Prodn of salt mixture for hardening of steel parts - by pressing together potassium cyanate, potassium carbonate and sodium carbonate.

摘要

A salt mixt to be used to make a hardening bath for steel parts is produced by reacting 2.2-2.3 mol thiourea with 1 mol potassium carbonate at 350-400 deg C. The product is ground to a powder of size 125-250 microns and mixed with sodium carbonate powder of size 20-125 microns. The obtd mixture is pressed into the solid bodies at 80-230 deg C and 65-100 KN/cm2. The ammonia given off during the reaction of thiourea and potassium carbonate is reacted with formaldehyde to produce hexamethylene tetramine solution. ADVANTAGE - Good yield of cyanate is achieved without producing any cyanide and without polluting the hexamethylene tetramine solution with sublimed thiourea.