537 posts
Re: high free lime
Hello Bazarah,
From what you have told us so far, I think your problem is more likely to be process-related rather than raw materials.
Do you measure burning zone temperature and CO concentration in the back end of the kiln?
If so, how do these parameters relate to clinker free lime? Is there any correlation?
If you have intermittently bad burning conditions and are generating CO, there would most likely be a positive correlation between free lime and kiln inlet CO, and an inverse correlation between free lime and burning zone temperature.
As well, you may have intermittent blockages of the smoke box/bottom cyclones or slabs of buildup falling occasionally into the kiln inlet.
Do you have any of these situations?
Regards,
Ted.
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6 posts
Re: high free lime
If you have not changed anything on your raw materials and fuels, then it sounds to me that it comes from the process. You need to check the following:
1. Let the process engineer do the complete kiln burner audit.
2. Check the burner position and adjustment of the radial/axial / central air then compare it to the previous setting.
3. Make sure that fuel fineness is on target on 90um and 200um.
4. Make sure that there are no abnormal readings on temperatures, pressure, torque, gas analyzers, etc.
5. Clinker should be able to give the desired secondary air and tertiary temperatures.
6. There are also situations that materials on the preheater splash boxes especially on the lower portion have build-up or materials on it that prevented the materials from splashing but instead it will go direct to the kiln inlet unprepared.
On the raw materials, the modulus looks good to me and LSF is low. Now it would only be the question of the effect coming from the coal or fuel to the chemistry. Normally, there is burnability test that you could do to evaluate the mix. A formula using the chemistry / residues will be applied.
18 posts
Re: high free lime
Dear sir Jojo
I am very much thank full to you for response
the type of fuel is crude oil if you have procedure for burn ability test
can you send to me my email :abazarah@hotmail.com
and how to evaluate the mix. A formula using the chemistry / residues will be applied.
Regards,
Bazarah
44 posts
Re: high free lime
Dear Bazarah
Our colleagues mentioned many cases that could cause unnormal burning. I want to add something: you can also determine quantity of FeO in your clinker, FeO especially comes from reducing and hot condition in the kiln, decomposes alite structure with release of additional free lime.
Maybe quantity of minor elements (esp. alkalis) becomes high in your kiln system?
You can also check the efficiency of your Preheater system and ID fan efficiency.
Believe me this is not a big problem. You can use all of the opinions of our friend and solve the problem.
Good Luck.
Davit