PROCESS AND APPARATUS FOR THE CONTINUOUS CALORIMETRIC DETERMINATION OF THE CYANIDE CONCENTRATION IN AQUEOUS SOLUTIONS

摘要

A B S T R A C TAccording to the invention, cyanide concentrationsof from about 0.001 to 5 mg cyanide/1 are continuouslydetermined colorimetrically by the known cyanide-picricacid color reaction. The solution containing freecyanide and/or cyanide releasable from cyano complexes isreacted for 1 to 60 minutes at 50 to 120°C in a gastightclosed system in the presence of chelating agentsto form the color complex and the extinction value ismeasured by spectral photometry.The process avoids the extraction step hithertonecessary for cyanide concentrations below 0.2 mg CN/1 anderrors attributable to HCN- outgassing losses, is simpleto handler largely immune to interference and suitable forthe continuous monitoring of wastewater streams or forthe control of cyanide detoxification processes.