AU594035B2 - Process for the production of aluminium hydroxide with low content of impurities, especially of iron, and with high degree of whiteness - Google Patents
Process for the production of aluminium hydroxide with low content of impurities, especially of iron, and with high degree of whiteness Download PDFInfo
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- AU594035B2 AU594035B2 AU52453/86A AU5245386A AU594035B2 AU 594035 B2 AU594035 B2 AU 594035B2 AU 52453/86 A AU52453/86 A AU 52453/86A AU 5245386 A AU5245386 A AU 5245386A AU 594035 B2 AU594035 B2 AU 594035B2
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- Australia
- Prior art keywords
- aluminium hydroxide
- magnesium sulphate
- production
- iron
- liquor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 45
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 title claims description 29
- 229910021502 aluminium hydroxide Inorganic materials 0.000 title claims description 29
- 238000000034 method Methods 0.000 title claims description 21
- 229910052742 iron Inorganic materials 0.000 title claims description 19
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 239000012535 impurity Substances 0.000 title claims description 6
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 42
- 150000004645 aluminates Chemical class 0.000 claims description 26
- 229910001570 bauxite Inorganic materials 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 12
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 10
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 10
- 235000013339 cereals Nutrition 0.000 claims description 9
- 230000029087 digestion Effects 0.000 claims description 6
- 238000004131 Bayer process Methods 0.000 claims description 5
- 230000000052 comparative effect Effects 0.000 claims description 4
- 238000000926 separation method Methods 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 150000004682 monohydrates Chemical class 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 2
- 150000002681 magnesium compounds Chemical class 0.000 claims description 2
- 229910052928 kieserite Inorganic materials 0.000 description 22
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 10
- 238000007792 addition Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 238000001914 filtration Methods 0.000 description 5
- 239000011734 sodium Substances 0.000 description 5
- 229910018626 Al(OH) Inorganic materials 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 238000013019 agitation Methods 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 150000001399 aluminium compounds Chemical class 0.000 description 2
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 229940077746 antacid containing aluminium compound Drugs 0.000 description 2
- 229910052785 arsenic Inorganic materials 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Inorganic materials [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 239000003610 charcoal Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 241000371652 Curvularia clavata Species 0.000 description 1
- 241001397173 Kali <angiosperm> Species 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- KIZFHUJKFSNWKO-UHFFFAOYSA-M calcium monohydroxide Chemical compound [Ca]O KIZFHUJKFSNWKO-UHFFFAOYSA-M 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 229910001679 gibbsite Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- -1 kieserite Chemical compound 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000012716 precipitator Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910001388 sodium aluminate Inorganic materials 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/46—Purification of aluminium oxide, aluminium hydroxide or aluminates
- C01F7/47—Purification of aluminium oxide, aluminium hydroxide or aluminates of aluminates, e.g. removal of compounds of Si, Fe, Ga or of organic compounds from Bayer process liquors
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/46—Purification of aluminium oxide, aluminium hydroxide or aluminates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/60—Optical properties, e.g. expressed in CIELAB-values
- C01P2006/62—L* (lightness axis)
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Luminescent Compositions (AREA)
Description
CMONWEALTH OF AUSTRALA Patents Act 1952 Tift~ doj~mest cottaiwa d swcw 4.
MAn 6i on.
C 0 M P L E T E S P E C I F I C A. T 1 0 N
(ORIGINAL)
Class Int. class Application Number 0 Lodged 6 A 145 I romplete Specification Lodged 04.
ELODG6D AT SUB-0IFFICE 7 JAN 1986 'Iy y y (r o 7
C
Priorit ies Accepted: Published; 17 January 1985 and 20 December 1985 tiRelated Art Get.
#5 0 4 Eu 01 aine of Applicant 0 so
S
4-~CL~ :ALCOA CHEMIE GmbH KALI SALZ A.G.
S ,Address of Applicant Giulinistrasse 2, 6700 Ludwigshafen/Rhein, Federal Republic of Germany and Friedrich- Ebert-Strasse. 160, 3500 Kassel, Federal Republic of Germany Actual Inventors :Dr. Horst Poblend and Dr. Bernhard Schepers Address for Service F.B. RICE CO., Patent Attorneys, 28A Montague St~re~et,, BALMAIN. 20414 Complete Specification for the invention entitled: PROCESS FOR THE PRODUCTION OF ALUMINIUM HYDROXIDE WITH LOW CONTENT OF IMPURITIES, ESPECIALLY OF IRON, AND WITH HIGH DEGREE OF WHITENESS The following statement is a full description of this invention including the best method of performing it known to us
ATACHED
MAIL OFFICER P P ICA1ON ACCEPTE AND AMENDM N i f 2 Object of the invention submitted is a process for the production of a low iron content aluminium hydroxide with a high degree of whiteness, which is obtained by decomposition in aluminate liquor through the alkaline digestion of bauxite (Bayer process) or aluminium hydroxide.
The aluminium compounds contained in the bauxite in various combinations dissolve as aluminates in aqueous alkaline liquor at high temperatures. The insoluble components of the bauxite remain present in suspension in the aluminate liquor, as so-called red mud. The red mud is agglommerated and separated from the aluminate liquor by decanting and filtration, washed and dumped, or diverted to other uses.
For the separation of the finer red mud p. icles the saturated hot aluminate liquor at about 100 0 C is submitted to a clarifying filtration in a pressure filter, in which for the improvement of filter performance, in o 0 many cases a filter aid (Precoat) CaO or Ca(OH) 2 02 20 pulverized charcoal or aluminium hydroxide, are used.
V"It Following this filtration, also called safety filtration, the aluminate liquor contains, besides, a large amount of C 'I alkali carbonates and compounds of vanadium, phosphorus, fluorine and arsenic, as impurities constituents in the form of iron compounds. Meanwhile the alkali carbonates and the impurities of vanadium, phosphorus, fluorine and arsenic by the addition of e.g. CaO and Ca(OH) 2 or through special crystallization processes, stay below the saturation point; in the clear filtered aluminate liquor, 30 dissolved or colloidally dissolved iron is separated ftogether with the crystallizing aluminium hydroxide, and contaminates this to a not inconsiderable extent.
The chemical purity and the degree of whiteness of the aluminium hydroxide are 'of greater significance for its further utilization. Aluminium hydroxide is the most F. B. RICE CO PATENT ATTORNEYS This form is suitable for any typo of Patent Application. No logallsation required.
3 3 important raw material for the production of inorganic as well as organic aluminium compounds. For these, and also in applications for catalysts and fillers, iron content and degree of whiteness are of greater importance.
Besides which through thermal treatment the aluminium hydroxide is converted into aluminium oxide (alumina), which serves as the raw material for the production of aluminium metal. Also for this process chemical purity plays a decisive role, particularly for certain special metals.
Thus in due course a series of processes has evolved, which have as their objective the enhancement of the purity of aluminium hydroxide, especially with respect to iron content.
So, for example, aluminium hydroxide is produced, according to US-PS 3 607 140 by a so-called pre-precipitation process. In this process, from the saturated clarified liquor in the first precipitator about 5 to 10 g/l aluminium hydroxide, which is very iron-rich, crystallizes out, and S, 20 from it a less A1203-rich, but cleaner aluminate liquor can be separated, from which a low iron content aluminium hydroxide can be crystallized. It has not to be especially mentioned that this process is particularly technically costly and loss involving.
Another, likewise very costly process is described in De-PS 11 72 246, according to which the aluminate liquor is treated with potassium permanganate and is purified by passing through a lime bed. According to this process, about 20% of the iron contained in the digested solution may be separated out.
o In yet another process, the iron content of the aluminate liquor is diminished, in which the latter is pressed through a bed of granular material such as sand or 0 monohydrate bauxite, 'activated charcoal or activated alumina clay, as described for instance, in -4- US-PS 3 832 442. The results obtained from this process are, however, unsatisfactory.
A special problem with alumina production by the Bayer process is evident from the treatment of otherwise high grade hydrargillite bauxite, which can contain a very low iron content. As a direct result of using this readily decomposable bauxite, hydroxide with too high an iron content is often obtained from the treatment of the aluminate liquor produced. Because of this, such a bauxite is perforce often used in a mixture with one richer in iron content or even, its iron content is increased through the addition of iron powder or pig iron.
The proposition of the present invention entails finding a purification process, with whose aid the problem posed may be solved without great expenditure of time and apparatus.
The present invention therefore comprises a process for the production of aluminium hydroxide with a low t 20 content of impurities, especially of iron, and a high grade of whiteness, from aluminate liquor from the digestion of bauxite by the Bayer process and the addition of magnesium compounds, whereby after separating out the i red mud, clarified pregnant liquor is cooled to a 25 temperature between 50 and 75 0 C, mixed with aluminium hydroxide seed and agitated for between 60 and 80 hours, thereafter precipitated aluminium hydroxide is separated and the filtrate is recycled to the bauxite digestion, 0 1C characterized in that after separation of the main part of S* 30 the red mud from the digested solution, the latter, at a temperature of between 75 and 105 0 C is mixed with a S, blend of between 1 and 10 g/L of CaO or Ca(OH) 2 and 0.05 and 20 g/L of Magnesium sulphate, and agitated for between and 45 minutes, and Mfinally the solid matter is o 35 separated from the di.gested solution.
a oa :-1 I Tt 4a Surprisingly, it has only now been shown that the iron content of an aluminate liquor (digested solution) separated from red mud at a temperature of from 75 to 105 0 C, especially 90 to 105 0 C, with a mixture of 1 to 10 g/L CaO and/or CaOH 2 and 0.05 to 20 g/L magnesium sulphate, can be lowered, if the added materials are stirred for 15 to 45 minutes in the aluminate liquor, and the solids contained in the aluminate liquor are separated out. The separation of the solids can for example be carried out by means of decanting or clarifying filtration through a pressure filter.
The clarified filtered aluminate liquor (pregnant liquor) undergoes cooling, is mixed with aluminium hydroxide seed and aluminium hydroxide precipitates. The 15 crystallized aluminium hydroxide already exhibits after the first cycle a higher grade of whiteness and a distinct w f. reduction in iron content.
The purity of the aluminium hydroxide is further I t 4 C r: i 4. 4 I I enhanced by progressive reduction of the iron content in the recycled aluminium hydroxide as seed.
Magnesium sulphate may be either anhydrous or a hydrate, for example monohydrate (kieserite). The grain size of the magnesium sulphate lies preferably below 0.10 mm. Especially effective is a magnesium sulphate, e.g. kieserite, in which about 80% by weight has a grain size of between 0.01 and 0.10 mm.
Obviously, the grain size can also be equal to, or larger than 0.10 mm, perhaps lying between 0.10 and 1.00 mm; however, the efficacy of such a mix is slightly reduced, so, that larger quantities of magnesium sulphate must be added. By the addition of kieserite with particle sizes from 0.01 to 0.1 mm along with kieserite with particle sizes from 0.20 to 0.50 mm, the quantity of kieserite can be reduced by half or more. Besides, smaller quantities of sulphate-irons will get into the liquor. By the o inclusion of kieserite with an average particle size of 20 0.10 to 1.00 mm, about 0.50 to 20 g/L of kieserite is required. According to a further improved developement of the above invention, CaO and/or Ca(OH) 2 is introduced, in particle sizes from 0.50 to 5.00 mm. The CaO or Ca(OH) 2 may also partially replace other granular materials such as technical aluminium hydroxide, calcined magnesite or dolomite, aluminium oxide and pulverized charcoal. The process of the invention may be carried out without any s.o r appreciable alteration of the Bayer process. The liquor treatment may be carried out either continously or sporadically, since the quality improvement of the aluminium hydroxide is already apparent only a few days after the treatment is incorporated.
Reference to the following examples will serve to illustrate the above invention more closely.
0r._ -6- Ca(OH)2 (1.00 to 2.00 mm grain size) and 15 g kieserite Example 1: A aturated sodium aluminate solution produced for alkaline decomposition from Australian Weipa bauxite, wasn parallel separated from red mud by decanting.
To a litre of this hot (96°C) aluminate liquor 5 g Ca(OH) 2 (1.00 to 2.00 mm grain size) and 15 g kieserite (0.10 to 1.00 grain size) was added, and stirred for minutes at an even temperatuce and filtered. In parallel with this a similar quantity of aluminate liquor into which 5 g/L Ca (OH)2 alone, was mixed, under similar conditions, and stirred and filtered in the same way.
Result: Comparative test Test in accordance with invention Composition of the Aluminate liquor Treated with Ca(OH) 2 aluminate liquor treated with Ca(OH) 2 and kieserite mix only I t t 0 U. t C C V F *4 0 tfC Vc a V 4 1 20 Na 2 0 g/L 158.60 156.80 Al 2 03 g/L 140.50 142.40 Na 2 CO3 (as 13.90 10.20 Na 2 0) g/L Fe 2 03 mg/L 7.80 3.00 The aluminate liquor obtained was cooled to 60 0
C,
and mixed and stirred with up to 1 litre of hydrate seed-suspension having a content of 50 g/L Al(OH).
After the completion of seeding, the temperature was reduced to 50 C and after a further 5 hours of agitation, reduced to 42 0 C, and agitated at this temperature to the end. After 50 hours agitation, 125.80 g/L alumina hydroxide was precipitated from the aluminate liquor treated only with Ca(OH) 2 and 132.80 g/L out of -7that treated with kieserite and Ca (OH) 2 Analysis of the precipitated aluminium hydroxide qualities, as per example 1 Result: Total Seed Comparative test Al (OH) 3 from liquor treated only Ca(OH) 2 Test according to invent ion Al (OH) 3 from liquor treated mix of Ca(OH) 2 and kieserite.
Quantity Al (OH) 3 total g/L .9 09 0 4- 94 9 t 0*t 4- **r4 0 0000 *0 6* t 9 c~
E~
99 150.70 82 157. 88 Whiteness 80 grade (Elrepho 457) Fe 2 0 3 0.012 0.011 0.004 0 .9 9 0 @9 0 o 00 Example 2 Production Example 1. Addition kieserite.
Result Composition of the Ca (OH) Aluminate liquor of the aluminate liquor as per of 10 g/L Ca(OH) 2 and only 2 g/L of Aluminate liquor With mix of Ca(OH) 2 treated only with and kieserite Ca(OH) 2 Na 2 O0 g/L 156. 50 162.20 .Al1 2 g/L 134.90 136.60 Na 2 C 1) 3 g/L 13.30 9.70 Fe203' g/L Fe 23 /L6.90 1.3.40 e
I
r
I
The Al(OH) 3 precipated as in Example 1 exhibits the following analyses values: Comparative test Test accol rding Total Seed Al(OH), from liquor treated only Ca(OH) 2 to invention Al(OH) 3 from liquor treated mix of Ca(OH) 2 and kieserite.
Quantity 25 149.00 158.30 Al (OH)3 total g/L Whiteness 80 82 87 grade (Elrepho 457), *9 o* 0 op 0 0 @00 4 4.44 O &C *b S *Y &t 0 00 I 4 05 *o 0 04 0$ 0 000$ 00o 0 o n o 0@C Fe 2 0 3 0.012 0.012 0.005 Example 3 20 A saturated sodium aluminate solution produced by alkaline digestion of a beaxite of African origin, was as in Example 2 treated with a mixture of Ca(OH) 2 and kieserite. Kieserite up to a total of 2 g/L was added however this was added in separate lots of 0.20 q/L of kieserite. Moreover, 80% by weight of the kieserite particles had a grain size of from 0.01 to 0.10 mm, the rest of the particles being smaller or larger.
The aluminium hydroxide resulting from Example 1 had a Fe 2 0 3 content of 0.0087% by weight. Had the addition of kieserite not been made, a Fe 2 0 3 content of 0.018% by weight would have been obtained. During the treatment a reduction in the Fe 2 0 3 content of around 51,7 by weight would have been obtained. By reducing the amount of kieserite by one tenth the same effect is -9 qualitatively achieved, if the particle size of the kieserite is reduced by a factor of about ten. In conclusion it should be mentioned again that the same effective results are obtained, whereby the additions are made continously or in batches.
o t t
(C
t 4 0 0 C I C
U
1C 08
Claims (4)
1. A process for the production of aluminium hydroxide with a low content of impurities, especially of iron, and a high grade of whiteness, from aluminate liquor from the digestion of bauxite by the Bayer process and the addition of magnesium compounds, whereby after separating out the red mud, clarified pregnant liquor is cooled to a temperature between 50 and 75 0 C, mixed with aluminium hydroxide seed and agitated for between 60 and 80 hours, thereafter precipitated aluminium hydroxide is separated and the filtrate is recycled to the bauxite digestion, characterized in that after separation of the main part of the red mud from the digested solution, the latter, at a temperature of between 75 and 105 0 C is mixed with a blend of between 1 and 10 g/L of CaO or Ca(OH) 2 and 0.05 6 and 20 g/L of Magnesium sulphate, and agitated for between 15 and 45 minutes, and finally the solid matter is separated from the digested solution.
2. Process according to Claim 1, characterized in that a hydrate of magnesium sulphate is introduced, in particular, the monohydrate. citl-kev
3. Process according to/Claim 1 emy 2, characterized in that magnesium sulphate with an average grain size of ooo between 0.01 and 0.10 mm is introduced.
4. Process according to Claim 1 or 2, characterized in that magnesium sulphate with a grain size of between 0.10 and 1.00 mm is introduced. A process for the production of aluminium hydroxide substantially as hereinbefore described with reference to the accompanying examples but excluding the comparative tests. Dated this 31st day of May 1989 ALCOA CHEMIE GmbH Patent Attorneys for the Applicant F.B. RICE CO.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3501350 | 1985-01-17 | ||
| DE19853501350 DE3501350A1 (en) | 1985-01-17 | 1985-01-17 | Process for preparing aluminium hydroxide having a low content of impurities, especially iron, and a high whiteness |
| DE3545284 | 1985-12-20 | ||
| DE19853545284 DE3545284A1 (en) | 1985-12-20 | 1985-12-20 | Process for preparing aluminium hydroxide having a low content of impurities, especially of iron, and high whiteness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AU5245386A AU5245386A (en) | 1986-07-24 |
| AU594035B2 true AU594035B2 (en) | 1990-03-01 |
Family
ID=25828591
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU52453/86A Ceased AU594035B2 (en) | 1985-01-17 | 1986-01-17 | Process for the production of aluminium hydroxide with low content of impurities, especially of iron, and with high degree of whiteness |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0188268A3 (en) |
| AU (1) | AU594035B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU661486B2 (en) * | 1991-07-19 | 1995-07-27 | Particle Engineered Hydrates Pty Ltd | Recovery of vanadium and aluminium values |
| WO2019227130A1 (en) * | 2018-05-28 | 2019-12-05 | Alcoa Of Australia Limited | Method for impurity control |
| WO2019227128A1 (en) * | 2018-05-28 | 2019-12-05 | Alcoa Of Australia Limited | Method for controlling the concentration of impurities in bayer liquors |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2728556B1 (en) * | 1994-12-22 | 1997-01-31 | Pechiney Aluminium | PROCESS FOR THE REMOVAL OF IRON FROM SODIUM ALUMINATE LIQUORS DERIVED FROM ALKALINE BAUXITE ALOHYDRATE ATTACK |
| AUPR105400A0 (en) | 2000-10-27 | 2000-11-23 | Nauveau Technology Investments Ltd | Processes and compositions for water treatment |
| CN1297480C (en) * | 2002-03-05 | 2007-01-31 | 平顶山市汇源化学工业公司 | Process for removing organics from sodium Bayer process aluminate solution |
| CA2672956C (en) | 2006-10-26 | 2015-02-10 | Amgen Inc. | Calcium receptor modulating agents |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1489775A (en) * | 1966-06-01 | 1967-07-28 | Pechiney Prod Chimiques Sa | Process for purifying sodium aluminate liquors |
| CA1044469A (en) * | 1974-04-17 | 1978-12-19 | Comalco Limited | Production of bauxite and aluminium chloride of low iron content |
| DE2518431C3 (en) * | 1975-04-25 | 1982-02-04 | Giulini Chemie Gmbh, 6700 Ludwigshafen | Process for the removal of harmful organic compounds from the aluminate liquor produced during the extraction of alumina according to the Bayer process |
| US4083925A (en) * | 1976-03-22 | 1978-04-11 | Martin Marietta Aluminum, Inc. | Method for removing ferrous iron from alkali metal aluminate liquor |
| US4045234A (en) * | 1976-08-23 | 1977-08-30 | Kaiser Aluminum & Chemical Corporation | Process for producing high density sintered alumina |
-
1986
- 1986-01-14 EP EP86100397A patent/EP0188268A3/en not_active Withdrawn
- 1986-01-17 AU AU52453/86A patent/AU594035B2/en not_active Ceased
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU661486B2 (en) * | 1991-07-19 | 1995-07-27 | Particle Engineered Hydrates Pty Ltd | Recovery of vanadium and aluminium values |
| WO2019227130A1 (en) * | 2018-05-28 | 2019-12-05 | Alcoa Of Australia Limited | Method for impurity control |
| WO2019227128A1 (en) * | 2018-05-28 | 2019-12-05 | Alcoa Of Australia Limited | Method for controlling the concentration of impurities in bayer liquors |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0188268A3 (en) | 1990-01-31 |
| AU5245386A (en) | 1986-07-24 |
| EP0188268A2 (en) | 1986-07-23 |
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