METHOD FOR THE PREPARATION OF A HARDENING SALT IN LUMP FORM

摘要

For the preparation of a salt mixture for hardening steel parts, consisting of potassium cyanate, potassium carbonate and sodium carbonate, 2.2 to 2.3 moles of urea is first reacted with 1 mole of potassium carbonate to form potassium cyanate. The escaping ammonia is converted with formaldehyde into hexamethylenetetramine. The reaction product, consisting of potassium cyanate and potassium carbonate, is ground, mixed with powdered sodium carbonate and pressed at between 80 and 230.degree.C into composites. The process has the advantages of: good recovery of ammonia, good yield of cyanate, very low formation of cyanide, and conventional powder press technology utilization.