摘要
从微观层次讨论火法熔炼过程中贱金属相及锍相捕集贵金属的原理。认为捕集作用的发生是由于熔融的渣相和贱金属相两者的组成结构差异很大。渣相靠共价键和离子键把硅、氧原子和Ca^2＋，Mg^2＋，Fe^2＋等离子束缚在一起，键电子都是定域电子，贵金属原子在熔渣中不能稳定存在。金属相靠金属键把原子束缚在一起，原子间的电子可以自由流动。贵金属原子进入金属相可降低体系自由能。锍在高温下具有相当高的导电率（数值在10^3～10^4S·cm^-1范围），且温度系数呈负值，属电子导电。熔锍的性质类似金属，因此，在造锍熔炼过程中，贵金属原子进入熔锍而不进入熔渣。
The micro-mechanism of precious metals trapped in pyro-metallurgical processes by base metals or their mattes were discussed in present paper. It was forwarded that the reasons for trace amount of precious metals trapped into base metals or mattes were that the melted slag phases possessing very different structure and properties from that the melted base metal or matte phases. For the slag phase, its formation is thought depending on the covalent bonds and the ionic bonds between Si, O atoms and Ca^2 ＋, Mg^2＋ , Fe^2＋ ions to tie up between each other. Because the bonding electrons in the slag phases are all thought as the localized electrons, the precious metal atoms are not stable among them. However, for the metal phase, its formation is thought depending on the metal bonds to bind up together the metal atoms. And because the electrons in the metal phases can move freely among the atoms, the precious metal atoms entering into the metal phase can cause the system free energy decreased. For the melted mattes phase,because it has high conductivities （between 10^3 - 10^4 S· cm^-1） at the higher temperature, and its temperature coefficients present the negative values, its conductance belongs to the electron conductance. The properties of the matte are in fact similar with that of metal at their melted state, therefore precious metal atoms will enter into the matte phase, but not the slag phase in matte-smelting process.
出处
《中国工程科学》
2007年第5期11-16,共6页
Strategic Study of CAE
基金
国家自然科学基金资助项目(50374060)
关键词
火法冶金
镍锍
贱金属
捕集
铂族金属
pyro-metallurgy
matte smelting
trapping
precious metals
