Demonstration Plant Equipment Design and Scale-Up from Pilot Plant of a Leaching and Solvent Extraction Process

Abstract

Germanium recovery from coal fly ash by hydrometallurgical procedures was studied at the pilot scale (5 kg of fly ash/h). Results were used to design the equipment of a demonstration-sized plant (200 kg of fly ash/h). The process is based on hydrometallurgical operations: firstly a germanium extraction from fly ash by leaching and a consequent Ge separation from the other elements present in the solution by solvent extraction procedures. Based on the experimental results, mass balances and McCabe-Thiele diagrams were applied to determine the number of steps of the solvent extraction stage. Different arrangements have been studied and a countercurrent process with three steps in extraction and six steps in elution was defined. A residence time of 5 min was fixed in both the extraction and elution stages. Volumetric ratios in extraction and stripping were: aqueous phase/organic phase = 5 and organic phase/stripping phase = 5, so a concentration factor of 25 is achieved. Mixers and decanters were completely defined. The maximum extracted and eluted germanium was estimated and a global efficiency of 94% was achieved. The cost-effectiveness of the equipment was estimated using the Lang factors.

Non-Dispersive Extraction of Ge(IV) from Aqueous Solutions by Cyanex 923: Transport and Modeling Studies

“…Gasification coal fly ashes (GCFAs) containing germanium can be leached with water to dissolve germanium as water-soluble species [5]. Several processes have been developed to recover and separate germanium from impurities such as precipitation [6], flotation [7], ion-exchange [8], distillation [2], adsorption [9], liquid-liquid extraction (LLX) [10], and supported liquid membrane (SLM) [11][12][13]. Among these techniques, the LLX processes have been extensively applied to separate germanium from aqueous solutions [14,15].…”

Non-Dispersive Extraction of Ge(IV) from Aqueous Solutions by Cyanex 923: Transport and Modeling Studies

“…Gasification coal fly ashes containing germanium can be leached with water to dissolve germanium as water-soluble species [6]. Several processes have been developed to recover and separate germanium from impurities such as precipitation [7], flotation [8], ion-exchange [9], distillation [3], adsorption [10], and liquid-liquid extraction (LLX) [11]. Among these techniques, the LLX processes have been extensively applied to separate germanium from aqueous solutions [12].…”

Non-Dispersive Extraction of Ge(IV) from Aqueous Solutions by Cyanex 923: Transport and Modeling Studies

“…Gasification coal fly ashes (GCFAs) containing germanium can be leached with water to dissolve germanium as water-soluble species [5]. Several processes have been developed to recover and separate germanium from impurities such as precipitation [6], flotation [7], ion-exchange [8], distillation [2], adsorption [9], liquid-liquid extraction (LLX) [10], and supported liquid membrane (SLM) [11][12][13]. Among these techniques, the LLX processes have been extensively applied to separate germanium from aqueous solutions [3,14].…”