Kinetics of Hydrochemical Oxidation of Antimonite in Solutions of Nitric Acid
The kinetics of hydrochemical oxidation of antimonite in solutions of nitric acid was studied using the rotating disk method and the factor experiment design. The dependences of the antimonites oxidation rate on concentration of nitric acid solutions, temperature, disk rotation frequency, and duration of interaction were determined. The adequate kinetic models allowing calculating the specific oxidation rate at any combination of the values of the influencing factors were obtained.The oxidation process is found to proceed in a mixed mode, close to chemically ontrolled.Gradually, as the sediments of elemental sulphur and Sb2O5 accumulate on the disk surface, the process becomes controlled by internal diffusion. The observed high (more than second) order of the oxidation rate with respect to the concentration of nitric acid was explained by the autocatalytic action of the acid reduction products.The apparent activation energy depends on the stage of interaction. At the initial stage (in a mixed mode of the process proceeding), it depends on nitric acid concentration and varies from 31.5 kJ·mol-1 (in 2 M HNO3) to 36.1 kJ·mol-1 (in 10 M HNO3). This trend indicates the weakening of diffusion limitations with a nitric acid concentration increase. When the process is controlled by internal diffusion, the apparent activation energy was found to be 14.5 kJ·mol-1.The obtained kinetic characteristics enlarge the database on hydrochemical oxidation kinetics of sulphides and can be used for the elaboration of the recommendations for the effective comprehensive exploitation of antimony-bearing ores and concentrates.
Antimonite Nitric acid Hydrochemical oxidation Kinetics
A.E. Sobolev V.I. Lutsik P.M. Solozhenkin
Tver State Technical University, Department of Chemistry, Russia Institute of Complex Exploitation of Mineral Resources, Russian Academy of Sciences, Moscow, Russia
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
2717-2722
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）