CA2178803A1 - Ion exchange resins - Google Patents

Abstract

A gold complex and/or silver complex selective ion exchange resin comprising a polyurethane matrix having an amine functionality and processes for recovery of gold and or silver from solutions using the above ion exchange resin.

Description

wo g5~l8lsg ~ 2 1 7 8 8 ~ 3 PcT/AU94~on793 ION ~Y~'~T~N~l~ RESINS
The present invention relates to a process for L OUVC:LY
S of gold and/or silver from solutions and ion ~rrh~nge resins for the recovery of gold and/or silver from solution.
The Le:uuv~Ly of gold cyanide from solutions and from pulps has been traditionally conducted using activated carbcn 10 as a solid/liquid separation -h;ln~ n in what has become known as the carbon-in-pulp (CIP) or carbon-in-leach (CIL) process. Activated carbon in this recovery process however, i8 known to 6uffer from a number of disadvallLages including:
* poor resistance to attrition, * slower loading kinetics than ion ~Yrh~nge resins, * requires thermal leycl~elaLlon for reactivation, * loads calcium and magnesium ions leading to pore bl nrk~ n~, * sorbs organic materials from solution leading to lower gold cyanide L~:Cuvc:ly.
.

In plant pulps, contact ls made by the activated carbon with silica and alumina such that the carbon can become 25 ScLulaLed with fine slurry particles in less than three hours.
It has been reported that the equilibrium loading of fines was ~nr1er~n~nt of their ~;ullot:rlLLaLlon in the slurry. FUL I ' ~ ~C, the presence of these particles inside an ~flcrrb~nt decreases the effective diffusion of gold cyanide into the ~rlc~rh-c~nt 30 matrix.
Different batches of activated carbon even from the same manurc.;LuL~:L have been found to have different pru~el Lies. It has been postulated that it is this difference which can 35 explain some of the diLLert~ s in capacity and pclLullllallce which has been reported by different workers.
The problems associated with activated carbon have led W0 9S118159 ' ! ~ PCT1AU9~100793 workers ln the f ield to evaluate 2nd use ion exchange resins as an alternative solld/liquid separation material. It has been suggested that the advantages of a proposed resin-in-pulp ( RIP ) process may be:

( a ) anion exchange reslns are superior to currently available activated carbon with respect to both the kinetics oi loadlng and the e~uilibrium loading of gold cyanide, ( b ) reslns may be eluted at room temperature, whereas activated carbon must be eluted at temperatures zpproaching 100C, ( c ) activated carbon requires thermal reactivation, (d) reslns do not appear to be ~oi l:nn~d by organic species such as flotation Ieayt~ s which have an adverse ef f ect on carbon, ( e ) resins do not load calcium carbonate to the same extent as activated carbon, and therefore do not require the same need for hydrochloric acid washing to remove precipitated calcite, ( f ) minerals such as clays and shales can inhibit the p~ of activated carbon. Resins do not suffer from this problem to the same extent, (g) resins do not suffer from attrition to the same extent as activated carbon. Carbon losses are of the order of 25 to 40 g/tonne of ore treated, whereas resin losses are said to be approximately 5 to lO g/tonne, WO g~tl8159 ~ 2 1 7 8 8 0 3 PCT/AU9~/OQ793 (h) reslns are not adversely affected by temperature increases to the same extent as is activated carbon during the adsorption stage, ( i ) resins may be used to recover free cyanide ions or metal cyanide ~ Y~a from ~Afl1n~a streams.
Resins are not poi s~nc~l by organic species such as flotation reagents, machine olls and lubricants, solvents, etc. to the same extent as observed for activated carbon. It has also been observed that species such as hematite, shales, clays, alumina, etc. decrease the loading of gold on activated carbon and also act as "preg robbers"; the same decrease in loading is not reported for resins.

Known ion e,~ e resins are manufactured in bead form generally from poly~ Ly~ e-divinyl benzene, acrylic, or phenol-fnrr~ hyde resins. It has been ~-u~o~ed that ion exchange fibres can be L~lud~lc~:d from either polyacrylonitrile onto which active ligands can be attached, or polypropylene fibres on to which polystyrene-dlvinyl benzene can be grafted.
Llgands can then be attached to the surf ace of the ion ~`hAn~e reslns or fibres by conducting one or Imore suitable ~h~ CAl reactions.

The perrullllal~ct~ of a number of ~ al strong-base and weak-base ion exchange regins have been compared with activated carbons in actual plant solutions. The distribution coefficient of gold and the selectivlty of gold over copper, iron, cobalt, nlckel and zlnc provide a useful lndlcator of llkely pl::L~UllllC~l~Oe. The fsllc~ng conclusions may be drawn:
( a ) Weak-base resins do not load c~uluuy~ide to the same degree as strong-base resins, ~3ut are more selective.

Wo 95/18159 t i } ~ 2 1 7 8 8 0 3 PCTIAU94100793 (b) Selectivity ~lPrr-~c.oc with mixed functional group resins, being controlled by the ratio of guaternary m groups to tertiary amine groups.
( c ) Selectivlty decreases as the deç~ree of cross-linking increases.
(d) Increasing the surface area to volume ratio, or porosity of the resln lncreases the loadlng.
~e) Generally, at a pH value of lO or higher, weak-base resins only poorly load gold cyanide.
( f ) High c;ul-u~lLL~tions of other metal cyanides ef~iclently compete Witil gold cyanide for loading sites on strong-base resins.
( g ) Gold/copper selectivity varles with free cyanide ion cvl Icel~ LL c~ Lion , ( particularly with carbon ), due to changes in Cu(CN)2-:Cu(CN)32- ratio.
(h) Zn(CN)~2~ and Co(CN)63~ load strongly onto many ion h;~n~ reslns but not onto carbon.
( l ) Background salts increase the gold loadlng onto carbon but can depress the loading onto weak-base ( in particular ) and strong-base resins .
FUL I ' ~::, lt has been shown that whilst certain 30 ~lla~;Lv~uivu::i resins provide good selectivlty ~Eor gold cyanide, these same resins exhibited poor elutlon wlth 1% NaCN + l~L
NaOH at 90C. These partlcular reslns were noted for their good reslstance to attritlon in pulps.
A problem associated with ~Lv~04ed RIP processes ls one of resin loss. The following potential sources of resin loss ln an RIP plant have been ldentlfled:

WO95/18159 ".. ~ 2 1 788~3 PCTIAU9~1007g3 ( a ) abrasion of the resin beads by physical contact with the ore pulp, ( b ) fracturing of the beads due to lmpact with moving S ~ n 1 r.~ 1 parts during mixing, pumping, or æcreening of the resln and pulp, ( c ) shattering of the beads due to osmotic shock caused by the cyclical s~el 1~ n~ of the beads in an 0 ;~ l k~ nP environment ( loadlng ) and contracting in an acidic environment (elution and r,~yelleLclLlon).
To date, the resins evaluated for gold recovery have had several disGJv~nL~ges, including, small partlcle size to provide a large surface-to-volume ratio, lower selectivity for gold over other base-metal cyanides LLe~uè--tly present in leach liquors, and pK, values which prevent the resin loading gold cyanide at pH values above lO.
Disadvantages of currently available ion ~ h~ e resins for gold recovery include:
( a ) purchase cost is higher than for activated carbon, ( b ) the present need for fine sized beads ( in order to achleve a ~ ~ gn ~ f ~ ci~nt ~;~ ...,é.. LL c.tion of llgands ) renders it difficult to recover them from pulps by screening, ( c ) stripping kinetics are slower and 2 more complex stripping regime is often required to efiectively recover the gold cyanide for electrowinning.
In an attempt to address these identified sorption 35 selectivity and elution problems with presently available ion exchange resins a number of suggestions have been made.
Japanese Patent 78 06,296 suggests the use of W~ 95/181~9 ( I ~ 2 1 7 8 ~ ~ ~ PCTIAU9~100793 g~l~n1r7~nP-based ion exchange resins for the recovery and separation of gold from silver and platinum group metals.
UK Patent Application GB 2186563 A also suggests solvent S ~LL~ Ld~Ls and ion ~-..r.l.An~ resins based on the gllAn~llnp ligand .
South African Patent ZA 89/2733 and Canad. Patent Application 2,005,259 also suggest the use of g~An~inp-based 0 resins.
None of these patents has ad-lLe:sY~:d the additional problems of osmotic shock, particle size, or abrasion loss.
PCT/AU93/00312, the ~1qrloql1re of which ls inCVL~ULl~ted herein 15 by reference, relates to ion PYrh~n~e resins comprising a polymer containing ion PYr-hAnJrln3 sites dispersed or distributed throughout a polyurethane matrix wherein the ion ng sites are introduced subsequent to the formation of the polyurethane matrix. It has surprisingly been found 20 that when the ion ~ .a..y~ resins of PCT/AU93/00312 are provided with an amine functionality that superior gold and/or silver extraction results are achieved. The particularly superior results as illustrated in the ~ , l PS were not expected from a review of the prior art. The resins of the 25 present application are not restricted to the type described in PCT/AU93/00312 but include any polyult~Lllal~e resin which has been provided with an amine functionality.
According to the present invention there is provided a 30 gold complex and/or silver complex selective ion exchange resin comprising a polyurethane matrix having an amine functionality .
The term "amine functionality" lnrlll~lPc all nitrogen-35 containing ~ , ~c inrlu~l1n~ primary, sernn-iATy and tertiary amines, ~uaternary amine salts, aromatic or heterocyclic amines, gllAn~ nP-based , lPYPq and imides.

W~? 95118159 ~ , 2 1 7 8 8 0 3 PCT1AU9~100793 The polyurethane matrlx may be a polyurethane foam or resin or an interpenetrated polyurethane foam or resin. A
second polymer having the amine functionallty may be dlspersed or dlstrlbuted throughout the polyurethane Lnatrlx or the 5 matrix may be provided wlth an amlne functlonality.
The term "dispersed or distrlbuted" when used hereln includes a dispersion of discrete particles as well as networks of polymers whlch are lntlmately mlxed throughout or 10 lncorporated within the PO1YUL~ matrix such as in interpenetrating polymer systems.
The present lnventlon also provldes a process for the extractlon of gold and/or sllver from solutions includlng the lS steps of:
( a ) contacting a gold complex and/or silver complex containlng solutlon with the abovementloned resln;
( b ) separatlng the resln; and (C) L~-_UV~Llng the sorbed gold complex by elutlon of the gold complex from the resln.
The above resln and process are partlcularly useful to extract cyanlde, ,1 ~Y~ from solutlon.
Polyurethane reslns are noted f or their abrasion and rh~rn1c~1 reslstance. These resins can be produced as beads, sheets or as fibres, but in particular, they may be ~Yr~nflF~cl to form foams with the r~ r p ~ L Lles varying from a mlcrocellular ~yr~nfl~ product to hlghly ~Yr~nrl~9 foams wlth a denslty ~of lO kg/m~. 3y the correct selectlon of polyols, blowlng agents arLd cell control agents these cells may be closed or open. In an open celled product, most of the cell windows are removed durlng production to leave only the struts behlnd. If a more open r,~ r product ls deslred, then the polyuL~:Lllal~e foam can be further 1 ~ uvt:d by "retlculatlon", a s~n1 r"~ well-known to those skilled in the productlon of polyuleLha-~e foams. FUL;' c:, if desired, particles includlng metal powders, metal alloy particles, norganic W0 95/18159 ~ ~ , l 7~ 8 ~3 PCT/AUg4/00793 materials ( such as barytes ), metal oxides ( such as magnetite or ferros~ l i r.rn ) may be added to the polyurethane to modify its final density and thereby match the density of the pulp solution and if re~uired, to assist in iec-,v~Ly of the resin 5 from the aqueous solutions or pulps by magnetlc means.
The ion exchange reC~in of the present invention comprlses a urethane polymer as a matrix or continuous phase. Ways ln which an amine functlonality may be provided to the matrlx are 10 described ln PCT~AU93/00312 as follows. A second polymer may be dispersed or dlstrlbuted L1-Luuy11~uL a polyurethane matrix, the second polymer belng provided with an amine functionality.
The amine functlonality may be provided in a number of different ways. For example a polymer havlng no amlne 15 functionality may be lntLuducie~ ln~o urethane raw materlals, a polyurethane polymerisation reactlon may then be conducted to form a polyurethane matrlx having the polymer dispersed or distrlbuted thereln. The inLL~..Iuc;~d polymer may then be rh~m1r::l1 ly modlfled ln one or more steps to provide the amine 20 functionality. In an alternative ~ , a polyurethane resin may be interpenetrated wlth one or more ~ ~;~, at least one of whlch has one or more ligands attached. The one or more r I ::i may then be polymerised to provide a polymer containing said ligands. The ligands may either have an amine

2~ functionality or be subsequently modified to provide an amine functionality. In yet another: ' -~I t, a polyurethane matrix may be provided, the matrix may be inLe~ eLLated with one or more I ~. The I ~i may be polymerised to provide a polymer and the polymer may then be rh~m1c:~1 ly 30 -~lif~ to provide an amine functionality.
As described above, polyuL~Lllane foams or resins can be interpenetrated with a second polymer prior to, during, or subsequent to production. Such an inteL~e- eLL a Lion may be by 35 any suitable polymer such as those described in PCT/AU93/00312. The .11 cp~rsed or distributed phase polymer typically may be a polymer formed from ~ of styrene, acrylonitrile, vinyl chloride, vinylidene chloride, divinyl WO 95/181S9 ~ 2 1 7 8 8 0 3 PCT/A~94/00793 benzene, butadiene, epichlorohydrin, capro1actone, thiodiglycol, thiodianiline, diallylamine, methylacrylonitri1e, hydrazldes, dicyclopentadiene, vinyl butyral, succinic anhydride, allyl halides, allyl malonic 5 acid, acryloyl chloride, polyacetal, vinyl alcohol, ~mlnmc;~l ~rylic acid, dimethylolpropionic acid, a-methyl styrene, p-methyl styrene, acrylates such as methyl-methacrylate, acrylamide, methylacrylamide, acrylic acid, llyd~ UAyl:thyl acrylate, IIYd1OAYY1UYY1 acrylate, glycidyl 10 methacrylate, ethylene dimethacrylate, methylacrylic acid, lly-lLoAy~thyl ~ ~I,a~:Lylate, ethylene glycol ~ tlla~:~ ylate~
ethyl acrylate, acrylimido salicylic acid, acrylimido diacetic acid, acrylimido malonic acid, acrylimido phthalic acid, acrylimido glycolic acid, N,N'-methylPnphic~rylamide~ 1-15 vinyl ~m~ 7ol~ vinylpyridine, gtyrylgli~n~ n~ lPYpqdiallylfl~ yl lllm chloride, styryl ~m1~1~7ml1nP
complexes, or comhinations of these monomers or f~hPm1c~l modifications of these " but is not llmited to these - s. Such ~hPm1c~1 modification may be, for example, 20 chlorinatlon, chluL, ~ ~I,ylatlon, hydroxylation, nitration, amination and the like. ~ , lPq are styrene monomer reacted with divinylhpn7pnp~ sub~e~ ,Lly chlul~ Ll~ylated and then amlnated: chloLI Lllylstyrene polymerlsed and then aminated;
acrylonltrlle monomer polymerlsed and then amlnated;
25 l-vinylim~ 7~ilp copolymerlsed with methylbisacrylamlde;
acrylonltrile polymerised with styrene monomer or dlvinyl hPn7PnP and then amlnated.
~ yplcal polymers which may form the dispersed phase 30 include poly~ Ly~ e-~:, styrene-divinyl benzene, styrene-acrylonitrile, styrene-acrylonitrile-methyl Li-a~:~ ylate~
acrylonitrile-methylmethacrylate, polyac1^ylonitrile, polyacrylates, acrylic or methacrylic esters, acrylonitrile-unsaturated dicarboxylic acid-styr~ne, vinylidene chloride-35 acrylonitrile, epoxy(glycidyl methacrylate)-acrylonitrile, poly p-methylstyrene, polyureas, aniline-phenol- E~rr-l ~lPhyde, phenol-fmrr~l rlPhyde, styrene-butadiene, styrene-acrylonitrile-butadiene, acrylonitrile-polyethylene glycol, polyamldes, _ _ _ . . . . .

Wo 9S/18159 ~ ,; h ~ ~ 2 1 7 8 ~ 0 3 PCTIA1194/00793 polyacrylamides, poly1m~ 7nlF~q~ allylglycidyl ether adducts of fll~m~nPc, ethylene and propylene carbonate adducts of mi n~c, polybutadlene-acrylates, polydiallylamine, epoxy adducts, polycaprolactone, caprolactone-acrylates, 5 polydicyclopentadiene, styrene-methacrylonitrile, methacrylonitrile-divinyl h~n7-~n-~, polyvinyl chloride, glycidyl methacrylate-ethylene dimethacrylate, acrylonitrile-methylacrylic acid, polyvinyl alcohol-acrylonitrile, methyl ~lla-_Lylate-llydLuAyt~Lllyl acrylate, hydLuAy~:L11yl methacrylate-10 oligo ( ethyl ene glycol ) dimethacryl ate, l~y dL n Ay ~ Ly L ~--e-methylmethacrylate, polyethyl acrylate-polystyrene, crosslinked butadiene, polystyrene-polyethyl F~n~1 m~ ne, poly:,LyLene-arsenazo, epoxy-polystyrene, epoxy-diaza crown ethers, polyacetal, cresol s~ hnn ~ c acid -phenol - f r- rr - l d~hyde ~
15 c,nLl.L~yuinone-fsrr-lflr~hyde, acryloyl chloride-~mlnnfl~cetic acid, acryloyl chloridc . 'nn,ci~l lcylic acid, acryloyl chloride-methyl niLLul,h~ triethylamine, methyl niLLu~htu.ol-acetic anhydride-acrylic acid, hydroxy ac~lv~lh~nrn~-substituted benzoic acid-forr-lfl~hyde~ or, other like polymers 20 or combination of polymers. Particularly suitable in the context of the present invention have been found to be polymers formed from a poly~LyL~ e-divinyl benzene, polyacrylonitrile and polyacrylates. The polymers may then undergo a further r.h~mlrs~l reaction such as ChlULI Ll.ylation 25 or amination.
This second polymer may then be further reacted by suitable rh~m~cAl modifications to include ligands. F , l~c of ways in which ligands can be inLLuduced lnto a polyurethane 30 matrix are discussed in PCT/AUg3/003l2 but are by no means limiting. For example, by chluL, Ll-ylation~ chlorination, carboxylation, amination, rhn jl.hn ylation~ thioureation, diazotisation, ~m~flny1r~tion~ oximation, etc. or other pLv~es5es to attach cp~r.l f~c. ligands to the second polymer.
35 Preferred in the context of the present invention is chluL~ Ll~ylation. The rh~mtc;~ tfication may also modify the polyuL~ a~e matrix. For example ligands may be attached to the amide groups, hydroxyl groups, reactive methyl groups, ~ WO 95118159 ~ 7 8 8 0 3 Pcr/AU94/0~793 or to the aromatic ring of the isocyanate ~ t of the polyurethane matrix if an aromatic isocyanate is used in the production of the polyurethane resin. Additionally, reactive sites may be incoL~oLaLed into the polyurethane by modifying S an isocyanate with a material containing reactive sites ( such as a dihydroxy compound ) to form a prepolymer and further reacting the prepolymer with additional materials to produce the desired polyurethane. The polyurethane resin containing ligands such as chluL L11ylated sites may then undergo a 10 further rhC~mlcAl ~tfl~tion such as amination.
In a preferred ~mhorl~ t, chll,L, ~ ~1~ylstyrene may be substituted for poly~LyLt:~e and therefore, an i~lLel~e.~eLLated polyurethane resin containing chlu~ ylated polystyrene, 15 croqCl ;nk~fl with divinyl benzene or other suitable monomer may be produced. This resin may then undergo further chemical - ~ f 1 r ,AtiOn such as amination .
In zl preferred ~ - L of the invention the I ( s ) 20 or blend of monomer(s) and ~_ -(s) is illLeL~e~eLLaLed into a polyurethane matrix which has been provided with unsaturated sites during its manufacture. For example " particularly reactive I ~ " such as hydroxy ethyl methacrylate, octene diol, hexene 1,2 diol, 25 polybutadiene diol may be illUUL ~Ul a Lt:d into the polyurethane during its manufacture to provide reactive u..saLuLc.ted sites in the cured polyul~Ll~al~e. One or more different unsaturated -:, may then be inter~.,eLLaL~d into the cured polyurethane and polymerised. The resultant polymer is thus 30 t'hPm1CAl ly bound into the polyul~Ll-alle matrix. 'Vinylpyridine, l-vinyl 1miflA7ole, diallylfli tl-y~ ~ chloride, [3-( methacryloyl ami no ) propyl ] trimethy l ~ m chlori de, styryl g11An~fl~n~ and/or lts ~ Y~C, styryl 1miflA7olP and/or its 1 ~Y~C, are ~ C of such s containing an 35 unsaturated functional group. Whilst it is L)~ft~ that the (s) or blend of - (s) and ~ ~ (s) be interpenetrated into a polyurethane matrix containing an unsaturated group it is not a requirement of the invention WO 95/18159 ~ 2 1 7 8 8 v~ 3 PCT/AU94/Oo~/93 that such reactive sites should be present in the polyurethsne matrix .
Alternatively, a hydroxyl-containing compound may be 5 reacted with a diisocy2nate to produce an isocyanate-termlnated prepolymer. Thls prepolymer may then be lncluded as one of the raw materlals ln the polyurethane resin manuf acture . ~ of the reactive ~ , _ ' are octene diol, hexene 1,2 diol, polybutadlene dlol. ~ ,1es of the 0 dlisocyanate include toluene dlisocyanate ( TDI ) and various grades of diphenylmethane-4,4'-diisocyanate (MDI). Prepolymer manufacturing techniques are well known to those skilled in the ~LvduvLlon of polyurethane resins.
An i~lLt:L~e~eLLCLted polyurethane which contalns a sultable llgand may be lnduced to undergo a further rh~mlrim reactlon such as alkylatlon. For example, a polyurethane may be lnterpenetrated with a second polymer such as vinylpyridine and then the pyridlne slte may be methylated by reactlon with 20 a methyl hallde or ethylated by reaction with an ethyl halide.
The i~L.3L~ LLCILlon may be conducted in the presence of a such as dlvlnyl hPn7~n~ . In a further example, a polyurethane resln containing an acrylonitrile polymer was reacted wlth an amlne to form an 1mltlA70l ln~. functional group 25 and then further reacted with a methyl or ethyl halide.
In another 5 ' '1 t copolymer polyols may be produced by the ~rafting polymerisation of uns~LuLc-L6sd - ~ 3rs on to poly(ethylene oxide) (EO) or poly (propylene oxide) (PO) or 30 mlxed EO-PO ccntaining polyols. Typical ~ ~ ~ ~ include styrene, divlnylbenzene, acrylonitrlle, acrylates, vinyl acetate, styryl g11An~ n~s, styryl lmlrlA7~ , vinylpyrldlne, l-vlnyllmldazole and [3-(methacryloylamlno)propyl]-trimethylammonium chloride and mixtures thereof. This polymer 35 polyol may then be inCUL~VLClt~d as a raw material in the manufacture of a polyurethane. It is also posczlhle for specific polymers to be induced to undergo further rh~mlcAl reactions .
_ _ _ _ _ _ _ _ Wo 9~/181~9 ~ , J 2 ~ 7 ~ 8 0 3 PCT/A~94/00793 Alternatively, a selected diisocyanate or lsocyanate-terminated prepolymer nay be reacted with amide groups or hydroxyl groups present in a polyurethane polymer. Suitable isocyanate ~ include toluene dilsocyanate ( TDI ), PAPI
5 (a polyaryl polymethylenepolyisocyanate as defined in U.S.
Patent No . 2, 683, 730 ), triphenylmethane-4, 4 ', 4 ", -triisocyanate, benzene-1,3,5-triisocyanate, toluene-2,4,6-triisocyanate, diphenyl-2, 4, 4 ' -triisocyanate, xylene diisocyanate, chlorophenylene dii~ouya~ , various grades of 10 diphenylmethane-4, 4 ' -diisocyanate ( MDI ) and 1 nr~ IJrl ~ ng mixtures containing adducts, dimers, trimers and higher functional isocyanates and/or çar~o,l~m~,lpc and trifunctional cyml~a~ L2i, naphthylene-l~5-dii4o~;y~aLe~ Yylene-alphs,3,3'-dimethyl-4, 4 ' -biphenylene diisocyanate, 3, 3 ~ I,o.,y-4, 4 ' -15 biphenylene diisv~:y~llaLe~ 4,4'-methylene(phenylisocyanate), 4,4'sulphonylbis(phenylisoGyanate), 4,4'-methylene diorthotolylisv~;yc..a~e, ethylene diisocyanate, he l,llylene diisocyanate ( HDI ), methylene bis ( cyclohexyl isocyanate ), trimethylPn~ socyanate, isv~hv.u..e diisouyallate~ 2,2,4-20 trimethyl-1,6-hexane dilsOuyallaLë, etc. Desir~d ligands can then be reacted with the u.~ ,Led isocyanate groups. For example, TDI, MDI or HDI may be reacted at elevated temperature in the presence of a uleLII2lle reaction catalyst such as triethylamine with hydroxyl groups and/or amide groups 25 present in the polyurethane resin such that one of the isocyanate groups remains u-- ~=avl_~d. This unreacted isocyanate group may then undergo a further reaction such as by amination by alkyl amines. Alternatively, the unreacted isocyanate group may then be reacted with water to form an 30 amine. This amine site may then be induced to undergo a further chemical reaction if so desired.
Any suitable amine functionality may be iL~troduced into the resin of the lnvention . As noted above the term " amine 35 functlonality" includes all nitrogen containing compounds ~nrl~--lin~ primary, secon~ y and tertiary amines, quaternary amine 8alts, aromatic or }~eLeLu~;y~ilic amines, g~An~inP-based ,1PY~PQ and imideg. PleLer ed amination in^luAPQ alkyl _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ .

WO 95/18159 ;; iJ ! ~ 2 1 7 ~ ~ 0 3 PCT/A1194/00793 amines wherein the alkyl chain i8 preferably between l and 6 carbons long, or which can be reacted to form an lm~ 7ollnP
ligand, or gl~n1~1~nQ, pyridine, qlllnnl~nQ, pyrrolidine, diallylamine, dibenzylamine, or other suitable amine as are 5 more fully discussed below.
In a preferred: ~ o~ll L of the present invention polyurethane foams incoL~uLclLe polystyrene-divinyl benzene.
The benzene ring is preferably then chloromethylated.
l0 Following this reaction, a further reaction may desirably be conducted in which amine functional groups are incuL~oLclted into the polyurethane foam or resin. Varying lengths of alkyl chain have been in~:UL~ULCl~d. Dimethylamine, diethylamine, dieth~nnl~m~nQ, hexamethylen~:Le:LL 'ne, ethylQnprll~m~nQ~ 2-5 ethyl QnQ~ ml nni ml tlA7nl 1 nP~ trimethylamine, triethylamine,tributylamine, dimethyleth~nol~m1nP, are typical of such alkylamines .
In a similar manner, various gll~n1111nP functional groups 20 have also been in~Ludu~d into the polyurethane foam or resin.
For example, gll~n~tllnP, 2-ethylhexylgll~n1A1nQ, di-o-tolyl gllAn~ nQ, di-n-alkyl gll~n1-l1nP, dioctylgll~n~ np~ N-(6-'nnhPYyl)-N~-butyl g-lAn~ nQ _lQYQ~, styryllm~ 7c~1~nP
l QYQC, are ~ 1 Q~ of such ligands.
Other amine functionality i~LLuduu~d ~nnl~lAQ~ pyridine, qll~nt-ll inQ, benzylamine, dibenzylamine, pyrrolidine, diallylamine, ~m1nn~ cetate, amino phn~rhnnlc acids, benzyl~ 1-ylamine, benzyl ;ml~70l ~nP~ 2-methyl lml~zl7nl lnP
30 (lysidine), benzyllysidine.
Other organic amines may also be inooL~uL~ted into the polyurethane foam or polyuL~sL1.a..e resln. This includes for example gll~nfrllnQ ~ ,1QYQ~ or ~ having gll:~n1tl1n~Q
35 iunctional groups such as those ~ l osecl in South African Patent iA 89/2733 and having the formula:-WO 9S/18159 ~ 21 7 8 8 0 3 PCT/AU9~100793 R
N - R2 which formula incl udes the N - RZ
S N - C tautomeric form: N = C
R1 ~ ~ R3 ~ - R3 R~ R' ln whlch each of Rl, R2, R3, and R~ ~nfl~ A~ tly of each other, represent I~YdLU9~ alkyl, alkenyl or aryl (lncludlng substltuted aryl) wlth the further poqq-lhillty that the functlonal group may be protonated and have a counter lon 5 assoclated therewlth;
and Britlsh Patent Appllcatlon GB 2186563A containing the functlonal group:-N-R
RI~ ll R3 ~N-C-N~
R'2 ~R~
whereln R1 through R5 ls selected from the group conslstlng of 25 H, a resin, aromatic and aliphatic groups containlng from 2-25 carbon atoms.
The contents of ZA 89/2733 and GB 2186563A are hereln ln iuL~ulat~3d by reference and the term "glli?ni~l~n~ Yes"
30 when used hereln ~n~ q those , "q ~qrl~se(l ln ZA 89/2733 and GB 2186563A.
In a further preferred: ' ~l t, polyacrylonltrlle or polyacrylonltrlle copolymers such as wlth styrene or 35 styrenedlvlnylhDn~n~ ls lnciul~olc-L~d into the polyurethane foam. Amine functionallty ls then preferably lllLLuduci~:d into the polymer. For example, dlethylenet~iamlne and ethyl~n-~1i 1n~ have been reacted wlth the nltrlle group lntroduced lnto the polyul~LIIane resln. By the selectlon of 40 reactlon condltlons, so ~m~rli~7O~ ~n~ groups may be formed.

WO 95/18159 !~ ' ' (' 2 ~ 7 ~ 8 0 3 PCT/AU94/00793 Organic ~L a~LallL:~ including tributylphosphate, dibutyl butyl phosphate, trioctylamine, tri-(C8-C1O) alkyl nethyl ammonlum chloride, gl-:qn1 .11 n~ functionality, ~ m~ dA7C~1 1 n~
functionality such as laurrl ~m1d~7nl ~nP~ may also be included 5 into the polyurethane foam or polyurethane resin.
The above description describes various ways of including an amlne functionality on a polyu t:LI.clle resin. It should be appreciated that more than one method may be used in 10 combination to include dlfferent types of amines and onto different parts of the ion Pyrh~n~e resin such as a first amine functionality on a second interpenetrated polymer and a second amine functionality grafted onto EO-PO polyol.
The resins of the present invention are also capable of impregnation with organic ~L~ ;La--L~ which are capable of removing desired metal ions from solution. Any suitable amine L~ La~L may be in~ yulc.Ltsd into the resin of the invention. Such amine e- L~ a~;L~1~L4 include trioctylamine, 20 guanidine functionality, tri-(C~-C~O) alkyl methyl ~m chloride, or other e~L~ .Lant, lnrl~ n~ tributylphosphate and dibutyl butyl phosphate. An example of such an extractant is Aliquat 336~TM) [tri-(Ca-C~O) alkyl methyl ~ chloride] a quaternary-based organic e. LL~I.;Lc---t manufactured by Henkel 25 C~,~ ~o~ c-Llon. The incol~ul~Llon of these e~L~ La~lL~ can be '~ f~e~ by either pre- or post-in~;u-~ul-,Llon of a diisocyanate or a diiso~;y~a L_ prepolymer onto the polyurethane foam and curing it such as by passing steam through the isocyanate-impregnated polyurethane foam 30 containing the organic ~I.L ~;L~.-L. Alternatively, the organic L ~ --t may be blended with the dlisocyanate t ( providing that the organic ea~, Lcnt does not react with the dilsocyanate to form a solid product prior to its in~iu,l~o ~Lion onto the polyurethane foam or resin). Resins 35 of the invention may include an amine functionality and also contain an organic extractant.
The resins of the present invention offer exceptional '''' 1'' -~ ' WO95118159 ' ~178$03 Pcr/Ars41nO7s3 abrasion resistance, and resistance to osmotic shock. These resins can be formed into particles of a size such that they can be readily l~uuve:Lt:d from gold and/or si]!ver circuits.
This particle size may be significantly larger than for S uu-1v~ Lional ion ~V~han~e resins. As previously noted, :UllVt:l~ Llonal ion ~v~-hRng~ resins re~uire a small particle size tû enable them to have sufficlent ~Y~-hange capacity.
Conventional resins are also generally made macroretlcular to increase their capacity and has been ,~t:pUl Lc:d leads to osmotic 10 shock which can degrade the resin. It has been le~u Led that this process may lead to pores being generated in the ion exchange resin which can block and reduce its capacity to remove metal ions from solution.
The resins of the present invention are particularly suitable for the e~Llc-uLlon of gold and/or silver , I~YeSr for example cyanide, ,1~Y~C~ from solutions. They may be used to extract gold cyanide from a gold cyanide containing solution which is part of a pulp or slurry.
It should be noted that the application of the polyurethane foams of the invention is not restricted to the :Cuvt:Ly of gold cyanide only. Extraction of other gold ,~ Y~S such as the gold halides, particularly chloride and 25 bromide, gold thiourea, gold thio51~1rhAte, gold thiu1y~llate can also be achieved by the application of i~Leryl:neLLated and modified polyurethane foams or ~ ~:yllated polyurethane foams.
Silver cyanide and other silver, , I~Ye~, particularly 30 thiosulphates, which may occur in solution, or in the leouv~:ly of silver from silver ores, or silver which may occur in association with gold in gold ores may also be recovered by the process of the inventlon.
Resins which are selective for different precious metals such as gold, silver and the platinum group n1etals may be oduced and used to se:pa~ ~te mixtures of precious metals.

WO 95118159 ~ 2 1 7 8 ~ 0 3 PCT/AUg4/00793 The solutions may be clarified, such as is normally obtained in gold heap l~ h1ng operations. Or it may be from pulps, such as occur in carbon-in-pulp or carbon-in-leach ~)L , ,~sses .
Stripping of the polyurethane resin of the invention may be ~ , 11 Qh ~-9 by a suitable solvent such as sodlum or ammonium thiosulphate, acidified thiourea, zinc cyanide, or in some instances, pH control by stripp$ng at a pH in excess l0 of 12.
It has been proposed that chlorine, or hypochlorite, or bromine be used as lixiviants for gold. Activated carbon has been proposed for the recovery of gold chloride ( CICL
lS process ) . Ion exchange resins have also been proposed for the recovery of these halides. The activated carbon rapidly reduces the gold to metallic gold by what is believed to be a diffusion-controlled ~n~ rm. Therefore, the metallic gold will build up on the edges oi the carbon and can easily be 20 abraded from its surface. Ion exchange resins have also been shown to reduce the gold to gold metal. In addition such resins may be ~ .11 c.,.1 by hypochlorite solutions.
A iurther adva~ ge of the present invention is that 25 polyurethane foams do not suffer from hypochlorite degradation and will not reduce the gold to gold metal during the period that they are in the plant providlng the solution conditions are correctly est~hl ~ Qh~l . If reduction occurs, it ls within the polymer, and therefore is not lost by abrasion as is the 30 case with activated carbon.
MPT~
Polyurethane f oams were interpenetrated with a mixture 35 of styrene monomer, divinyl benzene, and 2, 2 ' -F~7~hiq1 Q~hutryro-nitrile (AIB~) . The interpenetration and curing was conducted at 70~C in a nitrogen at. ~ . This ioam was then chloL~ -t11ylated by reacting l gram o~ the ~ W0 9S/181~9 ~ ' 2 ~ 7 8 8 0 3 PCTI~Ug~/00793 interpenetrated polyurethane foam at room temperature for 2 hours with 5 grams of octyl chluL~ yl ether together with stannic tetrachloride c2talyst in a suitable s~lvent.
S This chloII Lllylated polyurethane foam was then further reacted with the amines as listed in Table 1 and under the conditions as given.
0.1 g of each of these aminated polyurethane foams were then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 10.5. Typical ~:~L.c-oLion results are given in Table 1. Capacity loS~ln~ ~n~
dimethylamine modification of 15,000 g Au/tonne polymer and 59,000 g Au/tonne of polymer for the pyridine modified polyurethane. The ~ nt extraction ~Lu~:L Lles of the polyurethane foam is shown by comparison Witll the details provided by ûreen et al. in their C~n;~ n Patent Application 2, 005, 259 who indicated that a pyridine based polystyrene-divinyl benzene (9% DVB) extracted 23,400 g Au/tonne PS-DVB
from a synthetic pL~y-la-lt solution.

W0 95/18159 ~ 2 1 7 8 8 03 PCTIAI194/00793 TABLE 1 - Gold Cyanide Loading on Polyurethane Foams Bearing Various Amine Functionalities Amino Ligand used Reaction Gold Loading, Conditions mg Au/kg resin 5 Dimethyl amine 40% aqueous > 10, 000 ( CH3 ) 2NH solution methanol, 4 0 C, 18h Trlmethyl amine 3096 aqueous 9, 400 ( CH ) 3N solution methano1, 40 C, 24h Pyridine ~ acetone, ref . > 10, 000 0 Qll1nnl~n~ Toluene, > 10,000 [~ 70-80C, 24h acetone, reflux 8, 000 24h TOA toluene, > 10,000 70-80C, 24h Gll~nirl1n~ methanol, > 10,000 H2N-C-NH2 reflux, 24h di-n-alkyl 9920 gll~n1rlinF~
R-NH-C-NH-R

R~=octyl, 2-ethyl hexyl etc.

WO95/18159 ;. ~ 2 ~ 78803 PCTIAU9Sl00793 F~x~r'pLE 2 2 . 9 grams of a polyurethane foam ln whlch 10 % by weight of polybutadiene diol was included as a raw 0aterial during 5 its manufacture was interpenetrated with a mixture of 6 grams of acrylonitrile, 0.15 grams of divinyl ben~ene and 50 milligrams of AIBN as a polymerisation catalyst and then cured for 24 hours at 60C in a nitrogen a' ~ e. 1.0 grams of the resultant resin was then further reacted with 0 . 3 0 millilitres of diethylene triamine in toluene and in the presence of 20 milligrams of rubeanlc acid as a catalyst at 70 to 80C for 6 hours.
0.1 gram of this polymer was then pulsed for 3 hours in 15 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 10.5. The polymer loaded 6,800 mg Au/kg of resin from solution. 53% of the gold cyanide was able to be stripped from the resin at room temperature in 18 hours by a lM solution of sodium hydroxide.
ExAMpT~p~ 3

3 . 8 grams of a polyu~ 1.2lle foam ln whlch 10 % by welght of polybutadlene dlol was 1 nrm ~ as a raw materlal durlng 25 its manufacture was i~.teL~ eLL"~ed wlth a mlxlture of 10.1 grams o~ ~hl~ yl styrene monomer (CMS), 0 25 grams of dlvinylh~n~en~ and 0.037 grams of AIBN and then cured at 70C
for Z4 hours in a nitrcgen a' ~ ,' ~-~.
The resultant in~e~ .e~Lc.~d resin was then further reacted under the stated condltlons wlth various amines as given in Table 2.
0.1 g of each of these aminated polyurethane foams were then pulsed for 3 hours in 20 millilitres of a 50 ppm solutlon of potasslum gold cyanlde at a pH of 11. Typlcal extraction results are glven ln Table 2.

W0 95118159 ~ 1 7 8 ~ 0 3 PCT/AU9~/00793 Amine Reaction Gold Loading, Conditions mg Au/kg resin at pH~ll Pyridine 55-C in acetone, > 10,000 24 hour 5 Dimethylamine 60C in acetone, 6,300 1 8 hour GI~An~ n~ Sto~-~.h~ LL1C 9,100 quantity in water-methanol, 60 C, 24 hour Dioctyl gll~n~ n~ Stolr~hi, Lllc > 9,800 quantity in water-methano 1, 6 0 C, 24 hour Diethylene-triamine 70 to 80C in 6, 500 toluene 18 hour 0.1 g of polyurethane ioam containing the pyridine ligand was pulsed or 3 :hours in 100 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 11. The polymer loaded 65,100 mg Au/kg of resin from solution.
0.1 g of ~ polyurethane foam containing the dioctyl g~ n~rl1nP ligand was pulsed for 3 hours in 50 millilitres of a 50 ppm solution o potassium gold cyanide at a pH of 11.
The polymer loaded 29,000 mg Au/kg of resin from solution.

1.5 grams of a polyurethane foam in which 10 % by weight of polybutadiene diol was ~ n~ lrl~l as a raw material during _ . _ . _ _ _ _ _ _ _ _ _ . _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ W0 95118159 2 ~ 7 8 8 0 3 PCT/AU941~17g3 ~ . ;,.. . ';

its manufacture was interpene,trated with a mixture of solvent,

4 millilitres of vinylpyridine, 0.25 grams of divinyl benzene and 20 milligrams of AIBN and then cured at 70C for 24 hours under a nitrogen atmosphere.
0.1 gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potasslum gold cyanide at a pH of 11. The polymer loaded 6, 900 mg Au/kg of resin from solution.
The resin from the Example was then methylated by reactlng this resln wlth a 2 mole excess of methyl hallde dispersed ln a suitable solvent for 16 hours at room atuL~ .

0.1 gram of this polymer was then pulsed for 3 hours in 20 millllltres of a 50 ppm solutlon of potassium gold cyanlde at a pH of 11. The polymer loaded 9, 700 mg Au/kg of resln from solutlon.
FY~ApT,~ 5 1.5 grams of a polyurethane foam ln whlch 10 % by welght of poly~utadiene dlol was ~ nf~ 9ed as a raw materlal during, 25 lts manufacture was i--~e~ eL~ ~t~d with a mlxture of 4 grams of methyl methacrylate monomer, 0.1 gram of dlvlnylbenzene and 18 milligrams of AIBN and then cured for 24 hours at 700C
under a nltrogen a' ~ ~e.
0. 5 grams of thls resin was then reacted wlth 0 . 5 grams of diethylene ~ ml n~ ln the ~L~ o~ of 20 mllligrams of rubeanic acid as a catalyst at 70 to 80C for 6 hours.
0.1 gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 11. The polymer loaded 3,000 mg Au/kg of resin from solutlon.

WO 9S/18159 ~ ~ ~i , PCrIA~94/00793 ~ 1 78803 ~'~

1.5 grams of a polyuLc:L~ le foam in whlch 10 96 by weight of polybutadiene diol was 1 nrl ~ e~l as a raw material during S its manufacture was intt:L~t:neLLaLed with a mixture of 4 grams of 1-vinyl~m~rlA7ole monomer, 0.25 gram of divinylh~n7~n~ and 20 milligrams of AIBN and then cured for 24 hours at 70C
under a nitrogen a i ~ ~re .
0.1 gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 11. The polymer Loaded 3, 700 mg Au/kg of resin from solution.

l.g grams of a hydrophilic polyurethane foam was ~;ul~L~,Led with 0.8 grams of I - Lllylene diisocyanate dispersed in 1. 5 millilitres of toluene and containing 20 20 milligrams of triethylamine and then cured for 5 hours at 60C
under nltrogen. The resultant resin was then further reacted with diethylene triamine at 60~C for 12 hours under nitrogen.
0.1 gram of this polymer was then pulsed for 3 hours in 25 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of 11. The polymer loaded 4, 000 mg Au/kg of resin from solution.

25 grams of a 4800 MW glycerine-based poly(ethylene oxide)-poly(propylene oxide) polyol was slowly reacted with a mixture consisting of 15 grams of the same E0-P0 polyol, 10 grams of l-vinyl 1m~lA7Ol~ and 0.25 grams of AIBN to produce 35 a polymer polyol.

WO95/18159 - - -; 2 1 788~3 PCT/AU9S/00793 - 25 ~
A polyurethane foam was produced as follow6:
a mixture consisting of 18. 7 grams of the polymer polyol containing the polymerised vinyl im~ ol~, 5 grams of a S 4800 MW glycerine-based E0-P0 polyol, 0. 4 grams of water, 0 . 2 grams of a silane-based surfactant and 0 . l grams of ,. L~--nu~ octoate was reacted to produce a polyurethane foam by rapidly stirring this mixture for lO seconds with 5 grams of toluene dlisocyanate ( IDI ) .
0. l gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of ll . The polymer loaded 2, 400 mg Au/kg of resin from solution.

25 grams of a 4800 MW glycerine-based poly( ethylene oxide ) -poly( propylene oxide ) polyol was slowly reacted wlth 20 a mixture consisting of 15 grams of the same E0-P0 polyol, lO
grams of [ 3 - ( methacryloyl -amino ) propyl ] trimethylammonium chloride and 0.25 grams of 4,4' azobis(4-~;yt,n~,~æ-lk,roic) acid to produce a polymer polyol.
A polyurethane foam was produced as follows:
a mixture consisting of 18 gram~ of the polymer polyol containlng the [3-(methacrylol~ 'nr~)propyl]~ Lllyl-ammonium chloride polymer, 5 grams of a 5000 MW
glycerine-based E0-P0 polyol, 0 . 72 grams of water, 0. 2 grams of a silane-based ~UL~a~Ldl-L, 2 grams of methylene chloride, 0.03 grams of ~Lc11111uus octoate and 0.13 grams of a 7: 6 mixture of DMEA-DABC0 was reacted to form a polyul-:Ll.a-~: foam by rapidly 6tirring this mixture for lO seconds with 8 . l grams of TDI .

W0 95/18159 ~ . 2 ~ 7 8 ~ 0 3 PCT/AU94/00793 0 . l gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at 2 pH of ll. The polymer loaded 4,200 mg Au/kg of resin from solution.
S
EXAMPLE lO _ _ 25 grams of a 4800 MW glycerine-based poly( ethylene oxide)-poly(propylene oxide) polyol was slowly reacted with a mixture consisting of 15 grams of the same E0-P0 polyol, 20 grams of vinyl acetate and 0 . 25 grams of AT8N to produce a polymer polyol.
A polyurethane foam was produced as follows:
a mixture consisting of 22 . 5 grams of the polymer polyol containing the vinylacetate polymer, 5 grams of a 5000 MW
glycerine-based E0-P0 polyol, 0.72 grams of water, 0.2 grams of a silane-based surfactant, 2 grams of methylene chloride, 0.03 grams of stannous octoate and 0.13 grams of a 7:6 mixture of DMEA-DABC0 was reacted to form a pOlyuLt~ alle foam by rapidly stirring this mixture for lO seconds with 8 . l grams of TDI.
0 . 5 grams of the above resin was reacted with 0 . 3 grams of diethylenetriamine in 25 millilitres of toluene at 70C for 18 hours. The product was washed with toluene and dried under vacuum at 60~C.
0 . l gram of this polymer was then pulsed for 3 hours in 20 millilitres of a 50 ppm solution of potassium gold cyanide at a pH of ll. The polymer loaded 4,700 mg Au/kg of resin from solution.
EXAMPLE l l The polymer loaded with gold cyanlde from Example 7 was ~;ulltà~;Led wlth 20 mlllllltres oi a l molar solutlon of sodlum WO95/18159 , "i~ 2 1 7~803 PCTIAU9~/00793 hydroxide at room ~ e~ u~ ~ for 18 hours. The gold cyanide was eluted from the polymer.
T~XA~PLT~- 12 The guanidine-based polymer loaded with gold cyanide from Example 3 was contacted with 20 millilitres of a 1 molar solution of sodium hydroxide at room temperature for 18 hours.
The gold cyanide was eluted from the polymer.
EXAMPT~T~- 13 The resin in Example 7 was contacted at room temperature with a solution containing 160 ppm of free cyanide ions 15 together with the following metal cyanide I , l~Y~ at a pH
of 10. 5 for 1 hour and 3 hours to give the sorption results below:
Metal Initial Loading, mg metal/kg resin Cyanide Conc. ppm 1 hour 3 hours Au 8 .58 3, 520 3, 500 Ag 2 . 09 340 240 Zn 2. 60 400 800 Ni 2.12 80 180 Co 1 . 51 20 20 Cu 5 . 52 200 240 Fe 5.59 0 0 EX~MPT T 14 The dimethylamine-based resin ln Example 3 was contacted at room temperature wlth a solution contalning 160 ppm of free cyanide ions together with the following metal cyanide W0 95/181~9 ~ t ~ 2 1 7 8 8 a 3 PCTIAU94/00793 l P~PC at a pH of 10. 5 for 1 hour, 3 hours and 24 hours to give the sorption results below:
Metal Initial Loading, mg metal/kg resin

5 Cyanide Conc. ppm 1 hour 3 hour 24 hour Au 8 . 57 6, 040 5, 980 5, 860 Ag 2 . 35 0 0 984 Zn 2.00 0 0 200 Ni 2.32 120 80 140 10Co 1 . 59 40 20 120 Cu 5.58 1,080 960 560 Fe 5 . 41 0 0 440 Styryl gl~nlrl1nP monomer was syn~h~C~c~cl. 1.5 grams of a polyurethane foam in which 10 96 by weight of polyhutadiene diol was ~nrlu~lP~ as a raw material during its manufacture was 20 interpenetrated with a mixture of 4 grams of this monomer, 0.1 gram of divinyl hPn7PnP and 18 milligrams of AI3N and then cured for 24 hours at 70C under a nitrogen al - ~-re.
0.1 gram of this polymer was then pulsed for 3 hours in 25 20 millilitres of a 50 ppm solution of potassium gold cyanide at a p~ of 11. The polymer loaded >5, 000 mg Au/kg of resin from solution.

Claims (27)

CLAIMS:-

1. A gold complex and/or silver complex selective ion exchange resin comprising a polyurethane matrix having an amine functionality.

2. A resin according to claim 1 wherein a second polymer is dispersed or distributed throughout said polyurethane matrix, said second polymer being provided with said amine functionality.

3. An ion exchange resin according to claim 2 wherein said second polymer is a polymer formed from monomers of styrene, acrylonitrile, vinyl chloride, vinylidene chloride, divinyl benzene, butadiene, epichlorohydrin, caprolactone, thiodiglycol, thiodianiline, diallylamine, methylacrylonitrile, hydrazides, dicyclopentadiene, vinyl butyral, succinic anhydride, allyl halides, allyl malonic acid, acryloyl chloride, polyacetal, vinyl alcohol, aminosalicylic acid, dimethylolpropionic acid, .alpha.-methyl styrene, p-methyl styrene, acrylates such as methyl-methacrylate, acrylamide, methylacrylamide, acrylic acid, hydroxyethyl acrylate, hydroxypropyl acrylate, glycidyl methacrylate, ethylene dimethacrylate, methylacrylic acid, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, ethyl acrylate, acrylimido salicylic acid, acrylimido diacetic acid, acrylimido malonic acid, acrylimido phthalic acid, acrylimido glycolic acid, N,N'-methylenebisacrylamide, 1-vinylimidazole, vinylpyridine, styrylguanidine complexes, diallyldimethylammonium chloride, styryl imidazoline complexes, or combinations of these monomers or chemical modifications of these monomers.

4. An ion exchange resin according to claim 3 wherein the chemically modified monomers are selected from styrene, divinylbenzene, chloromethylstyrene, acrylonitrile and acrylates, including methylmethacrylate.

5. An ion exchange resin according to claim 2 wherein said second polymer is selected from polystyrene, styrene-divinyl benzene, styrene-acrylonitrile, styrene-acrylonitrile-methylmethacrylate, acrylonitrile-methylmethacrylate, polyacrylonitrile, polyacrylates, acrylic or methacrylic esters, acrylonitrlle-unsaturated dicarboxylic acid-styrene, vinylidene chloride-acrylonitrile, epoxy(glycidyl methacrylate)-acrylonitrile, poly p-methylstyrene, polyureas, aniline-phenol-formaldehyde, phenol-formaldehyde, styrene-butadiene, styrene-acrylonitrile-butadiene, acrylonitrile-polyethylene glycol, polyamides, polyacrylamides, polyimidazoles, allylglycidyl ether adducts of diamines, ethylene and propylene carbonate adducts of diamines, polybutadiene-acrylates, polydiallylamine, epoxy adducts, p o l y c a p r o l a c t o n e, c a p r o l a c t o n e - a c r y l a t e s, p o l y d i c y c l o p e n t a d i e n e, styrene-methacrylonitrile, methacrylonitrile-divinylbenzene, polyvinyl chloride, glycidyl methacrylate-ethylene dimethacrylate, acrylonitrile-methylacrylic acid, polyvinyl alcohol-acrylonitrile, methyl methacrylate-hydroxyethyl acrylate, hydroxyethyl methacrylate-oligo(ethylene glycol)dimethacrylate, hydroxystyrene-methylmethacrylate, polyethyl acrylate-polystyrene, crosslinked butadiene, polystyrene-polyethyleneimine, polystyrene-arsenazo, epoxy-polystyrene, epoxy-diaza crown ethers, polyacetal, cresol sulphonic acid-phenol-formaldehyde, anthraquinone-formaldehyde, acryloyl chloride-iminodiacetic acid, acryloyl chloride-aminosalicyclic acid, acryloyl chloride-methyl nitrophenol-triethylamine, methyl nitrophenol-acetic anhydride-acrylic acid, hydroxy acetophenone-substituted benzoic acid-formaldehyde, or combinations thereof.

6. An ion exchange resin according to claim 3 or claim 5 wherein said second polymer and/or the polyurethane matrix has been chemically modified by chlorination, chloromethylation, carboxylation, amination, phosphorylation, thioureation, diazotization, amidoximation, or oximation in one or more steps to attach ligands to said second polymer.

7. An ion exchange resin according to claim 1 wherein a polyurethane matrix has been provlded with unsaturated sites during its manufacture by incorporation of one or more unsaturated hydroxyl-containing compounds or isocyanate-terminated prepolymers containing these compounds.

8. A polyurethane resin according to claim 7 wherein said unsaturated sites are selected from hydroxyethylacrylate, octene diol, hexene 1,2 diol or polybutadiene diol.

9. An ion exchange resin according to claim 7 wherein the isocyanate-terminated prepolymer is produced from TDI or MDI
and by reaction with hydroxyl-containing polyols according to claim 7 or claim 8.

10. An ion exchange resin according to claim 7 wherein one or more unsaturated monomers is interpenetrated into a cured polyurethane matrix and polymerised.

11. An ion exchange resin according to claim 10 wherein said monomers are selected from vinylpyridine, 1-vinylimidazole, diallyldimethylammonium chloride, [3-(methacryloylamino)-propyl]trimethylammonium chloride, styryl guanidine and/or its complexes, styrylimidazole and/or its complexes.

12. An ion exchange resin according to claim 1 wherein a copolymer polyol is incorporated as a raw material in the manufacture of said polyurethane matrix, said copolymer polyol being produced by the grafting polymerisation of unsaturated monomers onto poly(ethylene oxide) or poly(propylene oxide) or mixed polyethylene oxide/poly(propylene oxide) containing polyols.

13. An ion exchange resin according to claim 12 wherein said monomers are selected from styrene, divinylbenzene, acrylonitrile, acrylates, vinyl acetate, styryl guanidines, styryl imidazoles, vinylpyridine, 1-vinylimidazole and [3-(methacryloylamino)propyl]-trimethylammonium chloride and mixtures thereof.

14. An ion exchange resin according to claim 1 wherein a ligand is incorporated into the polyurethane by reacting a di-or higher functionality isocyanate with hydroxyl and/or amide groups present in a polyurethane polymer.

15. An ion exchange resin according to claim 14 in which amine functionality is introduced into the resin by amination of unreacted isocyanate groups.

16. An ion exchange resin according to claim 1 wherein a diisocyanate is reacted with amide groups and/or hydroxyl groups present in a polyurethane polymer and then ligands are reacted with unreacted isocyanate groups.

17. An ion exchange resin according to claim 1 wherein said amine functionality is selected from alkyl amines, pyridine, quinoline, benzylamine, dibenzylamine, pyrrolidine, diallylamine, amino diacetate and amino phosphonic acids.

18. An ion exchange resin according to claim 1 wherein said amine functionality is a guanidine functional group or guanidine complex.

19. An ion exchange resin according to claim 18 wherein said guanidine functional group is guanidine, 2-ethylhexylguanidine, di-o-tolyl guanidine, di-n-alkyl guanidine, dioctylguanidine, N-(6-aminohexyl)-N'-butyl guanidine complexes, styrylimidazoline complexes.

20. An ion exchange resin according to claim 19 wherein the guanidine functional group or guanidine complex are compounds having the formula:

which formula includes the tautomeric form: in which each of R1, R2, R3, and R4 independently of each other, represent hydrogen, alkyl, alkenyl or aryl (including substituted aryl) with the further possibility that the functional group may be protonated and have a counter ion associated therewith, or compounds containing the functional group wherein R1 through R5 is selected from the group consisting of H, a resin, or aromatic and aliphatic groups containing from 2-25 carbon atoms.

21. An ion exchange resin according to claim 17 which is then methylated or ethylated.

22. An ion exchange resin according to claim 1 wherein an organic extractant is included into said polyurethane matrix.

23. An ion exchange resin according to claim 22 wherein said organic extractant is an amine extractant selected from tributylphosphate, dibutyl butyl phosphate, trioctylamine, tri-(C8-C10) alkyl methyl ammonium chloride, guanidine functionality or imidazoline functionality.

24. An ion exchange resin according to claim 1 wherein particles selected from metal powders, metal alloy particles, inorganic materials, metal oxides or mixtures thereof are added to said resin to modify the density of said resin and/or to assist in recovery of the resin from aqueous solutions or pulps.

25. A process for the extraction of gold and/or silver from solutions including the steps of:
(a) contacting a gold complex and/or silver complex containing solution with a resin as claimed in claim 1;
(b) separating the resin; and (c) recovering the sorbed gold complex by elution of the gold complex from the resin.

26. A process according to claim 25 wherein said-gold and/or silver complex is a cyanide complex.

27. A process according to claim 25 in which the gold-containing solution is part of a pulp or slurry of a Resin-in-Pulp process.