Research On Leaching Gold From Complex Sulfuration Mine With Chlorine Dioxide

After summing up the types of refractory gold ore for cyanide leaching, the causation of hard leaching and its pretreatment method,and literatures of non-cyanide gold-leaching,and reviewing the character of ClO₂, its preparation method, its detection method and its application instance,the paper proposed to use ClO₂ leach gold from complex sulfuration mine for the first time.The energetics equilibriums of Au and Ag, energetics actions of S, Fe, Cu and Pb and the effect of the leaching temperature, the concentration of matter and the value of pH to leaching gold were analyzed.The analyzed results showed: it is doable to leach gold with ClO₂- Cl^- and it can be realized to reclaim synthetically Au, Ag, Cu and Pb.The course of leaching gold with ClO₂- Cl^-, its mass-transfer, its velocity equation and its activation energy were analyzed,the research matter and the research method on kinetics were established that how to judge the determinative process of leaching velocity equation, how to ascertain the leaching apparent activation energy and how to ascertain the apparent reaction progressions.The condition experiments of leaching gold from complex baked sulfuration mine were carried out by pulling gas of C102.The educed optimum leaching-gold conditions for this mine were as follows: sodium chlorine concentration of 1.0mol·L-1, a pH of 2,a temperature of 50℃,a ratio of liquid to solid is 2.5 : 1 and a leaching duration of 6h.The validated experiments resulted in the optimum condition is that the extraction percentage of gold can reach 97.3%.The experiments validated that the correlative verdict of energetics is correct.In order to comparing with cyanide leaching,the experiments of leaching gold from the same mine were carried out by using cyanide in its general conditions.In addition,the kinetics experiments of leaching gold from baked complicated sulphide gold concentrate were carried out by pulling gas of ClO₂ andusing CIO2 solution.The experiments come to the conclusion that the leaching process of gold from the concentrate is under the control of mass-transfer of solid stratum,the leaching high-point velocity of stir is 800r/min^ the leaching apparent activation energy is 21.783kJmor1 and the apparent reaction progressions of CI" and CIO2 are 0.62 and 1.22 respectively,and the velocity equation of leaching gold is 1-3 (1- XB ) 2/3+2 (1- XB ) =4.56 e â–  C^} ? Cc/o2 ?' .The experiments validated that the correlative verdict ofkinetics is correct similarly.The research showed:the technology of leaching gold with chlorine dioxide are characteristics of high leaching ratio,high leaching velocity and environmental benignancy,furthermore,it is provided with extensive applicability,can be used to dispose of the refractory gold ore to cyanide leaching that contain Cu and Pb.The technology puts forward a new approach to make use of complex sulfuration mine integrativly.