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首页> 外文会议>International Conference on Copper 2003-Cobre 2003 v.6 book 1; 20031130-20031203; Santiago; CL >The role of non-oxidative processes in the leaching of chalcopyrite
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The role of non-oxidative processes in the leaching of chalcopyrite

机译：非氧化过程在黄铜矿浸出中的作用

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摘要

It has previously been believed that the dissolution of chalcopyrite in acidic ferric solutions occurs by a typical oxidative process which can be described by the mixed potential electrochemical model. However, it has been demonstrated in this study that a parallel non-oxidative dissolution process must also be taken into account in the description of the kinetics. Thus, the direct oxidation path is characterized by the well known rapid initial dissolution rate which decays to a slow rate at longer times. This has been shown to be the case for potentials within the so-called passive region in the anodic behaviour of chalcopyrite and is typical of the situation with ferric ions as the oxidant under ambient conditions. The effect of potential on the rate of the oxidative process has been found to be relatively small in the potential region 0.5 to 0.75 V with significantly increased rates only in the transpassive region above 0.75 V. The effect of potential on the rate of the non-oxidative process has also been studied at potentials below the oxidative region and there appears to be no noticeable effect of potential on the rate in this potential region. Rotating ring-disk experiments have been used to confirm the simultaneous production of copper ions, ferrous ions and hydrogen sulfide during the dissolution in sulfuric acid solutions. Furthermore, it is suggested, without direct experimental evidence, that the non-oxidative reaction can be sustained by oxidation of the hydrogen sulfide by ferric ions. This model for the oxidative process will be described and a quantitative simulation of this scheme has produced results which are remarkably consistent with the observed rates of dissolution. These observations could provide an alternative explanation for the enhanced dissolution previously observed at low potentials in the presence of ferrous and cupric ions.
机译：以前认为，黄铜矿在酸性铁溶液中的溶解是通过典型的氧化过程发生的，该过程可以用混合电势电化学模型来描述。然而，在这项研究中已经证明，在动力学描述中还必须考虑平行的非氧化溶解过程。因此，直接氧化路径的特征在于众所周知的快速初始溶解速率，该溶解速率在更长的时间内衰减为缓慢的速率。事实证明，在黄铜矿的阳极行为中，所谓的无源区内存在电势，这是在环境条件下以铁离子作为氧化剂的典型情况。已经发现，电势对氧化过程的速率的影响在0.5至0.75 V的电势区域中相对较小，只有在0.75 V以上的透射型区域中电势的影响才显着增加。还已经在低于氧化区域的电势上研究了氧化过程，并且似乎对该电势在该电势区域中的速率没有明显影响。旋转圆盘实验已被用于确认溶解在硫酸溶液中的同时产生铜离子，亚铁离子和硫化氢。此外，建议在没有直接实验证据的情况下，可以通过三价铁离子氧化硫化氢来维持非氧化反应。将描述该氧化过程的模型，并且对该方案的定量模拟已产生与观察到的溶解速率明显一致的结果。这些观察结果可以为先前在亚铁和铜离子存在下在低电势下观察到的增强溶解提供另一种解释。

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