用硝酸磷肥生产中副产的磷石膏制备硫酸铵和碳酸钙

随着磷矿品位的不断下降,磷复肥企业必然面对使用中低品位的磷矿。为了解决冷冻法硝酸磷肥生产中深度除钙副产磷石膏的堆积问题,以磷石膏、碳酸铵和氨水为原料进行复分解反应制备硫酸铵和碳酸钙,以实现硫资源的循环利用。考察了影响硫酸钙转化率的各种因素,通过正交实验确定了复分解反应的优惠工艺条件,并作了验证性实验。结果表明,在优惠工艺条件下磷石膏中硫的转化率可达96.7%。用磷石膏生产硫酸铵,不仅是环境保护的需要,也是废物利用、资源回收的需要,具有潜在的社会效益和经济效益。

Preparation of ammonium sulfate and calcium carbonate from phosphogypsum produced in the production of nitrophosphate

With the continuous decline in phosphate rock grade,the enterprises of phosphate compound fertilizers have to face the use of low-grade phosphate ore.In order to solve the problem of accumulation of phosphogypsum,which is a byproduct in the process of nitrophosphate production by freezing method,using phosphogypsum,ammonium carbonate and ammonia as raw materials,ammonium sulfate and calcium carbonate were prepared by double decomposition reaction,and the recycling utilization of sulfur resource was realized.The effect of the influence factors on calcium sulfate conversion was examined,and the optimal parameters of conversion process was determined by orthogonal experiment, then a confirmatory test was carried out.The results showed that the conversion rate of sulfur of phosphogypsum could reach 96.7% under the optimal conditions.The production of ammonium sulfate with phosphogypsum is not only the need of environmental protection but also the need of use waste material and resource recovery,therefore it has the potential social and economic benefits.