AU625812B2 - Method for the multistage, waste-free processing of red mud to recover basic materials of chemical industry - Google Patents

Description

I

AU-Al -21206/885 WORLD INTELLECTUAL PROPERTY ORGAVTI' PCT lntemational Bureau INTERNATIONAL APPLICATION PUBLISHED Ui4DER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Clissification 4. (11) International Publication Number: WO 89/ 00980 C02 F 9/00, 1/58, 1/64 Al (43) International Publication Date: 9 February 1989 (09.02.89) (21) Interniational Application Number: PCT/t U88100055 (22) International Filing Date: (31) Priority Application Number: (32) Priority Date: (33) Priority Country: 29 July 1988 (29.07.S8) 3524/87 31 July 1987 (31.07.87) LEBENYI, Zolifin [HU/HU]; Leni'a u. 183, H-9200 Mosonmagyarovar PINTER, J~nos [RU/HU]; Kossuth L. u. 84, H-9200 Mosonmagyar6v~r (HU).

(74) Agent: PATE NT A ND LA W OFFI CE FO R I NTE R- NATIONAL AFFAIRS, Dalszinh~iz u. 10, H-1061 Budapest (H U).

(81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European patent), FR (European patent), GB (European patent), IT (European patent), LU (European patent), NL (European natent), SE (European patent), US.

Published Withi international search report.

(71) Applicant (fc-r all designated~ States except US): AQUA- TECH KORNYEZETVEDELMI ES MtJSZAKI FEJ LESZT6 KISSZOVETKEZET [HIU/H Pf, 737, H-1365 Budapest (HU), (72) Inventors; and Inventors/Applicants (for US only) SZIRMAI, Endre [HU/HU]; N~phadsereg u, 30, H-1055 Budapest BABUSEK, Sitndor Epitb i t 28/b, H-1184 Budapest BALOGHJ Gaza [HU/HU]; Haj6s u. 1S, H-1065 Budapest NEDVES, Attila [RUJ/RU]; N~dor u, 17, H-1205 Budapest (HU).

HORVATH, Gyula Fej~r L, u, 34, H-1I1lS Budapest (HU), (54)Tifle; METHOD FOR THE MULTISTAGE, WASTE-FREE PROCESSING OF RED MUD TO RECOVER BA- SIC MATERIALS OF CHEMICAL INDUSTRY (57) Abstract The method of th 4 invention is advantageously applicable to realize a multistage chemical process during which liquid clarifiers suitable fot th purification of Water and sewage, furthermore, Fine-disperse pulverulent solid products utilizable as paint pigments ano 1- 1 lers may b, -,cwuered, Each final product of the multistage chemical processes is a useful material, so the whole technology is waste-free, A-0- I P- 2 0 A PR 198q~

AUSTRALIAN

I MAR 1989 PATE, IT OFFICE

LI

-1- METHOD FOR THE MULTISTAGE, WASTE-FREE PROCESSING OF RED MUD TO RECOVER BASIC MATERIALS OF CHEMICAL INDUSTRY The method of the invention is advantageously applicable to realize a mult stage chemical process during which liquid clarifiers suitable for the purification of water and sewage, furthermore, fine-disperse pulverulent solid products utilizable as paint pigment and filler, may be recovered. Each final product of the multistage chemical processes id a useful material, so the whole technology is waste-free.

It is well-known, that red mud, the final waste of the Bayer alumina production, is a great trouble all over the world. This material is alkaline and it heavily contaminates the waters leal; from the red mud storage places owing to both its alkali and iron oxide content, furthermore, in dry condition D its fine fly-powder is easily blown away by the wind. The large quantity of red mud gives also trouble, since its storage needs an enormous area, That is why a number of processes, among them several patents are concerned with the treatment of red mud. For instance, accDrding to FRG Patent No. 1.592.104 solid granules are prepared from red mn-id which is dissolved in the water to be purified. This material consists primarily of iron and aluminium sulfate.

Charging of the solid,water purifying agent is cumbersome, it dissolves slowly and results in plenty of remaining insoluble precipitate.

With the exception of the application No. Ml-1055/1987, filed on April 13, 1987, all these processes are, however, single-stage technologies, in the course of which either by-products (wastes) also arise, or the final product has a large refuse content, thus the specific efficiency of the product is small during the utilization. In case of multistage, more complex processes even more wastes arise and usually their object is only to recover a single particular target product.

S/ 911203,EJHCMC.003,2106,1ct4 8 \CC'* il -2- The object of the present invention is to provide a method where, in the course of several consecutive chemical digestions repeatedly "products" are obtained that are valuable end-products even without any further processing and separation, so all the important components of red mud are utilized as various final products, thus the entire technologic process is waste-free.

V

a a a. a 4 a a 4** The present invention is based partly on the recognition that in a reaction with CO 2 or CO 2 containing flue gas the alkaline sodium content hindering the processing of red mud may be dissolved up to pH 5 to 9 in the form of Na 2 C03, by leaving behind the other "useful" materials. This is the first useful product. The second cognition serves for the reprocessing of the mud recovered by filtration, in the course of which primarily inorganic pigment powders are prepared in several divergent technologic processes.

The essence of the method of the invention consists in that several series of technologic operations may be brought about which transform, in parallel akid/or series connection, the mud of the first operation into various target products free of wastes. First divergent step: the filtered mud is washed with water, a slurry is made thereof which is then refiltered. The washing water is returned into the sodium recovery process.

The filtered mud is: A) dried, B) reprocessed.

A) The dried product may be sold as a cheap inorganic pigment, such as concrete paint, etc.

25 B) Further divergent possibilities during reprocessing: 1. The muddy slurry is treated, under pressure, in a supersaturated state with COq, in the course of which the C. and Mg content are dissolved in the form of Ca- and MgHC03 solutions and may be separated from the other mud fractions by filtration. The solution may be utilized to produce Ca-, MgC03 or -sulfate or it may be introduced diluted into the channel. The filtered mud is treated in a third process as described herebelow in point 2.

i i 'i A! 9112o3,EJHCMC.0o3,2126.e I -3.

2. Without recovering the Ca and Mg content, the muddy slurry is reacted, while mixed, with cold, 10-33% HC1 solution in a stainless steel tank, preferably for 2 to 3 hours. During the parallel reactions the bulk of the Ca, Mg, Fe and Ti content as well as a minor part of the Al content go into solution, the whole quantity of Si (in the form of SiO 2 the bulk of the Al content and other micro-impurities remain in the floating, fine disperse phase. The dissolved product is a solution with clarifying activity.

The mud removed by filtration may be sold in a given case cleaned by a further acid treatment or washing and after drying as a varnish paint, a filler used in the rubber or plastics industry i or as a filter aid.

3. The Ca- and Mg-containing mud, or the mud filtered according to method 1 is reacted with cc. hydrochloric acid, in an S"enamelled double autoclave, while boiling and mixing. During S this, the (Ca, Mg) Fe, Al and Ti content, as well as other S' -im purities of the mud are dissolved and there arises a finedisperse solid phase with high SiOz content (70 on an average) and containing furthermore A1 2 0 3 and TiO 2 The solution may be utilized as a clarifier and the solid part, after washing and I drying, in the fields described in point 2.

i 4. The filtered mud of method 1 is treated with (preferably 5-50 citric acid in order to recover the Fe content. The filtered mud of the treatment is utilized as a filler, and the Fe-citrate solution is utilized as an active ingredient of fertilizers containing microelements, or Fe 2

CO

3 pigment may be obtained by evaporation and heating the solution or precipitating it further, filtering, drying and heating it.

911203XEJHCMC,003,2126.Ie3

V

-4- In the course of processing the mud of method 1, iron oxide pigments may be produced from the solutions obtained according to methods 2 and 3, by treating the solutions with alkali, during which treatment a Fe/OH/3 precipitate is separated. The precipitate is filtered, washed, dried and heat treated. The final product is depending on the heat treatment a yellow, red or black pigtient the shade of which depends on the purity.

The material with high SiO 2 content of the methods 2, 3 and 4 is also reprocessible by reacting it with a concentrated NaOH solution at a temperature of 100 to 140 OC under pressure or at atmospheric pressure, with constant mixing. The solution obtained may be utilized as a material corresponding to water glass. If the SiO 2 -containing materiaL is a powder, it is heated, mixed with soda (Na 2

CO

3 or K 2

CO

3 preferably with the product isolated from the Na 2

CO

3 solution obtained in the first step in the ratio Na 2

O

SiO 2 necessary for soda water glass or potassium water glass to obtain solid S. water glass, by the conventional well-known technique. The water glass may then be dissolved, in hot water, under pressure.

I I t I a« 91i203,EJHChC.003,21206.1e04

Claims (20)

1. A method for the processing of red mud, said red mud comprising a slurry of metal oxides, including Fe 2 0 3 A1 2 0 3 TiO 2 SiO 2 and Na 2 O, said method comprising a) reacting said slurry with carbon dioxide gas whereby to form a product including a solution of Na 2 C0 3 the reaction with carbon dioxide gas being allowed to proceed until said product attains a pH level of from 5 to 9; b) filtering the product of step a) to separate the solution of Na 2 CO 3 therefrom, thereby leaving a filtered mud; and c) treating said filtered mud to form one or more inorganic pigments, fillers and/or flocculants.

2. A method as claimed in claim 1 wherein the treatment of said filtered mud consists essentially of drying it to form an inorganic pigment. *4

3. A method as claimed in claim 1 wherein the treatment of said filtered mud comprises supersaturating the filtered mud with carbon dioxide under pressure to fractionate the filtered mud into a soluble fraction of CaHC03 and NaHCO 3 and an insoluble fraction comprising oxides of Fe, Al, Ti, and Si, said method further comprising a) separating said soluble CaHC03 and MgHCO 3 fraction from said insoluble fraction, b) digesting the insoluble fraction in an aqueous acid solution to form a soluble part comprising dissolved Fe, Al and Ti and an insoluble part comprising a high content of SiO 2 and c) separating said insoluble part from said soluble part whereby the insoluble part may be used as an additive and the soluble part may be used as a flocculant. 920505ehspe03,2206spe,5 920505,ejhspe,035,2l206.spe,5 -6-

4. A method as claimed in claim 3, wherein said method further comprises treating said soluble fraction to form a sulfate or carbonate of calcium or magnesium. A method as claimed in claim 3, wherein said aqueous acid solution comprises about 10-33% HC1.

6. A method as claimed in claim 1, wherein the treatment of said filtered mud comprises digesting the filtered mud with an aqueous acid solution to form a soluble portion comprising dissolved Ca, Mg, Fe, Al and Ti and an insoluble p. -tion comprising a high content of SiO 2 and separating said insoluble portion from said soluble portion whereby the insoluble portion may be used as an additive and the soluble portion may be used as a flocculant.

7. A method as claimed in claim 10, wherein said aqueous acid solution comprises 10-33% HC1. S,8. A method as claimed in claim 3, said method further comprising reat.ing the insoluble part with NaOH while mixing at a temperature of about 100 to 140 0 C to form a water glass solution.

9. A method as claimed in claim 3, said method further comprising washing and drying said insoluble part to form a powder which is substantially acid-free and treating said powder with Na 2 CO 3 or K 2 CO 3 to obtain water glass. A method as claimed in claim 9, wherein the powder is treated with Na 2 CO 3 which is separated from the product in step b) of claim 1. 92o05,ejhs l e O3521264pe,6 i -7-

11. A method as claimed in claim 1, wherein the treatment of said filtered mud comprises digesting the filtered mud with citric acid to form a Fe-citrate solution ind an insoluble fraction, whereby the Fe-citrate solution may be used as an active ingredient in a fertiliser and the insoluble fraction may be used as a filler.

12. A method as claimed in claim 11, said method further comprising evaporating and heating the Fe-citrate solution to obtain a FeCO 3 pigment.

13. A method as claimed in claim 11, said method further comprising treating the Fe-citrate solution with an alkali to separate FeOH 3 precipitate and converting the precipitate into iron oxide pigment.

14. A method as claimed in claim 3, wherein the alkali is NaOH or solution, 9 9 A method as claimed in claim 3, said method further comprising treating the soluble part formed in step b) of claim 2 with an alkali to separate FeOH 3 precipitate awd converting the precipitate into iron oxide pigment. 9i 9

16. A method as claimed in claim 15, wherein the alkali is NaOH or NH 4 OH solution. S17. A method as claimed in claim 6, said method further comprising treating the soluble portion with an alkali to separate FeOH3 precipitate and converting the precipitate into iron oxide pigment.

18. A method as claimed in claim 17, wherein the alkali is NaOH or NH 4 OH solution. 9 50,ejhspe.035,21206.spe,7 Jt/ V -8-

19. A method as claimed in claim 6, said method further comprising reacting the insoluble portion with NaOH while mixing at a temperature of about 100 to 140 0 C to form a water glass solution. A method as claimed in claim 6, said method further comprising washing and drying said insoluble portion to form a powder which is substantially acid-free and treating said powder with Na 2 CO 3 or K 2 CO 3 to obtain water glass.

21. A method as claimed in claim 3, said method comprising treating the soluble part formnd in step b of claim 7 with an alkali to separate FeOH3 precipitate and converting the precipitate into iron oxide pigment.

22. A method a claimed in claim 21, wherein the alkali is NaOH or NH 4 OH solution. 23, A method as claimed in claim 6, said method further comprising treating the soluble portion with an alkali to separate FeOH 3 precipitate and Sconverting the precipitate into iron oxide pigment.

24. A method as claimed in claim 23, wherein the alkali is NaOH or NH 4 OH solution. A method as claimed in claim 6, said method further comprising reacting the insoluble portion with NaOH while mixing at a temperature of about 100 to 1400 to form a water glass solution. A*L 9 920505,ejhspe.03.21206,spe,8 -9-

26. A method as claimed in claim 6, said method further comprising washing and drving said insoluble portion to form a powder which is substantially acid-free and treatingo said powder with Na 2 CO 3 or K 2 C0 3 to obtain water glass.

27. A method acco--uing to any one of claims 1 to 26 substantially as hereinbefore described with reference to the Examples. DATED this 5th day of May, 1992 AQUATECH KORNYFhZETMEDELMI ES MUSZSKI JEDLESZTO KISSZOVETKEZET By Its Patent Attorneys DAVIES COLLISON CAVE ft. ft. ft ft ft ft ft. ft. ft... ft.., ft. ft 'ft ft ft ft ,ft ft ft ft ft ft ft. ft ft ft.. ft ft. ft ft. 4* ft ft ft ft ft ft. ft ft.,. ft ft ft ft JS I ~ft ft 4 020505,ejhspe,035,212OW.spe,9 INTERNATIONAL SEARCH REPORT Irtorn~ne~oiietln~oprT/HU 88/00055 I. CLA11111PICAT100 OF SUBJECT 111AMWIN (it several classification symbols aopiy. rndicatio Will) ACCWvdJ4 to btflAVOMOi Paet Closeftcation (IPCI or to b"t Wtbnali Clapaificotionl and tP'- IPC: C 02 F 9/00,1/58,1/64 It WIRLD11 SeARCHED Mlinimumi Documnentation Setarcheid Ciessfleat,,. vO~ ,CtasGW="inf Symbols Int.Cl. 4 C 02 F 9/00,1/58,1/64,1/00,11/00,1/52 Dow~etts Srchedo e~e than Mlinimnum Docuffiehm~ion to thWi Want that such Documneef tti rIncludied In the Fields 5earehod 0 AT Ill. DOCUMENTS CONSIDERED TO UK1 RELEVA NT' Category I Citation of Document, 11 with Inldication, whers appotalle, ot the relevant ple"a 11 Relevant to Claim No 13 A.EP, Al, 0 072 885 (DECONTA) 02 March 1983 (1) 1(02.03.83), see abstract; page 9, line 25 page 10, line 19. A'EP, l, 0 47 044(M-T.ER) 10 March 1982(1 (10.03.82), see claims 1,3. A'DE, A, 2 058 630 (DAIMLEE-BENZ) 31 May 1972() (31.05.72), see claims A CH, A5, 661 264 (GRUTER) 15 July 1987() (1507,7),see abstract. A'US, A, 4 629 570 (KENNEDY) 16 December' 1986 i(2) (16,12.86), see abstract; column 2, Jlies

55-67. AI-IS, A, 4 678 586 (KEARNEY) 07 July 1987 (07.07.87), see abstract. Special cotegnofle re d disormentt 6 totr dOtUMOMIt published filife the Ilnabiitotisi Aline date doculment defining the gWoralst ate of the GM Which Is n&I 4o onrmlt oets an" not in cenowit with the asoicmilor out canadorad o b atpartcuit rlevncecited 10 Uneortand the principle of thosery underlying earlier decumnt lout published en of after tho imntenoieie document ot particuler roeoencet the claimed invention Aline data cannot be cenaidortd nOirol or carnfnet be climsidored to documeint which may 1 ntrOw doubls en "rOnlty cleim(s) Of involve an Inventive a"o Mich Is Cied to estabisah the publication OVe at owher decurrint of potW4ulleF smleacE thei clelmhod invenition Citation or ether asecis reason tas amofld) cannot be censiored to invgsaft anWfOWO~ It" whei the documntif rolerrngt to an oral dipcieeurs, use, inhibtion Or document Is cembenod1 With 01W of IWer ether such docil. ote "Me eents, such gsm W"n evvil" tO a peron M&illed dscilwion WWl to the in5'-,otieeil Aing ado but il In v at, lot than the p"irMy ame sminvell cumen m moflftfof the sanit patent torehty IV, CIRTIPICATI@N Dats at the Actual Comrpleton of the InternaIlea Search 0 0 bt tIi ettttetiS~ pr 16 eptmbr 188(16Q988) 07 October 198 (7138 Internationtal Searcihing AuthwMt Spa ofa Aitierapd 014w AUSTRIAN PATEMIT OrF'FICE Pennm NC1IS1AI lseonid ahwa4wisosy t11110 Anhang zurn intct'natio- Annex to the International Annexe au rapport de nalen Rechs-rchenbericht Search Report on Interna- recherche internationnolc Uber die internationale tional Patent Application relatif a la demande de Patentanmeldung No.PCT/HU 88/00055 brevet international Nr. nO. In diesen Anha' sind This Annex lists the patent La pr~sente ndique die Mtglieder der family members relating to les membres de la famille de Patentfamilien der im the patent documents cited brevets relatifs aux docu- obengenannten interna- in the above-mentioned Inter- ments de brevets cit~s dans ti .nalen Recherchenbe- national search report. The le rapport de recherche inter- richt angefUhrten Austrian Patent Office is in nationalevis& ci-dessus. Les Patentdokumente ange- no way liable for these par- renseignements fournis sont geben. Diese Ang~ben ticulars which are merely donn~s i titre indicatif et diene nu urUte-rich- given for the purpose of in- nengagent pas la responsa- tung und erfolgen ohne formation. bilitb de l'Office autrichien Gewahr. des brevets. Im Recherchenbericht Datum der Mitglied(er) der Datum der angefUhrtes Patent- Verbffentlichung Patentfamilie Ver~ffentlichung dokument Publication Patent family Publication Patent document cited date member(s) date in search report Date de Membre(s) de la Date de Document de brevet cit& publication famille de publication dans le rapport brevets de recherche 072 885 02/03/1983 AT-E 19 505 15/05/1986 '*-30/04/1986 JP-T2-59--500 088 19/01/1984 WO-Al- 8 302 446 21/07/1983 047 044 10/03/1982 JP-A2-57-0'/5 188 11/05/1982 CH-AS- 661 264 15/07/1987 DK-AO- 5 3,32/84 08/11/1984 DK-A 5 332/84 10/05/198H, DE-A -2 058 630 31/ 3/l972 None US-A -4 629 570 16/12/1986 CA-Al- 1 195 e,4 3 15/ 1 C/ 19 ev US-A -4 678 586 07/07/1987 AU-Al- 38 873/$5 27/08/19BE JP-T2-61-5Ql1 132 12/06/198C WO-Al- 8 503 459 15/08/198P CA-Al- 1 233 735 08/03/198E EP-A1- 0 205 429 30/12/198C GB-AO- 8 403 246 14,/03/1984 ZA-A -8 500 684 25/09/1985