasing extremely toxic cyanogen chloride gas, target oxidation below 0.1 ppm; stage 2 lowers pH with sulfuric acid, and modern systems often use up to a 4-hour detention time. Named cyanide-waste-generating processes: plating of copper, brass, gold and zinc; conversion coatings; chemical milling; barrel finishing; burnishing; heat treating; electrochemical machining.
Materials documented for this service
- Not a material cell — process-control chemistry; wetted materials come from the electrode and valve cells above
Products cited for this service
Sourced to
- data/vendor-sources/gf-signet-application-solutions.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.