white flash calcined metakaoline - explained

1. META
KAOLIN

2. RAW$KAOLINITE$
KAOLIN
CALCINED!
amorphous!
aluminium!silicate

3. content$
1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

4. 1. introduc+on,
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. Advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

5. KAOLINITE$
aluminium$silicate$
Al2O3$(SiO2)2$(H2O)2$$
amorphous,aluminum,silicate,
600° - 800° C.
dehydroxyla7on$breaks$the$crystaline$laQce$
$$$$$(temperature$depends$on$purity$of$kaolinite)$
Al2O3(SiO2)2(H2O)x+(2Gx)H2O$
high$reac7ve$pozzolan$
(temperatures$>900°$C.$recrystalliza7on$forming$mullite$with$no$pozzolanic$effect)$

6. Al,
O,
SiO,
OH,
de$hydroxyla7on$breaks$the$crystaline$laQce$
$
$
dehydroxyla7on$

7. Al2O3$×$2SiO2$+$Ca(OH)$2$+$H2O$
a$chemical$reac7on$of$calcium$hydroxide$with$amorphous$siliceous$material$forming$
calcium$silicate$hydrates$$
pozzolanic$reac7on$
ac7ve$alumina$is$soluble$in$basic$environment$,$pH>$11$(cemen77ous$matrix$)$forms$
stable$hydrates;$$
$ $$
• $$C4AH13 $$
• $$C3AH6$ $(hydrogarnet)$$
• $$C2ASH8$ $(strätlingite)$
• $$CGSGH $(calcium$silicate$hydrate)$$
$
$

8. metakaolin$reac7on$in$cement$
$ $ $$
Pozzolanic$reac7on$in$a$cement$mix$depends$on:$
$$
• rate$of$addi7on$
• dissolu7on$of$alite$and$belite$phases$
• temperature$$
• water$ra7o$
$
Two$main$stages$of$reac7on;$
$
• 0G14$days $80%$of$pozzolanic$reac7on$takes$place$$
$ $dissolu7on$alite$(C3S)$$
• 14G28$days$ $comple7on$of$reac7on$
$ $dissolu7on$belite$(C2S)$

9. Portlandcement$blend$
When$Portlandcement$hydrates$it$forms$Portlandite$(Ca(OH)2)$(phase$3$and$4)$and$
Ca2+$released$by$alite$(C3S)$and$belite$(C2S)$(phase$2$and$3)$
$
Amorphous$Metakaolin$reacts$with$OHGand$Ca2+$ions$forming$$CGSGH$$calcium$
silicate$hydratesGreducing$the$amount$of$free$lime.$
$
main$effects:$
$
$
$
• binds$calcium$$
• accelerate$hydra7on$of$silicates$
• addi7onal$calcium$silicate$hydrates$
• reduced$pH$
• dense$matrix$

10. 1.$cement$minerals$ 2.$metakaoline$fills$pores$d50$=$10$μ$
3.$Forma7on$of$new$hydrates$$
AL2O3$×$2SiO2$+$Ca(OH)$2$+$H2O$→$CSH,$
C4AH13,$C3AH6,$C2ASH8$
4.$closed$structure$improving$physical,$
mechanical$and$chemical$performance$

11. 1. introduc7on$
2. produc+on,
3. rheology$$
4. Chapelle$test$
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

12. rotary$kiln$calcina7on$flash$calcina7on$
raw$kaolinite$finely$ground$
+$
flash$calcina7on$$
(few$seconds$~670°C)$
core$grinding$/$pelle7zing$$
rotary$kiln$calcina7on$
(2/5h$~750°C)$
+$
$ground$
plate$structure$round$shaped$
different,morphology,
different$way$of$calcina7on$

13. CYCLONE$
GRINDING$
$$
PREGHEATING$
BURNING$ZONE$
COOLING$ZONE$
CYCLONE$
GRINDING$
RAW$$
FEED$
$$STORAGE$
FLASH&CALCINATION,

14. average$composi7on$
Al203 $ $ $ $40~45$%$
SiO2 $ $ $ $30~55$%$
$
small$amount$of$quarz$,$feldspath$
oxides:G$iron$,7tanium$,potassium$,phosphore$,sodium$,calcium$,magnesia$
$
LOI $ $ $ $<$2$%$
Par7cle$size $ $ $<$45$μm$
average$par7cle$size $ $5$μm$
$
Blaine $ $ $ $>$12,000$gm2/g$
$
large$surface$area$allows$$
density $ $ $ $2,6$$
shelf$live $ $ $ $indefini7ve$
$
colour $ $ $ $pink$G$white$$
$

15. 1. introduc7on$
2. produc7on$
3. rheology,,
4. Chapelle$test$
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

16. 90,
100,
110,
120,
130,
140,
150,
160,
0, 10, 20, 30,
flow$mm$
metakaolin$%$
Flow$table$test$:$cement/sand$=$1:$3$$w/c$=$0,5$$
$
Up$to$10%$subs7tu7on$of$Portland$cement$by$regular$metakaolin$rheology$was$slightly$effected.$
Addi7on$of$$flash$calcined$metakaoline$allows$a$higher$addi7on$$
,
tradi7onal$calcina7on$
$
$
$
flash$calcina7on$
$
$

17. 0,0,
5,0,
10,0,
15,0,
20,0,
25,0,
30,0,
0, 5, 10, 20, 30,
compressive$strength$$MPa$
metakaolin$%$
1$day$
$
7$days$
$
28$days$
op7mum$is$reached$at$10%$subs7tu7on$of$$Portlandcement$by$tradi7onal$calcined$metakaolin,

18. Lower$viscosity$$allows$higher$dosage$of$metakaoline$,$improving$further$strength$development$
Addi7on$of$a$plas7cizing$agent$will$improve$the$workability$and$further$increase$the$strength,
0,
5,
10,
15,
20,
25,
30,
35,
compressive$strength$MPa$
metakaoline$%$
1$day$
$
7$days$
$
28$days$

19. plas7cizing$agent$
Because$of$its$fineness$(10$7mes$finer$than$Portlandcement!)$
and$its$sponge$type$character,$the$addi7on$of$metakaoline$influences$the$rheology$
of$the$blend$$
$
This$increase$in$viscosity$can$be$overcome$by$adding$a$plas7cizingG$/$super$
plas7cizing$agent$$$
$
SeQng$7me$can$off$course$be$adjusted$by$addi7on$of$retarder$$
$

20. 0,
10,
20,
30,
40,
50,
60,
1,day, 7,days, 28,days,
compressive$strength$MPa$
7me$
reference$W/C$0,5$
poly$carboxylate$ether$0,2%$
W/C$0,375$
Addi7on$of$right$super$plas7cizing$agent$strength$can$be$further$increased$(20G50%)$

21. 1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle,test,
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

22. ,$
$
puzzolanic$ac7vity$(Chapelle$test)$
• pozzolanic$reac7vity$is$measured$by$mixing$1$g$metakaolin$with$2$g$CaO$in$$
$$$$$$$250$ml$of$water$
• s7rred$and$heated$for$16$hours$$
• aver$cooling$amount$of$lev$non$reacted$lime$is$$established$$
• result$is$expressed$in$mg$Ca(OH)2$bound$
• values$lies$between$1000$and$1400$mg$
$
$$
$$

23. comparision$of$puzzolanic$reac7vity$(Chapelle)$
materials$
average$
puzzolanic$ac7vity$mg$Ca(OH)2/g$
$$$$blast$furnace$slag$ 40$
$$$$silica$fume$ 430$
$$$$calcined$bauxite$ 535$
$$$$paper$sludge$ 600$
$$$$fly$ash$ 875$
$$$$metakaoline$ 1300$

24. 1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. advantages,
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion$
$
$
$

25. advantages$
METAKAOLIN$in$combina7on$with$Portlandcement$forms$a$denseGknit$
structure$improving,$physical,$mechanical$and$chemical$proper7es.$
$
• accelera7on$of$ses$–$lime$gel$is$bounds$allowing$C3A$,$C3S$to$dissolute$quickly$
• pH$is$reduced$giving$more$protec7on$to$glass$fibers$(GRC)$
• reduced$thermal$stress$slower$hardening$which$limits$shrinkage$and$cracking$
• increase$of$elas7c$modulus$(EMR)$
$$
• new$hydrates$formed;$calcium$silicate,$strätlingite,$and$hydrogarnet$$
• fewer$pores$and$smaller$pore$sizeGreduc7on$of$efflorescence,$

26. • lower$water$uptake$
• less$energy$needed$versus$tradi7onal$method$
• tight$$control$on$calcina7on$
• consistency$of$product$
• grinding$raw$kaolinite$first$contributes$to$round$structure$of$par7cles$$
• contribu7ng$to$an$improved$workability$
• higher$amount$cement$subs7tu7on$$
• higher$abrasive$resistance$
• improved$opacity$
flash$calcina7on$

27. 1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. advantages$
6. CalciumQSulpho,Aluminate,cement,
7. geo$polymer$
8. conclusion$
$
$
$

28. CSAGcement$
• calcium$sulpho$aluminate$cement$relies$on$forma7on$of$ye’elimite$(C4A3Š)$it$
takes$calcium$out$of$the$solu7on,$lowering$the$pH$
$
• low$pH$slows$down$the$dissolu7on$of$aluminium$silicates$$
$
• belite$(C2S)$goes$into$solu7on$at$a$later$stage$of$hydra7on$at$this$stage$the$
pozzolan$effect$is$reduced$$
$
• an$excess$of$calcium$hydrates$form$a$gel$/layer$on$the$pozzolan$grain$"isola7ng”$it$
to$go$solu7on$and$blocking$the$reac7on$kine7cs$
$
$
when$CSA$cement$is$blended$with$Portlandcements$it$is$recommended$to$first$make$
extensive$tests$to$establish$the$possible$pozzolan$effect$

29. 1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo,polymer,
8. conclusion$
$
$
$

30. alumino,silicate,
alkaline,reagent,
water,
geoQpolymer,
Metakaoline$combined$with$“waterglass”$is$currently$under$research$to$produce$
so$called$“geoGpolymers”$
sodium$or$potassium$
geoGpolymer$
WorldGwide$there$is$an$increased$interest$in$alterna7ve$binders,$“geoGpolymers”$
are$a$good$example$of$this.$$

31. 1. introduc7on$
2. produc7on$
3. rheology$$
4. Chapelle$test$
5. advantages$
6. CalciumGsulpho$aluminate$cement$
7. geo$polymer$
8. conclusion,
$
$
$

32. Decora+ve,,,durable,and,detailed,$
,$
Mortar$and$concrete$containing$metakaoline$proof$to$have$a$beser$durability.$$
The$consump7on$of$calcium$hydroxide$and$cement$alkalis$in$combina7on$with$the$
increased$density$give$beser$sulphate$resistance.$$
$
It$further$reduces$the$risk$of$alkaliGsilica$reac7on$and$so$called$“limeGbloom”.$
$
In$decora7ve$mortars$and$concrete$colours$are$more$durable.$Increased$density$and$
reduced$alkali$prevent$water$to$migrate$lime$and$alkali$preven7ng$primary$and$
secondary$efflorescence.$
$
Addi7on$of$metakaoline$increases$the$fineness$of$the$binder.$Fine$details$are$
followed$beser$and$the$surface$quality$is$improved.$White$metakaoline$can$easily$
be$integrated$in$a$white$Portlandcement$matrix.$
$
Combining$metakaoline$with$calcium$hydroxide$allows$a$simple$produc7on$of$a$type$
of$hydraulic$lime$oven$used$as$replacement$of$Portlandcement$in$restoring$natural$
stone.$
conclusion$$

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