Dependence of reaction rate of pyrite oxidation on temperature,pH and oxidant concentration  

作　　者：LU Long1, WANG Rucheng2, XUE Jiyue2, CHEN Fanrong1 & CHEN Jun2 1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Department of Earth Sciences, Nanjing University, Nanjing 210093, China 

出　　处：《Science China Earth Sciences》2005年第10期1690-1697,共8页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant No.40025209);the Hundred Talents Program of the Chinese Academy of Sciences(Grant No.2000[254]).

摘　　要：The kinetic sstudy of pyrite oxidation was performed in a series of experiments by a mixed flow reactor. The release rates of Fe(II) are in the order of 3.22×10?9-5.51×10?7 mol·m?2·s?1 at temperature (T ) 25 to 44℃, initial pH (pH )1.4 to 2.7, and initial Fe(III) concen-tration ([Fe(III)]i) 10?5 to 5×10?3 mol·kg?1. The release rate of Fe(II) increased with increasing T or/and pH or/and [Fe(III)]i in the above range. The rate law and activation energy of pyrite oxida-tion were derived by statistical analyses of RFe(II) vs. [Fe(III)]i, RFe(II) vs. pH and RFe(II) vs. T, and are given as (1) Rate law: RFe(II) 4.65 64.54 103 8.310.600.4510 e[Fe(III)][H ]? ×Ti= +; (2) activation energy: 64.54 ± 8.07 kJ·mol?1. The expression can be applied to more cases (e.g., quantifying the pollutant re-leased from sulfide-rich mining waste and assessing reliable performance of underground re-pository sites where pyrite acts as an engineered barrier material). Using the rate law derived from this study, the magnitude of the pollutants transferred to secondary phases, soil and water from oxidized pyrite during Jiguanshan mine waste weathering was preliminarily estimated. The estimated magnitude is very high, suggesting that the pile has possibly posed significant impact on the water quality in this region.The kinetic sstudy of pyrite oxidation was performed in a series of experiments by a mixed flow reactor. The release rates of Fe(II) are in the order of 3.22×10?9-5.51×10?7 mol·m?2·s?1 at temperature (T ) 25 to 44℃, initial pH (pH )1.4 to 2.7, and initial Fe(III) concen-tration ([Fe(III)]i) 10?5 to 5×10?3 mol·kg?1. The release rate of Fe(II) increased with increasing T or/and pH or/and [Fe(III)]i in the above range. The rate law and activation energy of pyrite oxida-tion were derived by statistical analyses of RFe(II) vs. [Fe(III)]i, RFe(II) vs. pH and RFe(II) vs. T, and are given as (1) Rate law: RFe(II) 4.65 64.54 103 8.310.600.4510 e[Fe(III)][H ]? ×Ti= +; (2) activation energy: 64.54 ± 8.07 kJ·mol?1. The expression can be applied to more cases (e.g., quantifying the pollutant re-leased from sulfide-rich mining waste and assessing reliable performance of underground re-pository sites where pyrite acts as an engineered barrier material). Using the rate law derived from this study, the magnitude of the pollutants transferred to secondary phases, soil and water from oxidized pyrite during Jiguanshan mine waste weathering was preliminarily estimated. The estimated magnitude is very high, suggesting that the pile has possibly posed significant impact on the water quality in this region.

关 键 词：temperature  OXIDANT concentration  pH  oxidation rate  pyrite  environmental effect. 

分 类 号：P595[天文地球—地球化学] P618.31[天文地球—地质学]