金的氰化物在白云母表面的吸附研究

Study on adsorption of gold cyanide on muscovite surface

针对浸金过程中白云母与金的氰化物的吸附现象,采用实验与量子化学计算相结合的方法进行研究。在不同搅拌时间条件下,搅拌吸附实验证明金的氰化物与白云母表面均能发生吸附,最大吸附率和单位吸附量分别为8.07%和0.019 mg/g。利用Materials Studio软件中基于密度泛函理论的CASTEP模块进行量子化学计算,计算金的氰化物在白云母(001)表面的吸附,得到白云母最佳结构优化参数为密度泛函GGA-PBESOL,k点为6×3×1,截断能为360 eV;确定白云母的原子层厚度为3.8188 nm,真空层厚度为1.6 nm。模拟计算表明,金的氰化物在白云母表面的吸附能分别为-134.63 kJ/mol、-185.28 kJ/mol,两种离子均能吸附在白云母(001)表面。Mulliken布居分析表明,金的氰化物中的N原子电子转换到白云母表面Si原子上,N原子与Si原子成键,且成键作用较强。

The method of combining experiments and quantum chemical calculations is used to study the adsorption phenomenon of muscovite and gold cyanide in the gold leaching process.The stirring adsorption experiments under different stirring times prove that adsorption occurs on both gold cyanide and muscovite surface,and the maximum adsorption rate and unit adsorption amount are 8.07%and 0.019 mg/g,respectively.The CASTEP module based on density functional theory(DFT)in Materials Studio was used to perform quantum chemical calculations of gold cyanide adsorption on muscovite surface of(001).The optimum structure parameters of muscovite include a density functional GGA-PBESOL,a k-point of 6×3×1,and a cutoff energy of 360 eV were received.The atomic layer thickness and the vacuum layer thickness of the muscovite were determined to be 3.8188 nm and 1.6 nm,respectively.The simulations show that the adsorption energies of the gold cyanide on the muscovite surface are-134.63 kJ/mol and-185.28 kJ/mol,respectively,and both kinds of ions can be adsorbed by the muscovite surface of(001).The Mulliken charge population analysis shows that the electrons of N atoms in the gold cyanide transfer to Si atoms of the muscovite surface,and the N atoms form bonds with the Si atoms with a strong bonding effect.