Magnesium casting process

The category business/processes/production/magnesium/castingprocess/ is aimed towards industry professionals to enable them to prepare inventories of greenhouse gas emissions from magnesium casting processes. This category should be used alongside the primary production category. The emissions detailed here are SF₆ emissions from the magnesium casting process segment. As in the primary production category, the methodology provided by this category represents the Tier 1 (default values) and Tier 2 (facility- or country-specific values) approaches described by the IPCC Guidelines for National Greenhouse Gas Inventories (NGGIP).

There are other compounds emitting during magnesium production. Both HFC-134a and FK 5-1-12 are less thermodynamically stable (and thus have much lower GWP) than SF₆. Therefore, it is expected that these gases will decompose/react extensively in the contact with liquid/gaseous magnesium, leading to the production of various fluorinated gases (e.g., PFCs). Unfortunately there is little historic data upon which to base emission factors for these products. However, if the GHG emission from the use of magnesium cover gases is a national key category, it is good practice, for inventory preparation purposes, to collect direct measurements and or reliable indirect measures of GHG emissions (fugitive emissions of HFC134-a and FK 5-1-12 as well as emissions of PFCs as decomposition products) from magnesium foundries using HFC-134a or FK 5-1-12 as cover gases. This may be considered a Tier 3 approach. Over time, it may be possible to use Tier 3 measurements as a means of developing emission factors that could be used for Tier 2.

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How to use this category

Selecting an emissions scenario

To use this category use the magnesiumCastingProcess drill-down to select the process for magnesium casting from the following options:

1. all casting processes

Specifying activity data

The only required profile item value is the quantity of magnesium casting, mgQuantity. The emission factor for the casting process has a default value provided, but this can be over-ridden, using the massSF6PerMassProduct profile item value, by the user if more precise site or country-specific values are known. Over-riding the default values represents the Tier 2 approach described by the IPCC Guidelines for National Greenhouse Gas Inventories (NGGIP) and should be used where users have facility-specific data.

Results and calculation

The quantities returned represent the greenhouse gas emissions associated with the quantity of casting specified. The following quantities are returned:

• SF6: absolute quantity of SF₆ emissions for the quantity specified
• CO2e: CO₂e emissions (SF₆ emissions converted using the appropriate global warming potential)