Study On The Recovery And Utilization Of Ru/AC Catalyst

As the second generation catalyst for ammonia synthesis,ruthenium has great significance for energy saving and emission reduction.Ru based ammonia synthesis catalyst has high activity,but ruthenium belongs to noble metal and has high cost.It is very important for the industrialization of Ru ammonia synthesis catalyst to recover the ruthenium in the catalyst conveniently and efficiently.A series of single component samples K/AC,Ba/AC,Ru/AC samples,two components samples KxRu/AC,BaxRu/AC,and three components samples KxBaRu/AC and BaxK.Ru/AC samples were prepared with graphitized activated carbon as earrier.N2 physical adsorption,chemisorption mass spectrometry,TG,EA,XRD,ICP and other characterization methods were used to study the mass change,the product and the composition and proportion of the final products of roasting.The main conclusions are as follows:During the process of catalytic oxidation of different K sources,the similarity between K2CO3/AC and KOH/AC is very high.The KNO3/AC decomposes oxygen at about 430 ?.From the point of view of economy,safety and equipment,K2CO3 is a suitable catalyst for the catalytic oxidation of graphitized activated carbon.The activated carbons containing different amounts of oxygen were obtained by nitric acid oxidation and high temperature heat treatment,and the functional groups containing oxygen played the role of reaction sites in the gasification process of activated carbons.The mechanism of K2CO3 catalyzed graphitization of activated carbon is the reaction with surface oxygen-containing functional groups,which leads to the initiation of reaction.K,Ba and Ru can significantly reduce the initial reaction temperature and the maximum weightlessness rate temperature,and are favorable for CO2 generation.When the metal content in the catalyst is more than 8%,the catalytic effect will be weakened.In the BaxRu8/AC system,the increase of Ba content is conducive to the oxidation of carbon,reduce the oxidation temperature and reduce the formation of CO.The roasting products include BaRuO3 and RuO2.In the KxRu8/AC system,Ru basically exists in the form of K2RuO4,and has little filtration residue which is conducive to the recovery of ruthenium.The recovery of ruthenium can be over 71%.In the KBaRu/AC system,the proportion of BaRuO3 and K2RuO4 in roasting products can be controlled by adjusting the amount of Ba and K in the catalyst.If the recovery product is K2RuO4,the KBaRu/AC component catalyst can be soaked in HNO3 to remove barium,then soaking K.After roasting,K2RuO4 can be obtained,and the recovery rate of ruthenium can reach up to 90%.