Emissions Control

Smelter Emissions Control

Environmental management and control is now a major priority in the global aluminium industry. Combined with the ever increasing need to make smelting more energy efficient, many smelters in many developed countries are investing in minimising emissions of air pollutants and greenhouse gases. 

Light Metals Research Centre has developed expertise in the following environmental fields :

Fluoride Emission Control and Management

 

Generation of hydrogen fluoride gas in the aluminum smelting process is unavoidable but has over the years been controlled through pot design and operation, and most significantly through the design and operation of gas treatment centers (GTC). LMRC developed a Fluoride Emission Management Guide (FEMG) – a simple, illustrated and practical guide for managing fluoride emissions – in order to lead smelters along the path to improvement. This was sponsored by the Asia Pacific Partnership for Clean Development and Climate (APP). To download a snapshot of the Guide, please click here. For a complete copy of the FEMG, please send your request to lightmetals@auckland.ac.nz.

  The operation and optimal performance of a GTC hinges on an understanding of the interplay between the chemical, physical and textural properties of alumina and the HF-laden pot gas. This interplay has been studied extensively at the LMRC's dedicated HF scrubbing laboratory and some results have been published in Langmuir  and TMS Light Metals 2016. The setup includes a lab-scale GTC reactor and ancillary equipment for investigating the interactions between alumina and HF gas. Modern experimentation techniques are used to test the different factors that influence dry scrubbing efficiency. The performance of differently calcined aluminas is assessed against simulated parameters in our HF scrubber setup which is also fitted with real-time data logging and alarm systems for control and safety.

 

The LMRC provides the following analytical and research experiments for alumina refineries and aluminium smelters alike:
•    Reaction of dry or humid HF with alumina
•    Breakthrough curve characterization
•    19F Solid State NMR quantification of fluoride loading on alumina
•    Modelling and analysis of the evolution of textural and chemical properties of the aluminas (surface area, pore size distribution, occluded Na)

Before and after reaction with HF gas, we offer the following characterisation services:
•    27Al MQ-MAS NMR
•    BET Surface Area
•    BJH Pore Size Distribution
•    Particle Size Distribution
•    Phase Analysis by X-Ray Diffraction
•    Quantification of acid/base sites concentration on SGA (before and after reaction with HF)
 

Perfluorocarbon (PFC) Emission Management

PFCs – most notably CF4 and C2F6 – are generated as by-products of aluminium smelting and exhibit global warming potentials (GWP, relative to carbon dioxide) of 6,500 and 9,200, respectively.
 LMRC continues to be a leader in research on the generation of PFCs, particularly on emissions generated outside of conventionally understood anode effects. As with fluoride emissions, LMRC has developed a simple PFC Emission Management Guide (PFC-MG) to help smelters manage and control PFC emissions. For a copy of the PFC-MG, please send your request to lightmetals@auckland.ac.nz.

 Management of Potroom Dust Emissions

The release of dust in aluminium smelting potrooms has the potential to adversely impact both the environment and the occupational health of workers.   LMRC offers:
expertise in understanding the dominant sources of dust and the mechanisms by which dust in each potroom is generated
Provide ways in which the smelter can make targeted reductions in potroom dust. 
 Our team has conducted smelter-based sampling campaigns for particulate emissions in the potroom, at both the operating cell level as well as in potroom roof vents, relating these emissions to operations, processes and material sources in the potroom

For detailed discussion with regards to environmental impacts and improvements, please contact Professor David Wong, LMRC Emission specialist.