Cyanide, Hexavalent Chromium and Solvent Management
This is the part of industrial pretreatment where an operating error can kill someone in the
building, or in a manhole a street away. It deserves to be learned precisely.
The incompatibility that comes first
Cyanide and acid must never be allowed to meet. Acidifying a cyanide solution liberates
hydrogen cyanide gas, which is acutely lethal at very low airborne concentrations. Hydrogen
cyanide is sometimes described as smelling faintly of bitter almonds, but the ability to detect it
is genetically variable and olfactory fatigue sets in quickly, so odour may be absent
entirely at a dangerous concentration.
Practical consequences:
- Cyanide lines, sumps, tanks and containment are kept physically segregated from acid systems
- separate containment with no shared drain or spill path, separate and clearly identifie