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
The similarities and differences in seepage flow evolution laws of CH4 and CO2 during complete stress- strain process of samples were comparatively analyzed. The results show that the seepage flow evolution laws of CH...The similarities and differences in seepage flow evolution laws of CH4 and CO2 during complete stress- strain process of samples were comparatively analyzed. The results show that the seepage flow evolution laws of CH4 and CO2 are extremely similar during the stress-strain process, showing that the character- istic first decreased and then increased. A mathematical model was also established according to the rela- tionship of seepage velocity and axial strain. However, due to the strong adsorption ability of CO2, the coal samples generated a more serious ''Klinkenberg effect'' under the condition of CO2. Owing to this, the CO2 seepage flow resulted into occurrence of ''stagnation'' phenomenon during the late linear elastic stage II. In the strain consolidation stage III, the increment rate of CH4 seepage velocity was significantly greater than that of CO2. In the stress descent stage IV, when the axial load reached the peak pressure of coal, the increment rates of CH4 seepage velocity presented a turning point. But the changing rate of CO2 seepage velocity still remained slow and a turning point was presented at one time after the peak of thestrain pressure, which showed an obvious feature of hysteresis.展开更多
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.
基金supported by the National Natural Science Foundation of China (Nos. 51074197 and 50674111)the Natural Science Foundation of CQ CSTC (No. 2010BB6118)the Fundamental Research Funds for the Central Universities (No. CDJXS11241181)
文摘The similarities and differences in seepage flow evolution laws of CH4 and CO2 during complete stress- strain process of samples were comparatively analyzed. The results show that the seepage flow evolution laws of CH4 and CO2 are extremely similar during the stress-strain process, showing that the character- istic first decreased and then increased. A mathematical model was also established according to the rela- tionship of seepage velocity and axial strain. However, due to the strong adsorption ability of CO2, the coal samples generated a more serious ''Klinkenberg effect'' under the condition of CO2. Owing to this, the CO2 seepage flow resulted into occurrence of ''stagnation'' phenomenon during the late linear elastic stage II. In the strain consolidation stage III, the increment rate of CH4 seepage velocity was significantly greater than that of CO2. In the stress descent stage IV, when the axial load reached the peak pressure of coal, the increment rates of CH4 seepage velocity presented a turning point. But the changing rate of CO2 seepage velocity still remained slow and a turning point was presented at one time after the peak of thestrain pressure, which showed an obvious feature of hysteresis.
