摘要
采用热分析法研究了黄铁矿的氧化反应历程,得出升温速率分别为5℃/min、10℃/min和15℃/min条件下的TG-DTG曲线和表征参数;通过耦合Popescu法、Coats-Redfem法及Flynn-Wall-Ozawa法确定了黄铁矿氧化反应机理的模式函数为Avrami-Erofeev方程(n=3/2),符合随机成核和随后生长机理,3种升温速率下的活化能分别为230.2 k J/mol、198.8 k J/mol和187.4 k J/mol,指前因子分别为2.06×1010s-1、1.28×108s-1和1.43×107s-1;根据活化络合物理论,活化能和指前因子之间存在补偿效应,其动力学补偿方程为ln A=0.16729E-14.72689。
The present paper is aimed to study the kinetics of pyrite oxidation and its compensation function at different heating rates. As is known, FeS2 spontaneous combustion is one of the severe natural disasters in the metal mines and the main cause leading to the coal gangue spontaneous combustion and the spontaneous combustion of the sour oil tank. In order to solve the problem, we have adopted the X-ray fluorescence spectrometer for analyzing the pyrite ore sample and made a conclusion that the sample in the pyrite ore contains FeS2 by a rate of 88.15 %. Furthermore, when we applied the simultane- ous thermal analysis technology to study the oxidation process of pyrite ore sample, we have found that it would be possible to obtain the TG - DTG curves and characteristic parameters of pyrite at the heating rates of 5 ℃/min, 10 ℃/min arid 15 ℃/min. Based on the analy- sis of the thermo-gravimetric and derivative thermo-gravimetric curves, it can be concluded that the initial reaction temperatures can be 489 ℃ , 483 ℃ and/or 491 ℃, whereas the termination reaction temperatures should be 540 ℃, 557℃ and/or 598 ℃ , in addition to the maximum weight loss rate at the temperatures of 520 ℃ , 518 ℃ and/or 529 %, with the corresponding weight loss in the order of 3.6 mg, 3.3 mg and 3.4 mg at the heating rates of 5 ℃/min, 10 ℃/min and 15 ℃/min. When the data processing is over, it would be possible to apply the Popescu, Coats-Redfem and FWO methods in a.comprehensive manner. In addition, it has to be pointed out that the kinetic mechanism function of the pyrite oxidation can be taken as the combined use of the Avrami-Erofeev equation （ n = 3/2） and the kinetics reaction process of pyrite oxidation with the random nucle- ation and later growth mechanism. Furthermore, we have worked out the amount of the corresponding activation energy, which is equal to 230.2 kJ/mol, 198.8 kJ/mol and 187.4 kJ/mol, respectively at 5 ℃/min, 10 ℃/min and 15 ℃/min, with the corresponding pre-ex- ponential factors being 2.06 × 10l·s-1 , 1.28 x l0s s-1 and 1.43 × 107 s- 1, respectively. According to the activated complex theory, we can find the compensation effect is displaying its role between the ac- tivation energy and pre-exponential factor, which can be expressed as lnA = 0.16729E- 14.72689 and the correlation coefficient is 0. 999 62.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2016年第1期77-81,共5页
Journal of Safety and Environment
基金
国家自然科学基金项目(51174153
51374164)
中央高校基本科研业务费专项(2014-zy-097
2012-Ⅱ-011)
关键词
安全工程
黄铁矿氧化
动力学
补偿效应
safety engineering
pyrite oxidation
kinetics
compen- sation effect
