CO2 produced per kg of clinker

Hello DJ,

When calculating CO2 emissions from raw material chemistry, certain assumptions have to be made. eg you can calculate the CO2 given off by the limestone component if you assume all of the CaO comes from limestone. (some CO2 is also often associated with MgCO3 but let's concentrate on the CaCO3 for now)

In your example above this calculation would become;- 48.51 * 44 / 56 = 38.11%

However, if you look at your loss on ignition result you will see that it is significantly less than this calculated figure... 35.26% compared to 38.11%

Since all of the CO2 from the limestone would be evolved during the ignition test, this means that not all of the CaO in the raw meal comes from CaCO3. Therefore there may be calcium silicates or other loss-free calcium compounds in your raw mix.

Another explanation could be that the oxidation state of your iron component is lower than 3.  ie. some FeO is present. This would result in a slight gain on ignition  which would offset the loss of CO2 from the CaCO3 and result in a lower than expected loss on ignition.

So, you see there are several factors that make a simple CO2 emission calculation from raw-meal chemistry very complex indeed.

In your case you need to quantitatively analyse the minerological content of your rawmeal so that you can determine the exact amounts of CaCO3, MgCO3 and the ratio of FeO/Fe2O3.

This is the only way you can more accurately calculate the CO2 emissions just  from the rawmeal chemistry.

An easier and more accurate way would be to directly measure the amount of CO2 evolved from a given amount of rawmeal using a Schrotter apparatus. (apparatus and methods can be found on the web)

Regards,

Ted.