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Technical Cement Forum / Raw mix adjustment for courser quartz and calcite

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Raju Verma 11/05/2013 05:17:25

Raw mix adjustment for courser quartz and calcite

Dear All

Raw mix having courser quartz and calcite is difficult to burn. The first attempt one has to take is to grind raw meal finer.

But plant having wet grinding has limitation as finer raw meal creates filter cloth jamming and hence affects the productivity.

A typical raw mix details are as follows

Acid insoluble residue on 45 micron , quartz - 7-8%

Normal residue on 212 micron is 2.9 - 3.1%

Chemical composition of clinker

SiO2 - 22.0 to 22.2 , Al2O3 - 5.2 to 5.5 , Fe2O - 3.9 to 4.1 , CaO - 64.8 to 65.0 , MgO - 0.7 , K2O - 0.5 , Na2O - 0.2 , SO3 - 0.6 to 0.8 , LSF - 90-92, C3S - 40 -42, SM - 2.3 - 2.4 , AM - 1.3-1.5 , Liquid content at 1338 deg C - 23-25 and at 1400 deg C is 25 to 28

Plant is using pet coke in kiln firing only and coal firing in calciner. ASR is more or less balanced.

What actions can be taken further to improve clinker reactivity?

Regards

Raj Sahu 13/05/2013 05:14:47

Could you please sent more details of your raw mix as given under:

Raw Meal

LOI

SiO2

Al2O3

Fe2O3

CaO

MgO

Na2O

K2O

SO3

Residue of raw mix (by wet sieving)on +90 micron & 212 micron

Calcite and quartz grain size in limestone determined by Optical Microscopy

Regards,

Raj Sahu

Raju Verma 13/05/2013 06:46:15

Dear Sahuji

Thanks for your interest...

Please find the Kiln feed analysis

SiO2 - 13.4-13.6% , Al2O3 - 3.2-3.3 ,Fe2O3 - 2.5 - 2.6 , CaO - 43.3-43.5 , MgO - 0.5, Na2O - 0.2 , K2O - 0.4 , SO3 - 0.4 , LOI - 34.5

Residue on 212 micron ~ 3.0

Residue on 90 micron ~ 20%

Average quartz content (> 45 micro) ~ 7-9%

Regards

Ted Krapkat 13/05/2013 06:57:22

Hello COE,

In addtion to the extra data requested by Raj, could you also let me know the normal % residue on 45 microns, the typical range of clinker free lime and the type and quantity(%) of silica corrective, if you use one.

Also, I calculate your clinker C3S to be about 53-55% not 40-42%, was this a typing error?

Either way, your C3S is lower than most plants and you could benefit by an increase in LSF to ~95. This should increase the C3S content in the clinker.

If high free lime in your clinker is a problem, and you can't reduce the fineness of your kiln feed, you might gain some improvement by lowering the SM to say 2.3-2.4. The only other way would be to use raw materials and correctives that contains less coarse quartz.

Regards,

Ted.

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