GB2080272A - Flocculating red mud suspension - Google Patents
Flocculating red mud suspension Download PDFInfo
- Publication number
- GB2080272A GB2080272A GB8122135A GB8122135A GB2080272A GB 2080272 A GB2080272 A GB 2080272A GB 8122135 A GB8122135 A GB 8122135A GB 8122135 A GB8122135 A GB 8122135A GB 2080272 A GB2080272 A GB 2080272A
- Authority
- GB
- United Kingdom
- Prior art keywords
- flocculant
- acrylic acid
- molar percent
- recovery circuit
- stage
- 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.)
- Granted
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
- C01F7/0646—Separation of the insoluble residue, e.g. of red mud
- C01F7/0653—Separation of the insoluble residue, e.g. of red mud characterised by the flocculant added to the slurry
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical & Material Sciences (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- Inorganic Chemistry (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
Aqueous suspensions of red mud are effectively removed from the Bayer process for making alumina by the addition to at least the first stage of the recovery circuit of a flocculant selected from starch, homopolymers of acrylic acid or acrylates, copolymers of acrylic acid or acrylates containing at least 80 molar percent acrylic acid or acrylate monomers and combinations thereof and subsequent addition to later, more dilute stages in the recovery circuit of a copolymer containing from about 35 to 75 molar percent of acrylic acid or acrylate and from about 65 to 25 molar percent of acrylamide monomers.
Description
SPECIFICATION
Process for alumina recovery
The instant invention is directed to a process of alumina manufacture via the Bayer process. The
Bayer process is the almost universally used process for the manufacture of alumina. In its broadest aspects, this method is carried out almost exclusively in aqueous solution, and is achieved by reaction of bauxite and a strong base such as caustic soda or lime in steam heated autoclaves whereby the alumina is transformed into a soluble aluminate form. In this step, a considerable amount of insoluble impurities results or is released from the bauxite, which recrement must be separated from the desired alumina constituent. These residues commonly known as red muds include iron oxides, sodium aluminosilicate, titanium oxide and other materials. Generally these muds appear as very fine particles which are difficult to separate out.Yet the red muds which usually constitute about 10 to 50 by weight of the ore must be rapidly and cleanly separated from the solubilized alumina liquor in order to make this particular step economically efficient. If the rate of separation is too slow, output is materially diminished and overall process efficiency impaired. Likewise, if the spearation is not clean, the resultant alumina in the form of aluminate is somewhat crude and undesirable for a number of enduses. The insoluble impurities present in the alumina as carry-through from the manufacturing process tend to add extraneous non-active matter into the specific media, such as water, being treated with aluminate for a variety of purposes.For example, low grade sodium aluminate containing relatively large amounts of mud impurities when used to treat water results in a situation of increased tendency to form slime masses as the direct result of the insoluble impurities present, which masses tend to foul feeding equipment. Also, if the crude sodium aluminate contains substantial amounts of impurities as an admixture, solution problems are quite difficult to overcome if the aluminate is fed in the form of a solid.
One method of overcoming the above problems, and materially speeding up separation of red muds from alumina as well as effecting a cleaner separation of the constituents is disclosed in U.S. Patent
No. 3,390,959 wherein it is disclosed that the use of homo- or copolymers of acrylic acid and acrylates which contain not more than 20% of other ethylenically unsaturated polymerizable polar monomers as red mud flocculants improves the overall efficiency of the Bayer process.
The '959 patent teaches the use of copolymers of acrylic acid or acrylates with ethylenically unsaturated monomers as red mud flocculants, it likewise discloses, however, that when the ethylenically unsaturated monomers constitute more than 5 molar percent the separation rate dramatically drops and at more than 20 molar percent no significant separation is obtained. Although this teaching is accurate for the initial or "head" stage of the recovery circuit, it has surprisingly been found not to apply to the results obtained at the latter, more dilute stages of the recovery circuit.
The present invention provides for a novel process for recovering alumina via the Bayer process wherein red muds are flocculated from the recovery circuit by adding to at least the first stage of the recovery circuit an effective amount of a flocculant selected from the group consisting of starch, homopolymers of acrylic acid or acrylate, copolymers of acrylic acid or acrylates containing at least 80 mole percent acrylic acid or acrylate monomers and combinations thereof and thereafter adding to some subsequent stage or stages an effective amount of a copolymer comprising from about 35 to 75 mole percent of acrylic acid or acrylate and from about 65 to 25 mole percent of acrylamide.The employment of a second, distinct polymer in the latter stages of the recovery circuit where the system is more dilute and the conditions are less harsh has surprisingly shown effective flocculation of the red muds.
In accordance with the present invention there is provided a novel process for flocculating red muds produced as a by product in the Bayer process of recovering alumina from bauxite. This process comprising utilizing a conventional red mud flocculant in at least the first or "head" stage of the recovery circuit and at some subsequent stage employing a copolymer of about 35 to 75 mole percent acrylic acid or acrylate and about 65 to 25 mole percent acrylamide as the red mud flocculant.
The conventional flocculantto be employed in at least the first stage includes starch, homopolymers of acrylic acid or acrylate, copolymers of acrylic acid or acrylate wherein the copolymer contains at least 80 mole percent acrylic acid or acrylate monomers, hydrolyzed acrylamide monomers or polymers and combinations thereof. By acrylate what is meant is the salt of an acrylic acid wherein such salts are either alkali metal, or ammonium salts. When copolymers of acrylic acid or acrylate are employed a wide variety of comonomers may be employed in amounts up to about 20 mole percent.Typical comonomers include acrylamide, methacrylamide, acrylonitrile, the lower alkyl esters of acrylic and methacrylic acids, vinyl methyl ether, methacrylic acid salts, maleic anhydride and salts thereof, isopropenyl acetate, itaconic acid, vinyl acetate, alphamethyl styrene, styrene, fumaric acid, aconitric acid, citraconic acid, amides of any of the foregoing acids, alkali metal derivatives (e.g., sodium, potassium and lithium), and ammonium salts of any of the above monomeric acids or others, the partial alkyl ester amides and salts of various polycarboxylic acids, vinyl toluene, chlorostyrene, vinyl chloride, vinyl formate, ethylene, propylene, isobutylene, etc. Of the just-mentioned comonomers, greatly preferred materials among these contain a hydrophilic group in a side chain off the ethylenically unsaturated hydrocarbon group.Those monomers which do not contain such hydrophilic solubilizing group should be used in lesser amounts of say about 1-5% by weight based on total weight of monomer present.
Still other monomeric substances which may be employed in conjunction with the acrylic acid or acrylic acid salt constituent include materials such as sulfoethyl acrylate, carboxyethyl acrylate, diethyl vinyl phosphonate, crotonic acid or salts thereof, vinyl sulfonate, or salts thereof, vinyl alcohol and vinyl aryl hydrocarbons containing solubilizing groups such as sulfonates, etc.
Particularly useful homopolymers orcopolymers of the type described above should preferably have a molecular weight in excess of 50,000, and more preferably in excess of 100,000. Excellent additive polymers have molecular weights even as high as ten million.
Starch materials useful in the instant invention include potato, corn, tapioca, amylose, sorghum and other readily available starches.
The effective amount of the conventional flocculant employed in at least the first stage of the recovery circuit will vary depending upon the specific bauxite composition being processed, the conditions present in the recovery stage i.e., temperature, pH, solids concentration and the like, and the red mud floccul ant or flocculants employed. Generally, however, when starch or combinations containing starch is employed, the effective amount will range from 0.05 to 2.0 percent by weight of the dry mud residue.
When synthetic polymers or copolymers are employed, the effective amount will generally be between 0.01 and 2.0 pounds of chemical per ton of dry mud residue.
The copolymer added to some of the subsequent stages of the recovery circuit is specifically a copolymer comprising from about 35 to 75 mole percent of acrylic acid or acrylate (with acrylate being defined as set forth above) and from about 65 to 25 mole percent of acrylamide. Although it is believed that ethylenically unsaturated monomers besides acrylamide may be effectively employed in this copolymer, for considerations such as economy, availability and performance the acrylamide comonomer is the preferred comonomer for employment in the instant inventions. These subsequently added copolymers should have a molecular weight such that the Brookfield viscosity of a 0.15% solution of the polymer in 1 M NaCI at pH 8, UL adaptor at 60 r.p.m. is at least 2.0 centipoise, preferably at least 3.0 centipoise.
The effective amount for these subsequently added copolymers will also vary depending upon the specific bauxite composition being processed and the conditions present in the recovery stage.
Generally, however, the effective amount will be between 0.01 and 1.0 pound of copolymer per ton of dry red mud solids, preferably about 0.05 to 0.5 pound of copolymer per ton of dry red mud solids.
At what specific stage subsequent to the initial or "head" stage in the recovery circuit the copolymer comprising from about 35 to 75 mole percent acrylic acid or acrylate and from about 65 to 25 mole percent acrylamide will be effective depends upon a number of variables within the recovery system.
Stage conditions such as temperature, pH, dilution of liquor, and concentration of red mud solids are believed to play an important role. The type of bauxite ore itself may also contribute to the effective location. Insofar as the exact mechanism of the interaction between the flocculant and the red mud solids is as yet unknown, the predictability as to which stage or stage variable controls the copolymer's effective ness remains outside of simple categorization. Generally, the copolymer has been observed to be highly effective in the fourth or latter stages where the grams of mud residue per liter of NaOH plus Na2CO3 are less than about 100.Since this figure is extremely approximate and may rest more upon coincidence than the controlling stage variable it is recommended that the following test be undertaken to determine which stage in a given recovery circuit is the effective location at which to add the copolymer. This test entails:
The stage in the recovery circuit to be tested, which stage is not the "head" stage, is referred to as the "nth stage" for the purposes of this test The (n 1 Xth stage washer underflow is diluted to 1:4 with nth stage washer overflow to produce a simulated nth stage washer feed. This high dilution level is necessaryto produce a level of reproducible free settling in a test cylinder, preferably a 500 to 1000 ml.
graduated cylinder.
To this simulated nth stage washer feed there is added the flocculantto be tested in a 0.05 weight percent solution. The solution can be either water or diluted spent liquor (NaOH). The tested dosage of flocculant is added by syringe and mixed into the simulated washer feed by five strokes of a perforated plunger. The descent of the liquid/solid interface is timed in feet per hour to determine the utility of the flocculantto the stage being tested.
Whereas the exact scope of the instant invention is set forth in the appended claims, the following specific examples illustrate certain aspects of the present invention, and more particularly, point out methods of evaluating the same. However, the examples are set forth for illustration only and are not to be construed as limitations on the present invention except as set forth in the appended claims.
All parts and percentages are by weight unless otherwise specified.
EXAMPLE 7 Following the General Test Procedure set forth above, a red mud flocculant copolymer containing 60 weight percent sodium acrylate and 40 weight percent acrylamide having a molecular weight between 5-10 million and added to a simulated washer feed of an Australian red mud circuit wherein the initial stage was treated with a 95 weight percent sodium acrylate, 5 weight percent acrylamide copolymer. Dosages employed and settling rates obtained for the individual stages are set forth in
Table I below.
COMPARATIVE EXAMPLE A
The procedure of Example 1 is followed in every
material detail exceptforthe employment of a 95
weight percent sodium acrylate, 5 weight percent
acrylamide copolymer as the red mud flocculant in
the test stage. Test results are set forth in Table I
below.
COMPARATIVEEXAMPLEB The procedure of Example 1 is followed in every
material detail except that the red mud flocculant
employed in Comparative Example A is used in addi
tion to the red mud flocculant of Example 1. Test results are set forth in Table I below.
COMPARA TIVE EXAMPLE C The procedure of Example 1 is followed in every material detail except that there is now employed a sodium acrylate emulsion having a molecular weight of 5-10 million as the red mud flocculant. Test results are set forth in Table I below.
TABLE I Simulated Settling
Washer Red Muds Flocculant Dosage Rate
Feed Stage Solids Content (Example) (gm/ton) (Ft/hr) 2nd 70 gm/liter 1 36 NE*
Comp. A 18 36.5
Comp. A 36 81.6 Comp. B 18 of 1 16.3 18 of A 3rd 100 gm/liter 1 13 17.3 Comp. A 13 3.5
Comp. C 30 1.3
4th 100 gm/liter 1 13 27.2
Comp.A 13 2.8
Comp. C 30 1.6
5th 100 gm/liter 1 13 14.9
Comp. A 13 6.0
Comp. C 30 2.2 * NE-NoEFFECT EXAMPLE 2
A sample from a Jamaican red mud circuit is taken from the washer stage underflow and diluted accord
ing to the General Test Procedure. To this is added a
flocculant in an 0.05 weight percent solution of
NaOH.The flocculant tested is a 5-10 million molecular weight copolymer of sodium acrylate and acrylamide in the proportions set forth in Table II.
Following the General Test Procedure in every material detail, the results listed in Table II are obtained.
TABLE 11 Simulated Red Muds Settling
Washer Solids Content Flocculant (Wt O/ol Dosage Rate
Feed Stage (gmsiliter) Na Acrylate Acrylamide (Ibslton) (Ft/Hr) 1 38 95 5 0.2 6.3
1 38 70 30 0.2 NE
1 38 60 40 0.2 NE
1 38 50 50 0.2 NE
3 27 95 5 0.2 7.6
3 27 70 30 0.2 30.0
3 27 60 40 0.2 5.5
3 27 50 50 0.2 3.0
3 27 40 60 0.2 NE
6 34 95 5 0.2 4.2
6 34 70 30 0.2 14.2
6 34 60 40 0.2 16.3
6 34 50 50 0.2 8.2
6 34 40 60 0.2 3.6
7 34 95 5 0.1 10.3
7 34 60 40 0.1 17.0
7 34 50 50 0.1 75.0
7 34 40 60 0.1 75.0
As can readily be seen from the foregoing data, employment of copolymers of sodium acrylate and acrylamides produce dramatic increases in flocculation at later stages in the recovery circuit. Although a copolymer of 40 weight percent sodium acrylate and 60 weight percent acrylamide did not show any noticeable effect in the early stages of the test, the same copolymer produced surprisingly excellent results in a later stage, thus emphasizing the importance of evaluating the appropriateness of the indi vidual stages in relation to the copolymer employed.
Claims (8)
1. A process for flocculating red muds from the
Bayer alumina recovery circuit which comprises adding to at least the first stage of the recovery circuit an effective amount of a flocculant selected from the group consisting of starch, homopolymers of acrylic acid or acrylates, copolymers of acrylic acid or acrylates containing at least 80 molar percent acrylic acid or acrylate monomers and combinations thereof and thereafter adding to some subsequent stage or stages of the recovery circuit an effective amount of a copolymer containing from about 35 to 75 molar percent of acrylic acid or acrylate monomers and from about 65 to 25 molar percent of acrylamide monomers.
2. The process of Claim 1 wherein the flocculant added to at least the first stage of the recovery circuit is a copolymer of acrylic acid or acrylate containing at least 90 molar percent acrylic acid or acrylate monomers and no more than 10 molar percent acrylamide monomers.
3. The process of Claim 1 wherein the flocculant added to some subsequent stage or stages of the recovery circuit is a copolymer containing 50 to 70 molar percent of acrylic acid or acrylate monomers and from 50 to 30 molar percent acrylamide monomers.
4. The process of Claim 1 wherein the flocculant added to at least the first stage of the recovery circuit is a copolymer of acrylamide acid or acrylate containing at least 90 molar percent acrylic acid or acrylate monomers and no more than 10 molar percent acrylamide monomers and wherein the flocculant added to some subsequent stage or stages of the recovery circuit is a copolymercontaining 50 to 70 molar percent of acrylic acid or acrylate monomers and from 50 to 30 molar percent acrylamide monomers.
5. The process of Claim 1 wherein the effective amount of the first added flocculant is between 0.01 and 2.0 percent by pounds of flocculant per ton of dry mud residue and the effective amount of the subsequently added flocculant is between 0.01 and 1.0 pound of flocculant perton of dry mud residue.
6. The process of Claim 1 wherein the subsequently added flocculant is added to a stage or stages wherein the grams of mud residue per liter of
NaOH plus Na2CO3are less than about 100.
7. The process of Claim 1 wherein the subsequently added flocculant is added to the fourth or latter stages of the recovery circuit
8. The process of Claim 1 wherein the subsequently added flocculant is a copolymer containing 70 molar percent sodium acrylate and 30 molar percent acrylamide with a molecular weight in the range of 5-10 million.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17161680A | 1980-07-23 | 1980-07-23 |
Publications (2)
Publication Number | Publication Date |
---|---|
GB2080272A true GB2080272A (en) | 1982-02-03 |
GB2080272B GB2080272B (en) | 1984-06-13 |
Family
ID=22624471
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8122135A Expired GB2080272B (en) | 1980-07-23 | 1981-07-17 | Flocculating red mud suspension |
Country Status (13)
Country | Link |
---|---|
JP (1) | JPS5751117A (en) |
AU (1) | AU7319781A (en) |
BR (1) | BR8104729A (en) |
CA (1) | CA1176031A (en) |
DE (1) | DE3129019A1 (en) |
ES (1) | ES8204397A1 (en) |
FR (1) | FR2487325A1 (en) |
GB (1) | GB2080272B (en) |
GR (1) | GR81418B (en) |
HU (1) | HU186395B (en) |
IE (1) | IE51418B1 (en) |
IT (1) | IT1195978B (en) |
YU (1) | YU43029B (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2518985A1 (en) * | 1981-12-30 | 1983-07-01 | American Cyanamid Co | ALUMINA RECOVERY PROCESS |
GB2164639A (en) * | 1984-09-17 | 1986-03-26 | Nalco Chemical Co | Improved flocculants for bauxite (red mud) |
EP0314855A2 (en) | 1987-02-11 | 1989-05-10 | American Cyanamid Company | Polymers containing hydroxamic acid groups for reduction of suspended solids in bayer process streams |
EP0636578A1 (en) * | 1993-07-29 | 1995-02-01 | S. N. F. | Process for the fluidization of aqueous red mud suspensions during the preparation of alumina by the Bayer process |
US5853677A (en) * | 1996-04-26 | 1998-12-29 | Cytec Technology Corp. | Concentration of solids by flocculating in the Bayer process |
US5951955A (en) * | 1995-11-07 | 1999-09-14 | Cytec Technology Corp. | Concentration of solids in the Bayer process |
US6036869A (en) * | 1997-12-12 | 2000-03-14 | Nalco Chemical Company | Water continuous methyl acrylate emulsion polymers for improved flocculation of red mud in the Bayer process |
US6048463A (en) * | 1997-12-12 | 2000-04-11 | Nalco Chemical Company | Water continuous methyl acrylate emulsion polymer combinations and methyl acrylate emulsion homopolymers for improved flocculation of red mud in the bayer process |
US6086771A (en) * | 1997-12-12 | 2000-07-11 | Nalco Chemical Company | Water continuous emulsion polymers for improving scale control in the bayer process |
WO2002070411A1 (en) * | 2001-02-09 | 2002-09-12 | Ciba Specialty Chemicals Water Treatments Limited | Scale removal or prevention |
US6979405B2 (en) * | 2000-11-29 | 2005-12-27 | Ciba Specialty Chemicals Water Treatments, Ltd. | Flocculation of mineral suspensions |
AU2013231168B2 (en) * | 2012-04-26 | 2015-05-14 | Showa Denko K.K. | Washing method of goethite-containing red mud |
WO2020089271A1 (en) | 2018-10-31 | 2020-05-07 | Basf Se | Enhanced dewatering of mining tailings employing chemical pre-treatment |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH03122694U (en) * | 1990-03-20 | 1991-12-13 |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3390959A (en) * | 1965-04-30 | 1968-07-02 | Nalco Chemical Co | Process of making alumina |
US3445187A (en) * | 1966-05-25 | 1969-05-20 | Nalco Chemical Co | Process for separation of red mud from dissolved alumina |
JPS4837678B1 (en) * | 1969-04-17 | 1973-11-13 | ||
NL6906483A (en) * | 1969-04-30 | 1970-10-27 | ||
JPS4929080B1 (en) * | 1970-08-24 | 1974-08-01 | ||
GB1378981A (en) * | 1972-01-13 | 1975-01-02 | Nalco Chemical Co | Process for the separation of red mud from alumina solutions |
GB1439057A (en) * | 1973-10-10 | 1976-06-09 | Allied Colloids Ltd | Flocculating agents for alkaline systems |
US4083925A (en) * | 1976-03-22 | 1978-04-11 | Martin Marietta Aluminum, Inc. | Method for removing ferrous iron from alkali metal aluminate liquor |
-
1981
- 1981-06-09 CA CA000379321A patent/CA1176031A/en not_active Expired
- 1981-07-17 GB GB8122135A patent/GB2080272B/en not_active Expired
- 1981-07-22 BR BR8104729A patent/BR8104729A/en not_active IP Right Cessation
- 1981-07-22 IE IE1647/81A patent/IE51418B1/en not_active IP Right Cessation
- 1981-07-22 GR GR65583A patent/GR81418B/el unknown
- 1981-07-22 FR FR8114249A patent/FR2487325A1/en active Granted
- 1981-07-22 JP JP56113777A patent/JPS5751117A/en active Granted
- 1981-07-22 YU YU1812/81A patent/YU43029B/en unknown
- 1981-07-22 DE DE19813129019 patent/DE3129019A1/en active Granted
- 1981-07-22 AU AU73197/81A patent/AU7319781A/en not_active Abandoned
- 1981-07-22 IT IT48957/81A patent/IT1195978B/en active
- 1981-07-22 ES ES504178A patent/ES8204397A1/en not_active Expired
- 1981-07-23 HU HU812156A patent/HU186395B/en not_active IP Right Cessation
Cited By (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2518985A1 (en) * | 1981-12-30 | 1983-07-01 | American Cyanamid Co | ALUMINA RECOVERY PROCESS |
GB2164639A (en) * | 1984-09-17 | 1986-03-26 | Nalco Chemical Co | Improved flocculants for bauxite (red mud) |
GB2164639B (en) * | 1984-09-17 | 1989-03-30 | Nalco Chemical Co | Process for flocculation of bauxite (red mud) |
EP0314855A2 (en) | 1987-02-11 | 1989-05-10 | American Cyanamid Company | Polymers containing hydroxamic acid groups for reduction of suspended solids in bayer process streams |
US5653946A (en) * | 1993-07-29 | 1997-08-05 | S.N.F. | Process for fluidifying aqueous suspensions of red muds in the production of alumina by the bayer process |
FR2708587A1 (en) * | 1993-07-29 | 1995-02-10 | Snf Sa | Process for thinning aqueous suspensions of red mud in the manufacture of alumina by the Bayer technique. |
AU669633B2 (en) * | 1993-07-29 | 1996-06-13 | S.N.F. | Process for fluidifying aqueous suspensions of red muds in the production of alumina by the bayer process |
CN1035322C (en) * | 1993-07-29 | 1997-07-02 | S·N·F·公司 | Process for fluidifying aqueous suspensions of rod muds in the production of alumina by the bayer process |
EP0636578A1 (en) * | 1993-07-29 | 1995-02-01 | S. N. F. | Process for the fluidization of aqueous red mud suspensions during the preparation of alumina by the Bayer process |
US5951955A (en) * | 1995-11-07 | 1999-09-14 | Cytec Technology Corp. | Concentration of solids in the Bayer process |
US5853677A (en) * | 1996-04-26 | 1998-12-29 | Cytec Technology Corp. | Concentration of solids by flocculating in the Bayer process |
US6036869A (en) * | 1997-12-12 | 2000-03-14 | Nalco Chemical Company | Water continuous methyl acrylate emulsion polymers for improved flocculation of red mud in the Bayer process |
US6048463A (en) * | 1997-12-12 | 2000-04-11 | Nalco Chemical Company | Water continuous methyl acrylate emulsion polymer combinations and methyl acrylate emulsion homopolymers for improved flocculation of red mud in the bayer process |
US6086771A (en) * | 1997-12-12 | 2000-07-11 | Nalco Chemical Company | Water continuous emulsion polymers for improving scale control in the bayer process |
US6979405B2 (en) * | 2000-11-29 | 2005-12-27 | Ciba Specialty Chemicals Water Treatments, Ltd. | Flocculation of mineral suspensions |
WO2002070411A1 (en) * | 2001-02-09 | 2002-09-12 | Ciba Specialty Chemicals Water Treatments Limited | Scale removal or prevention |
AU2013231168B2 (en) * | 2012-04-26 | 2015-05-14 | Showa Denko K.K. | Washing method of goethite-containing red mud |
WO2020089271A1 (en) | 2018-10-31 | 2020-05-07 | Basf Se | Enhanced dewatering of mining tailings employing chemical pre-treatment |
Also Published As
Publication number | Publication date |
---|---|
IE51418B1 (en) | 1986-12-24 |
BR8104729A (en) | 1982-04-13 |
CA1176031A (en) | 1984-10-16 |
ES504178A0 (en) | 1982-05-16 |
JPS5751117A (en) | 1982-03-25 |
DE3129019A1 (en) | 1982-03-18 |
HU186395B (en) | 1985-07-29 |
IT1195978B (en) | 1988-11-03 |
IT8148957A0 (en) | 1981-07-22 |
JPH024532B2 (en) | 1990-01-29 |
GR81418B (en) | 1984-12-11 |
FR2487325B1 (en) | 1985-04-26 |
DE3129019C2 (en) | 1993-08-26 |
ES8204397A1 (en) | 1982-07-16 |
AU7319781A (en) | 1982-01-28 |
YU181281A (en) | 1983-10-31 |
FR2487325A1 (en) | 1982-01-29 |
YU43029B (en) | 1989-02-28 |
IE811647L (en) | 1982-01-23 |
GB2080272B (en) | 1984-06-13 |
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