A separation technique based on the selective adsorption characteristics for an acid-salt mixture on an anion-exchange resin was used to separate acid and salt from solution. Its application can lead to the recovery and reuse of the waste acid solution in such metallurgical process as steel pickling and mineral extraction. Experimental studies were carried out in this work. Concentrated nitric acid and cuprous nitrate were treated with the strong anion-exchange resin Dowex 1. In column experiments the concentrated acid solution used was about 3 N and the cuprous nitrate concentration about 15 to 25 g/L. After the treatment, about one-fifth to one-third of the treated waste solution can be recovered and reused.