磷石膏制备硫酸铵的工艺

Process for preparation of ammonium sulfate from phosphogypsum

为了降低磷石膏生产造成的环境污染及资源浪费,利用磷石膏与氨水、二氧化碳的反应,制备出硫酸铵.用单因素试验法研究了氨碳摩尔比、液固摩尔比、反应时间、加入批次4个因素对磷石膏中硫酸钙转化率的影响,并得到了优化工艺参数.在室温条件下(25℃),工艺条件是氨碳摩尔比为1.15∶1,反应时间为1.5h,液固摩尔比为2.5∶1,加入批次为3次.结果表明,在优化工艺条件下磷石膏中硫酸钙最大转化率可达到99.08%,硫酸铵中氮质量含量(干基)可达到国家标准一等品指标,游离酸(硫酸)可达合格品指标.用磷石膏生产硫酸铵,不仅解决了磷石膏堆放造成的环境问题,同时也实现了硫资源的循环利用,具有潜在的社会效益和经济效益.

The production of ammonium sulfate using byproduct phosphogypsum and ammonia water, carbon dioxide was investigated to reduce the economic costs and energy consumption. The four factors affecting the conversion of phosphogypsum to ammonium sulfate, such as molar ratio, the ratio of liquid to solid, reaction time and batch of ammonia water were studied. At room temperature （25 ℃）, the optimum reaction conditions obtained with molar ratio of 1.15：1, reaction time of 1.5 h, the ratio of liquid to solid of 2.5： 1 and batch of ammonia water of 3 times. The maximum conversion rate of phosphogypsum to ammonium sulfate reaches 99.08% under these conditions, the content of nitrogen in ammonium sulfate （dry basis） reaches the national standard grade index, free acid （sulfate acid） reaches qualified standard. The production of ammonium sulfate with phosphogypsum not only solve the problem of environmental protection, but also realize recycling utilization of sulfur resource, therefore the method has the potential social and economic benefit.