Ferroalloy raw materials methodology

The category business/processes/production/ferroalloy/rawmaterials is aimed towards industry professionals to enable them to prepare inventories of greenhouse gas emissions from ferroalloy production. Ferroalloy is the term used to describe concentrated alloys of iron and one or more metals such as silicon, manganese, chromium, molybdenum, vanadium and tungsten. Silicon metal production is usually included in the ferroalloy group because silicon metal production process is quite similar to the ferrosilicon process. Ferroalloy production involves a metallurgical reduction process that results in significant carbon dioxide emissions.

The methodology provided in this category represents the Tier 2 and Tier 3 approach described by the IPCC Guidelines for National Greenhouse Gas Inventories (NGGIP) and calculates on the basis of raw material inputs to the ferroalloy production process.

How to use this category

To use this category use the typeOfReducingAgent drill-down to select the reducing agent type being used from the following options:

1. coal (for FeSi and Si-metal)
2. coal (for other ferroalloys)
3. coke (for FeMn and SiMn)
4. coke (for Si and FeSi)
5. coke (for other ferroalloys)
6. prebaked electrodes
7. electrode paste
8. petroleum coke

The following profile item values are required in order to accurately calculate CO₂ emissions:

1. reducingAgentQuantity
2. oreQuantity
3. oreCarbonContent
4. slagQuantity
5. slagCarbonContent
6. productQuantity
7. productCarbonContent
8. nonProductOutgoingStreamQuantity
9. nonProductOutgoingStreamCarbonContent

The CO₂ emission factor for the reducing agent has a default value provided but this can be over-ridden using the massCO2PerMassReducingAgent profile item value, by the user if more precise site or country-specific values are known.

For Tier 3 calculations the following profile item values can also be specified.

Use either:

1. reducingAgentCarbonContent (decimal fraction, 0-1)

Or:

1. percentageAsh: within reducing agent (decimal fraction, 0-1)
2. percentageVolatiles: within reducing agent (decimal fraction, 0-1)
3. carbonContentInVolatiles: within reducing agent (decimal fraction, 0-1)

CarbonKit converts the carbon content of each source and product into CO₂ emissions using molecular mass ratios, seen in Stoichiometries_ratios. This assumes complete combustion of carbon into CO₂.