Abstract:The recent technological advancement has made the rare earth elements (REEs) more significant and they in turn have facilitated the culmination of more new technological applications owing to their unique physical and chemical properties. In this regard, renewable energy applications such as wind turbine and hybrid cars testify to the increasing demands on permanent magnet in the future. Considering such increasing demands on REEs, it is felt necessary to identify alternative producers of REEs outside of China as one of the measures to create a fair competition and control the price on the market. It is worth highlighting that the separation of rare earth can be both complex and challenging owing to similar properties which are shared by them. The purpose of this paper is to comprehensively review and summarize the rare earth processing routes, the mostly employed rare earth separation methods, supply and demand of rare earth around the world and some possible scenarios in rare earth market. This review has critically looked into a few authors' recent reviews on six major processes of rare earth processing steps and each step is considered as important to produce both high quality and better quantity of REEs.

Anaerobic digestion (AD) involves a series of biological processes in which organic material is broken down and transformed into biogas. A simulation model of the AD process in treating food waste to produce biogas was developed using Aspen Plus software. The components list, thermodynamic property package, reaction list, reactor model, and process condition were specified in Aspen Plus. Sensitivity analysis was performed to study the effect of hydraulic retention time and changes in food waste composition on the biogas production. The methane composition in biogas decreased when the hydraulic retention time was increased which is due to the reduction of substrate consumption during the AD process. The process model is able to represent the AD process and provides a good approximation on the production of biogas under various process operating conditions.

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iffusion coefficient study gains an interest to know the mass transfer properties of molecules especially in study of the absorption process. The main objective of this study is to investigate the effect of temperature on diffusivity of MEA absorption process for CO₂ capture. Three different values of process temperature were chosen for simulation was carried out at 25°C, 40°C. The MD simulation was carried out at NVE (200ps) and NPT (INS) ensemble in Material Studio 7.0 software.

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