Commercial process for the recovery of metals from ITO etching industry wastewater by liquid–liquid extraction: simulation, analysis of mechanism, and mathematical model to predict optimum operational conditions

What is it about?

A commercial process for recovery of metals from Indium-Tin-Oxide (ITO) etching industry wastewater by liquid-liquid extraction has been developed. A suitable cross current simulated batch process was developed; extraction mechanisms involved in the process were analyzed. Mathematical models were proposed to correlate metal extractability with respect to extractant concentrations and metal loading with respect to solvent/solution volume ratio. Optimum conditions required for complete scrubbing of Mo and Sn using Cyanex 272, quantitative extraction of pure In using DP-8R were estimated by a proposed model. A good agreement between proposed model and observed results were indicated. Based on the laboratory scale simulation a pilot plant batch process was developed and simulated. The developed process is a techno economical feasible, environment friendly, occupational safe, clean and green process for the commercial treatment of ITO etching industry wastewater and recovery of metal values through liquid-liquid extraction. In with 99.999 % purity, Cu nanopowder with 99.999 % purity, Mo and In with 99 % purity has been recovered.

Featured Image

Why is it important?

• A commercial techno economical feasible, environment friendly, occupational safe, clean and green pilot scale wastewater treatment process has been developed for the treatment and recovery of metal values from ITO etching industry wastewater through liquid-liquid extraction. • Based on the laboratory scale optimization a complete treatment and recovery process has been proposed, for various process parameters suitable working mathematical models were proposed. Through the proposed model-equation, possible operation parameter was decided for pilot scale operation purpose. Validity of model, process and simulation was verified for pilot scale. • Most of the In recovery processes reported in the open literature are about laboratory scale process; deal with several ml of solution, but our commercial process offers versatile, flexible and robust approach for mass production capability of In up to kilogram scale. A batch process pilot plant capable of handling at least 1 m3 water/day, with potential for continuous operation through automation has been designed. • By the developed process simultaneously the valuable industrial (high pure) metals like In, Mo, Sn and Cu can be recovered to enter mainstream material flow. After values recovery and treatment, the wastewater is heavy metal free (mostly chloride free) can be disposed of or reused in the same ITO etching process. • All the organic extractant can be regenerated and reused; no hazardous chemical used for process makes the process a clean and green economical process. • As the process is a versatile, flexible and robust process capable operating both by batch and by continuous process can be used in small, medium and mega-scale industrial wastewater treatment where ITO etching wastewater is a concern.

Perspectives