METHODS FOR UTILIZATION OF RED MUD

Transcription

1 METHODS FOR UTILIZATION OF RED MUD Attila Lengyel János Lakatos University of Miskolc, Institute of Chemistry 3515-Miskolc-Egyetemváros

2 KEYWORDS Red mud or bauxite residue Difficulties of utilization Possibilities of utilization Selectivity Complexity Perspectivable methods 2

3 Motto For a long time know that red mud could be processed for the last grain of sand - said engineer George Baksa, who worked at the Hungalu for decades, and also led the company for a long time. But there are serious doubts that this can be done economically. Huge multinational companies dominate the world s aluminum industry,, but so far none of them got involved into this work. But if it would be big business they didn t put off doing it. In a reports after the red mud cunami, Kolontár Stored: 2,7 billion tons Porduced: 120 million tons/a 3

4 PRACTICAL DIFFICULTIES OF UTILIZATION Components and minerals Al 2 O 3 :16-18% Empirical formula Free and bounded water Gibbsite (hidrargrillit) Al(OH) 3 2Al(OH) 3 Al 2 O 3 + 3H 2 O Böhmite γ-alo(oh) H 2 O Diaspore α-alo(oh) H 2 O Alumogoethite (goethite-diaspore) α-fe(al)o(oh) H 2 O Sodium-aluminum-silicates (sodalite, cancrinite), SAS 3(Na 2 O.Al 2 O 3.2SiO 2 ).Na 2 X.yH 2 O X anions depend on conditions of digestion: CO 2-3, SO 2-4, 2Cl -, 2OH -, 2[Al(OH) 4 ] - Calcium-aluminum-silikates (CAS) 3CaO.Al 2 O 3.xSiO 2.(6-2x)H 2 O Tricalcium-aluminate 3CaO.Al 2 O 3.6H 2 O 4

5 PRACTICAL DIFFICULTIES OF UTILIZATION TG/100 DTA/100*25 DTG/100* DERIVATOGRAM -15 temperature, o C 5

6 Fe 2 O 3 : 33-48% Hematite α-fe 2 O 3 Goethite α-feo(oh) H 2 O Maghemite γ-fe 2 O 3 Pyrite or Marcasite FeS 2 SiO 2 : 9-15% Kvarc SiO 2 Sodalite, cancrinite (SAS) 3(Na 2 O.Al 2 O 3.2SiO 2 ).Na 2 X.yH 2 O Calcium-aluminum-silikate (CAS) 3CaO.Al 2 O 3.xSiO 2.(6-2x)H 2 O TiO 2 : 4-6% Sodium-titanates Na 2 O.xTiO 2 (x=3 or 4 or 6) Calcium-titanate CaO.TiO 2 Rutile or Anatase TiO 2 C O M M E R C I A L L I M I T 6

7 Others Na 2 O: 8-12% Sodalite, cancrinite (SAS) 3(Na 2 O.Al 2 O 3.2SiO 2 ).Na 2 X.yH 2 O Sodium-titanates Na 2 O.xTiO 2 (x=3 or 4 or 6) MgO: 0,3-1% TiO 2 : 4-6% CaO: 0,5-3,5% V 2 O 5 :0,2-0,3% P 2 O 5 : 0,5-1,0% ZrO 2 : 0,1%; CO 2 : 2-3% S: 0,10-0,3% F: 0,10-0,15% Cr 2 O 3 : 0,1%; MnO: 0,2-0,3%; Ga: 0,003%; Ce: 0,04%; La:0,02%; Nd:0,02%; Gd:0,015%; Y: 0.01%; Sc: 0,005%; Sm: 0,002%; Pr: 0,001% C O M M E R C I A L L I M I T 7

8 Synthesis and structure of perrhenate sodalite Shas V. Mattigod a,*, B. Peter McGrail a, David E. McCready b, Li-Quong Wang c, Kent E. Parker a, James S. Young b Microporous and Mesoporous Materials 91 (2006)

9 What does red mud mean? What does bauxite residue mean?

10 Possibilities of utilization of red mud Civil and building applications Cement production Aggregats Light-weight Low-stength Sand substitution Q U A L I T Y Bricks, blocks and other elements Kiln fired Not kiln fired Geopolymers Chemical applications Catalysts supporters, adsorbents Ceramics, coatings Fillers of plastics Pigments R a d i o a c t i v i t y NORM 10

11 Possibilities of utilization of red mud Environmental applications Treatment of waste water and acidic mine water Decontamination of soils Treatment of abgases and flue gases Adsorption of SO 2 Absorption/adsorption of CO 2 Agronomic applications Treatment of acidic soils (general soil amendment Phosphate retention Decontamination of soils R a d i o a c t i v i t y NORM 11

12 Possibilities of utilization of red mud Metallurgical applications Al-extraction Steel making Extraction of minor elements Ti V, Ga, Ge RFF 12

13 Statistics of patent activities; world wide; % 4% 2% 3% Civil and building construction Catalysts/adsorbents 9% 7% 34% Ceramics, coatings, pigments Water treatment Recovery of major componets (Fe, Al, Ti, Na) Steel making and fluxing Soil amendment 12% 12% 13% Fuel gas purification Recovery of minor elements Others

14 THE EXPECTATIONS for METALLURGICAL UTILIZATION 1. Complexity Coupled utilisation: combine the extraction of the minor elements to the utilisation of the main components. Results: no waste remains, the operating costs of extraction of minor elements has shared by the main elements. 2. Utilisation of the main components: iron and aluminum recycle by the known metallurgical process (aluminum in the Bayer process, iron in the steel making) 14

15 THE EXPECTATIONS for METALLURGICAL UTILIZATION 3. Basic material of complex utilization will be the original sludge (no dry material), 4. The recovery includes the presence of small amounts of metals (Ti, rare and rare earth metals), 5. Produced as a result of the processing intermediates (e.g. ferroalloys) could be processed more, economically 6. During processing, avoid the formation of hazardous wastes. 15

16 SELECTIVITY Al Fe Al koncentráció, mg dm Fe koncentráció a kivonatban, mgdm Deszt.víz 1 M MgCl2 1 M HAc NH2OH-1 MHAc H2O2-HNO3 Királyviz HF LiBO2 H2O 1 M MgCl2 1 M HAc NH2OH-1 M HAc H2O2- HNO3 LiBO2 Kivonószerek Bauxit Vörösiszap 16

17 sample EXTRACTION assisted by MICROVAWE S:L = 1:20; 300 W, 1 h, 140 o C mg/l Al Ca Fe Mg P Cr Mn mother liguore 1388, ,5 0,53 0,46 0,02 mother liguore + sample 2869, ,2 0,43 0,86 0,02 2 m H 2 SO , ,7 62,5 10,9 116,94 0,5 m H 2 SO 4 490,4 418,8 85,5 233,5 17,6 1,42 92,3 2 m HCl ,27 5,9 75,2 0,5 m HCl 1893, ,11 2,45 74,5 V Ti Zr Ga Ce La Nd mother liguore 2,47 0,1 0,01 2,66 0,01 0,01 0,01 mother liguore + sample 9 0,1 0,01 3,31 0,01 0,01 0,01 2 m H 2 SO 4 9,17 970,5 12,38 1,202 7,66 4,02 3,39 0,5 m H 2 SO 4 1,62 1,5 0,6 0,07 0,41 0,16 0,12 2 m HCl 4,87 102,8 0,36 0,57 6,1 2,7 2,51 0,5 m HCl 1,45 1,1 0,038 0,07 8,9 4,42 4,79 Lengyel Attila, Lakatos Janos: Vörösiszap hasznosítása mikrohullámú feltárással, VII. Kárpát-medencei környezettudományi konferencia. Kolozsvár, március I-II. kötet 17

18 SUGGESTED METALLURGICAL METHODS BAUXITE RESIDUE WET MIXING PIG IRON Reduction Sintering o C SMELTING SLAG GYPSUM RFF WATER LEACHNG S/L SEPARATION MAGNETIC SEPARATION ACID LEACHING To Bayer Process TiO 2 HYDROLISYS PIGA, L; POCHETTI, F; STOPPA, L: Recovering metals from red mud generated during alumina production, JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY, 45 (11): NOV

19 Bauxite SUGGESTED METHODS Complex utilization BAYER-process RED MUD Flue gas Na-discharge Na free sludge Calcination Ox. chlorination Decomposition Red. Chlorination Leaching Condensation Purification Decomposition Separation Decomposition Szépvölgyi, AKKI 19

20 PRIORITIES IN THE RESEARC and INNOVATION Knowledge gap A lot of processes heve been proposed without implementation for metallurgical recovery of the major from red mud? What are BAT? Expected activity Choose the most usable ones!! What means: zero waste objective? Risks of red mud depositions Rise the assurence of red mud landfields Market potencial and permitted condition at construction and agriculture application Make standards; NORM; OUALITY Essurance! 20

21 PRIORITIES IN THE RESEARC and INNOVATION Knowledge gap Economy of the processes for utilization Technical possibilities of the complex utilization (from operation on landfields to metallurgy/making products/agronomy applications) Expected activity Expect publication of capital and operation costs of the processes compared with the cost of deposition. Govermental encourage for developing new complex utilization technologies linking known and economic procedures 21

22 PRIORITIES IN THE RESEARC and INNOVATION HUNGARY Knowledge gap What are the impacts of usage of red mud? Are there any receptivity for red mud usage by international and domestic owned firms? Expected activity Make standards and technical specification of process and products in which red mud are used. Make a survay!

23 PRIORITIES IN THE RESEARC and INNOVATION HUNGARY Knowledge gap Expected activity Is it worth to install a complex technological system? Classify the patented and published processes! Research work to base the development of complex technologie(s) for dry Bayer process mud and historical storaged materials Make a pilot plan

24 THANK YOU VERY MUCH FOR YOUR KIND ATTENTION!