Experimental and modelling Studies of High Temperature HF Capture & Speciation on the Surface of SGA

工业上生产金属铝的方法是在熔融的电解液中电解冶炼厂级氧化铝(SGA)，采用著名的Hall-Héroult工艺。回收氟排放对环境和金属生产成本至关重要。电解槽的排放物由气体组成，例如氟化氢(HF)。电解槽产生氢氟化氢的机理包括氢气以(主要)SGA表面松散结合的水分的形式进入电解槽的热和电化学反应，SGA的不完全焙烧，以及环境空气中的水分被吸入电解槽。**到目前为止，还没有经济上可行的替代方案(传统操作制度)来从电解槽工艺气体中回收氟化物，其捕集效率与今天相同或更高。该项目的重点是探索在源头减少HF形成的方法，同时通过SGA脱水和高温下的形态变化来增强HF的捕获和保留；最大限度地减少或消除与当前操作实践和SGA对相对高水分的规范相关的冲突。这项工作有可能从根本上改变冶炼实践，通过在回收能源的同时减少HF排放来改善环境。所有将这些系统商业化的研究、工艺工程和设计开发工作都将来自贝克特尔加拿大公司，从而帮助在加拿大创造和保持卓越的工程技术。

Aluminum metal is produced industrially by electrolysis of Smelter Grade Alumina (SGA) in a molten electrolyte, using the well-known Hall-Héroult process. Recovery of fluoride emissions are of primary importance to the environment and metal production costs. Emissions from the electrolytic cell are comprised of gaseous such as hydrogen fluoride (HF). The mechanics involved with the generation of HF by the electrolytic cell include thermal and electro-chemical hydrolysis of hydrogen entering the cell in the form of (predominately) loosely bound moisture on the surface of SGA, incomplete SGA calcination and, moisture from ambient air drawn into the electrolytic cell. **To date, no economically viable alternatives (to conventional operating regimes) are known for recovering fluorides from the electrolytic cell process gases at the same, or better, capture efficiency that is achieved today. This project is focused on exploring methods for reducing HF formation at the source whilst enhancing HF capture and retention through SGA dehydration, and morphological change at elevated temperatures; minimizing or eliminating the conflict associated with current operating practices and the SGA specification for relatively high-water content. This work has the potential to radically change smelting practices which would improve the environment by reducing HF emissions while recovering energy. All research, process engineering and design development work to commercialize these systems would come from Bechtel Canada, thereby helping to create and maintain engineering excellence in Canada.