WO2002036493A1

WO2002036493A1 - Method of separating red mud containing goethite

Info

Publication number: WO2002036493A1
Application number: PCT/JP2001/009376
Authority: WO
Inventors: Isao Ishikawa; Haruo Washikita; Yasuo Kawai; Koyuki Mesuda
Original assignee: Showa Denko K. K.
Priority date: 2000-10-30
Filing date: 2001-10-25
Publication date: 2002-05-10
Also published as: JP2002137919A

Abstract

A method of separating a red mud containing goethite which comprises: treating an alumina-containing ore containing an iron ingredient as goethite with an alkali solution with heating at 110 to 160°C to extract the alumina; subsequently adding to the extract a water-soluble polymer precipitant comprising as the active ingredient a copolymer having an average molecular weight of 12,000,000 or higher and containing monomer units derived from (A) a vinylhydroxamic acid compound or salt thereof to thereby cause a red mud to settle; and then separating the red mud. By the method, a red mud can be efficiently separated in the extraction of alumina from an alumina-containing ore containing an iron ingredient as goethite.

Description

Method for separating red mud containing goethite

The present invention relates to a method for separating an extraction residue (red mud) of an alumina-containing ore containing a gay site. More specifically, red mud in a sodium aluminate solution obtained by treating an alumina-containing ore containing an iron component as a goethite with an alkaline solution is used as a sedimentation agent consisting of a specific water-soluble polymer copolymer. The present invention relates to a method for separation using the method. Background art

As a method for extracting alumina from alumina-containing ore, the Bayer method is generally employed. In the Bayer method, bauxite, which is usually derived from the place name of the place of origin as an alumina-containing ore, is mixed with an alkaline solution, wet-milled to form a slurry, and then the slurry is extracted to extract the alumina contained in the poxite. Is treated at a high temperature to extract the alumina content, and then the undissolved pauxite residue (extraction residue; usually called red mud because it contains iron hydroxide and has a red color) is solid-liquid separated. Aluminum hydroxide is precipitated from the alumina extract (aqueous sodium aluminate solution) from which red mud has been removed, and the aluminum hydroxide is calcined to obtain alumina.

Separation of the residue (red mud), which is an undissolved component of bauxite, is performed by cooling the extracted slurry heated at high temperature to around 100 ° C under atmospheric pressure. As a separator, a thickener with a mud collector is usually used, but solid-liquid separation takes a long time because the particle size of the residual liquid is very small at 10 m or less. Therefore, in order to promote the sedimentation of the poxite residue, conventionally, a water-soluble polymer flocculant has been used. It is used.

As the polymer coagulant, sodium acrylate, a copolymer of sodium acrylate and acrylamide, and the like are used. In addition, sedimentation aids such as slaked lime and starch are also used to improve the sedimentation rate of the residue and to improve the solid concentration of the lower solution of the thickener and the clarity of the upper solution.

However, these polymeric flocculants, slaked lime, starch, etc., are not effective in separating extraction residues from all alumina-bearing ores. For example, it has been found that it is effective for accelerating red mud settling of poxite from Australia gore ore, but not for pond red mud from Southeast Asia, especially Indonesia.

This is because poxite residue mainly contains components such as iron, silica, aluminum, titanium, and soda, but the crystal form and the like containing these components vary depending on the type of poxite. This is due to the influence on sedimentation speed, solid concentrating property, clarity, etc.

As sedimentation rate is good compositions, for example, to hematite (F e ₂ 〇 ₃₎ Ana evening - peptidase (T I_〇 _2), base one mite (§ - AIO OH) and the like, whereas good sedimentation rate As non-compositions such as goethite (F e〇 (OH)), sodalite (Na ₄ C 1 S i ₃ A 13 ₃ 〇 ₁₂ ), rutile (T i 0 ₂ ), gibbsite (A 1 (OH ) ₃ ) (Κ · Yamada, etc., Light Metals, 1980, pp39-pp50).

Alumina-bearing ore represented by Bintan ore in Indonesia is imported in large quantities into Japan. It contains the alumina component as trihydrate (gibbsite) and the iron component as FeO (OH) (goethite), but when processed by the usual Plier method, the sedimentation rate in the extraction residue (red mud) It is difficult to settle and separate using a conventional flocculant because of the presence of a slow-growing site. Therefore, in order to improve the sedimentation of such porksite-extracted residues with a high content of goethite, Various proposals have been made.

JP 5 0 - 1 5 9 4 9 7 No. (British Patent No. 144,070), the conversion of goethite contained in Pokisa I bets, raising the alumina extraction temperature magnetite (F e ₃ 0 ₄₎ A method for causing this is described. This is because, as an alumina extraction condition, by setting the extraction temperature to 270 ° C or more in the presence of a reducing organic substance, the gaseous site is converted into magnetite with good sedimentation and sedimentation is improved. It is said. This method has a problem that it requires energy consumption and expensive equipment materials and is not economical.

Japanese Patent Publication No. 54-3838 and Japanese Patent Publication No. 58-42131 describe a method in which a substance having good sedimentation properties is used in combination. In this method, a substance containing a composition having a good sedimentation property is added and mixed, and a composition ratio in a residue is changed to thereby satisfactorily separate a substance having a poor sedimentation property. However, in this method, it is necessary to prepare a composition having good sedimentation at all times, which makes the process complicated and is not economical.

Japanese Patent Application Laid-Open No. 56-92116 proposes to use a quaternary ammonium-type cationized starch as a sedimentation aid. The use of this sedimentation aid for red mud separation of alumina-containing ores containing goethite slightly improves the sedimentation, but is not sufficient for industrial treatment.

As described above, in the red mud separation treatment of alumina-containing ore containing a large amount of Indonesian gesite, which is imported in large quantities into Japan, it has both sedimentation separation and economic efficiency, and is practically satisfactory when used alone. No sedimentation aid with a possible performance has hitherto been known. Disclosure of the invention

The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that a vinyl hydroxamic acid compound or a salt thereof having an average molecular weight of 2,000 or more is contained as a flocculant (precipitation aid). By using a water-soluble polymer containing a copolymer as an active ingredient, it was found that separation of red mud during treatment of an alumina-containing ore containing an iron component as a goethite was performed very quickly, and the present invention was completed.

It is disclosed that the water-soluble polymer compound containing a vinylhydroxamic acid group or a salt thereof as a monomer component used in the present invention can be used as a precipitation aid in the treatment of an ore-containing ore (US Pat. No. 4,767). No. 540), but there is no description that it is effective in separating red mud when treating an alumina-containing ore containing an iron component as a goethite. Therefore, it is difficult for a person skilled in the art to easily come up with the present invention relating to the separation of red mud containing goethite based on the description in U.S. Pat. No. 4,767,540.

That is, the present invention relates to a method for separating red mud including the following goethite.

1) In a method for separating red mud in a sodium aluminate solution obtained by heat-treating an alumina-containing ore containing an iron component as a gay site with an alkaline solution at a temperature of 110 to 16; (A) adding a water-soluble polymer sedimentation aid containing a copolymer having an average molecular weight of 2,000 or more containing a vinylhydroxamic acid conjugate or a salt thereof as an active ingredient to precipitate and separate red mud; A method of separating red mud containing a single site.

2) A copolymer having an average molecular weight of 2,000 or more comprises (A) a vinyl hydroxamic acid compound or a salt thereof, (B) (meth) acrylic acid or a salt thereof, (C) (meth) acrylamide and (D) 2. The method for separating red mud containing goethite according to the above item 1, which is a copolymer containing at least one kind of monomer selected from N-vinyl carboxylic acid amide compounds.

3) A copolymer having an average molecular weight of 2,000 or more comprises (A) a vinylhydroxamic acid compound or a salt thereof, (B) (meth) acrylic acid or a salt thereof, and (C) (meth) acrylamide as monomer components. Described in 1 above, which is a copolymer containing Separation method of red mud including the above mentioned game site

4) The method for separating red mud containing goethite according to 1 above, wherein an alumina-containing ore raw material in which 60% by mass or more of the iron component is goethite and 70% or more of alumina is gibbsite is used.

5) The water-soluble polymer sedimentation aid contains, as a monomer component, (A) a copolymer containing the bierhydroxamic acid compound or a salt thereof in an amount of 20% by mass or more. Separation method.

6) The method for separating red mud containing goethite as described in 2 above, wherein the ratio of the vinyl hydroxamic acid compound or the salt of the monomer component (A) to one monomer component is 5 mol% or more.

7) The water-soluble polymer compound is added in an amount of 0.003 to 0.05% by mass, based on the total mass of the monomer components (A), (B), (C) and (D), based on the red mud. 3. The method for separating red mud containing the goethite according to 2. Detailed description of the invention

Hereinafter, the present invention will be described in more detail.

(1) Ore containing alumina

The method of separating red mud during the treatment of an alumina-containing ore according to the present invention comprises a main part of an iron component as a gay site, which is difficult to separate by a method using a conventional sedimentation aid, and an alumina component of alumina 3 This is intended for ores containing alumina mainly containing hydrates (gibbsite). In particular, alumina trihydrate contains 70% by mass or more of alumina, and goethite contains iron components (in terms of iron oxide). It is effective for those with 60% by mass or more.

A typical alumina-bearing ore having such a composition is a poxite from Southeast Asia, for example, Indonesia.

The alumina-containing ore to which the present invention can be applied is limited to Indonesian ore. The amount of gibbsite and the amount of iron contained in the goethite are not limited to those described above. The amount of gibbsite is less than 70% by mass, and 80% by mass of the iron component contained in goethite (in terms of iron oxide). Less than one is also effective.

(2) Alkaline solution

As the alkali solution used in the present invention, an alkali solution used in the Bayer method can be used. Among them, a sodium aluminate solution is preferable. As the sodium aluminate solution, those having an alkali concentration (in terms of NaOH) of 100 to 400 gZL, preferably 120 to 220 g / L can be used.

(3) Flocculant (settling aid)

The flocculant (precipitation aid) used in the present invention is a water-soluble high-molecular-weight copolymer containing, as an active ingredient, a copolymer having an average molecular weight of 2,000 or more and containing (A) a vinylhydroxamic acid compound or a salt thereof as a monomer component. It is a molecular compound.

As the pinyl hydroxamic acid compound or a salt thereof (A), the following general formula (1)

CH ₂ = C (R ¹ ) CONHOM ¹ (1)

(In the formula, R ¹ represents a hydrogen atom or a methyl group, and M ¹ represents a hydrogen atom or an alkali metal atom.)

The monomer shown by these is mentioned. Specific examples include vinyl hydroxamic acid, isoprobenyl hydroxamic acid and their alkali metal salts (sodium salt, potassium salt, etc.), and vinyl hydroxamic acid or its sodium salt is preferred.

The monomer to be copolymerized with the monomer component (A) includes at least one selected from (B) (meth) acrylic acid or a salt thereof, (C) (meth) acrylamide and (D) an N-vinylcarboxylic acid amide compound. Types of monomers.

As the (meth) acrylic acid or its salt (B), the following general formula (2) CH ₂ = C ( ² ) C〇〇M ² (2)

(In the formula, R ² represents a hydrogen atom or a methyl group, and M ² represents a hydrogen atom or an alkali metal atom.)

The monomer shown by these is mentioned. Specific examples include acrylic acid, methacrylic acid and their alkali metal salts (sodium salt, potassium salt, etc.), and acrylic acid or its sodium salt is preferred.

As the (meth) acrylamide (C), the following general formula (3)

CH ₂ = C (R ³ ) CONH ₂ (3)

(In the formula, R ³ represents a hydrogen atom or a methyl group.)

The monomer shown by these is mentioned. Specific examples include acrylamide and methyl acrylamide, with acrylamide being preferred.

As the N-vinylcarboxylic acid amide compound (D), the compound represented by the general formula (4)

CH ₂ = CHNR ⁴ COR ⁵ (4)

(In the formula, R ⁴ and R ⁵ may be the same or different and each represents a hydrogen atom or a methyl group.)

The monomer shown by these is mentioned. Specific examples include N-vinylformamide, N-bieracetamide, N-methyl-N-vinylformamide, N-methyl N-vinylacetamide, and N-vinylacetamide is preferred.

In addition to the monomers (B), (C) and (D), an acrylic acid derivative or a vinyl alcohol derivative (E) represented by the following general formula (5) can be contained as a copolymer component.

CH ₂ = CR ⁶ X (5)

(Wherein, R ⁶ represents a hydrogen atom or a methyl group, X represents one CN, one CO〇R ⁷ , one CONH ₂ , one CONHR ⁸ , —COR ⁹ , one OCOR ¹⁰ or one OR ¹¹ ; R ⁷ represents an alkyl group having 1 to 4 carbon atoms; One hydrogen atom of the group can be replaced by 1 OH or 1 NR ¹² R ¹³ . R ⁸ represents an alkyl group having 1 to 4 carbon atoms, and one hydrogen atom of the alkyl group can be replaced by 1 OH or 1 NR ¹² R ¹³ , and R ⁹ , R ^1Q , R ¹¹ , R ¹² and R ¹³ represent an alkyl group having 1 to 4 carbon atoms. Here, the alkyl group having 1 to 4 carbon atoms means methyl, ethyl, propyl, ethyl or an isomer thereof.

Specific examples of the compound represented by the general formula (5) include methyl acrylate, ethyl acrylate, propyl acrylate, 2-hydroxyethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylamide, acrylonitrile, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, vinyl acetate, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, methyl methyl acrylate, ethyl methacrylate, propyl methacrylate, 2-hydroxy Shetyl methacrylate, 2-hydroxypropyl methacrylate, N, N-dimethylaminoethyl methacrylate, methacrylamide, N-isopropylacrylamide, N, N-dimethylaminopropyl Examples thereof include compounds such as methylacrylamide, N, N-dimethylacrylamide, and N, N-getylacrylamide.

The copolymer used in the present invention contains (A) a vinylhydroxamic acid compound or a salt thereof as an essential component as a monomer component, and further comprises at least (B) (meth) acrylic acid or a salt thereof and (C) (meth) It preferably contains acrylamide.

The water-soluble polymer precipitation aid preferably contains the copolymer as an active ingredient in an amount of 20% by mass or more, more preferably 25% by mass or more.

Further, in the copolymer, the ratio of the vinyl hydroxamic acid compound or the salt of the monomer component (A) to all the monomer components is 5 mol% or more. And more preferably 10 to 30 mol%. If the amount of the monomer component (A) is small, the coagulation effect of red mud (residue) is reduced, and a sufficient sedimentation speed cannot be obtained. Even when the monomer component (C) is contained, its proportion in the copolymer is preferably at least 5 mol%, more preferably 10 to 30 mol%.

The amount of the water-soluble polymer precipitating agent added to the extract containing red mud is 0.1% based on the total mass of the monomer components (A), (B), (C) and (D). It is preferably from 003 to 0.05 mass%, more preferably from 0.007 to 0.04 mass%. The average molecular weight of the water-soluble polymer compound is 2,000 or more, preferably 10,000 or more. If the average molecular weight is less than 2,000, the coagulation effect of red mud (residue) is reduced and a sufficient sedimentation speed cannot be obtained.

In the method of the present invention, the residue can be quickly separated only by adding the above water-soluble polymer compound to red mud without using a sedimentation aid such as slaked lime or starch.

(4) Separation method of red mud

In carrying out the separation method of the present invention, the alumina-containing ore, which is a raw material, is pulverized to a size of 12 mesh or less while mixing with an Alri solution using a pulverizer or the like, and an alumina component is extracted. It is sent to the extraction device. As the extraction device, a closed tubular reactor or a container type reactor is generally used.

The extraction temperature and the extraction time cannot be specified unconditionally because they vary depending on the ground particle size of bauxite, the type of alkaline solution, the concentration thereof, etc., but it is sufficient to set the conditions for economically extracting alumina including the equipment conditions. Usually, the extraction temperature is 110 ° C. (: up to 160 ° C., preferably 115 ° C. to 150 ° C.) and the extraction time is within 5 hours, preferably several minutes to 2 hours. when using sodium aluminate solvent solution as Al force Li solution, the alumina in the solution after the extraction with (a 1 ₂ 0 ₃₎ considering concentration ratio of soda (N a OH), the concentration ratio of aluminum Nano soda (mass ratio) = 0. Set the soda concentration, the alumina concentration, and the amount of the solution so as to be 7 to L0.

The slurry containing the poxite residue (red mud) after the extraction treatment is cooled to about 100 ° C. under normal pressure, immediately sent to a solid-liquid separation device, and used as the sedimentation aid according to the present invention. Add compound and stir. After stirring uniformly, the extract (sodium aluminate solution) and the extraction residue are separated by a separator. As a solid-liquid separator, a thickener with a mud collector is generally used. In the separation of the extraction residue of alumina-containing ore containing goethite, the mechanism by which the water-soluble polymer compound works well as a sedimentation aid is not necessarily clear. This is thought to be due to the fact that chemical trapping power is added to the original physical trapping power of the molecular coagulant, and that the flocculation reaction with ionic substances on the residue surface is promoted. Industrial applicability

Separation of red mud during alumina extraction of alumina-containing ores containing gausite conventionally required special operations and was inferior in economic efficiency, but according to the method of the present invention, Separation can be performed quickly with simple processing operations. That is, the method of the present invention is a method having both separability and economy, and its industrial value is extremely large. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the red mud separation method according to the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to the following description. Pork site

The alumina-containing ore (bauxite) used as a raw material in the examples below is an iron component Indonesian porksites, including goethite, and Australian porksites, which consist of hematite in the iron component. Table 1 shows the results of the analysis of each poxite analyzed according to JIS standard M8361-19668. In addition, the crystal forms of goethite and hematite in the raw material poxite were identified by diffraction X-ray analysis under the following conditions. As a result, it was confirmed that 70% of the iron component in Indonesian bauxite was Gesite and 90% of the iron component in Australian Poxite was hematite.

Diffraction X-ray device: RAD_2RV, manufactured by Rigaku Denki Co., Ltd.

Measurement conditions: Tube: Cu,

Acceleration voltage: 40 kV,

Acceleration current: 30 mA,

Scan speed: 1 ° Z min,

Receiving slit: 1 ° Table 1 Results of analysis of each poxite

G /: Game Extraction processing

The alumina extraction treatment was performed according to the following procedure under the conditions of 140 and 60 minutes at 120 ° C and 15 minutes for the alumina component extraction temperature and extraction time of the raw material poxite.

First, each Pokisaito pulverized to at most 0.99 m, NaOH concentration l 60 g ZL and A 1 ₂ 〇 ₃ concentration 76 g / L sodium aluminate solution 1 liter consisting of extraction after the completion of solution A 1 ₂ 0 ₃ The required amount of ground poison was added and the mixture was dispersed and mixed so that the mass ratio of the concentration of / NaOH was 0.88, and the mixture was transferred to a cylindrical pressure vessel (60 mm in diameter, 200 mm in height) and sealed. The sealed pressure vessel was placed in an oil bath preheated to the extraction temperature, and the alumina was extracted by inverting and stirring the closed vessel for a required extraction time. Thereafter, the pressure vessel was quickly taken out of the oil bath, rapidly cooled to 100 ° C, and the mixture was taken out of the vessel. A part of the mixed solution was taken out and the composition and solid concentration of the red mud were measured. The component analysis of red mud was performed according to JIS standard M8361-1968. Table 2 shows the results.

Table 2 Results of analysis of pork site residues

Evaluation of sedimentation

The mixed solution obtained by the above treatment was transferred to a 250 ml heat-resistant glass sedimentation tube (inner diameter: 30 mm, height: 25 Omm), and kept in a thermostat controlled at a constant temperature of 98 ° C. The necessary sedimentation aid was added to the sedimentation tube containing the mixture according to the conditions of Examples and Comparative Examples, and the mixture was stirred uniformly under the same conditions, and the height of the sedimentation interface was measured every minute. Assuming that the height of the interface of the mixed solution in the settling tube at the start of the settling was 100%, the height of the interface containing the solids over time was calculated as a percentage. Examples 1-4

Using Indonesian porksite, extraction conditions were as follows: Examples 1 and 2 were extracted at 140 ° C for 60 minutes, and Examples 3 and 4 were extracted at 120 ° C for 15 minutes to obtain a residue (red mud). In Examples 1 and 3, the composition ratio (mol%) of the repeating units derived from sodium acrylate, acrylamide, and sodium vinyloxamidate was 71:16:13, and the solid content concentration was 29, as the polymer flocculant. %, Average molecular weight of 2000 or more In Examples 2 and 4, using a polymer flocculant (trade name: HX-200 manufactured by Scitech), the composition ratio of repeating units derived from sodium acrylate, acrylamide, and sodium vinyloxamate as the polymer flocculant ( (Mol%) was 65:16:20, the solid content concentration was 30%, and the average molecular weight was 2,000 or more. Using a polymer flocculant (trade name: HX-400, manufactured by Cytec), each residue was used. 100 ppm was added based on the mass of the solid, and the sedimentation was measured by the above method. Table 3 shows the results.

The composition ratio of the polymer flocculant was measured by a nuclear magnetic resonance analyzer (AMX-400 manufactured by Bruker), and the molecular weight was determined by gel permeation chromatography (CLAS SLC-10 manufactured by Shimadzu, column Shodex) OHpakSB-806MHQ> using pullulan as a standard). Comparative Examples 1-3

Comparative Example 1 was performed in the same manner as in Example 1 except that sodium polyacrylate having an average molecular weight of 10,000,000 or more (manufactured by Nippon Kayaku Co., Ltd., trade name: Panakayak CSG-K) was used as a polymer flocculant in an amount of 0.01% based on the residual solid mass. The treatment was performed in the same manner as described above, and the sedimentation property was measured. Comparative Example 2 was treated in the same manner as in Example 1 except that 0.08% of slaked lime and 1.0% of starch (both based on the residual solid mass) were used instead of the polymer flocculant, and the sedimentability was measured. . In Comparative Example 3, the sedimentation property was measured under the same conditions as in Comparative Example 1 except that the extraction conditions were set to 120 ° C. and 15 minutes.

Table 3 shows the results. Comparative Examples 4 to 7

Comparative Example 4 was the same as Example 1, Comparative Example 5 was Example 4, Comparative Example 6 was Comparative Example 1, and Comparative Example 7 was Comparative Example 3, except that the ore was replaced with Australian porkite. The sedimentability was measured with. The results are shown in Table 3. Table 3 Extraction conditions and sedimentation of residue liquid Example No.Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Bauxite Indonesian Indonesian Australian

Extraction temperature 14U then 14U then 1U Ι Ό 14U 14U 丄し 41) then U 丄 4U then 1U

r-

60 minutes 15 minutes 15 minutes 60 minutes 15 minutes eight 15 minutes 60 minutes 15 minutes

ΗΧ-200 ΗΧ-200 HA-4UU Φ / Cool, Li / acrylic acid hiX-OU ΗΧ-40ϋ Lilycrylic acid Polyacrylic acid Polymer flocculant lOOppm lOOppm lOOppm lOOppm lOOppm 0 lOOppm lOOppm lOOppm lOOppm lOOppm

Amount added

0 0 0 0 0 1.0% 0 0 0 0 0

I

CO

Ash 口 mouth 0 0 0 0 0 0.08% 0 0 0 0 0

Settlement day interface iti interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface interface 5 interface interface interface interface interface interface interface interface interface interface interface %%%

0 100 100 100 100 100 100 100 100 100 100 100

5 34 35 35 36 95 75 94 95 94 35 37

10 25 26 27 28 88 55 87 89 88 25 27

20 22 24 23 25 70 40 72 75 74 22 23

30 21 23 21 23 55 30 59 60 62 21 22

60 20 21 20 22 50 29 50 49 48 19 20

As is evident from Table 3, when polyacrylic acid, which has been conventionally used as a flocculant, is used in the extraction residue separation of Australian poxite consisting of hematite as an iron component, it shows good sedimentation. Examples 6 to 7), when the flocculant is applied to Indonesian poxite whose iron component is made of goethite, the sedimentation property is remarkably deteriorated (Comparative Examples 1 and 3). Also, when starch and slaked lime were used as flocculants, the sedimentation was not good (Comparative Example 2). On the other hand, according to the separation method of the present invention, it can be seen that excellent sedimentation is exhibited (Examples;! To 4).

Further, when the separation method of the present invention was applied to the extraction residue of Australian porkite, the sedimentation was not good (Comparative Examples 4 to 5). It shows a unique effect on

Claims

The scope of the claims

1. A method for separating red mud in a sodium aluminate solution obtained by heat-treating an alumina-containing ore containing an iron component as a site at a temperature of 110 to 160 ° C with an alkaline solution, comprising: (A) A sedimentation and separation of red mud by adding a water-soluble polymer sedimentation aid containing as an active ingredient a copolymer having an average molecular weight of 2,000 or more, including a vinylhydroxam oxide compound or a salt thereof. Separation method of red mud including game site.

2. The copolymer having an average molecular weight of 2,000 or more is composed of (A) a vinylhydroxamic acid compound or a salt thereof, (B) (meth) acrylic acid or a salt thereof, (C) (meth) acrylamide and (D) as monomer components. 4. The method for separating goethite-containing red mud according to claim 1, wherein the method is a copolymer containing at least one monomer selected from N-biercarboxylic acid amide compounds.

3. A copolymer having an average molecular weight of 2,000 or more is composed of (A) a vinyl hydroxamic acid compound or a salt thereof, (B) (meth) acrylic acid or a salt thereof, and (C) (meth) acrylamide as monomer components. The method for separating red mud containing goethite according to claim 1, which is a copolymer containing:

4. The method for separating red mud containing gaysite according to claim 1, wherein an alumina-containing ore raw material in which 60% by mass or more of the iron component is goethite and 70% or more of the alumina content is gibbsite is used. .

5. The water-soluble polymer sedimentation aid contains 20% by mass or more of a copolymer containing (A) a vinylhydroxamic acid compound or a salt thereof as a monomer component. 4. A method for separating red mud comprising the game site according to the above.

6. The method for separating red mud containing a gay site according to claim 2, wherein the ratio of the Bierhydroxam oxide compound of the monomer component (A) or a salt thereof to all the monomer components is 5 mol% or more.

7. Claim 2 wherein the water-soluble polymer compound is added in an amount of 0.003 to 0.05% by mass, based on the total mass of the monomer components (A), (B), (C) and (D), based on the red mud. Separation method of red mud including gecite.