With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission c...With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.展开更多
Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decompositio...Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.展开更多
基金Project(50904001) supported by the National Natural Science Foundation of ChinaProject(2010SQRL032D) supported by Anhui Provincial Key Science Foundation for Outstanding Young Talent,ChinaProject(TD200909) supported by Program for Innovative Research Team in Anhui University of Technology,China
文摘With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.
基金Project(51404296)supported by the Young Scientists Fund of National Natural Science Foundation of ChinaProject(134414)supported by the Postdoctoral Funded Program of Central South University,China
文摘Carbonate decomposition of carbonic refractory gold ore and the following pressure oxidation were studied.In the carbonate decomposition procedure,the effects of liquid-to-solid ratio and reaction time on decomposition ratio of carbonate were investigated.The experimental result shows that the decomposition ratio of carbonate is 98.24%under the conditions of liquid-to-solid ratio of 5:1,Fe^(3+)concentration of 20 g/L,sulfuric acid concentration of 20 g/L,reaction temperature of 80 ℃ and reaction time of 2 h.Then,the slurry obtained from carbonate decomposition was put into the titanium autoclave for pressure oxidation leaching.Effects of liquid-to-solid ratio,temperature,time and oxygen partial pressure on sulfur oxidation ratio were studied during pressure oxidation.With the prolonged time,pyrite and arsenopyrite are oxidized to ferric subsulfate,hydrated ferric sulfate and jarosite,resulting in the increasing residue ratio.The residue ratio and the sulfur content in the residue can be decreased by ferric subsulfate dissolution.The oxidation ratio of the sulfur is 99.35% under the conditions of oxidation time of 4 h,temperature of 210 ℃,oxygen partial pressure of 0.8 MPa and stirring speed of 600 r/min.
