title: Extraction of molybdenum and vanadium from the spent diesel exhaust catalyst by ammonia leaching method.
abstract: Molybdenum (Mo) and vanadium (V) were effectively extracted from the spent diesel exhaust catalyst (V2O5-MoO3/TiO2) by using an ammonia leaching method. Meanwhile, the structure of the spent catalyst carrier (TiO2) was not destroyed and might be reused. The effects of ammonia (NH3 · H2O) concentration, leaching temperature and time, concentration of hydrogen peroxide (H2O2) and liquid to solid ratio on the extraction of Mo and V were systematically investigated. It is shown that the extraction efficiency of Mo increased from 68.68% to 96.45% while the extraction efficiency of V remained stable at 27% with increasing ammonia concentration from 2.95 to 7.38 mol/L, leaching temperature from 298.15 to 473.15K, and reaction time from 1 to 8h. With the concentration of H2O2 solution increasing from 1.0 to 2.5 mol/L, the extraction efficiency of V increased from 26.87% to 39.73%. Under the optimum conditions (the ammonia concentration of 4.5 mol/L, leaching temperature of 413.15K, reaction time of 2h, the H2O2 solution concentration of 1.0 mol/L and the liquid to solid ratio of 20/1 mL/g), the extraction efficiencies of Mo and V reached 95.13% and 46.25%. Moreover, the catalyst carrier TiO2 with anatase crystal phase was also obtained.
authors.affiliation: Beijing key Laboratory of Green Recycling and Extraction of metals, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China.
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Beijing key Laboratory of Green Recycling and Extraction of metals, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China. Electronic address: guomin@ustb.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Guo
authors.affiliation: Beijing key Laboratory of Green Recycling and Extraction of metals, School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, PR China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D008982:Molybdenum / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry; D014639:Vanadium / Q000737:chemistry*; D001335:Vehicle Emissions
chemical_list: D001335:Vehicle Emissions; D014639:Vanadium; C009495:titanium dioxide; D000641:Ammonia; D008982:Molybdenum; D014025:Titanium
keywords: Ammonia leaching; Anatase TiO(2); Molybdenum; Spent diesel exhaust catalyst (V(2)O(5)–MoO(3)/TiO(2)); Vanadium