EP1735356A2 - Use of copolymers for reducing precipitates and deposits from inorganic and organic impurities in the bayer process for the extraction of aluminium hydroxide - Google Patents
Use of copolymers for reducing precipitates and deposits from inorganic and organic impurities in the bayer process for the extraction of aluminium hydroxideInfo
- Publication number
- EP1735356A2 EP1735356A2 EP05752621A EP05752621A EP1735356A2 EP 1735356 A2 EP1735356 A2 EP 1735356A2 EP 05752621 A EP05752621 A EP 05752621A EP 05752621 A EP05752621 A EP 05752621A EP 1735356 A2 EP1735356 A2 EP 1735356A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- use according
- unsaturated
- acid
- acid groups
- bayer process
- 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.)
- Withdrawn
Links
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
- C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
- C01F7/066—Treatment of the separated residue
-
- 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
- C01F7/04—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom
- C01F7/06—Preparation of alkali metal aluminates; Aluminium oxide or hydroxide therefrom by treating aluminous minerals or waste-like raw materials with alkali hydroxide, e.g. leaching of bauxite according to the Bayer process
- C01F7/0606—Making-up the alkali hydroxide solution from recycled spent liquor
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/002—Scale prevention in a polymerisation reactor or its auxiliary parts
- C08F2/005—Scale prevention in a polymerisation reactor or its auxiliary parts by addition of a scale inhibitor to the polymerisation medium
Definitions
- the invention relates to the use of copolymers of monomers bearing mono-ethically unsaturated acid groups and unsaturated hydrophobic components for preventing or reducing inorganic and organic deposits from strongly alkaline aqueous process lyes.
- bauxite is boiled with a sodium hydroxide solution, which produces sodium aluminate in the form of a supersaturated solution.
- Impurities such as iron oxides, silicates, titanium compounds are separated as insoluble components in the so-called red mud flocculation.
- considerable amounts of dissolved bauxite impurities remain in the sodium aluminate solution, especially dissolved silicates and silica.
- Particle sizes below 45 ⁇ m are generally below 10% by weight, and below 90 ⁇ m it is 55 to 65% by weight. If the fraction of fine particles increases, the subsequent drying process in particular is greatly delayed. Since approx. 70 to 80% of the fine-particle aluminum hydroxide crystals obtained are added to the process again as seed crystals, the fine particles would accumulate undesirably.
- BESTATIGUNGSKOPIE The used sodium hydroxide solution (Spent liqour) obtained after the crystallization is circulated in the Bayer process, whereby inorganic and organic components accumulate.
- bauxite varies depending on the area of origin of the bauxite ore.
- bauxite consists of oxides and hydroxides of aluminum and iron and contains, as secondary components, silica, titanium dioxide and numerous inorganic and organic impurities such as the oxides of vanadium, chromium, phosphorus, arsenic, fluorine, sulfur, calcium, manganese, copper, zinc, Berylliums, galliums and rare earths and often organic components like humic acids.
- silicates and sometimes also Si0 2 dissolve in the hot sodium hydroxide solution.
- the soluble silicates eg kaolin
- Such insoluble compounds consist of sodium aluminum silicate and are sometimes referred to in the literature as "desilication products” (DSP), which separate out as deposits in containers and pipelines of the process plants.
- the chemical composition of the DSP coverings varies greatly depending on the process and from one production site to the next.
- the temperature and the alkali composition also influence the composition of the coverings.
- DSP are very often physical mixtures of different compounds, which is why variations in the composition are normal.
- several layers of different composition can grow on top of one another, and iron and titanium-containing coatings can also be present in addition to calcium carbonate.
- EP 0 582 399 A2 describes a method for changing the morphology of silicate materials which separate out in Bavarian process liquors, ammonium or amine compounds being added.
- the morphological structural changes relate to the rounding of the corners and edges of the crystals, and the prevention of crystal growth.
- the examples show that relatively high dosages of the products according to the invention (500 ppm -5000 ppm) at approximately 230 ° C./30 min are required.
- the process of EP 0 586 070 A2 uses polymeric quaternary ammonium compounds, for example poly-DADMAC or polyacrylamides, for the above-mentioned purpose. Due to the alkaline conditions of the Bayer process liquor, such compounds have a limited shelf life.
- WO 97/41075 describes the change in the morphology of the coatings based on DSP, titanates and silicates with respect to the Bayer process.
- the use of a hydroxamic acid polymer with a molecular weight average of 1,000-10,000 is claimed.
- high molecular weight polyacrylamides or acrylamide / acrylic acid copolymers are used to change the morphological properties.
- the changed morphological properties of these silicate-containing materials ensure a lower tendency to deposit in the modified form on the surfaces of the system during the process.
- WO 2004/003040 A1 describes water-soluble copolymers containing acid groups with hydrophobic components and others. from the group of unsaturated hydrocarbons and terpenes, as well as their use in water-bearing systems, etc. to avoid organic / inorganic deposits or as a dispersant for pigments.
- the agent is also intended to suppress the formation of firmly adhering deposits in order to reduce the cleaning effort on the surfaces.
- an effect on the crystallization process of the aluminum hydroxide in the sense of a higher purity and an improved particle distribution should be sought for the agent.
- the object was achieved by using water-soluble copolymers formed from monomers a) bearing monoethylenically unsaturated acid groups and at least one of the following hydrophobic components b) containing unsaturated double bonds.
- b1) an acyclic, monocyclic and / or bicyclic terpene, in particular terpene hydrocarbon
- b2) an unsaturated, open-chain or cyclic, normal or isomeric hydrocarbon with 9-30 carbon atoms
- the unsaturated monomers a) bearing acid groups, from which the copolymers to be used according to the invention are composed, are selected from the monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, vinyl acetic acid, maleic acid semiesters, maleic acid halamides, the dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid Sulfonic acids such as vinylsulfonic acid, allylsulfonic acid, (meth) allylsulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid.
- monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, vinyl acetic acid, maleic acid semiesters, maleic acid halamides
- the dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid
- Sulfonic acids such as vinylsulfonic acid
- the monocarboxylic acids are preferably used, in particular selected from the group consisting of acrylic acid, methacrylic acid and vinyl acetic acid. Of the monocarboxylic acids, acrylic acid is particularly preferred.
- sulfonic acids are present, these are preferably selected from the group consisting of vinylsulfonic acid, (meth) allylsulfonic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid.
- monocarboxylic acids and monomers containing sulfonic acid groups are combined in the copolymers to be used according to the invention, the proportion of the monomers containing sulfonic acid groups being 0.1 to 40% by weight, preferably 1 to 25% by weight.
- the acid groups in the copolymers to be used according to the invention can be partially or completely neutralized. They are usually in the form of alkali or ammonium or amine salts, with the alkali salts being preferred. In a preferred embodiment, they are neutralized to 1 to 75%, particularly preferably 2 to 50% and very particularly preferably 5 to 30%.
- hydrophobic components b) for b1) are: natural and synthetic terpenes, for example pinene such as alpha-pinene and beta-pinene, terpinolene, limonene (dipentene), beta-terpinene, gamma-terpinene, alpha-thuene, sabinene , delta .-.
- pinene such as alpha-pinene and beta-pinene, terpinolene, limonene (dipentene), beta-terpinene, gamma-terpinene, alpha-thuene, sabinene , delta .-.
- sup.3 - carenes camphene, beta-cadines, beta.-caryophyllenes, cedrenes, bisalbones such as alpha.-bisalbones, beta.-bisalbones, gamma-bisalbones, zingiberenes, humulene, (alpha.-caryophyl 1ene), alpha-citronellol, linalool, geraniol, nerol, ipsenol, alpha-terpineol, D-terpineol- (4), dihydrocarveol, nerolidol, farnesol, alpha.-Eudesmoi, beta-Eudesmol, citral, D-citronellal, carvone , D-Pulegone, Piperitone, Carvenone, Bisabolene, beta-Selinene, alpha-Santalene, Vitamin A, Abetic acid and mixtures of these agents, as well as extracts from
- Terpenes prefer: pinene, nerol, citral and citronellal, camphene, limonene / dipentene and linalool. Limonene / Dipentene and Pinene are particularly preferred.
- Examples of unsaturated hydrocarbons b2) are decene, hexadecene, examples of b3) are a fatty acid monoalkyl ester, a fatty acid amide or a fatty acid monoalkylamide of an unsaturated fatty acid, a mono- or polyester of an unsaturated fatty acid with polyols, with the exception of polyethylene glycols, a mono- or Polyamide of unsaturated fatty acids and aliphatic polyamines with two to six nitrogen atoms, oleic acid, oleic acid octyl ester, glycerol mono- and trioleate and sorbitan oleate.
- the proportion of component b) in the copolymer is generally from 0.01 to 30% by weight, preferably from 0.1 to 20% by weight and particularly preferably from 0.2 to 10% by weight.
- the copolymers to be used according to the invention can also contain up to 40% by weight of other comonomers c) free of acid groups in copolymerized form.
- examples include acrylic acid and methacrylic acid esters and amides or substituted N-alkyl amides.
- the weight average molecular weights Mw of the copolymers according to the invention are in a range from 750 to 500,000 g / mol, preferably 1,000 to 100,000 g / mol and particularly preferably between 1,500 and 10,000 g / mol.
- the polymers to be used according to the invention are usually added to the Bayer process liquor in the form of aqueous solutions.
- the polymers to be used according to the invention are produced by methods known to the person skilled in the art, for example by the free-radical polymerization process in the aqueous phase.
- the polymers to be used according to the invention have a very good deposit-preventing effect in the strongly alkaline process liquors of the Bayer process for the production of aluminum hydroxide.
- the prevention of deposits not only refers to the so-called DSP but also to all types of coverings, e.g. insoluble Ca and Mg compounds, ferrous coatings and titanium compounds.
- the resulting precipitates no longer or only to a small extent and are easy to remove with little mechanical effort.
- the use of the polymers to be used according to the invention also leads to a quantitative reduction in the amount of precipitations of the deposit formers.
- the composition of the DSP coverings can be changed by the products according to the invention.
- Those in the literature Described substrate-controlled crystallization of the DSP on the metal surface is a mechanism of deposit formation.
- the mechanism of the crystallization of the scale formers from the solution is also influenced without the participation of metal surfaces.
- the reduction in deposits is accompanied by a change in the chemical composition of the coverings.
- the content of Si0 2 in the DSP can be reduced from 40 to 20%, while at the same time the carbonate content in the DSP is reduced from 4-7% to 2-3%.
- the polymer to be used according to the invention also advantageously liquefies the red mud, which after its precipitation is in the form of concentrated aqueous suspensions which are difficult to handle. These approximately 45 to 70% by weight sludges are easier to handle with the previously described polymers and are therefore easier to dispose of.
- the polymers to be used according to the invention can be metered into the Bayer process liquor at any stage of the process. Due to the recycle mode of the process liquor, in which the polymers are partly carried along, the optimal dosage is to replace the polymer components discharged in other process stages. In a preferred embodiment, the metering is carried out immediately upstream of heat exchangers or evaporators. To achieve a good effect, the polymer to be used according to the invention should be present in the process liquor in amounts of 1 ppm to 5,000 ppm, preferably from 50 to 500 ppm.
- Water glass is added to this artificial spent liquor shortly before the start of the test in order to set an Si0 2 concentration of 1.2 g / l.
- the solution After adding the deposit-preventing substances, the solution is boiled in an open system for 8 hours with stirring at approx. 108 ° C. The evaporated water is constantly replaced so that the liquid level never drops below 5 mm. In order to record the resulting turbidity, an absorbance measurement at 440 nm is carried out in the first 5 hours.
- the solution is allowed to cool without stirring and filtered through two blue band filters.
- the filtrate is rinsed several times with deionized water.
- the filter residues are dried at 70 ° C for 4 hours and weighed.
- the filter residues are analyzed by inductively coupled plasma emission spectroscopy (ICP) and / or wet chemical.
- ICP inductively coupled plasma emission spectroscopy
- Table 1 shows the composition and characterization of the polymers used in the examples and comparative examples (polymers of comparative examples V2 to V6, polymers B1 to B6 according to the invention).
- the polymers are determined by the monomer composition and by the molecular weight average. Comparative example V1 was carried out without the addition of polymer.
- Table 2 shows the results of the effectiveness test with these polymers at different use concentrations. Here, the amount of deposit agent that failed and its composition was determined.
- B5 79.2 20 0.8 3,500 B6 94.2 0.8 3,500 1 sodium acrylate, A sodium methallylsulfonate, a : quaternized dimethylaminopropylacrylamide,
- the test results show that the copolymers according to the invention significantly reduce the precipitation of scale builders.
- the precipitates are of a loose structure and do not tend to form solid deposits.
- the change in the composition of the precipitates is also completely surprising. In particular, the proportions of Si0 2 and carbonate are shifted in favor of Al 2 0 3 . These changes are believed to be the cause of the positive effects of the polymers according to the invention.
- Example 7 Influence of the polymers according to the invention on the formation of aluminum hydroxide
- the use of chemical aids in bauxite digestion with sodium hydroxide solution for the production of aluminum hydroxide can lead to impairment of the aluminum hydroxide crystals in the stirring process. That means the crystal growth will be disturbed, and the hydroxide produced is too fine in its grain fractions. The crystal fractions ⁇ 45 ⁇ m and ⁇ 90 ⁇ m are usually assessed.
- Preparation for the experiment Required utensils - Bayer process liquor. Sampling immediately before entering the stirring kettle (after the safety filtration (eg Kelly filter) - washed aluminum hydroxide crystals from the company (seed crystals) - laboratory stirrer (roller stirrer in a water bath)
- the polymer used according to the invention shows no negative effect on the growth of aluminum hydroxide crystals in the so-called stirring process (crystallization process) of an aluminum hydroxide production.
- the particle size distribution is even positively influenced by the formation of fewer undesirable fine-particle crystals in favor of coarser crystals. This is surprising insofar as the function of the polymers according to the invention is more effective in preventing precipitation.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Analytical Chemistry (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Polymerisation Methods In General (AREA)
- Detergent Compositions (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102004017034A DE102004017034A1 (en) | 2004-04-02 | 2004-04-02 | Use of copolymers to reduce precipitates and deposits by inorganic and organic impurities in the Bayer process for the production of aluminum hydroxide |
PCT/EP2005/002093 WO2005095477A2 (en) | 2004-04-02 | 2005-02-28 | Use of copolymers for reducing precipitates and deposits from inorganic and organic impurities in the bayer process for the extraction of aluminium hydroxide |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1735356A2 true EP1735356A2 (en) | 2006-12-27 |
Family
ID=34970414
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP05752621A Withdrawn EP1735356A2 (en) | 2004-04-02 | 2005-02-28 | Use of copolymers for reducing precipitates and deposits from inorganic and organic impurities in the bayer process for the extraction of aluminium hydroxide |
Country Status (9)
Country | Link |
---|---|
US (1) | US20090008335A1 (en) |
EP (1) | EP1735356A2 (en) |
CN (1) | CN1953999A (en) |
AU (1) | AU2005229337A1 (en) |
BR (1) | BRPI0509398A (en) |
CA (1) | CA2561407A1 (en) |
DE (1) | DE102004017034A1 (en) |
RU (1) | RU2365595C2 (en) |
WO (1) | WO2005095477A2 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8029752B2 (en) * | 2009-04-06 | 2011-10-04 | Nalco Company | Approach in controlling DSP scale in bayer process |
US9487408B2 (en) | 2009-09-25 | 2016-11-08 | Nalco Company | Reducing aluminosilicate scale in the bayer process |
US8545776B2 (en) * | 2009-09-25 | 2013-10-01 | Nalco Company | Reducing aluminosilicate scale in the Bayer process |
US8282834B2 (en) | 2009-09-25 | 2012-10-09 | Nalco Company | Di- and mono-alkoxysilane functionalized polymers and their application in the Bayer process |
US9416020B2 (en) | 2009-09-25 | 2016-08-16 | Nalco Company | Surfactant based small molecules for reducing aluminosilicate scale in the bayer process |
CN103803722B (en) * | 2012-11-15 | 2015-07-22 | 中国石油化工股份有限公司 | Non-phosphorus copolymer antiscale dispersant and preparation method thereof |
CN113401927A (en) | 2013-12-24 | 2021-09-17 | 塞特工业公司 | Method for reducing scale in bayer process |
CN115231594A (en) | 2014-10-21 | 2022-10-25 | 塞特工业公司 | Anti-degradation scale inhibitor |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5415782A (en) * | 1993-11-22 | 1995-05-16 | Nalco Chemical Company | Method for the alteration of siliceous materials from bayer process liquors |
US5733459A (en) * | 1996-04-29 | 1998-03-31 | Cytec Technology Corp. | Use of hydroxamated polymers to alter bayer process scale |
US5670055A (en) * | 1996-08-08 | 1997-09-23 | Nalco Chemical Company | Use of the linear alkylbenzene sulfonate as a biofouling control agent |
US6086771A (en) * | 1997-12-12 | 2000-07-11 | Nalco Chemical Company | Water continuous emulsion polymers for improving scale control in the bayer process |
FR2781488B1 (en) * | 1998-07-07 | 2001-04-13 | Snf Sa | NOVEL ACRYLIC POLYMERS IN ESSENTIALLY AQUEOUS DISPERSIONS, THEIR PREPARATION PROCESS AND THEIR APPLICATIONS |
US6372882B1 (en) * | 2000-04-03 | 2002-04-16 | Nalco Chemical Company | Method for producing substantially dry water-insoluble polymers for improved flocculation in the bayer process |
FR2812295B1 (en) * | 2000-07-27 | 2003-01-31 | Snf Sa | CATIONIC POLYMERS OF HIGH MOLECULAR WEIGHT, PROCESS FOR THEIR PREPARATION, AND THEIR APPLICATIONS |
US7138472B2 (en) * | 2001-01-29 | 2006-11-21 | Nalco Company | High molecular weight polymers containing pendant salicylic acid groups for clarifying bayer process liquors |
US6527959B1 (en) * | 2001-01-29 | 2003-03-04 | Ondeo Nalco Company | Method of clarifying bayer process liquors using salicylic acid containing polymers |
DE10228628A1 (en) * | 2002-06-26 | 2004-01-22 | Stockhausen Gmbh & Co. Kg | Copolymers to avoid deposits in water-bearing systems, their production and use |
US6814873B2 (en) * | 2002-07-22 | 2004-11-09 | Cytec Technology Corp. | Method of preventing or reducing aluminosilicate scale in a bayer process |
-
2004
- 2004-04-02 DE DE102004017034A patent/DE102004017034A1/en not_active Withdrawn
-
2005
- 2005-02-28 CA CA002561407A patent/CA2561407A1/en not_active Abandoned
- 2005-02-28 CN CNA2005800158692A patent/CN1953999A/en active Pending
- 2005-02-28 US US11/547,506 patent/US20090008335A1/en not_active Abandoned
- 2005-02-28 RU RU2006138500/04A patent/RU2365595C2/en active
- 2005-02-28 AU AU2005229337A patent/AU2005229337A1/en not_active Abandoned
- 2005-02-28 WO PCT/EP2005/002093 patent/WO2005095477A2/en active Application Filing
- 2005-02-28 BR BRPI0509398-8A patent/BRPI0509398A/en not_active IP Right Cessation
- 2005-02-28 EP EP05752621A patent/EP1735356A2/en not_active Withdrawn
Non-Patent Citations (1)
Title |
---|
See references of WO2005095477A3 * |
Also Published As
Publication number | Publication date |
---|---|
RU2365595C2 (en) | 2009-08-27 |
US20090008335A1 (en) | 2009-01-08 |
WO2005095477A3 (en) | 2006-02-02 |
CA2561407A1 (en) | 2005-10-13 |
CN1953999A (en) | 2007-04-25 |
AU2005229337A1 (en) | 2005-10-13 |
WO2005095477A2 (en) | 2005-10-13 |
DE102004017034A1 (en) | 2005-10-20 |
RU2006138500A (en) | 2008-05-10 |
BRPI0509398A (en) | 2007-09-18 |
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