Potassium nitrate prodn in high yield - from excess calcium nitrate with potassium chloride in low temp aqs alcohol

摘要

A water-miscible additive consisting of mono- or poly-alcohols or ketones is added to the reaction mixture at 10 - 65%, keeping the aqs. additive mixture at max. + 5 degrees C and using excess calcium nitrate to give a ratio E = equiv. Ca++/equiv. Cl- of 1.05 - 1.55 in the soln. The KNO3 obtd. is then separated from the mother liquors. Prefd. reaction temp. is -5 to +5 degrees C and ratio E is 1.10 to 1.35. Prefd. additives are methanol, ethanol, glycol or acetone. The calcium nitrate used is pref. an impure by-product of fertiliser mfr. obtd. in the reaction of natural phosphates with H2SO4. Before reaction with KCl, lime or CaCO3 is pref. added. Process gives yield of ca. 95% and prevents formation of double-salt CaCl2. KNO3.2H2O.