| 摘要 |
<p>Ammonium chloride is made from tower liquors of an ammonia-soda process by passing dry gaseous ammonia and carbon dioxide into said liquors in such amounts that at 35-40 DEG C. the ammonia concentration does not exceed 4.5% by weight and the carbon dioxide concentration does not exceed 5.4% by weight, saturating the resulting liquors with sodium chloride at 35-40 DEG C., cooling to - 11 DEG C., and separating crystallized ammonium chloride. The tower liquors, i.e. those remaining after sodium bicarbonate removal, are a solution of ammonium chloride and sodium chloride saturated with sodium bicarbonate, and containing small amounts of ammonium carbonate/bicarbonate complexes. An increase in yield of ammonium chloride from 15 to 20% is achieved over a process in which tower liquors are treated using 25% by weight aqueous ammonia solution instead of gaseous ammonia and carbon dioxide.</p> |
