Recycling method for the preparation and processing of a hydroxyl ammonium salt solution

摘要

An improved process is described for the reduction of ammonium ions, while avoiding any increase in nitrate ion concentration, in a liquid stream recycled between a zone of synthesis of hydroxyl ammonium salt and a zone for synthesis of oxime, wherein the liquid stream is contacted with a gas stream consisting essentially of nitrogen monoxide and containing nitrogen dioxide at a pressure above 1 atmosphere, at a temperature of at least 80 DEG C., such that after the contact the molar NO2/NO ratio of the gas stream is within the range of between about 10-1 to 10-4:1.