BS ISO 20950-1:2018

This document specifies operationally defined methods for the determination of available WAD cyanide in various types of water such as drinking, ground, and surface, waters, and metallurgical processing tailings reclaim, heap leach barren, mill slurry tailings and leaching solutions, with cyanide concentrations from 5µg/l to 2000mg/l expressed as cyanide ions in the undiluted sample. The range of application can be changed by varying the operation conditions, e.g. by using a different injection volume, thicker membrane, detector response, etc.

NOTE ISO2080:2008, 3.105, defines free cyanide. The concentration of available WAD cyanide includes free cyanide and some of the metals complexed in solution as determined by a specified analytical method but not all of the metal complexes present in total cyanide(3,191).

In this method, six suitable mass concentration ranges from 5µg/l to 50µg/l, from 50µg/l to 500µg/l, from 0,5mg/l to 5mg/l, from 5mg/l to 50mg/l, from 50mg/l to 500mg/l and from 500mg/l to 2000mg/l are described.