Hydrometallurgical separation methods

Transcription

1 Introduction to hydrometallurgical separation methods Sami Virolainen BJ90A1000 LUONNONVARAT JA NIIDEN PROSESSOINTI KEMIAN- JA ENERGIATEOLLISUUDESSA klo Sami Virolainen Hydrometallurgical separation methods q Selective leaching q Selective precipitation q Ion exchange q Solvent extraction 1

2 Selective precipitation Talvivaaran kaivoshanke, Kainulainen, 2006 Sulphide precipitation ( Sulfide versus hydroxide precipitation - BioMineWiki, 2010) M +S MS(s) 2+ + M +HS MS(s)+H Hydroxide precipitation 2+ - M +2OH M(OH) 2(s) Ion exchange: Basic consepts Distribution coefficient/factor qi Di =, c i where q is concentration of i component i in resin phase Separation factor Experimental value, depends on total concentration of solution and temperature A mm cc xx αb = = mm cc xx A B A B A B B A B A B A (Helfferich, 1962) Selectivity coefficient For theoretical purposes z z z z z z B B B A A A A B A B A B z z z z z z A A A B B B B A B A B A A m m c c x x KB = = m m c c x x 2

3 Ion exchange: materials Zeolites (Alumosilicates) Minerals Mostly cation exchangers Chabazite, (Ca,Na)[Si 2 AlO 6 ] 2. 6H 2 O Harmotome, (K,Ba)[Si 5 Al 2 O 14 ] 2. 5H 2 O Montmorillonite, Al 2 [Si 4 O 10 (OH) 2 ]. nh 2 O Synthetic Mostly molecular sieves ( Rock, limestone and clay - Zeolite - Te Ara Encyclopedia of New Zealand, 2010) ( Chabazite-Ca Image, 2010) ( NASA Quest > Space Team Online, 2010) Ion exchange: materials Ion exchange resins Frameworks: PS-DVB Acrylic Silica ( INDIAN ION - Resins, 2010) Functionalities: Strong cation exchanger Weak cation exchanger Weak anion exchanger Strong anion exchanger Chelating 3

4 Ion exchange: resins Strong cation exchanger AMBERLITE FPC22 H : PS-DVB framework Sulfonic acid functionality Weak cation exchanger AMBERLITE IRC86 : Polyacryl framework Carboxylic acid functionality Applicability Food processing Mg, Ca Ion exchange: resins Strong anion exchanger Weak anion exchanger Chelating resin Amberjet 4200Cl: PS-DVB framework Quaternary ammonium functionality WP-1: Silica framework Polyethylene imine functionality Lewatit TP-260: PS-DVB framework Amino methyl phosphonic acid functionality Applicability Zn Cu, Pd Alkaline earth metals, U 4

5 Ion exchange: operation - columns ( Water softeners, 2010) (Hiltunen, 2010) ( Ion-Exchange Demineralisation Plants, 2010) Operation usually in 4-5 stages: 1. Loading 2. Wash 3. Elution 4. Wash 5. (Regeneration) Possibility of continuous operation SMB (Simulated moving bed) Solvent extraction: history First law about metal distribution between two immiscible phases 1872 (Berthelot and Jungfleisch) First industrial scale operations in 1940 s: Recovery of radioactive materials, especially uranium 5

6 Solvent extraction: Basic consepts Extraction coefficient c c c Ei = = c c 0 i,org i,aq i,aq i,aq i,aq c c c i,org i,aq 0 i,aq is concentration of the metal in organic phase is concentration of the metal in aqueous phase is initial concentration of the metal in aqueous phase Separation factor between metals i and j Ei SFi/j = E j ( PUREX process, 2010) ph 0.5 If extraction is dependant on ph, ph when E is 0.5 Solvent extraction: Types of extraction systems According to (Ritcey, 2006) Compound formation Acidic and/or chelating extractants extract metal cations (Cation exchange) n M + nha MA + nh + + n Ion association Amine extractants extract ion pairs or anionic complexes (Anion exchange) + - R N+HX R NH X 3 3 R NH X +MY R NH MY +X Solvation Oxygen containing extractants make metal compelexes or inorganic molecules more soluble to organic phase UO 2(NO 3) 2+2TBP UO 2(NO 3) 2 2TBP 6

7 Solvent extraction: reagents Acidic extractants Phosphoric acid derivatives Carboxylic acids Di-2-ethylhexylphosphoric acid (D2EHPA, P-204, etc.) Bis(2,2,4-trimethylpentyl)phosphinic acid (Cyanex 272, Ionquest 290) Branched C-10 carboxylic acid (Versatic 10) Commercial uses Zn, In Selective Co/Ni separation Cu, Co, Ni, Fe Solvent extraction: reagents Chelating extractants Amine extractants Hydroxyoximes (Acorga M5640, LIX-984, etc.) Trioctylamine (TOA, Alamine 308) Quaternary ammonium salt (Aliquat 336) X = H, (Cl) Y = H, CH 3 R = C 9 H 19, C 12 H 25 Commercial uses Cu U, V, W, Mo U, Cd, Co, Zn, Rare earths 7

8 Solvent extraction: reagents Solvating extractants Phosphoric acid derivatives Tributylphosphate (TBP) Trioctylphosphine oxide (TOPO, Cyanex 921) Commercial uses U, Rare earths Selective Co/Ni separation, U Solvent extraction: typical flowsheet (Rydberg et al., 2004) 8

9 Solvent extraction: equipment Mixer-Settler ( solvent extraction in precious metal refining, 2010) ( KCCL - Site Photos, 2010) Solvent extraction: equipment Columns Non agitated columns: Agitated columns: Spray column Packed column Sieve-Tray column ( solvent extraction in precious metal refining, 2010) Bateman pulsed & doughnut pulsed column Rotating disc contactor Electrostatic contactors Etc. ( Pulsed Columns, 2010) 9

10 Literature Handbook of solvent extraction, Krieger, Malabar (FL) Helfferich, F., Ion Exchange. McGraw-Hill Book Co. Ritcey, G.M., Solvent extraction: Principles and applications to process metallurgy. G.M. Ritcey & Associates, Ottawa Rydberg, J., Cox, M., Musikas, C., Choppin, G.R., Editors., Solvent Extraction Principles and Practice, Second Edition, Revised and Expanded. Marcel Dekker, Inc. 10