low sulfur/alkalis ratio

Dear Experts,

Is there any negative effect for low sulfur-alkalis ratio in hot meal ? we use coal (low sulfur) and the S/A in hot meal ~0.3

N.B. clinker free lime is within target ~1%

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Re: low sulfur/alkalis ratio

Hello Emad,

The possible negative effects of a low Sulphur/Alkali ratio are that;-

1. The excess of alkalis over sulphur could increase the likelihood of alkali-related buildups in the smokebox/kiln inlet, especially in the presence of chlorides.

2. The clinker produced would not have an optimised alkali sulphatisation level. ie alkali sulphate levels would not be maximised. Soluble alkali sulphates can improve early cement strengths.

3. The excess of alkalis over sulphur (particularly Na) will promote the formation of the orthorhombic modification of C3A at the expense of the cubic variety. Orthorhombic C3A is the more reactive of the two (faster hydration and higher water consumption) and could cause problems with setting times and workability of cement. If Na2O and K2O are equally balanced with sulphur (as alkali sulphates), they are not available for incorporation into C3A.

Regards,

Ted.

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Re: low sulfur/alkalis ratio

Dear Mr. Ted,

Thank you very much, We have just made a decision to take prompt action to balance S/A ratio. Actually we have built up material & coating formation tendency in the kiln inlet, which support the above mentioned first point

Regards

Emad

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