An in situ characterization technique called electrochemical noise(ECN) was used to investigate the bioleaching of natural pyrite.ECN experiments were conducted in four active systems(sulfuric acid,ferric-ion,9k culture medium,and bioleaching solutions).The ECN data were analyzed in both the time and frequency domains.Spectral noise impedance spectra obtained from power spectral density(PSD)plots for different systems were compared.A reaction mechanism was also proposed on the basis of the experimental data analysis.The bioleaching system exhibits the lowest noise resistance of 0.101 MΩ The bioleaching of natural pyrite is considered to be a bio-battery reaction,which distinguishes it from chemical oxidation reactions in ferric-ion and culture-medium(9k) solutions.The corrosion of pyrite becomes more severe over time after the long-term testing of bioleaching.
研究在硝/硫混酸体系中浸出铜阳极泥中硒的动力学和影响硒的浸出过程的主要参数。结果表明,硒的浸出速率与搅拌速度无关,而与浸出温度以及硫酸和硝酸的浓度相关。硒的浸出包括两个阶段:在第一阶段,硒的浸出活化能为103.5 k J/mol,硒的浸出主要由化学反应控制,硒的浸出与硫酸浓度无关,而与硝酸浓度相关,其反应级数为0.5613;在第二阶段,硒的浸出活化能为30.6 k J/mol,硒的浸出由扩散和化学反应混合控制。此时,硒的浸出与硝酸的浓度基本无关。
