Study On The Ferric Nitrate Preparation Technology Using Waste Acid Of Stainless Steel

Stainless steel products is widely used in daily life and industrial and agriculturalproduction as a good performance in the new material, and in it production processwill produce the large amount of waste acid which major part are waste HNO3.Theexisting domestic and overseas on the recycling of waste acid pickling stainless steelmethod is mainly to high temperature high-temperature calcinations, andneutralization process, the film filtering method, solvent extraction anddecompression evaporation method which exist equipment disposable investment big,technical difficulties of high and energy consumption high of problems. This study isused to this kind of technology is simple and feasible crystallization, low cost ofrecycling waste of nitric acid method Fe(NO₃)₃·9H₂O, realize the hazardous wasteresources, environmental benefit optimization, in line with the policy of sustainabledevelopment.Research is use existing waste of nitric acid, analysis of its contain impurity ionsand content, through the experimental analysis of various impurity ions oncrystallization method recovery Fe(NO₃)₃·9H₂O influence and studies thecorresponding treatment plan. The experiment got the Fe(NO₃)₃·9H₂O industrialproduction of crystal condition, the mother liquor to concentrate the proportion ofcrystallization of1.52, nitric acid additives in the mother liquor quality concentratedaround3%, adding amount of seed in the mother liquor quality5%, the crystallizationtemperature control in0℃and85r/min speed mixing1h after the quiet placecrystallization after1h centrifugal; Get the crystallization in sulfate on the influenceof nitric acid iron crystallization, when its content than the1.56g/L when the ironrecovery nitric acid is lower than50%; Get the raw materials need to be controlled inthe heavy metal Cu, Zn, Ni, Cr impurity ions under the condition of the way to dealwith, take control of3.2%nitric acid added when heavy crystallization method ofremoving impurity ions into crystals; Get the small production process conditions andproducts. After the study on the product quality inspection and analysis and the energy analysis, crystallization method can effectively recycling waste simple nitricacid, and the product Fe(NO₃)₃·9H₂O accord with industrial standards.Through the research of stainless steel pickling liquid waste got in thepreparation of industrial waste nitric acid Fe(NO₃)₃·9H₂O of crystal condition factors,and related the impurity ions removal process control conditions and simple, make upfor scrap nitric acid treatment the shortcomings of the methods to some extent.