Method comparison for the determination of total cyanide in deposited blast furnace sludge

摘要

Blast furnace sludge is a cyanide-containing waste created during pig iron production.In this study the determination of total cyanide in 32 sampels of a disused blast furnace slugdge deposit was investigated using two methods.One method is based on a weight-in of solid material followed by an acid digestive distillation .If using a distillation time of 1hk,which is based on a weight-in of solid material followed by an acid digestive distillation.If using a distillation time of 1h,which is laid down in Germany as the standard emthod,total cyanide is understimated.If the distillation time is prolonged to 2h,the cyanide determination is quantitative.Resulsts of these modifications of the German standard emthod were statistically equal to those obtained by an alkaline extraction using 1 M sodium hydroxide repeated three-fold,and followed by an acid digestive distillation of the extracts 9y=8.4+0.991x;r=0.996;n=32).On an average,in the first extract 85%,in the second extract 12%,and in the extract 3% of total cyanide was dissolved.Determination of total cyanide in deposited blast furnace sludge can be performed by an acid digestive digestion ofsolid matewrial for 2h as well as by a repeated extraction by means of 1M sodium hydroxide.