Fe3+作用下煤矸石中黄铁矿的氧化速率和化学计量学特征

金属矿山 ›› 2021, Vol. 50 ›› Issue (11): 121-128.

Fe3+作用下煤矸石中黄铁矿的氧化速率和化学计量学特征

金韬^1，2孟庆俊^1，2，3凤阳^1，2 胡振琪^1，2 崔雅红^1，2 冯启言^1，2，3

1. 江苏省老工业基地资源利用与生态修复协同创新中心，江苏徐州 221116；2. 中国矿业大学环境与测绘学院，江苏徐州 221116；3. 中国矿业大学矿山生态修复教育部工程研究中心，江苏徐州 221116

出版日期:2021-11-15 发布日期:2021-12-16
基金资助:
“十三五”国家重点研发计划项目（编号：2019YFC1805001）

Oxidation Rates and Stoichiometry Characteristic of Pyrite in Coal Residue under Effect of Fe3+

JIN Tao1，2 MENG Qingjun1，2，3 FENG Yang1，2 HU Zhengqi1，2 CUI Yahong1，2 FENG Qiyan1，2，3

1. Collaborative Innovation Center for Resource Utilization and Ecological Restoration of Old Industrial Base， Xuzhou 221116， China； 2. School of Environment Science and Spatial Informatics， China University of Mining and Technology， Xuzhou 221116， China； 3. Engineering Research Center of Ministry of Education for Mine Ecological Restoration，China University of Mining and Technology， Xuzhou 221116， China

Online:2021-11-15 Published:2021-12-16

摘要/Abstract

摘要： 硫铁矿含量较高的煤矸石在水、氧存在的条件下会发生氧化反应产生酸性矿山废水（AMD），而Fe3+是该氧化反应过程中的强氧化剂。为了研究Fe3+作用下各类型煤矸石的氧化特征，设置不同初始Fe3+浓度的酸性条件，对来源于3种煤系、不同硫含量的煤矸石样品KL、DZ、SX及黄铁矿样品进行氧化产酸模拟试验，并通过产酸模拟试验中的［SO42?］/［Fe2+］化学计量比来验证试验体系遵循的化学反应。结果表明，在酸性条件下，各试样的氧化速率随液相中初始Fe3+浓度的增加而增加，第1~7 d为煤矸石及黄铁矿的快速氧化反应期，氧化产酸反应主要受化学反应的控制，试验条件下该阶段黄铁矿的氧化速率可达5.23×10-5 mol/ （L·h），而KL、DZ、SX的最大氧化速率分别为1.91×10-5 mol/（L·h）、1.1×10-7 mol/（L·h）和1.5×10-6 mol/（L·h）。煤矸石试样的氧化产酸过程与纯黄铁矿有显著区别：黄铁矿的氧化速率高于煤矸石，但煤矸石的铁溶出率却高于黄铁矿。不同煤矸石的氧化特征有较大差异：净产酸潜力最低的煤矸石DZ（22.89 kg/t，以H2SO4计，后同）氧化速率低于其他矸石样品；净产酸潜力值相当的KL（92.21 kg/t）和SX （90.58 kg/t）在Fe3+的氧化反应过程中有较大差异，表现在［SO42?］/［Fe2+］化学计量比上。其中KL有着与黄铁矿相似的比值规律，遵循FeS2在对应条件下的氧化机理，但SX的［SO42?］/［Fe2+］化学计量比远高于理论值，DZ的［SO42?］/［Fe2+］化学计量比总体最高，这可能由煤矸石的产碱矿物导致的。总体而言，煤矸石所含矿物情况和风化程度造成其产酸过程的差异，含硫量越高的煤矸石其产酸污染潜力随风化程度而增加。

关键词: 风化程度及含硫量, Fe3+初始浓度, 氧化速率, 净产酸量, 化学计量比, 酸性矿山废水（AMD）

Abstract: Coal residue with high pyrite contents could be oxidized in the presence of water and oxygen，and produce acid mine drainage （AMD）. Fe3+ is a stronger oxidant in this oxidation reaction. In order to study the oxidation characteristics of coal residue under the effect of Fe3+， the acid conditions with different Fe3+ initial concentrations were set up to simulate the oxidation of coal residue samples KL， DZ， SX from three coal measures with different sulfur contents and pyrite samples， and the ［SO42?］/［Fe2+］ stoichiometry in the acid production simulation test was used to verify the chemical reaction followed by the experimental system. The results showed that the oxidation rate of each sample increases with the increase of Fe3+ initial concentration in the liquid phase under acidic conditions. The experimental period of 1~7 days is the rapid oxidation reaction period of coal gangue and pyrite， and the acid production reaction is mainly controlled by chemical reaction. Under the experimental conditions， the oxidation rate of pyrite could reach 5.23×10-5 mol/(L·h)， the maximum oxidation rates of KL， DZ and SX were 1.91×10-5 mol/（L·h）、1.1×10-7 mol/（L·h） and 1.5×10-6 mol/（L·h）， respectively. It is found out that the oxidation process of coal residue is significantly different from that of pure pyrite. The oxidation rate of pyrite is higher than that of coal residue， but the iron dissolution rate of coal residue is higher than that of pyrite. The oxidation characteristics of different coal residue are quite different. DZ （22.89 kg/t， converted by H2SO4， the same later） with the lowest net acid production potential has lower oxidation rate than other coal residue， but KL （92.21 kg/t） and SX （90.58 kg/t） with the same net acid production potential have great differences in the oxidation process of Fe3+， which is showed in the ［SO42?］/［Fe2+］ stoichiometric ratio. KL has a similar ratio with pyrite， which follows the oxidation mechanism of FeS2 under the corresponding conditions ， but the ratio of SX is much higher than the theoretical value. This may be due to the composition of alkali producing minerals of coal residue. In general， the mineral contents and weathering degree of coal residue lead to the difference of acid production process. The higher the sulfur contents of coal gangue， the acid production pollution potential increases with the degree of weathering.

Key words: weathering degree and sulfur contents, Fe3+ initial concentration, oxidation rate, net acid production quantity, stoichiometric proportion, acid mine drainage（AMD）

金韬, 孟庆俊, 凤阳, 胡振琪, 崔雅红, 冯启言, . Fe3+作用下煤矸石中黄铁矿的氧化速率和化学计量学特征[J]. 金属矿山, 2021, 50(11): 121-128.

JIN Tao, MENG Qingjun, FENG Yang, HU Zhengqi, CUI Yahong, FENG Qiyan, . Oxidation Rates and Stoichiometry Characteristic of Pyrite in Coal Residue under Effect of Fe3+[J]. Metal Mine, 2021, 50(11): 121-128.

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