Research On Recovery Of Acid Water In Production Of Concentrated Nitric Acid

In the production of concentrated nitric acid by the magnesium nitrate process,a large quantity of acid water has been produced,the majority of which be discharged to the neutralizing pond,and after neutralization with an alkali to the standard has been then discharged.That leads to a great loss.This paper did some simulation research on acid wastewater treatment which produced by Lanzhou Petrifaction company’s nitric acid plant.Furthermore,it was mainly aimed at reforming the process of nitric acid wastewater by caustic neutralization to recycling dilute nitric acid form wastwater,which in order for the wasterwater to be recyled.The simulation process separated acid gas through its quantity of heat and vacuum distillation technique.And then,the dilute nitric acid which be separated returned to the dilute nitric acid unit.Finally,60%nitrate would being getted by concentrated.With this technique,nitrate content in water was lower,and the water quality was up to the recycling standard.The reseach showed that the reforming process could recycled a large quality of nitric acid and water,and removed the liquid caustic which used in neutralizion.After transformation,the unit will recycle 1.56t 30%dilute nitric acid per hour(12,500t per year),10.34t water per hour(82,700t per year),reducing 20%neutralization alkali to 1.5t per hour(being converted to pure alkali 2,400t per year),reducing emission of 13.5t reaching standard wastewater per hour(108,000t per year).All of this will create good effects on social and economy.