Advances in Ma terials Physics and Chemistry, 2012, 2, 216-220
doi:10.4236/ampc.2012.24B055 Published Online December 2012 (htt p://www.SciRP.org/journal/ampc)
The Study of Method for Complex Processing Turgay
Sub-S tandard Aluminum-Containing Raw Materials
G. Sarsenbay , L. A. Myltykbaeva, R. A. Abdulwalyev, S. B. Satylganova
Cen ter of Eart h Sciences, Metallurgy and O re Beneficiation, JSC, Science an d Educati on Ministry of the Republic of Kazakhstan
Received 2012
ABSTRACT
obj ects of the r esearch are Ka zakhs tan’s Tur gay clay, studied of method for alumina and potassium metasilicate obtaining from Tur-
gay sub-standard aluminum raw materials. Concluded that optimal conditions for the process of Turgay clay: reaction temperature
100°C, original solution K2O concentr ati o n to 300 g/ dm3, reaction time 120 min, liquid-solid ratio of 3:1; optimized the conditions of
digestion alumina concentrate: original Na2O solution concentration of 400 g/dm3, temperature 280°C, molar ratio CaO : SiO2 =
1. Recovery is 99.6% of alumina digestion under this condition; crystallized solid phase components as Na2O·Al2O3·6H2O sodium
hydroaluminate crystals. Extracted of alumina from solution of sodium hydroaluminate.
Keywords: Potassium Hydroxide Solution; Leaching; Clay; Alumina Concentrate; Sodium Aluminate Solution; Digestion;
Desilication; Alumina
1. Introduction
With the reduction of bauxite resources, the application of low-
grade aluminum-containing raw materials i n aluminum produc-
tion will be the key question. Kazakhstan is rich of low grade
bauxite mine (burnt ash, clay), which were the storage of Tur-
gay clay long enough to provide raw materials for alumina
production [1]. For low grade aluminum ore, chemical benefic-
iation processing – alkali leaching to removal some silicon-
containing to extraction silicate mineral, and alumina produc-
tion by using concentrate can be comprehensive utilization of
raw materials, solve problems of production effectively. Study
on alkaline leaching of high-silicon aluminum ore, treated by
sodium hydroxide solution and extraction silicate widely visible
[2,3], not seen on the potassium hydroxide reports. Potassium
silicate as main ingredient for high-quality potassium fertilizer
of chloride-free is widely used in agricultural production. For
the purpose of this study to complex processing Turgay clay,
potassium hydroxide solution used for the first time of low
grade aluminum-containing raw materials dressing process, by
planning central composite second order rotatable experiment
and hydrochemical test, to find the best reaction condition of
extraction from Turgay clay industrial alumina and chlorine-
free po tash fertil izer processing methods.
2. Experimental
2.1. Optimization Process of Clay ore Dressing
Potassium silicate solution and alumina concentrate can be
obtained by baking clay leaching by potassium hydroxide solu-
tion, using central composite second order rotatable test [4] to
find the optimal leaching conditions.
Chemical composition of Turgay’s baking clay samples for
experiments is: SiO2 37%; Al2O3 42.6%; Fe2O3 13.8 %; CaO
1.3%; Na2O 0.8%; other 1.5%; A/S=1.15. The experiments an d
results: using of the central composite of second order rotata-
ble to develop test, factors influencing the leaching effect of
three is made for the variabl e: X1 as the concen tration for K2O
in original solution, g/dm3; X2 for leaching time, min; X3 for
liquid-solid ratio, percentage of SiO2 into solution (y) selected
optimization parameter. Experiment conditions and results of
Second order rotatable as shown in Table 1.
Table 1 Conditions and results of experiments.
Ν Conditions, g/dm 3, min Solu tion components, g/dm3, %
X1 X2 X3 K2O Al2O3 SiO2 SiO2
1 100 60 2:1 61.1 1.38 98.0 48.21
2 300 60 2:1 211.5 2.46 243.5 79.00
3 100 180 2:1 56.4 1.63 99.5 48.94
4 300 180 2:1 253.8 2.89 2 28.5 78.40
5 100 60 4:1 61.1 1.13 70.5 69.32
6 300 60 4:1 282.0 2.64 105.0 79.44
7 100 180 4:1 61.1 1.63 72.5 71.29
8 300 180 4:1 282.0 3.13 97.5 82.84
9 31.8 120 3:1 30.25 2.6 4 26.5 20.93
10 336.4 120 3:1 235.0 1.13 162.5 80.86
11 200 19 3:1 188.0 1.13 95.0 65.02
12 200 221 3:1 188.0 2.64 112.0 76.66
13 200 120 1,31:1 188.0 2.64 208.0 62.26
14 200 120 4,68:1 188.0 0.12 74.0 79.06
15 200 120 3:1 164.5 1.63 114.3 78.23
16 200 120 3:1 188.0 1.13 114.5 78.37
17 200 120 3:1 164.5 1.13 114.0 78.03
18 200 120 3:1 164.5 1.13 115.0 78.71
19 200 120 3:1 164.5 1.63 113.5 77.69
20 200 120 3:1 88.0 1.63 115.3 78.88

G. SARSENB AY ET AL.
217
According to the planning of matrix and experimental results
the regression equatio n cal culated, t he equati on is following:
У= 78.14 +13.38Х1 +1.84Х2 +5.61Х3 –8.36Х 12
–1.30Х22 –1.36Х32 – 4.8 3Х 13
Analysis equation can reach the following conclusion: the
factors influencing the silica into solutio n of potassium hydroxide,
the action of the concentration of alkali solution mostly strong.
And compared to other factors, influence of reaction time on
the translate silicon dioxide into solution is weak. Combined
effects of three factors are more complex; factor values from 0
to 1, optimization parameters (у) grows, factor value is higher
than the 1, у value decreases. Three f actors affect t he complex-
ity can be interpreted as, dissolution and precipitation of silicon
dioxide in the system are two processes occur simultaneously,
the result of precipitation forming insoluble compounds - hydro
aluminum silicate of potassium. When baking clay samples
contact with potassium hydroxide solution, silicon dioxide dis-
solves faster than the hydrated aluminum silicate, β – cristoba-
lite (Beta-SiO2) in quartz and silicon into solution, this solution
(potassium silicate) as the main ingredient for fertilizer produc-
tion of potassium is chloride-free. At the same time mullite
(3Al2O3.2 S iO2) break down into solution, concentration of
alumina in solution at lower relative will exist of alumi-
num-silicon complexes, where the proportion of aluminium in
silicon atoms as a unit, as reaction continues, the complexes
with alkali solution combining format insoluble hydrated alu-
minum silicate of potassium. Experiments concluded that the
optimal conditions for the process of Turgay clay: reaction
temperature 100°C, original solution concentration K2O 300
g/dm3, reaction time 120 min, liquid-solid ratio of 3:1.
2.2. Optimization of Process of Digestion Alumina
Concentrate in Sodium Aluminum Solution
The process of extraction alumina products from alumina con-
centrate carried out by hydrochemical methods [5]. Optimal
preparation of alumina under leaching condition concentrate
chemical composition as follows: SiO2 10.4%; CaO 0.2%; K2O
0.2%; Fe2O3 9.55%; Al2O3 62.8%; other 5.0%; A/S 6.04. Phase
compositions are mainly for Mullite and Hematite, with small
amounts of hydrated aluminum silicate of potassium, amorph-
ous SiO2 content low, shows many SiO2 in clay in the process
is dissolved of solution. Concentrate aluminum oxide digestion
in sodium aluminate solution optimizated by hydrochemical
proces s. Test conditions: temperature of 200~280˚C, time 60
min, original Na2O concentration of sodium aluminate solution
330~450 g/dm3, аk 30, CaO: SiO2 = 1.2~ 2. Affect of three fac-
tors of temperature, concentration and calcium oxide on the
aluminum recovery shown in Figure 1-3.
Figure 1 test results view, increasing temperatures from
200˚C to 280˚C, percentage of Al2O3 into sodium aluminate
solution accordingly increased from 90.6 % to 97.63% .
Figure 2 test resu lts, when concen trati on gradu ally increased
to 450 from 330 g/dm3, the alumina recovery into solution co r-
responding increased from 89.3% to 98.56%.
As shown in Figure 3, when the calcium oxide content in-
creased from molar rati o CaO: Si O2 = 1 to 2 , alumina reco very
solution corresponding decreased from 99.6% to 94 %. Studied
the best conditions of d igestion: original solution Na2O concen-
tration of 400 g/dm3, temperature 280˚C, molar ratio CaO :
SiO2 = 1. Recovery is 99.6% of alumina digestion under this
condition.
2.3. Optimization of Process for Desilication of
Sodium Aluminate Solution
The chemical composition of sodium aluminate solution from
processing alumina concentrate by hydro chemistry method as
follows: Na2O 376.7 g/dm3; Al2O3 65.93 g/dm3; SiO2 4.22
g/dm3, αk 9.4, αk high value of this solution, is not conducive
to decomposition out Al(OH)3 from aluminate solution, there-
fore, need ed to be decrease valu es αk before processing of crys-
tallization. This test uses the crystallization from solution of
hydrated sodium aluminate, water soluble crystals method gets
the αk ~1,6 of sodium aluminate solution. When crystallization,
small amounts o f SiO2 will affect t he cr ystall ization in solution,
so before the sodium aluminate hydrate, pre-desilication
process of sodium aluminate solution. Take into account the
effects of concentration on silicon removal efficiency, Na2O
dilute solution concentration from 376.6 g/dm3 to 200 g/dm3,
other components as Al2O3 35 g/dm3 accordingly, iO2 2.2
g/dm3.
Calcium oxide for desilication agent, add amount CaO : SiO2
to 1.5, 2 and 3 calculated, reaction time is 30 - 180 min, test
conducted in the temperature range of 150-250°C, as shown in
Table 2.
Figure 1. The effect of temperature on the aluminum recovery.
Figure 2. The effect of concentration on the alumina recovery.
Figure 3. The effect of calcium oxide content on the al umina recov-

G. SARSENB AY ET AL.
218
ery.
Test results showed highest conditions of sodium aluminate
solution desilication rate: reaction temperature 200 °C, CaO
added molar rat io CaO : SiO2 is 3, time for 120 min. Under this
condition, sodium aluminate solution desilication rate of 79.5%,
solution composition for Na2O 191 g/dm3, Al2O3 34 g/dm3,
SiO2 0.594 g/dm3, αk 9,2.
2.4. Study on Formation of Alumina from
Desilicated Sodium Aluminate Solution
1) Separating out sodium hydroaluminate crystals from de-
silicated sodium aluminate solutio n
Consists of sodium aluminate solution crystallization of so-
dium hydroaluminate - Na2O·Al2O3·nH2O test: to evaporation
solution concentration of Na2O for 500-550 g/dm3, from which
separation crystals. Test results are shown in Table 3. After
enrichment to concentrations of Na2O 548 g/dm3, removal of
sodium aluminate solution concentration to concentrations of
Na2O after 548 g/dm3, crystallization temperature of 45°C,
under the conditions to quality ratio of 0.05 to join seed crystal,
constant stirring. Conditions and results of crystallization shown
in Table 3.
Table 2. Experimental conditio ns and res ults of desilication of sodium aluminate solutio n.
N
Conditions Components, g/dm3 Des .
rate, %
t,°C CaO:SiO2 min Na2O Al2O3 SiO2
1 100 3 120 182,4 33,7 1,93 13,4
2 150 3 120 188 33,3 0,6 76 ,8
3 200 3 120 190,5 34 0,594 79,5
4 250 3 120 196 20,1 0,65 75
5 200 1 120 196 30 0,747 66,7
6 200 1 ,5 120 190 32 1,0 0 55,6
7 200 2 120 192 33,5 0,56 75
8 200 3 120 191 34 0,47 79,5
9 200 3 30 196 34 0,725 67,6
10 200 3 60 189 3 3 ,3 0,6 77
11 200 3 120 191 34 0,594 79
12 200 3 180 188 34 0,6 7 69,2
Table 3. Experimental conditio ns and res ults of crystallization of sodium hydroaluminate.
T
°С T
h
Test conditions,
composition, g/dm3 Test results
composition, g/dm3
Al2O3 Na2O αk Al2O3 Na2O ακ
45 10 91,89 561,1 10 76,67 550,6 11,8
45 20 91,89 561,1 10 71,44 538,5 12,4
45 30 91,89 561,1 10 31 ,2 527,3 27,8
45 40 91,89 561,1 10 29 ,5 502,1 29,0

G. SARSENB AY ET AL.
219
45 50 91,89 561,1 10 27,33 501,8 30,2
Crystallization rate test results in mixing continuously when
50 h reached the highest value. Chemical composition of sepa-
rated sodiu m h ydroa lu minat e cryst als: AI2O3 25.5%; Na2O 24.1%;
other 34.2%, αк 1.58 solid phase components as
Na2O·Al2O3·6H2O, sodium hydroaluminate crystal x-ray dif-
fraction curve as shown in Figure 4 .
2) Extraction of aluminum hydroxide from solution of so-
dium hydroaluminate
Separate sodium hydroaluminate crystal αk is 1.58, this wa-
ter-soluble crystals available αk value breaks and crystal de-
composition conditions of sodium aluminate solution, from
which precipitation Al (OH) 3 crystal [6]. Test pr oced u res are as
follows: dissolving sodium hydroaluminate crystal
Na2O·Al2O3·6H2O, get aqueous chemical composition for,
AI2O3 100.9 g/dm3; Na2O 98.1 g/dm3; αk is 1.58, according to
the quality of the ratio of 0.3, to join seed – aluminum hydrox-
ide in water solution, temperature of 62ºC - 44 ºC cond itions, to
70 p/min speed mixing hydrolysis of sodium aluminate solution
to 48 h. According to table4 test findings, when 24 h reaction,
hydrolysis rate of 41%, when 48 h reaction, hydrolysis rate
Increased to 59 %. (Table 4)
After the complete hydrolysis of sodium aluminate solution,
the liquid-solid separation are obtained solid aluminum hy-
droxide, chemical components for AI2O3 61.30%, Na2O 0.23%,
other 35.75%, X ray diffraction curve shows the solid formation
is divided into size 20-50 µm of gibbsite, as shown in Figure 5.
3) prepara t ion of alumina from aluminum hydroxide
From solid aluminum hydroxide under the condition of tem-
perature of 1050˚C, calcined 1h we are meeting the criteria of
production alumina solid products. Analysis and identification
of aluminum oxide crystals derived from chemical co mposition
as: AI2O3 98.5%, Na2O 0.78%, SiO2 0.02%, Ti+V+Gr+Mn
0.01%, ZnO 0.01%, P2O5 0.002%, Fe2O3 0.026%, weight re-
duction is 1.2%. X-ray diffraction analysis and its solid groups
are divided into: δ Al2O3, χ · Al
2O3,Al2O3, θ Al 2O3, κ Al2O3,
beta-Al2O3, as shown in Figure 6.
Figure 4. Sodium hydroaluminate crystal x-ray diffraction curve.
Table 4. Hydrolysis of sodium aluminate solution test results.
Seed content Tim e, h
Composition,
g/dm3 αк Hydrolysis
rate, %
Na2O AI2O3
0.3 24 100. 3 61.5 2.7 5 41
0.3 48 105. 7 42.7 4.1 59
Figure5. Aluminium hydroxide crystals by x-ray diffraction curve.

G. SARSENB AY ET AL.
220
Figure 6 aluminum oxide crystal by x-ray diffraction curve.
3. Summary
By research: summary out KOH solution processing Turgay
clay process and sodium aluminate solution digested out alu-
mina concentrate process best reaction conditions ; Optimizatio n
conditions of dissolving sodium aluminate solution desilication;
crystalline solid phase components as Na2O·Al2O3·6H2O so-
dium hydroaluminate crystals; preparation meeting the criteria
of production alumina solid products; study for the first time
out complex alkaline processing method of clay application of
KOH solution.
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