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

铝金属在工业上是通过在熔融电解质中电解冶炼级氧化铝（SGA）来生产的，使用众所周知的Hall-Héroult工艺。 氟化物排放的回收对环境和金属生产成本至关重要。来自电解池的排放物由气态如氟化氢（HF）组成。与通过电解池产生HF有关的机制包括以SGA表面上（主要）松散结合的水分的形式进入电解池的氢的热和电化学水解、不完全的SGA煅烧和来自环境空气的水分被吸入电解池。 迄今为止，还没有已知的经济上可行的替代方案（对于常规操作方案）用于以与今天实现的相同或更好的捕获效率从电解池工艺气体中回收氟化物。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增强HF捕获和保留;最大限度地减少或消除与当前操作实践和相对高含水量的SGA规范相关的冲突。 这项工作有可能从根本上改变冶炼实践，通过减少HF排放量同时回收能源来改善环境。 使这些系统商业化的所有研究、工艺工程和设计开发工作都将来自加拿大柏克德公司，从而有助于在加拿大创造和保持卓越的工程。

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.