RAW MEAL TO CLINKER RATIO -THEORY & CALCULATION

RAW MEAL TO CLINKER RATIO

Raw meal to clinker ratio is the amount of raw meal required to produce 1 kg of clinker.

If you are using kiln feed containing dust material then you have to consider this dust  into the account to calculate "raw mix to clinker ratio".

let's suppose, you start with 100 tons of fresh raw meal. In the kiln feed bin you are adding 8% kiln dust. i.e. 8 tons of dust. So for every 100 T of fresh raw meal going through the kiln, you will really measure 108 T of kiln feed. Therefor, the kiln feed to clinker ratio will be the raw meal to clinker ratio multiplied by 

=108/100 = 1.08

If your fresh raw meal to clinker ratio is 1.55. then you kiln feed to clinker ratio will be

= 1.55 *1.08 = 1.674

However, using the LOI data, you can calculate your actual fresh raw meal to clinker ratio:

Given:
D = % Dust in kiln feed =8
K = %  LOI of kiln Feed = 35.54
L = % LOI of the Dust = 38
if R = % LOI of fresh raw meal

Then
R = (1+D/100) * { K - (D * L/100 )}
    = ( 1+ 8/100) * { 35.4 - (8 *38/100)}
    = (1.08 * 35.4 - 0.08 * 38)
    = 35.2

Now you know that the LOI of your fresh raw meal is 35.2%, then we can calculate the actual raw meal to clinker ratio for fresh raw meal using below formula:
= 1/ (1-R/100)
= 1/(1-35.2/100)
= 1/(1-0.352)
=1.54

Therefor, your meal to clinker ratio for kiln feed leaving the kiln bin is really:
= 1.54 * 1.08
= 1.66

With 4% bypass:
Assuming the LOI of the bypass dust is close to zero then the kiln feed to clinker ratio would be:
= 1.66 * 1/ (1-4/100)
= 1.73

if the LOI of the bypass is > 10% then you have to consider the LOI while doing calculation:

Kiln feed to clinker ratio with 4% bypass:
= 1.66 * 1 / (1-4/100* (1- 10/100))
= 1.72