Do I need to add lime kiln dust to my kiln's carbon dioxide, and does it matter if I run a vertical shaft kiln?

Only at Tier 2 or 3, and mostly for rotary kilns. The Intergovernmental Panel on Climate Change (IPCC) says an average rotary kiln loses 9 to 10% of its lime output as dust, and with no data you add 2% to the carbon dioxide (CO2). Vertical shaft kilns make little dust, so the correction is negligible.

Why the dust matters

Lime kiln dust leaves the kiln as a by-product and is not weighed as lime. A typical high-calcium dust may hold about 75% combined calcium oxide and uncalcined calcium carbonate, roughly half and half, with silica, aluminium and iron oxides and sulphur making up the rest. The uncalcined part still holds CO2.

Rotary against vertical shaft

• Rotary kiln: the guide quotes dust loss of 9 to 10% per tonne of lime produced, or 16 to 18% of the raw material fed.
• Vertical shaft kiln: relatively small amounts of dust. The guide judges the correction negligible and says it need not be estimated.

What each tier asks

• Tier 1: no dust correction.
• Tier 2, working from lime output: with no data, multiply the CO2 by 1.02. Collect typical ratios of dust to lime and the dust's composition if you can.
• Tier 3, working from stone fed: add up the carbonate fed times its factor times the share calcined, then subtract the CO2 still locked in uncalcined carbonate that left in the dust. If you do not know how calcined the dust is, assume fully calcined, which sets the subtraction to zero. With no better data, use the calcium carbonate factor for the dust.

What to record

• Dust collected from the filter or settling chamber, in tonnes, dry weight.
• A loss on ignition test of the dust, which shows how much carbonate is left.
• Whether the dust goes back to the kiln, to a landfill or to another buyer.

Rotary kiln against shaft kiln, 10,000 tonnes of high-calcium lime

• Process CO2 at the 0.75 default: 10,000 x 0.75 = 7,500 tonnes
• Rotary kiln, Tier 2 default dust correction: 7,500 x 1.02 = 7,650 tonnes, 150 tonnes more
• Vertical shaft kiln: 7,500 tonnes, no correction needed

Production is an example number. Kiln fuel is counted separately.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records. Dust weights and loss on ignition tests are lab and plant records you keep beside them.

• Carbon calculators
• Quicklime kiln: CO2 per tonne
• Process CO2 from limestone calcination
• Cement kiln dust and calcination

Sources: IPCC, 2006 Guidelines for National Greenhouse Gas Inventories, Volume 3, Chapter 2: Mineral Industry Emissions

Last reviewed 2026-11-04. The 2006 Guidelines are written for national inventories. A plant's own lab assay, production log and fuel invoices replace these defaults wherever you have them.