Gold recovery with ion exchange used resins
Gold recovery with ion exchange used resins
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DOI：
10.1016/s1383-5866(00)00211-2
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发表时间：
2001-06-01
影响因子：
8.6
通讯作者：
Loureiro, JM
中科院分区：
文献类型：
--
作者：
Gomes, CP;Almeida, MF;Loureiro, JM
本文研究了一种强酸、一种强碱和一种弱碱性离子交换树脂在工业除盐装置中的失效情况。用于从氰化物溶液中回收金。基于观察到的恢复能力和再生的容易性。选用弱碱性阴离子交换剂Purolite A-100。这种废树脂在60 ℃之前是稳定的，再生后也是如此。与新的相比保持了其物理性质。测定了树脂的平衡数据。证明了树脂对金的非常高的容量（类似于500 mA Au/g干树脂），并通过Freundlich和质量作用等温线模型建模。一个动力学实验中进行的一批吸附器和建模与等效菲克的扩散率使用线性驱动力近似，表明膜阻力传质控制操作。最后，用氰化金使固定床吸附器饱和，并用氢氧化钾溶液再生。用于模拟这两个步骤的模型包含轴向分散和离子扩散率的相同等效性。在洗脱过程中。在树脂内部发生二水合金氰化钾的沉淀，增加了颗粒内对传质的阻力。该模型能够合理地代表实验洗脱结果时，使用一个大的内部传质阻力。在该饱和/洗脱过程中获得初始金溶液的25倍浓度，尽管沉淀，但显示该方法用于回收金、增加树脂的使用寿命和减少污染的可行性。阴离子Purolite A-100树脂也显示出显著的除去银的能力，尽管低于除去金的能力，这可能是因为银氰化物络合物平均占据树脂中多于一个的离子交换位点。(C)2001 Elsevier Science B.V.保留所有权利。
In this paper one strong acidic, one strong basic and one weak basic ion-exchange resins, considered as exhausted in an industrial demineralizing plant. are screened for gold recovery from cyanide solutions. Based on the observed ability for the recovery and on the ease of regeneration. the weak base anion exchanger Purolite A-100 is selected. This spent resin is stable until 60 degreesC and, after regeneration. conserves its physical properties as compared with a new one. Equilibrium data for the resin are determined. proving the very high capacity of the resin for gold ( similar to 500 ma Au/g dry resin) and modeled by the Freundlich and mass action isotherm models. A kinetic experiment is conducted in a batch adsorber and modeled with an equivalent Fick's diffusivity using the linear driving force approximation, showing that the film resistance to mass transfer controls the operation. Finally, a fixed bed adsorber is saturated with gold aurocyanide and regenerated with a potassium hydroxide solution. The model used for the Simulation of both steps incorporates axial dispersion and the same equivalence for the ionic diffusivity. During the elution process. precipitation of dihydrated potassium aurocyanide occurs inside the resin, increasing the intraparticle resistance to mass transfer. The model is able to reasonably represent the experimental elution results when a large internal resistance to mass transfer is used. A 25-fold concentration of the initial gold solution is obtained in this saturation/elution process, albeit the precipitation, showing the feasibility of the method for the recovery of gold, increasing the useful life of the resins and decreasing pollution. The anionic Purolite A-100 resin showed also a significant capacity for removing silver, although less than for gold, probably because silver cyanide complexes occupy, on the average, more than one ion exchange site in the resin. (C) 2001 Elsevier Science B.V. All rights reserved.