32 posts
re boulder in kiln
yes, the center is broken and analysed.
lsf : 97,36 , AR : 1.66 , AS : 2.72 , freecao = 1.09 %
K2O = 0.8 , N2O = 0.05 , S/Alk = 0.8
SO3 = 0.63
I note only one thing, the alklis are very hight compare to normal clinker on witch
K2O ~ 0.40
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537 posts
re boulder in kiln
Hello Siddhant,
It is likely that these balls are caused by too much liquid phase. Your Silica Ratio (SR) is quite low at 2.24 - 2.27. There is also a significant contribution from alkali sulphates to the liquid phase. Alkali sulphates also reduce the temperature of formation of the liquid phase.
The combined effect is that there is likely to be nodulisation at a lower temperature in the kiln. This means that nodules may grow larger and occur earlier in the kiln.
Also, increased liquid phase content tends to promote rings in the kiln. Even quite small rings can act as retaining walls to hold smaller balls behind them. The balls roll around picking up more and more liquid phase, growing bigger until they are large enough to roll over the ring and out of the kiln.
To help with this problem, I would suggest you try to increase your SR to help reduce the quantity of liquid phase. Changing the SR to 2.45 - 2.55 would be a good start.
Also high MgO can have an influence on quantity of liquid phase. What is your clinker MgO content and does it vary much?
Regards,
Ted.
537 posts
re boulder in kiln
Hello Yndiaye,
Thanks for your results. The low free lime indicates that your clinker boulders are not due to unburnt buildup material moving down the kiln. Which means that your problem may be due to a higher than optimum liquid phase content or a fluctuating liquid phase content and rings in the kiln. (please read my reply to Siddhant above to see if it may apply to you)
Also, your AR is very close to 1.38 which is the point where, chemically, the maximum amount of liquid phase will be produced at the lowest temperature. If the AR fluctuates significantly around this value ie frequently moves up and down within the range 1.3 to 1.45, the quantity of liquid phase in the burning zone and the position in the kiln where liquid phase starts to form could both vary enough to promote abnormal nodulisation of the clinker. (ie form balls instead of smaller clinker nodules)
I would suggest that you try to increase your AR to 1.45-1.55. This will help reduce the chance of liquid phase content fluctuations by keeping clear of the critical AR point of 1.38. Your SR of 2.4 -2.5 is okay, but you could try to increase it a bit, if changing the AR has no effect.
Often, the cause of rings, balls and boulders is more related to kiln operation than it is to the kiln feed chemistry. Fluctuating fuel rates and fuel quality, burner position & alignment, burning zone temperature, can all have a big effect on the quantity and location of formation of liquid phase, as well as its viscosity. All of which will affect clinker nodulisation, coating formation and the tendency towards rings, balls and boulders.
Regards,
Ted.
32 posts