J. Cent. South Univ. (2017) 24: 489−495
DOI: 10.1007/s11771-017-3451-7
Effect of ferrite content on dissolution kinetics of gibbsitic bauxite under
atmospheric pressure in NaOH solution
YANG Hui-bin(杨会宾)1, 2, PAN Xiao-lin(潘晓林)1, YU Hai-yan(于海燕)1,
TU Gan-feng(涂赣峰)1, SUN Jun-min(孙俊民)2
1. School of Metallurgy, Northeastern University, Shenyang 110004, China;
2. Datang International High Aluminum Coal R&D Center
(National Energy Sources High Aluminum Coal Development and Utilization Key Laboratory), Ordos 010321, China
© Central South University Press and Springer-Verlag Berlin Heidelberg 2017
Abstract: The dissolution property of high-ferrite gibbsitic bauxite and the effect of ferrite content on the dissolution kinetics of
gibbsitic bauxites in sodium hydroxide solution under atmospheric pressure from 50 to 90 °C were systematically investigated. The
dissolution property of high-ferrite gibbsitic bauxite is increased by increasing the dissolution temperature and the NaOH
concentration or decreasing the particle size of bauxite, which is easy to dissolve under atmospheric pressure. The kinetic equations
of gibbsitic bauxites with different ferrite contents during the dissolution process at different temperatures for different times were
established, and the corresponding activation energies were calculated. The ferrite in the gibbsitic bauxite reduces the dissolution
speed and increases the activation energy of dissolution, the diffusion process of which is the rate-controlling step.
Key words: gibbsitic bauxite; dissolution; kinetics; ferrite; Bayer process
1 Introduction
More than 90% of the alumina output is produced
by the Bayer process, which is the major production
technology in the alumina industry. Depending on the
dissolution temperature, the Bayer process can be
classified into three kinds, i.e. low-temperature digestion
Bayer process, medium-temperature digestion Bayer
process and high-temperature digestion Bayer process. In
the industry, lower dissolution temperature would reduce
the equipment specifications [1], and then the investment
will be reduced. It is very important to strengthen the
research on the low temperature or atmospheric pressure
during the Bayer process. The selection of Bayer process
depends on the kinds of bauxite. Low temperature Bayer
process only can deal with gibbsitic bauxite [2−4].
Goethite and hematite are commonly found together with
gibbsite in the gibbsitic bauxite, because their parent
rocks of pyroxene and plagioclase are associated
minerals. Ferrite is the main impurity in gibbsitic bauxite.
CHEN et al [5] studied the lateritic gibbsitic bauxite and
confirmed the shapes of gibbsite, goethite and hematite.
Gibbsite crystal presents hexagonal-platelet morphology
or flaky, goethite is kidney shape, crusty or bean oolitic
and hematite presents granular aggregates. The crystal
structure of goethite and hematite as well as the way
mixed with gibbsite will affect the dissolution of
gibbsite.
The dissolution process can be improved easily by
rising digestion temperature or increasing the caustic
soda concentration in the alumina industry. Little
attention was paid to the dissolution step and the theory
research on the gibbsite dissolution kinetics until 1970.
There is no consensus about its limiting step during the
dissolution process in the literatures so far. Chemical
reaction was considered to be the limiting step during the
dissolution of gibbsite by PEREIRA et al,
GLASTONBURY (1967), ROACH (1985) and LI et al
(1995) [6]. BAO et al and HERMANN (1953) found the
rate-controlling step is diffusion [7]. BOMTRAGER et al
(1974) and YIN (1988) considered that both the chemical
reaction and diffusion are important. YIN et al (1991)
reported that chemical reaction is the rate-controlling
step when the temperature is under 80 °C, while the
diffusion is the limiting step when the temperature is
above 115 °C [7]. As shown in the literatures, most of the
samples used in the kinetic experiments are aluminum
hydroxide or pure gibbsite. However, the raw gibbsitic
bauxite contains various impurities including goethite,
Foundation item: Projects(51104041, 51174054, 51374065) supported by the National Natural Science Foundation of China; Project(N130402010)
supported by the Fundamental Research Funds for the Central Universities of China
Received date: 2015−12−14; Accepted date: 2016−05−11
Corresponding author: PAN Xiao-lin, PhD; Tel: +86−24−83686460; E-mail: [email protected]
J. Cent. South Univ. (2017) 24: 489−495
490
hematite, quartz, kaolinite etc. Pure gibbsite and gibbsitic
bauxite are different in several aspects, such as the
crystal growth process, crystal structure and the doping
way of impurity minerals and the gibbsite. Therefore, the
dissolution property of gibbsitic bauxite in caustic
solution can be affected by those differences.
The dissolution activation energy of pure gibbsite
and gibbsitic bauxite is affected by the growing process
of the gibbsite crystal, which is difference in the crystal
structure and impurities. PEREIRA et al [6] and
ADDAI-MENSAH et al [8] calculated that activation
energy of the gibbsite is 110 kJ/mol and 90 kJ/mol,
respectively, using Al(OH)3 as the experiment sample.
BAO et al [9], YIN et al [10] and LI et al [11] figured out
that the activation energy values are (75±1) kJ/mol,
76.20−76.85 kJ/mol and 76.85 kJ/mol using pure
gibbsite, respectively [9−11].
The dissolution property and kinetics of gibbsitic
bauxites with different ferrite contents were investigated
under the atmospheric pressure in this work. The effect
of ferrite content on the rate-controlling step and the
kinetic equation of gibbsitic bauxite were also discussed.
2 Materials and methods
2.1 Materials
The raw gibbsitic bauxite (named Bauxite 1) used in
this research was exploited from West Kalimantan of
Indonesia. The bauxite samples were dried at 105 °C for
6 h, and then crushed by the jaw crusher and crushing
roller. Three samples with different particle sizes were
sieved by standard sieves, the average particle sizes of
which are 2.00 mm, 0.75 mm and 0.20 mm (named
Sample 1, Sample 2 and Sample 3). All these three
samples are raw bauxite and the chemical and mineral
compositions are the same. The main chemical
compositions of the raw bauxite are given in Table 1. The
XRD pattern of the bauxite is shown in Fig. 1, and the
mineral components of bauxite are given in Table 2. As
shown in Table 2, the main minerals of the bauxite are
gibbsite, goethite and hematite.
Table 1 Main chemical compositions of raw bauxite (Bauxite 1)
(mass fraction, %)
Al2O3
Fe2O3
SiO2
CaO
TiO2
LOI
39.30
31.03
2.78
1.31
1.78
23.40
The samples with lower ferrite contents were
obtained by the magnetic method to remove part of the
ferrite. The ferrite content in the samples was controlled
by adjusting the intensity of the magnetic field. First, the
raw gibbsitic bauxite was ground to a particle size of
0.10−0.50 mm. Then, the magnetic selector was used to
separate the high-ferrite parts and the low-ferrite parts,
Fig. 1 XRD pattern of raw bauxite
Table 2 Main mineral compositions of raw bauxite (mass
fraction, %)
Gibbsite Hematite Goethite Kaolinite
53.10
18.50
17.10
4.40
Quartz
Anatase
0.70
1.78
and the intensities of magnetic field are 0.6 and 0.9 T,
respectively. Wet magnetic separation was selected, and
the high-ferrite parts were discarded and the low ferrite
parts were dried for dissolution experiments. Compared
with the raw bauxite, the separated samples were named
Bauxite 2 and Bauxite 3, which corresponds to the parts
separated by 0.6 and 0.9 T, respectively. The main
chemical compositions of the samples are given in
Table 3.
Table 3 Chemical compositions of Bauxite 2 and Bauxite 3
(mass fraction, %)
Sample
Al2O3
SiO2
Fe2O3
LOI
Bauxite 2
43.24
3.25
24.07
24.67
Bauxite 3
46.88
3.55
18.60
26.93
2.2 Experimental methods
The dissolution experiments were conducted in an
isothermal batch reactor. The reaction temperature (T)
and the sodium hydroxide concentration (CNaOH) vary
from 50 °C to 90 °C and from 1 mol/L to 5 mol/L,
respectively. The stirring speed (R) is between 250 and
450 r/min. The liquid-to-solid ratio for dissolution (L/S)
is 5−30.
The bauxite residues were washed by hot distilled
water, and then dried for the analyses of XRD. The
alumina dissolution efficiency (μA) was calculated
according to
μA=(cAc0V0)/(CAW0c1)
(1)
where cA is the alumina concentration in sodium
aluminate solution after dissolution, g/L; c0 and c1 are the
NaOH concentration before and after dissolution, g/L; V0
is the volume of the initial solution, L; CA is the alumina
J. Cent. South Univ. (2017) 24: 489−495
491
content in the bauxite, %; W0 is the addition of the
bauxite, g.
As given in Table 1, the silica content in the bauxite
is relatively low, which makes the estimated error
brought by the SiO2 is 0.05% for the alumina dissolution
efficiency and 0.04% for the changes of caustic soda
concentration. Therefore, the presence of the silica is
ignored in this work.
2.3 Analysis methods
The particle size of the gibbsitic bauxite was
detected by standard screens, while the bauxite residue
was detected by a laser nanometer size analyzer. The
chemical compositions of the bauxite were detected by
national or industry standards methods. The alumina is
analyzed by the EDTA titration method. The silicon
oxide is analyzed by the molybdenum blue photometric
method. The iron oxide is analyzed by the
orthophenanthrolene spectrophotometry method and the
titanium dioxide was detected by the diantipyrylmethane
spectrophotometry method. The sodium oxide
concentration of the solution was detected by acid-base
neutralization method and the alumina concentration was
detected by EDTA complexometry.
The mineral phases were analyzed by the BRUKER
X-ray diffraction using Cu target cathode. The voltage is
30 kV and the current is 15 mA. The scanning angle is
from 3° to 80° with the step size of 0.02°.
Fig. 2 Dissolution efficiencies of samples with different
particle sizes (T=85 °C; L/S=10; CNaOH=3 mol/L; R=350 r/min)
The dissolution results of Sample 2 with different
stirring speeds are shown in Fig. 3. As shown in Fig. 3,
the alumina dissolution efficiency is affected by the
stirring speed obviously. The dissolution speed is
increased with increasing the stirring speed, which
indicates that diffusion may affect the dissolution speed.
The relative motion of the particles and liquid is
increased as the stirring speed increases, which enhances
the diffusion velocity of the liquid reactants and products.
But the stirring speed does not affect the shape of the
dissolution efficiency curves. All the curves are similar
to the parabola shape.
3 Results and discussion
3.1 Dissolution property of high-ferrite gibbsitic
bauxite
The particle size of bauxite is one of the main
factors to affect the alumina dissolution speed. As shown
in Fig. 2, the alumina dissolution speed of Sample 3 is
the fastest. The dissolution efficiency is closed to 80%
when the dissolution time is 10 min. The dissolution
speed of Sample 1 is the slowest and becomes more
stable after 40 min. The dissolution efficiency of Sample
2 is 77.01% for 20 min, which is between that of Sample
1 and Sample 3. The dissolution efficiencies of the three
samples increase slowly after 20 min. The dissolution
efficiencies of Sample 1 and Sample 2 have little
difference when the dissolution time is 40 min, which are
82.26% and 81.40%, respectively. The dissolution
efficiency of the Sample 3 is higher than that of the other
samples obviously. When the bauxite particles are fully
ground, the gibbsite crystal are fully exposed, which
increases the contact area in caustic solution. Meanwhile,
fully grinding also makes large damage to the crystal
surfaces, which enhances the reactivity of the bauxite
particle and increases the gibbsite dissolution in caustic
solution.
Fig. 3 Dissolution efficiencies of Sample 2 with different
stirring speeds (T=85 °C; L/S=10; CNaOH=3 mol/L)
During dissolution process, the liquid-to-solid ratio
is very important. The higher the liquid-to-solid ratio is,
the higher the αk is, which makes the driving force of the
dissolution stronger and the dissolution speed faster. The
dissolution efficiencies of Sample 2 under different
liquid-to-solid ratios are shown in Fig. 4. As shown in
Fig. 4, the alumina dissolution efficiency is the lowest
when the liquid-to-solid ratio is 5, which is only 67.00%
for 30 min. The increase of the dissolution efficiency is
obvious when the liquid-to-solid ratio increases to 10,
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492
gibbsite dissolution speed is faster when the temperature
is above 80 °C. The alumina dissolution efficiency is
higher than 90% at 90 °C for 20 min, and it does not
increase with the dissolution time, indicating that the
dissolution process has almost finished when the
dissolution time is 20 min.
Fig. 4 Dissolution efficiencies of Sample 2 with different
liquid-to-solid ratios (T=85 °C; R=350 r/min; CNaOH=3 mol/L;
t=30 min)
which increases by 18.40% compared with the liquid-tosolid of 5 for the same dissolution time, but it does not
change much when the liquid-to-solid ratio is over 10.
The NaOH concentration is one of the most
important factors during the dissolution process. The
dissolution results of various NaOH concentrations are
shown in Fig. 5. As shown in Fig. 5, the alumina
dissolution efficiency is low when the NaOH
concentration is low, which is only 44.40% for 60 min
when the NaOH concentration is 1 mol/L. The alumina
dissolution efficiency increases with the increase of the
NaOH concentration and higher NaOH concentration
shortens the dissolution time. The dissolution curves of
NaOH concentrations with 3−5 mol/L are very close,
indicating that the proper NaOH concentration is
3 mol/L.
Fig. 6 Dissolution efficiencies of Sample 2 with different
temperatures (CNaOH=3 mol/L; L/S=10; R=350 r/min)
3.2 Dissolution kinetics of high-ferrite gibbsitic
bauxite
The pure gibbsite dissolving in the caustic solution
is simple liquid−solid reaction and no new solid product
appears during the dissolution process, which accords to
the shrinking nonporous models [12]. The chemical
reaction is given as
Al2O3·3H2O(s)+2OH−(aq)= 2Al(OH)4 (aq)
The digestion process of the gibbsite involves
basically three steps. The first step corresponds to the
diffusion of liquid reactants towards the liquid−solid
reaction surface, which is external diffusion. Next step is
the reaction at the interface. The final step is the
diffusion of products from the interface towards the
liquid, which is internal diffusion. When the limiting step
is chemical reaction or external diffusion, the equation of
the dissolution efficiency is calculated by [12−15]
1−(1−α)1/3=kt
Fig. 5 Dissolution efficiencies of Sample 2 with different
NaOH concentrations (T=90 °C; L/S=10; R=350 r/min)
The results of different dissolution temperatures are
shown in Fig. 6. As shown in Fig. 6, the dissolution
temperature affects the dissolution efficiency and
dissolution speed obviously. The alumina dissolution
efficiency increases slowly when the temperature is
below 70 °C, which is less than 72.00% for 40 min. The
(2)
(3)
where α is the dissolution efficiency of alumina, k is the
apparent efficiency constant and t is the dissolution time.
The gibbsitic bauxite is not a pure crystal, which
contains impurity minerals such as goethite, hematite,
quartz and kaolinite. The gibbsite dissolution process
may be influenced by the impurity minerals, resulting in
the change of the dissolution equation. When diffusion is
the limiting step, the dissolution equation is as shown as
[12, 13]
1−2α/3−(1−α)2/3=kt
(4)
where α is the dissolution efficiency of alumina, k is the
apparent efficiency constant and t is the dissolution time.
J. Cent. South Univ. (2017) 24: 489−495
493
The curves of dissolution efficiency with
dissolution time according to Eqs. (3) and (4) are shown
in Fig. 7. The linear relationship between 1−2α/3−
(1−α)2/3 and t are much better compared with that of
1−(1−α)1/3 and t. The values of R2 (the correlation
coefficient) shown in Fig. 7(b) are higher than those in
Fig. 7(a). This suggests that the alumina dissolution
efficiency is affected by the impurity minerals attached
on the gibbsite crystals and the diffusion is the ratecontrolling step.
The slopes of k, the apparent rate constants of the
straight lines in Fig. 7(b), are calculated, as given in
Table 4.
Fig. 8 Arrhenius curve of dissolution for Sample 2
to the data calculated by PEREIRA et al [6]
E=−k'×R
(6)
According to the Arrhenius equation, A can be
figured out, which is 1.32×1015 min−1. The Equation of
rate constants and dissolution efficiency equation can be
obtained:
k=1.32×1015exp[−117485/(RT)]
(7)
1−2α/3−(1−α)2/3=1.32×1015exp[−117485/(RT)]t
(8)
The rate equation suggests that the limiting step is
diffusion. It is because the impurity minerals affect the
dissolution process obviously. The impurity minerals mix
with or wrap the gibbsite crystal, which prevent the
diffusion of the products and reduce the gibbsite
dissolution speed. The limiting step is internal diffusion.
Fig. 7 Relation curves of dissolution efficiencies with time for
Sample 2: (a) 1−(1−α)1/3 vs t; (b) 1−2α/3−(1−α)2/3 vs t
Table 4 Values of k of bauxite
t/°C
−4
−1
k/10 min
50
60
70
80
90
0.81
6.39
22.60
61.40
102.90
The Arrhenius equation is shown as Eq. (5) and the
Arrhenius curve of the dissolution process is shown in
Fig. 8. The slop of the straight line (k′) is −14.13:
lnk=−E/(RT)+lnA
(5)
where k is the efficiency constant, E is the activation
energy and A is the preexponential factor or frequency
factor.
The activation energy was calculated to be
117.485 kJ/mol according to the Eq. (6), which is close
3.3 Effects of ferrite content on dissolution kinetics
Goethite and hematite are the main impurities in the
gibbsitic bauxite. The two kinds of ferrite-bearing
mineral can influence the dissolution process of the
gibbsite [16, 17].
Bauxite 2 and Bauxite 3 have the lower ferrite
content, as given in Table 3. The dissolution tests of
Bauxite 2 and Bauxite 3 were carried out at different
temperatures varying from 50 °C to 90 °C. The liquid-tosolid ratio is 10 and the NaOH concentration is 3 mol/L.
The dissolution efficiency curves of the Bauxite 2 and
Bauxite 3 are shown in Fig. 9.
The dissolution equations are selected by the same
method as that of Sample 2. The two relationship curves
of the equation 1−2α/3−(1−α)2/3 and t can be obtained.
The relationship curves are shown in
Fig. 10 and the
corresponding Arrhenius figures are shown in Fig. 11.
The diffusion is also the limiting step, which indicates
that the rest ferrites in the bauxite still influence the
dissolution process.
The apparent activation energies of Bauxite 2 and
Bauxite 3 were calculated to be 99.14 kJ/mol and
98.93 kJ/mol, resp ectiv ely. Th e correspond ing
J. Cent. South Univ. (2017) 24: 489−495
494
Fig. 9 Dissolution efficiencies of Bauxite 2 and Bauxite 3 at
different dissolution temperatures (R=350 r/min): (a) Bauxite 2;
(b) Bauxite 3
Fig. 11 Arrhenius curves of Bauxite 2 and Bauxite 3:
(a) Bauxite 2; (b) Bauxite 3
preexponential factors A are 2.42×1012 min−1 and
1.75×1012 min−1. The dissolution efficiency equations of
Bauxite 2 and Bauxite 3 were obtained:
1−2α/3−(1−α)2/3=2.42×1012exp[−99144/(RT)]t
(9)
1−2α/3−(1−α)2/3=1.75×1012exp[−98928/(RT)]t
(10)
By comparing Eq. (8) with Eqs. (9) and (10), the
activation energy and the corresponding preexponential
factors during dissolution decrease with decreasing the
ferrite content. The correlation coefficients of main
chemical compositions and the activation energies were
calculated by the Excel function (CORREL), as given in
Table 5. CE-S, CE-F and CE-A are the correlation
coefficients of silica content, ferrite content and alumina
content with the activation energy, respectively.
As given in Table 5, the value of CE-F is 0.90, which
is the biggest correlation coefficient. This indicates that
the ferrite content is the main reason for the change of
activation energy. The activation energy decreases when
the ferrite content decreases, which benefits to the
Table 5 Correlation coefficients of main chemical compositions
vs activation energies
Fig. 10 Relation curves of dissolution efficiency vs time for
Bauxite 2 and Bauxite 3: (a) Bauxite 2; (b) Bauxite 3
CE-S
CE-F
CE-A
−0.85
0.90
−0.88
J. Cent. South Univ. (2017) 24: 489−495
dissolution process and makes the gibbsite dissolution
easier. ADDAI-MENSAH et al [8] estimated that the
value of activation energy is 90 kJ/mol, which is close to
98.93 kJ/mol (Bauxite 3, ferrite content is relatively
low). In addition, BAO et al [9], YIN et al [10] and LI
et al [11] calculated the activation energy between
74.00 kJ/mol and 76.85 kJ/mol using pure gibbsite. This
also suggests that the less the impurity minerals in the
gibbsitic bauxite are, the less the value of activation
energy is. For the Bauxite 1, the activation energy is
comparatively higher because of the more goethite and
hematite. The dissolution performance of the gibbsitic
bauxite is improved when some ferrite is removed.
The effect of ferrite content on the dissolution
kinetics is only a surface phenomenon, and it actually
reflects the mix or wrap status of gibbsite and ferrite in
the gibbsitic bauxite. The mix or wrap status of them is
higher while the ferrite content is higher, so the
dissolution activation energy of gibbsite is higher and the
dissolution is difficult. While partial ferrite is removed,
the mix or wrap status of them is reduced and the
dissolution activation energy correspondingly becomes
smaller. But, the mix or wrap status of the gibbsite and
ferrite do not disappear completely in the three kinds of
gibbsitic bauxite, so the dissolution rate equation types of
them are the same.
4 Conclusions
1) The gibbsite dissolution process of the highferrite gibbsitic bauxite is influenced by the impurity
minerals, which prevents the diffusion of products and
reduces the gibbsite dissolution speed. Diffusion is the
limiting step during the dissolution process. Increasing
dissolution temperature and NaOH concentration or
decreasing the bauxite particle size increases the
dissolution speed of bauxite. The dissolution efficiency
of gibbsite is over 90% for 20 min under atmospheric
pressure.
2) The kinetic equations of Bauxite 1, Bauxite 2 and
Bauxite 3 with different ferrite contents were established
as 1−2α/3−(1−α)2/3=1.32×1015exp[−117485/(RT)]t, 1−
2α/3−(1−α)2/3=2.42×1012exp[−99144/(RT)]t and 1−2α/3−
(1−α)2/3=1.75×1012exp[−98928/ (RT)]t, respectively.
3) The activation energy and the preexponential
factor of gibbsitic bauxite during the dissolution process
are reduced by the ferrite. Decreasing the ferrite content
reduces the activation energy and accelerates the
dissolution process.
495
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
BI Shi-wen, YU Hai-yan. Alumina production technology [M].
Beijing: Chemical Industry Press, 2006: 40−41. (in Chinese)
CERTINI G, WILSON M J, HILLIER S J, FRASER A R, DELBOS
E. Mineral weathering in trachydacitic-derived soils and saprolites
involving formation of embryonic halloysite and gibbsite at Mt.
Amiata, central Italy [J]. Geoderma, 2006, 133(3, 4): 173−190.
MULYANTO B, STOOPS G, VAN R E. Precipitation and
dissolution of gibbsite during weathering of andesitic boulders in
humid tropical West Java [J]. Geoderma, 1999, 89(3, 4): 287−305.
HERRMANN L, ANONGRAK N, ZAREI M, SCHULER U,
SPOHRER K. Factors and processes of gibbsite formation in
northern Thailand [J]. Catena, 2007, 71(2): 279−291.
CHEN Jian-guo, LIU Yun-hua, XU Jun-wen. Differences of
mineralization of two gibbsitic bauxites in Guangxi province [J].
Earth Science Frontiers, 1999, 6(S): 251−256. (in Chinese)
PEREIRA J A M, SCHWAAB M, DELL'ORO E, PINTO J C,
MONTEIRO J L F, HENRIQUES C A. The kinetics
of gibbsite dissolution in NaOH [J]. Hydrometallurgy, 2009, 96(1, 2):
6−13.
BAO Li, NGUYEN A V. Developing a physically consistent model
for gibbsite leaching kinetics [J]. Hydrometallurgy, 2010, 104(1):
86−98.
ADDAI-MENSAH J, DAWE J, RALSTON J. The dissolution and
interactions of gibbsite particles in alkaline media [J]. Developments
in Mineral Processing, 2000, 13: C6-1−C6-7.
BAO Li, ZHANG Ting-an, LIU Yan, DOU Zhi-he, LU Guo-zhi,
WANG Xiao-min, MA Jia, JIANG Xiao-li. The most probable
mechanism function and kinetic parameters of gibbsite dissolution in
NaOH [J]. Chinese Journal of Chemical Engineering, 2010, 18(4):
630−634.
YIN Ai-jun, CHEN Qi-yuan, ZHANG Ping-min. Studies on the
kinetics of digestion process of synthetic gibbsite by DSC [J].
Chemical Journal of Chinese Universities, 1991, 12(11): 1507−1509.
(in Chinese)
LI Chao-qun, ZHANG Ping-min, CHEN Qi-yuan, CHEN Xin-min.
Investigation of digestion process kinetics of gibbsite [J]. Nonferrous
Metals, 1991, 43(4): 52−55. (in Chinese)
HUA Yi-xin. Introduction to metallurgical process dynamics [M].
Beijing: Metallurgical Industry Press, 2004: 188−198. (in Chinese)
LI Hong-gui. Hydrometallurgy [M]. Changsha: Central South
University Press, 2005: 74−79. (in Chinese)
LIU Zhi-xiong, YIN Zhou-lan, CHEN Yi-guang, XIONG Li-zhi.
Leaching kinetics of molybdenum from Ni-Mo ore in sulfuric acid
solution with sodium peroxodisulfate as oxidant [J]. Journal of
Central South University, 2015, 22(3): 874−879.
LIU Zhi-xiong, YIN Zhou-lan, HU Hui-ping, CHEN Qi-yuan.
Leaching kinetics of low-grade copper ore with high-alkality gangues
in ammonia-ammonium sulphate solution [J]. Journal of Central
South University, 2012, 19(1): 77−84.
WEBSTER N A S, LOAN M J, MADSEN I C, KNOTT R B,
KIMPTON J A. An investigation of the mechanisms of goethite,
hematite and magnetite-seeded Al(OH)3 precipitation from synthetic
Bayer liquor [J]. Hydrometallurgy, 2011, 109(1, 2): 72−79.
LIU Hai-bo, CHEN Tian-hu, FROST R L. An overview of the role
of goethite surfaces in the environment [J]. Chemosphere, 2014, 103:
1−11.
(Edited by YANG Bing)
Cite this article as: YANG Hui-bin, PAN Xiao-lin, YU Hai-yan, TU Gan-feng, SUN Jun-min. Effect of ferrite content
on dissolution kinetics of gibbsitic bauxite under atmospheric pressure in NaOH solution [J]. Journal of Central South
University, 2017, 24(3): 489−495. DOI: 10.1007/s11771-017-3451-7.