Method for washing and purifying phosphogypsum

The invention discloses a method for washing and purifying ardealite. Calcium and sulfur in the ardealite are fully utilized. The ardealite is digested without generating secondary waste residues; acid-making tail gas absorption is well controlled, and up-to-standard tail gas emission can be achieved; the byproduct sulfur is used for sulfuric acid production, so that the outsourcing amount and the transportation amount of sulfuric acid are reduced, and the cost is reduced. Meanwhile, the method increases the yield of sulfuric acid, so that 85%-90% of sulfuric acid used in phosphoric acid production is circulated, and the ardealite does not need to be stored in a storage yard and also does not need to be transported outwards. 本发明设计公开了一种磷石膏水洗净化的方法，磷石膏中的钙和硫得以充分利用；磷石膏被消化而不产生二次废渣；控制好制酸尾气吸收，可实现尾气达标排放；副产的硫用于硫酸生产，减少了硫酸的外购量和运输量，降低了成本。同时，该方法增加了硫酸产量，使磷酸生产使用的硫酸有85%～90%自身循环，磷石膏不需要堆场，也不需要外运。