Kinetics of gibbsite leaching in sodium hydroxide aqueous solution

[ !"]

# $ % & % $ $ $

' $ $ % $ %

γ!()*$

( + + $ $ ,-R. /- µ & 0

& (!1"2,3 !"/413 5!-663 !-72 )8* )&$ 9$ +$ :* --8 % $

) *

# '&( 426R.$ "26R. 61-R. & "/" 8 46! ---R.

+ / ;!

& υ)* "6-- "1-- ² δ)* 726 -46 ²

#

(()(V)+²→$O()² ) * $ % &

! $ & < "4"!"1" =

! % $ρ< /62!"-226 >

! $τ< "--!7--

& $

! _"

#$"$ %&'(%)*(&+%&,(--.-,/,,(0,*(-&

,Q RUGHU WR VWXG\ WKH NLQHWLFV DQG PHFKDQLVP RI WKH UHDFWLRQ ODERUDWRU\ OHDFKLQJ ZDV FDUULHG RXW ZLWK LQGXVWULDOO\ SURGXFHG JLEEVLWH γ²$O2+ LQ DTXHRXV VROXWLRQV FRQWDLQLQJ DQ H[FHVV RI VRGLXP K\GUR[LGH 7KH UHVXOWV REWDLQHG UHDFWLRQ WHPSHUDWXUH GXUDWLRQ DQG EDVH FRQFHQWUDWLRQ YDULHG 7KH EDVLF NLQHWLF SDUDPHWHUV ZHUH GHWHUPLQHG IURP WKH UHDFWLRQ UDWH FRQVWDQW N ⋅H[S ²57 DQG WKH SURFHVV DFWLYDWLRQ HQHUJ\ LQ WKH UDQJH (D ² N-PRO

!" ##$$$ % & '( #! )$$)

&& * + #$ )$$)

! "# $# $# % !

$ $! $ & '( % ) ! $ &

* ! '( !

! ! ' ! ! !& ' & ! + , - & &

! & $ %.

τ=#⋅ ! . # " " "

$ $ % ! $ // #.

₀0_{" 0} =⋅#⋅ τ ! . 0" '( $ " 0 " % $ " ! $ ,1 % .

α = " (²,⋅ τ3) / ! . α " , " " * ≥ # # $ ≤ # $$

' 2#3 [] , # ! .

#=⋅, 4 $ & $ % ! ! $ $ 5

6% / 1 & # !.

[" ( "α)] =Q⋅τ +ORJ//⋅# + ! α .

α=0₀ 7

& $ # % ! & % $ 4 ! 8& $ $ '( & * / $ ! $ 8() ρ 5 77 & & 8() 4 # $ $ 4 & # % ! * $ ,1 % / & $ % *

ρτ ! "#DQG JGP1D2

)LJXUH ρ²τ FXUYHV RI JLEEVLWH OHDFKLQJ LQ 1D2+ VROXWLRQ DW FRQFHQWUDWLRQV RI JGPDQG JGP1D2

! " ±

# ! $% && '%( !) ) * '% # ) !) ! ) * '%

$ +, & # - . . "/) $ / & && . .

# [0" 0α] "τ* && '%(

!! ! ) * '% # !) ) *'%

1& .

& -

- .

2.3 -") + +, - "!

1 1& && '% !) * ! ) *& + $ ) * '% ) 1 . & 45 ( & 1 $

)LJXUH /RJDULWKPLF FKDQJHV RI WKH $O2FRQFHQWUDWLRQ XSRQ

WLPH IRU WKH JLEEVLWH OHDFKLQJ UHDFWLRQ LQ 1D2+ VROXWLRQ DW FRQ FHQWUDWLRQV RI DQG JGP1D2

)LJXUH /RJDULWKPLF FKDQJHV RI WKH $O2FRQFHQWUDWLRQ XSRQ

WLPH IRU WKH JLEEVLWH OHDFKLQJ UHDFWLRQ LQ 1D2+ VROXWLRQ DW FRQ FHQWUDWLRQV RI DQG JGP1D2

)LJXUH 7KH GHSHQGHQFH RI ORJ[²ORJ²α]YV ORJ τ IRU WKH JLEEVLWH OHDFKLQJ UHDFWLRQ LQ 1D2+ VROXWLRQ DW FRQFHQWUDWLRQV RI DQG JGP1D2

)LJXUH 7KH GHSHQGHQFH RI ORJ[²ORJ²α]YV ORJ τ IRU WKH JLEEVLWH OHDFKLQJ UHDFWLRQ LQ 1D2+ VROXWLRQ DW FRQFHQWUDWLRQV RI DQG JGP1D2

# 1 1&

1 '%( ! ) *'% ) *'% 1 &

1 & !) ! ) * '% 6D/ !± .7*

1 $ - . 8 ./ 9"0 !*:1 1 &[)] " .7* &&

1 '%( - & '%( & 9 & 2 ;&[)]

&21&/86,216

1 && . . - & " ) * '% 1 & 9 1 3 +, - ± && . . 1 && & & + & !) ! ) *'% 0. & ! 1 && $ - 8 ./ ⋅ 9"0 !*:1

5()(5(1&(6

[1] )*+, ,- .-,/ 0,1,0 ' ,,/ / 2,3 /* 4 5/16 %!7'

[2] ,8 ,,-* /9 :;10,- .-,/* -;3 /9 -//03 :;103 01 %!7< +'=#$ <7=

[3] >?*, 1,61=@0 ++1;1 19*-,6 %!!"%7#

ρ

R ⋅⋅ ² ⋅⋅ ² ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ρ

[4] )* *+, ,-. / -*, 0 %!$("!$

[5] 1 2345*4 1 -36.47 , %!8%"

[6] 939*: 04+39*: %!!$" %(% * 46*"

[7] 0*3;9*: ) 939*: <3-*2 3*2 0*4 1= 04*- 534 342* >- 0 ,4 %!!$ * 46*"

,=92'

_{! " # $% #&}

' ( )* + ,-& ../// 0&

_{' # & 1 + 2& ../// 0} 3 * 4 * 5 6 γ7"89 5 !"8 & * *: *6 & ! 4 46 : 4 ;,&< ./< =*7<2>/ ?$9 * 5 ); <@&A<>-&,. B?&

1 %: C γ7"89 • + =• 1• 6 • • 1 : C • !6 • 1 • 5 • ) •