Process for the continuous preparation of calcium cyanamide

摘要

Continous preparation of calcium cyanamide from urea and calcium oxide, calcium hydroxide or calcium carbonate by stepwise reaction at a temperature increased in steps, by a) carrying out the reaction by means of a travelling grate furnace (kiln) at temperatures of from 160 to 800 DEG C or b) reacting urea and the calcium compound at from 130 to 350 DEG C in a reactor having a horizontal axis and containing internal fittings for conveying and comminuting and also for scraping off the reaction mixture from the reactor wall and/or from the central shaft, and further reacting the mixture of calcium cyanurate obtained, which is here formed as a free-flowing powder, in a manner known per se at from 650 to 750 DEG C in a fluidised-bed reactor or in a rotary kiln to give calcium cynamide.