It is demonstrated that a low grade, silver containing manganese deposit can be exploited by reaction with a ZnS concentrate. In the process, Mn(IV) is reduced to Mn(II) and the ZnS converted to ZnSO4. In the process,...It is demonstrated that a low grade, silver containing manganese deposit can be exploited by reaction with a ZnS concentrate. In the process, Mn(IV) is reduced to Mn(II) and the ZnS converted to ZnSO4. In the process, Mn and Zn are solubilized. By studying the effects of quantity of reducing agent and sulfuric acid added and of time, temperature and liquid-to-solid ratio on the leaching process, the optimum technological conditions have been achieved under which the amount of manganese leached was 98 %. The silver can be removed from remaining solids by adding ammonia liquor. Then by adding hydrazine hydrate, sponge silver with purity up to 99 % can be obtained with a recovery of 87 %.展开更多
The kinetics of internal chlorination of Ni-Cr-Ce alloy in chlorine at 575℃ has been studied.Internal chlorination of Ni-Cr-Ce alloy occurred to formation of CrCl_(2) and CeCl_(3) solid precipi-tates which is thermod...The kinetics of internal chlorination of Ni-Cr-Ce alloy in chlorine at 575℃ has been studied.Internal chlorination of Ni-Cr-Ce alloy occurred to formation of CrCl_(2) and CeCl_(3) solid precipi-tates which is thermodynamically stable and has lower vapor pressure at the temperature along grain boundaries.At initial corrosion stage,the internal chlorination rate nearly followed parabolic rate law,the internal chlorination was accompanied by the consumption of the alloy by volatilization corrosion which obeyed a linear rate equation,the thickness of the internal chlorination region would be governed by a paralinear rate equation.After a sufficiently long period of corrosion,the rate of internal chlorina-tion would be equal to the rate of overall metal consumption,the depth of internal chlorination approaches a steady state value.Addition of Ce to Ni-Cr alloy increased the degree of internal chlorination.展开更多
文摘It is demonstrated that a low grade, silver containing manganese deposit can be exploited by reaction with a ZnS concentrate. In the process, Mn(IV) is reduced to Mn(II) and the ZnS converted to ZnSO4. In the process, Mn and Zn are solubilized. By studying the effects of quantity of reducing agent and sulfuric acid added and of time, temperature and liquid-to-solid ratio on the leaching process, the optimum technological conditions have been achieved under which the amount of manganese leached was 98 %. The silver can be removed from remaining solids by adding ammonia liquor. Then by adding hydrazine hydrate, sponge silver with purity up to 99 % can be obtained with a recovery of 87 %.
文摘The kinetics of internal chlorination of Ni-Cr-Ce alloy in chlorine at 575℃ has been studied.Internal chlorination of Ni-Cr-Ce alloy occurred to formation of CrCl_(2) and CeCl_(3) solid precipi-tates which is thermodynamically stable and has lower vapor pressure at the temperature along grain boundaries.At initial corrosion stage,the internal chlorination rate nearly followed parabolic rate law,the internal chlorination was accompanied by the consumption of the alloy by volatilization corrosion which obeyed a linear rate equation,the thickness of the internal chlorination region would be governed by a paralinear rate equation.After a sufficiently long period of corrosion,the rate of internal chlorina-tion would be equal to the rate of overall metal consumption,the depth of internal chlorination approaches a steady state value.Addition of Ce to Ni-Cr alloy increased the degree of internal chlorination.
