Dear sir,

You are right, but using high inherent moisture indonesian coal will show a very low temp of burning zone and the kiln atmosphere will not be clear for visiability. Buning this coal in kiln gives a vertual feeling of high dust load in kiln atmosphere,

Hello Laxmikanth,

Although the formula for liquid phase at 1450°C is normally written with respect to the oxides. i.e.

LP(@1450) = 3.0*Al2O3 + 2.25*Fe2O3 + Na2O + K2O + SO3 + MgO      (Eq.1)

this formula can also be expressed in terms of C3A and C4AF, since these minerals contain all of the Al2O3 and Fe2O3 and make up most of the liquid phase.

So, from the Bogue equations we have;-

C4AF = 3.04* Fe2O3

Therefore;-

Fe2O3 = C4AF/3.04        (Eq.2)

Also from the Bogue equations;-

C3A = 2.650*Al2O3 - 1.692*Fe2O3

Rearranging this equation;-

2.650*Al2O3 = C3A + 1.692*Fe2O3

Al2O3 = (C3A + 1.692*Fe2O3)/2.650        (Eq.3)

Substituting the value obtained for Fe2O3 in Eq.2 into Eq.3 we get;-

Al2O3 = (C3A + 1.692*C4AF/3.04)/2.65
Al2O3 = (C3A + 0.556*C4AF) / 2.65
Al2O3 =  C3A/2.65 + 0.21*C4AF
Al2O3 =  0.377* C3A + 0.21*C4AF             (Eq.4)

Substituting the values for Fe2O3 and Al2O3  obtained above in Eq.2 and Eq.4 into the equation for liquid phase at 145O°C (Eq.1) gives;-

LP(@1450) = 3.0*(0.377*C3A + 0.21*C4AF) + 2.25*C4AF/3.04 + Na2O + K2O + SO3 + MgO 
LP(@1450) = 1.13*C3A + 0.63*C4AF + 0.74*C4AF + Na2O + K2O + SO3 + MgO 
LP(@1450) = 1.13*C3A + (0.63*C4AF + 0.74*C4AF) + Na2O + K2O + SO3 + MgO
LP(@1450) = 1.13*C3A + 1.37*C4AF + Na2O + K2O + SO3 + MgO                        (Eq.5)

So you can see that the last equation (Eq.5) is just the familiar liquid phase equation; LP(@1450) = 3.0*Al2O3 + 2.25*Fe2O3 + Na2O + K2O + SO3 + MgO,  expressed in terms of C3A and C4AF instead of the oxides Fe2O3 and Al2O3.

Good explanation,, thank u sir