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Technical Cement Forum / CLINKER FROM ROTARY OR VERTICAL SHAFT KILN

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Davide A. 06/02/2008 23:41:55

CLINKER FROM ROTARY OR VERTICAL SHAFT KILN

Dear Sirs,

what is the difference between a clinker produced in a rotary kiln and the clinker produced in a vertical shaft kiln?

I know that the disadvantages of the VSK kiln are the inclusion of ash in the clinker, the problem with homogeneity of heat distribution, the low production.

But I can't understand how much the two clinkers can differ and why.

For example: starting from the same raw materials, and supposing a well working VSK and a well working SP Rotary kiln,what could be the difference in the portland cement (95% clinker 5% gypsum) derived from the two different clinkers in terms of 5 days and 28 days strength?

Buying clinker produced in VSK would be a completely wrong move or it can depend from other parameters?

Many thanks for Your attention.

Davide A.

Michael Clark 07/02/2008 09:07:06

Dear Davide,

There are a number of reasons why the clinkers might differ, but buying clinker from a VSK would not be a completely wrong move. It would depend on the degree of combination of the clinker, the lime saturation and the silica modulus.

There are at least 2 principle reasopns why the clinker from a VSK might have a low lime combination factor: (i) the difficulty of achieving the high temperature required to achieve a high degree of combination, and (ii) the lack of the tumbling action which is achieved in a rotary kiln, which in turn promotes the combination via the sintering reaction.

Before making your decision you must know the lime combination of the clinker and be asured that this is consistently achieved.

Dr Michael Clark

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