The dissolution and leaching of minerals Mechanisms, myths and misunderstandings
The dissolution and leaching of minerals Mechanisms, myths and misunderstandings
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DOI：
10.1016/j.hydromet.2013.08.003
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发表时间：
2013-07-01
期刊：
影响因子：
4.7
通讯作者：
Crundwell, F. K.
中科院分区：
文献类型：
--
作者：
Crundwell, F. K.
矿物的溶解对许多领域都很重要。特别是，溶解的速度是重要的。对动力学的了解可能会使速度加快或减慢，这取决于努力的领域。在了解溶解机理时，人们特别感兴趣的是反应的顺序。在氧化剂中，矿物的溶解动力学常常被发现接近半个数量级。溶解的电化学机制描述了这种依赖关系。然而，关于矿物溶解和电化学机制的一些误解反复出现，需要加以解决。本文解决了其中的七个误区，并得出以下结论：(I)机理不同于化学途径，(Ii)表面不分离为阳极点和阴极点，(Iii)不存在电子流过矿物主体，(Iv)氧化和还原反应是通过电子转移而不是通过化学键合的活化态耦合的，(V)多硫化物不钝化表面，(Vi)溶解反应的第一步不是酸，以及(Vii)固体不需要是电导体就可以通过电化学机制溶解。(C)2013爱思唯尔B.V.保留所有权利。
The dissolution of minerals is of importance to a number of fields of endeavour. In particular, it is the rate of dissolution that is important. Knowledge of the kinetics might allow the rate to be accelerated or retarded, depending on the field of endeavour. In understanding the mechanism of dissolution, it is the order of reaction that is of particular interest. The kinetics of dissolution of minerals are frequently found to be close to one-half order in the oxidant. The electrochemical mechanism of dissolution describes this dependence. However, a number of misunderstandings about the dissolution of minerals and the electrochemical mechanism recur, and need to be addressed. This paper addresses seven of these misunderstandings, and makes the following conclusions: (i) mechanism is not the same as chemical pathway, (ii) there is no separation of the surface into anodic sites and cathodic sites, (iii) there is no flow of electrons across the bulk of the mineral, (iv) the oxidation and reduction reactions are coupled by the transfer of electrons, not by a chemically bonded activated state, (v) polysulphides do not passivate the surface, (vi) the first step of the dissolution reaction is not by acid, and (vii) the solids do not need to be electrical conductors to dissolve by the electrochemical mechanism. (C) 2013 Elsevier B.V. All rights reserved.