CN1201439A - Concentration of solid in bayer process - Google Patents
Concentration of solid in bayer process Download PDFInfo
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- CN1201439A CN1201439A CN96198061.3A CN96198061A CN1201439A CN 1201439 A CN1201439 A CN 1201439A CN 96198061 A CN96198061 A CN 96198061A CN 1201439 A CN1201439 A CN 1201439A
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- 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
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Abstract
Processes for improving solids/liquids separation efficiency in the Bayer process are disclosed, wherein solids are flocculated with hydroxamated polymers and centrifuged.
Description
Technical field
The present invention relates to make the Bayer method of aluminum oxide, more particularly, relate to the improvement of Bayer alumina method, the materials flow that is about in this procedure contacts with the polymkeric substance that contains hydroxamic acid group or its salt, make the solid flocculation of suspension, the flocculation solid that generates is carried out centrifugal, remove the solid of suspension thus.
Technical background
The method that the manufacturing aluminum oxide almost generally uses is a Bayer process.In typical commercial Bayer process, the bauxitic ore raw material is worn into fine powder.Then the finely disintegrated ore is added in the slip agitator, the caustic alkali of water, waste liquid and interpolation is made into slip therein.Then with the dilution of this alum clay slip, make its by a succession of temperature between 300-800 °F, pressure is at 100-2000 pound/inch
2Between digester, from the ore of the aluminum oxide that may contain trihydrate and monohydrate form, extract the major part in total the efficient oxidation aluminium.Again by a series of flash tank, along with it is cooled to about 230 °F and return to barometric point, heat and phlegma promptly are recovered in flash tank from the effusive logistics of digester.The aluminate liquid (ejection product) that leaves flash distillation operation contains the 1-20% solid of having an appointment, this solid by bauxitic ore be used in afterwards residual insoluble sludge of reaction between the alkaline matter of digestion ore and the digestion process sedimentary insoluble product and form.Here, all per-cent all on the basis of gross weight by weight, except as otherwise noted.Thicker solid particulate generally uses " sand launder formula " cyclone to remove.For from liquid, telling thinner insoluble particle, usually slip is added in the centre hole of a main mud subsider, in this mud subsider, it is handled with flocculation agent (for example polyacrylamide polymers, polyacrylate polymers, hydroxamic acid fluidized polymer (hydroxamated polymer), flour and/or starch).When the mud sedimentation, the clarifying sodium aluminate solution that becomes (being called " fresh liquid " or " mother liquor ") overflows from the overflow weir at mud subsider top, delivers to next process.The solid that settles down (" red soil ") is then extracted out from the bottom of main mud subsider as underflow, and the countercurrent washing device by generally being made up of a succession of washer reclaims sodium aluminate and alkali then.The common every liter of suspended solids that still contains 50-200mg of aluminate liquid that overflows from main subsider.This liquid generates the filtrate of suspended solids below 10mg/l more after filtration.After filtering operation, the content of suspended solids should be enough low in this filtrate, can provide the alumina product that meets all industrial standardss by the precipitation operation.
Then, aluminum oxide that will be purer from filtrate is precipitated out with alumina trihydrate crystalline form.Remaining liquid phase is that waste liquid is sent top digestion operation back to, adds the digestion agent of ore as other after adding some caustic alkali.
Remove suspended solids from the Bayer process materials flow effectively, be a main problem for many years always.Above-mentioned insoluble composition should be separated to improve the total efficiency of Bayer process with fast speeds.Ideal situation is, Bayer process should be able to be separated insoluble substance for a full due from aluminate liquid efficiently, generates to contain seldom or not contain the high red soil of caustic alkali or aluminate liquid, solid content and to contain the dissolved aluminum oxide liquid that seldom or not contains insoluble dispersion residue.
Can overcome the problems referred to above, and accelerate from materials flow, to isolate the speed of suspended solids greatly, make the component separating method more completely in the materials flow again, in the U.S. Patent No. 3 of using polyacrylic ester as anionic flocculant, 390,959 and in Bayer process alumina recovery flow process, be used in combination in the U.S. Patent No. 3,681,012 of polyacrylic ester and starch narration is all arranged.In addition, it should be noted that the U.S. Patent No. 3 of using the multipolymer of vinylformic acid and methylolation acrylamide for same purpose, 975,496 and the british patent specification No.2080272 and 2112366 that uses the combination of polyacrylic acid and acrylate-acrylamide copolymer successively.The other technologies scheme that has proposed has: Japanese patent gazette No.56092116 (7/23/81) disclose to carry out the method for the starch of cationization with a kind of quaternary ammonium salt as condensing agent; U.S. Patent No. 4,083, the 925 alkali aluminate metal saline solutions that make that disclose contact in the mud subsider with anion-polyacrylamide under given conditions, promote the method that suspended solids is separated with this from alkali aluminate metal saline solution; What Deutsches Wirtschafts Patent No.2552804 (8/11/77) disclosed handles starch with sodium tetraborate and magnesium salts, improves the method for starch flocculating property; Russ P No.507526 (4/06/76) is about formula (R-AR-CH
2-N-Ph)
+Cl
-The solid throwing out of cationic flocculant is better than the report of other known flocculation agents; A kind of inorganic calcium compound of usefulness and sodium polyacrylate that Japanese Patent No.J74018558 (10/05/74) discloses precipitate and filtering method.People such as Appleton are at Jour.So.African Inst.of Mining and Metallurgy; Vol.76; Disclosed a kind of method of using the hydroxamic acid fluidized polymer to be used for cassiterite as flocculation agent among the p117-119 (1975).U.S. Patent No. 4,767,540 have disclosed and adopt the polymkeric substance that contains hydroxamic acid group that the suspended solids in the Bayer process materials flow is reduced, and this patent is herein with reference to using.U.S. Patent No. 4,994,244 have described some separation methods, for example sedimentation under the synthetic flocculant existence condition, filtration or centrifugal, this separation must be carried out being higher than under the atmospheric pressure.
Because the rheological characteristics of solid (solid that comprises flocculation) can not be separated solid with centrifuging usually in most of Bayer process materials flows from materials flow.And generally be to use subsider, decanting vessel, thickener, classifier and strainer separate solid.Except that strainer, these equipment rely on the solid gravity settling to separate.The solid flocculation makes many smaller particles be condensed into faster settled larger particles, thereby helpful to settling process.Flocculation is also helpful to filtration procedure, because the smaller easier elimination of particle of bigger agglomerate, and be difficult for blocking filter.
" red soil " generally obtains as underflow from subsider.It mainly is extracted the residual superfine insoluble sludge that is difficult to elimination in back by the composition that dissolves in caustic alkali and forms.Come the red soil underflow of autonomous subsider to reclaim sodium aluminate and alkali by the countercurrent washing device of mainly forming usually by a succession of washer.Treatment process commonly used is that the underflow of last washer and other red soil stream are delivered to storage pool and the lake that is used for this purpose and builds as rarer shurry pump.The actual limit of this slip is the 25-49% solid content, and solid content is 40% usually.Those skilled in the art agrees such viewpoint: the red soil seasoning is not the ideal processing scheme.The dyke in mud lake must keep in repair, and the danger of river and water channel existed all the time near collapse and mud overflowed and enters.In addition, the big water gaging that enters the seasoning pond with the red soil that suspends may contain caustic alkali and dissolved aluminum oxide, and these caustic alkali and dissolved aluminum oxide run off in the aluminum oxide manufacturing processed, and will therefore be subjected to very big economic penalties.
Brainstrust has been studied the problem of utilizing of red soil; its example has herein with reference to the Environmental Protection Agency B.K.Parekh that uses and " can utilize the assessment of the technology of Bayer process red soil " of W.M.Goldberger; see Off.Res.Dev., EPA-602/2-76-301 (1976).In fact, red soil is used in industrial all and is all required degree that it is dewatered and can transport and/or store with fixed exsiccant form to solid, and does not have the trend of leaching or pulping.Therefore, the dehydration of the low cost of red soil is considered to the key that can it be utilized in the future.The solid content that increases red soil will be very favorable.The red soil that solid content is high can be transported to elsewhere economically, as for example batching of pottery, cement, material of construction etc.These purposes also can alleviate the problem of seasoning.Centrifugal is known solid-liquid separating method, but is not used to make the red soil dehydration usually always.Those skilled in the art will appreciate that red soil is carried out centrifugal only effective slightly to increasing solid content.
Surprisingly, have now found that, combine as flocculation agent with using the polymkeric substance that contains hydroxamic acid group, can improve the dehydration of Bayer process materials flow (especially subsider underflow and digester discharging jet) greatly centrifugal.The solid content of the efflux of solids of separating by increase can improve the efficient of solid-liquid separation in the Bayer process.
Method of the present invention is intended to increase the red soil amount of solid and reclaims wherein contained dissolved composition such as aluminate and alkali etc.Improvement as basis of the present invention is, carries out the materials flow that contains suspended solids (especially red soil solid) of flocculating out with the polymkeric substance that contains hydroxamic acid group centrifugal.Have found that, carry out centrifugal effective not as good as method in common for solid that is not aggregated thing flocculation or the solid that do not contained the polymkeric substance flocculation of hydroxamic acid group.
The detailed description of preferred forms
The invention provides a kind of especially red soil dehydration method of Bayer process suspended solids of improving, it is that the polymkeric substance that will contain hydroxamic acid group or its salt joins in the Bayer process materials flow so that remove wherein suspended solids effectively, and the flocculation solid of gained is carried out centrifuge dehydration again.
The polymer type that can use in the present invention is quite widely.This polymkeric substance should sufficiently be stablized, and (for example, high temperature and strong alkaline condition, typical temperature are 185-225, and total alkali is 80-400 grams per liter (representing with the yellow soda ash equivalent)) effect effectively under used processing condition.
For example, can use any water-soluble polymers that contains hydroxamic acid or its salt in the method for the invention.The best example of useful polymkeric substance is those polymkeric substance that contain formula (1) side group:
In the formula, R represents hydrogen or positively charged ion.These polymkeric substance are known in this area, and the polymkeric substance of group such as ester that can be by containing side, acid amides, acid anhydride, nitrile and the reaction of hydroxamic acid or its salt obtain, and also can carry out polymerization by the monomer that will contain hydroxamic acid or hydroxamate group and obtain.Preferably derive from the hydroxamic acid fluidized polymer of the polymkeric substance (for example polyacrylamide) of phosphinylidyne-containing amine group.
But hydroxamic acidization is so that the example of the polymkeric substance of Shi Yonging in the method for the invention, acrylic polymer, methacrylate based polymers, crotonate polymer class etc. are arranged, for example by polymerizations such as methyl acrylate, ethyl propenoate, tert-butyl acrylate, methyl methacrylate, Jia Jibingxisuanyizhi, cyclohexyl methacrylate, dimethylaminoethyl methacrylate, vinylformic acid dimethylamino ethyl ester, methyl crotonates and the polymkeric substance that makes, the polymkeric substance of maleic anhydride and its ester, or the like; Nitrile polymer, for example those polymkeric substance that make by vinyl cyanide etc.; Acylamide polymer, for example those polymkeric substance that make by acrylamide, Methacrylamide etc.
The hydroxamic acid fluidized polymer is that those skilled in the art is known, and its preparation method is disclosed in UK Patent Application No.2 particularly, 171,127 and U.S. Patent No. 3,345,344,4,480,067,4,532,046,4,536,296,4,587,306,4,767,540,4,902,751 and 5, in 128,420, these documents are all herein with reference to using.These hydroxamic acid fluidized polymers generally can be by containing the side reactive group polymkeric substance in solution, hour obtain in about 10-100 ℃ of (being preferably in below 50 ℃) stoichiometric number with hydroxylamine or its salt, pH is preferably in more than 10 during reaction.According to described these methods, available hydroxamic acid group replaces effective side reactive group of about 1-90%.
Except that the reaction of hydroxylamine or its salt and polymers soln, known polymer latex or emulsion can be directly and hydroxylamine or its reactant salt.This latex can be the multipolymer of acrylamide and methyl acrylate for example, also the multipolymer of vinylformic acid and methyl acrylate.In these cases, the main and ester group reaction of hydroxylamine or its salt forms hydroxamic acid group.
In addition, the known polymkeric substance that derives from inverse emulsion and anti-microemulsion (being also referred to as emulsion and microemulsion herein) also can play a role in the method for the invention effectively.These emulsions and microemulsion are made of for example aqueous polyacrylamide or the acrylamide/acrylic acid copolymer that is dispersed in the oil, and they and hydroxylamine or its salt direct reaction produce the very large polymkeric substance of molecular weight that contains hydroxamic acid group.The dilute aqueous soln of these polymkeric substance that can use in the present invention can be obtained by emulsion and microemulsion by " breaking of emulsion " (for example emulsion and microemulsion are added in the water, or can add tensio-active agent again, stir then and make polymer dissolution).
The hydroxamic acid degree is that the concentration in the useful herein polymkeric substance of formula I unit can between about 5-75 mole %, be preferably between about 10-50 mole % between about 1-90 mole % preferably.The hydroxamic acid degree can be measured with the known nucleus magnetic resonance spectral technology of those skilled in the art.
Suitable hydroxylamine salt comprises vitriol, sulphite, phosphoric acid salt, perchlorate, hydrochloride, acetate, propionic salt etc.Add acid or alkali in the solution, the pH regulator of solution between about 3-14, is preferably about more than 7, be more preferably about more than 10.
Can use any water-soluble polymers in the method for the invention, it can make the solid settlement of suspension after the process hydroxamic acidization.Can use above-named monomeric homopolymer, multipolymer, terpolymer etc.Suitable comonomer (by copolymerization can account for suitable polymers herein up to about 95 moles of %) can comprise other compounds that disclose in the patent known in the art and that introduce such as vinylformic acid, sodium acrylate, methacrylic acid, maleic anhydride, vinyl-acetic ester, vinyl pyrrolidone, divinyl, vinylbenzene and above-named ester, acid amides and/or nitrile etc. in the above, as long as these multipolymers, terpolymer etc. are water miscible after hydroxamic acidization.The weight-average molecular weight of the polymkeric substance that can use in the method for the invention is about 1 * 10
4-1 * 10
8Between, be preferably in about 3 * 10
5-5 * 10
7Between.Weight-average molecular weight can be measured with the known light scattering technique of those skilled in the art.
Polymkeric substance using method in the present invention is, usually its dilute aqueous soln joined to contain dissolved oxygen aluminium and fully in any materials flow of the bauxite of the digestion of dispersive suspended solids, the amount of adding should be enough to make described suspended solids sedimentation at least.Preferably polymkeric substance is added in the underflow and/or digester discharging jet of underflow, washer unit of subsider.Can carry out other chemical treatments (for example acidifying) to materials flow before polymkeric substance adds, in the interpolation process or after adding.Generally speaking, for obtaining optimum, add at least about 0.1mg hydroxamic acid fluidized polymer in every liter of materials flow.
The mixture of hydroxamic acid fluidized polymer and other water-soluble polymerss (for example polyacrylic ester, acrylate/amide copolymer, starch, dextran etc.) is effectively and may is preferable.For example, 1% solution that side contains the polymkeric substance of hydroxamic acid group or hydroxamate group can mix with 1% solution of polyacrylic acid or its salt, the gained mixture can be used to make the red soil flocculation, perhaps, mixes in the time of multiple polymers can being taken advantage of it still for emulsion form.The mixture of hydroxamic acid fluidized polymer and other useful pharmaceutical chemicals (for example tensio-active agent) in Bayer process also may be effective.
The amount that should be appreciated that use is also comparable described just now big, and this does not also depart from scope of the present invention, though generally speaking, after reaching maximum separation speed, further adds the hydroxamic acid fluidized polymer and can't make segregation rate that raising is arranged again.Therefore, after reaching this optimum point, it is uneconomic using the hydroxamic acid fluidized polymer after amount.
Centrifugation technique is that those skilled in the art is known, and its detailed description can be referring to for example rolling up 11-1 to 11-27 page or leaf with reference to " industrial chemistry encyclopaedia " B2 of the UllmanShi that uses herein.Any whizzer all can use in the present invention, comprises filtering centrifuge, screen centrifuge, precipitation whizzer, decanting centrifuge etc.Preferred precipitation whizzer and the decanting centrifuge of adopting, what most preferably adopt is the classification decanting centrifuge.
The whizzer optimization in Properties is known in this area, for example can be referring to the D.E.Sullivan and the P.A.Vesiland of reference use herein, " Centrifuge Trade-Offs ", Operations Forum, pp.24-27 (1986).Inlet amount depends on the size and the type of whizzer.The rotating cylinder diameter is about 20 inches, length is about 80 inches horizontal classification decanting centrifuge, the inlet amount per minute is about the 4-250 gallon, is about the 20-100 gallon preferably, preferably is about the 30-90 gallon.The charging solid content can be between 0.01-45%, preferably between 15-30%.Centrifugal force is generally between 500-3000 * G, preferably between 1000-1500 * G.The difference of the rotating speed of scroll and rotating cylinder is generally less than 150 rev/mins (rpm), is about 1-100rpm preferably, better is about 10-50rpm, preferably is about 30-40rpm.
The water-soluble polymers that side contains hydroxamic acid or hydroxamate group can mix in a storage tank with Bayer process materials flow (preferably subsider underflow or digester discharging jet), just import whizzer then, perhaps be pumped in the materials flow feeding line, perhaps directly add in the whizzer by a feed-pipe.Polymkeric substance preferably directly adds in the whizzer with the form of dilute solution (its concentration is for example between about 0.01-3%).It will be readily apparent to those skilled in the art that the optimum concn of polymkeric substance in the dilute solution depends on the solids content in the Bayer process materials flow, it can be determined by normal experiment.
After using hydroxamic acid fluidized polymer (being preferably in the above-mentioned scope) that the Bayer process solid (the preferably solid in subsider underflow, subsider overflow, washer unit underflow, the overflow of washer unit or the digester discharging jet) of suspension is flocculated, the solid that is about to flocculation is centrifugal, obtains centrifugal solid (cake piece) and the aqueous liquid (centrifugate) that comes out.Centrifugally operated preferably is optimized by the known principle in this area.The preferably main subsider underflow of subsider underflow.Washer unit underflow can be the underflow from any washer in the washer unit, but the underflow of last washer preferably.The cake piece is that the solid content (weight percent of water-insoluble substance) in the centrifugal solid that comes out is higher than the charging solid content, is preferably approximately greater than 40%, is more preferably approximately greater than 50%, preferably approximately greater than 60%.Though generally speaking, the solid content of cake piece is preferably high as far as possible, when solid content very high (for example 90%), whizzer may occur and stop up.Clearly, the obstruction of whizzer must be avoided.In practice, how the required solid content that reaches generally depends on the required handling property of the centrifugal solid that comes out.Method of the present invention is especially to be suitable for to the common i.e. dehydration that concentrates from the red soil of subsider underflow and/or discharging jet.
Generally speaking, be that the centrifugate that constitutes of aluminate liquid is preferably limpid as much as possible by aqueous liquid, promptly the concentration of its suspended solids should be low as far as possible, to avoid polluting final product.The solid content of aqueous liquid (weight percent of water-insoluble substance) is preferably below 1% less than the solid content of charging, is more preferably below 0.5%, is more preferably below 0.2% again, is preferably in below 0.1%.The solid content of centrifugate as shown in the Examples, is represented through the transparency of centrifugate commonly used.
In practice, for realize the red soil dehydration and make aqueous liquid become limpid to the solid of flocculation carry out centrifugal, often the running condition according to other workshops is optimized.For example, the degree of dehydration of red soil and the transparency of aqueous liquid can be regulated up or down, in order that obtain the effect that other are wanted, for example reduce power consumption, reduce the offal treatment expense, improve throughput rate, improve product purity, reduce raw materials consumption etc.Available flocculation and centrifugally replace in the Bayer process equipment for separating liquid from solid (for example subsider, decanting vessel, thickener, classifier and strainer) commonly used, perhaps when using these usual means, also use flocculation and centrifugal method, perhaps these usual means are used in combination with flocculation and centrifugal method.For example, directly will spray product and flocculate and centrifugal, and can reduce or do not use subsider.Also can use a succession of whizzer of successive or interruption, with the charging of one of them discharging as another.
The following examples only play illustration, should not think limitation of the invention.
In the following embodiments, the measuring method of the centrifugal solid solid content (cake piece solid content) that comes out is: the centrifugal solid sample that comes out is weighed, with deionized water it is washed, be dried to constant weight in force ventilated about 105 ℃ of baking ovens.Cake piece solid content is expressed as (dry weight/initial weight) * 100 with weight %.The transparency of centrifugate (aqueous liquid) is that the measuring method of water-insoluble substance weight % therein is: the centrifugate sample is weighed, filter this centrifugate sample with 45 microns polypropylene of weighing in advance or glass filter, wash the solid on the filter with water, filter is dried to constant weight in force ventilated about 105 ℃ of baking ovens.The value of centrifugate transparency is expressed as ((the filter weight of drying-initial filter weight)/centrifugate weight) * 100 with weight %.
Polymkeric substance D is a commercially available product, and it contains have an appointment 90 moles of % ammonium acrylates and about 10 moles of % acrylamides, and molecular weight is about 15,000,000.Embodiment A
The preparation method of polymer A: 18% aqueous solution and 3 parts of Sulfothiorine stablizers of 100 parts of polyacrylamides (molecular weight is about 500,000), 54 parts of hydroxylamine sulfates and 35 part of 50% aqueous sodium hydroxide solution are mixed in suitable containers.Mixture was stirred 2 hours at about 30-40 ℃, allow it be cooled to envrionment temperature then.After 2 days, the hydroxamic acid degree of measuring gained 12.5% polymers soln is about 60 moles of %.Embodiment B
The preparation method of polymer B: 65 part of 30% hydroxylamine sulfate aqueous solution, 25 parts of Sulfothiorine stablizers, 142 parts of water and 160 part of 50% aqueous sodium hydroxide solution are mixed formation solution in a suitable containers.This solution joined by 141 parts of aliphatic oil, 1 part of ethoxylated amine tensio-active agent and 438 parts of molecular weight be about 15,000,000, contains in the mixed solution that the pam microemulsion dispersion liquid of 25% polymer solids forms, temperature was kept about 24 hours or longer below 35 ℃ about.The little dispersion liquid of gained hydroxamic acid fluidized polymer contains 11% polymer solids of having an appointment, and its hydroxamic acid degree is about 14 moles of %.Embodiment C
The preparation method of polymkeric substance C: 1% solution and 30 parts of commercially available molecular weight of 70 parts of polymkeric substance that make by the method for Embodiment B are about 10,000, and 1% polymers soln of 000 sodium polyacrylate mixes.Embodiment 1-12
The used Bayer process materials flow of these embodiment is the underflow from the red soil subsider.With a variable-speed pump underflow slip being added the rotating cylinder diameter is about in the horizontal classification decanting centrifuge that 20 inches, length are about 80 inches.Centrifugal force is between about 1000-1600 * G.The speed difference is about per minute 15-35 rev/min (rpm).By feed-pipe polymkeric substance (its～0.5% solution) is directly sent in the feed chamber of whizzer.The consumption of polymkeric substance sees Table 1, and its unit is the solid kiloton (g/DT) that the gram/centrifugal of true polymers comes out.Red soil has been carried out centrifugally under the condition of not using polymkeric substance, gained filtrate is muddy shape, and this is unacceptable.The input speed (unit is gpm (g/m)) of the polymkeric substance that table 1 has also shown is used, make by embodiment A, B and C, the solid content (weight %) of red soil slip, red soil slip, cake piece solid content (solid content (weight %) in the centrifugal red soil solid that comes out) and centrifugate transparency (can filter solid weight % in the aqueous liquid).The result shows, the hydroxamic acid fluidized polymer improves the centrifugal cake piece solid content that comes out, and makes centrifugate become transparent.
Table 1
Embodiment 13-15
| Embodiment | Red soil slip solid content (weight %) | Red soil slip input speed (gpm) | Polymer flocculant | Polymer loading g/DT | Cake piece solid content weight % | Centrifugate transparency weight % |
| ????1 | ????20.1 | ????50 | Polymer B | ????243 | ????71.4 | ????0.4 |
| ????2 | ????21.3 | ????55 | Polymer B | ????249 | ????66.1 | ????0.055 |
| 3 (comparative examples) | ????21.3 | ????55 | Polymkeric substance D | ????741 | Non-constant | Non-constant |
| ????4 | ????16.5 | ????84 | Polymer B | ????663 | ????60.3 | ????0.09 |
| ????5 | ????21.4 | ????55 | Polymer B | ????275 | ????63.7 | ????0.09 |
| ????6 | ????15.5 | ????55 | Polymkeric substance C | ????412 | ????63.7 | ????0.16 |
| ????7 | ????18.9 | ????55 | Polymkeric substance C | ????260 | ????63.6 | ????0.1 |
| ????8 | ????18.9 | ????55 | Polymer A | ????1156 | ????65.2 | Do not survey |
| ????9 | ????18.9 | ????55 | Polymkeric substance C | ????301 | ????63.2 | ????0.07 |
| ????10 | ????20.3 | ????55 | Polymer B | ????218 | ????63 | ????0.1 |
| ????11 | ????20.3 | ????55 | Polymer B | ????172 | ????64.2 | Do not survey |
| ????12 | ????20.3 | ????55 | Polymer B | ????224 | ????63.4 | Do not survey |
Used Bayer process materials flow is that the charging solid content is about 0.015% main subsider overflow among these embodiment.Used condition is identical with embodiment 1-12's, but lower slip solid content has been carried out suitable adjustment.Substantially equate that the transparency of gained centrifugate is less than 0.015% in the polymkeric substance that use makes by the method for embodiment A, B and C, the solid content of gained cake piece and table 1.Embodiment 16-18
Used Bayer process materials flow is the underflow that the charging solid content is about last washer of 30% among these embodiment.Used condition is identical with embodiment 1-12's, but higher slip solid content has been carried out suitable adjustment.Equating substantially in the polymkeric substance that use makes by the method for embodiment A, B and C, the solid content of gained cake piece and the transparency of centrifugate and table 1.Embodiment 19-25
Used red soil slip is the ejection product among these embodiment.The charging solid content of slip is about 2%, and input speed sees Table 2.With variable-speed pump slip being sent into the rotating cylinder diameter is about in the horizontal classification decanting centrifuge that 20 inches, length are about 80 inches.Centrifugal force is about 1200 * G.The speed difference is about 10rpm.Polymer A and B make as stated above, are diluted to 1% solution, directly send into the feed chamber of whizzer by feed-pipe.The consumption of polymkeric substance sees Table 2.Use polymkeric substance and do not use the transparency of the centrifugate of polymkeric substance all to be listed in the table 2.
Table 2
| Embodiment | Slip input speed (gpm) | Polymer flocculant | Polymer loading g/DT | Centrifugate transparency (weight %) |
| ????19 | ????50 | Polymer A | ????150 | ????0.37％ |
| ????20 | ????50 | Polymer A | ????300 | ????0.31％ |
| ????21 | ????50 | Polymer A | ????375 | ????0.31％ |
| ????22 | ????50 | Polymer B | ????131 | ????0.23％ |
| 23 (comparative examples) | ????50 | Do not have | ?????- | ????0.42％ |
| ????24 | ????42 | Polymer B | ????150 | ????0.05％ |
| 25 (comparative examples) | ????42 | Do not have | ?????- | ????0.38％ |
Claims (10)
1. the method for the solid-liquid separation efficiency by the materials flow of centrifugal raising Bayer process aluminum oxide, it is the water-soluble polymers that Bayer process materials flow and side contain hydroxamic acid or hydroxamate group is contacted and effectively to mix, carry out the solid of gained flocculation centrifugal, the centrifugal solid that comes out is separated with the aqueous solution, the amount of wherein said polymkeric substance should be able to make the suspended solids flocculation in the Bayer process materials flow effectively, and the molecular weight of described polymkeric substance is about 1 * 10
4-1 * 10
8Between.
2. the method for claim 1, wherein described Bayer process materials flow contains red soil.
3. the method for claim 1, wherein described Bayer process materials flow is the ejection product.
The method of claim 1, wherein described polymkeric substance is from a kind of emulsion.
4. the method for claim 1, wherein carry out described centrifugal with decanting centrifuge.
5. method as claimed in claim 2, wherein, the solid content in the described centrifugal solid that comes out is 50% or bigger, described per-cent is based on the weight percent of gross weight.
6. method as claimed in claim 2, wherein, described solution contains the solid less than 1%, and described per-cent is based on the weight percent of gross weight.
7. method as claimed in claim 2, wherein, described polymkeric substance is from acrylamide polymer.
8. method as claimed in claim 2, wherein, the hydroxamic acid degree of described polymkeric substance is between 1-90 mole %.
9. method as claimed in claim 2, wherein, described materials flow is the subsider underflow.
10. method as claimed in claim 2, wherein, described materials flow is the subsider overflow.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US630095P | 1995-11-07 | 1995-11-07 | |
| US60/006,300 | 1995-11-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1201439A true CN1201439A (en) | 1998-12-09 |
Family
ID=21720235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96198061.3A Pending CN1201439A (en) | 1995-11-07 | 1996-10-29 | Concentration of solid in bayer process |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0859744A1 (en) |
| CN (1) | CN1201439A (en) |
| AU (1) | AU712311B2 (en) |
| BR (1) | BR9611355A (en) |
| WO (1) | WO1997017292A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104768874A (en) * | 2012-04-12 | 2015-07-08 | 科瑞瑟斯有限公司 | Process and apparatus for obtaining material of value from a bauxite residue |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| UA89663C2 (en) * | 2005-02-25 | 2010-02-25 | Сайтек Текнолоджи Корп. | method for flocculation and composition COMPRISING water-in-oil-in-water emulsions |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR924112A (en) * | 1946-02-27 | 1947-07-28 | Alais & Froges & Camarque Cie | Improvement in the manufacture of alumina by the bayer process |
| US4767540A (en) * | 1987-02-11 | 1988-08-30 | American Cyanamid Company | Polymers containing hydroxamic acid groups for reduction of suspended solids in bayer process streams |
| CA1330865C (en) * | 1989-01-31 | 1994-07-26 | George Dennison Fulford | Process for producing alumina from bauxite |
| DK0514648T4 (en) * | 1991-05-23 | 2000-12-04 | Cytec Tech Corp | Microdispersions of hydroxamated polymers |
-
1996
- 1996-10-29 WO PCT/US1996/017247 patent/WO1997017292A1/en not_active Application Discontinuation
- 1996-10-29 AU AU74798/96A patent/AU712311B2/en not_active Ceased
- 1996-10-29 CN CN96198061.3A patent/CN1201439A/en active Pending
- 1996-10-29 BR BR9611355A patent/BR9611355A/en not_active Application Discontinuation
- 1996-10-29 EP EP96937034A patent/EP0859744A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104768874A (en) * | 2012-04-12 | 2015-07-08 | 科瑞瑟斯有限公司 | Process and apparatus for obtaining material of value from a bauxite residue |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0859744A1 (en) | 1998-08-26 |
| AU7479896A (en) | 1997-05-29 |
| WO1997017292A1 (en) | 1997-05-15 |
| AU712311B2 (en) | 1999-11-04 |
| BR9611355A (en) | 1999-03-30 |
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