| 摘要 |
Fertilizers are prepared by treating solid mineral acid decomposition products of raw mineral phosphates with concentrated ammonia in countercurrent at above 75 DEG C., the water evaporated by the reaction being prevented from condensing in the decomposition products or in the ammonia reaction products obtained therefrom which have absorbed less ammonia than 1-2 molecules of ammonia per molecule of phosphoric acid. The water vapour produced by the reaction may be wholly or partially condensed in such reaction products as contain ammonia in the ratio of approximately 2 molecules of ammonia to 1 molecule of phosphoric acid. The product may be completely saturated with ammonia. The process may be carried out in a rotary drum having means for feeding in the solid decomposition products at one end and ammonia at the other, a cooling tube extends half-way along the drum from the end at which the solid products enter and underneath this is a gutter or channel in which the condensed water is collected and removed, e.g. into contact with such products as have absorbed approximately 2 molecules of ammonia per molecule of phosphoric acid. Alternatively the treatment with concentrated ammonia in countercurrent at above 75 DEG C. may be carried out so that the main reaction with ammonia takes place as close as possible to the place of entry of the solid decomposition products into the apparatus, an excess of ammonia being used.ALSO:Fertilizers are prepared by treating solid mineral acid decomposition products of raw mineral phosphates with concentrated ammonia in counter current at above 75 DEG C., the water evaporated by the reaction being prevented from condensing in the decomposition products or in the ammonia reaction products obtained therefrom which have absorbed less ammonia than 1-2 molecules of ammonia per molecule of phosphoric acid. The water vapour produced by the reaction may be wholly or partially condensed in such reaction products as contain ammonia in the ratio of approximately 2 molecules of ammonia to 1 molecule of phosphoric acid. The product may be completely saturated with ammonia. The process may be carried out in a rotary drum having means for feeding in the solid decomposition products at one end and ammonia at the other; a cooling tube extends half-way along the drum from the end at which the solid products enter and underneath this is a gutter or channel in which the condensed water is collected and removed, e.g. into contact with such products as have absorbed approximately 2 molecules of ammonia per molecule of phosphoric acid. Alternatively the treatment with concentrated ammonia in counter current at above 75 DEG C. may be carried out so that the main reaction with ammonia takes place as close as possible to the place of entry of the solid decomposition products into the apparatus, an excess of ammonia being used. |
