Solvent extraction in analytical geochemistry : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University of Manawatu

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Copyright is owned by the Author of the thesis. Permission is given for

a copy to be downloaded by an individual for the purpose of research and

private study only. The thesis may not be reproduced elsewhere without

the permission of the Author.

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8 0 L V E N T E X T R A C T I 0 N I N

A N A L Y T I C A L G E 0 C H E M I S T R Y

A thes i s

presented in partial fulfilment o f the requirements for the degree o f

Doctor of Phi l o s ophy at

Mas s ey Univers i ty of Manawa tu

Colin Ralph Bo swell

1966

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ACKNOWLEDGEMENTS

The author is indeb t ed to hi s sup ervis or, Dro R,R. Brooks 9 for his guidanc e , advi c e and enthus iasm9 wi t h

out which thi s work c ould never have been undertaken;

n.l s o to the members of hi s supervis ing c ommi ttee ⁹ Dr . C . V . Fife nnd Dr. J . C . Hawke 9 for their valuable a s s i s tanc e and advice .

He is gra teful to Geo l o gical Divi s i on D.S. I . R . for the provi s i on of the many spec imens provided by them;

Profes sor A.T . Wil s on, Vi c toria Univers i ty of Wellington for the samples of Antarctic lake wa ters and to Chemi s try Divi s i on , D.S. I.R. for the . loan of their 120-tub e Cra i g c ountercurrent s olvent extra c t i on appara tus .

The author would a l s o l ike to thank hi s wife for her enc oura gement and pat i enc e during the c ours e of thi s s tudy .

"No man i s an Iland9 intire of i t s elfe "

(

Donne � 1623

)

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ABSTRACT

A procedure c onbining s o lvent extrac ti on enrich

oent techniQues and spectrographic analys is wa s developed for the QUanti tative deteroina tion of nany trace elenents in a wide range of s ilicate rocks and in ^a s eries of hi ghly saline Antarc t i c lake wat ers .

Since a great deal of the work depended on s pec

trographi c ana lys i s 9 an inves t i gation wa s carried out t o improve the precis ion and sens i t ivi ty o f exis ting methods .

An inproved me thod for the det ermina t i on of spec tral line intens ities wa s developedq Thi s was ba s ed on the author's nodifica t i on of the partial S e idel func t i on , referred to as B-func tions. A convers i on table for the s e is given . A s cale cal ibrat ed in B-funct i ons wa s inco rpora ted into a Hilger micropho tome t er enabl ing euch values to be obtained direc tly wi thout the us e of c onvers i on tabl e s . B-va lue s can b e plotted directly o n to the linear ordina t e of s emi

l o g paper if the s elf-cal ibra t i on nethod is us ed for eval

uo.t:Lng line intens i t ies. Thi s result s in a s tra ightening of the characteristic curve with an a t tendant t ine saving and o.n improvement in the accuracy of the ba ckground ex

t rapo lation . A nomographic t echniQUe wa s a l s o developed for use in conjur�c t i on with this scale and resul ted in a rapid evaluation of line intens i ti e s but with s ome l o s s in prec i s i on.

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Cathode exc i tation as dist inct from ca thode

layer was c ompared with anode exc i ta t i on under the same

c ondi t ions. Da ta on 33 elements were used t o study rela t ive self-absorp t i on Dffects , absolute s ens i t ivi t i es , volatil

isat i on curves , times for complete c ombustion9 and ba ckground effects . Data on

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elements and 3 5 l ine pa irs were used to s tudy reproduc ib i l i t i es in the three ma tri c es, NaCl , CaCl2 and carbon . I t was shown that ca thode exc i ta t i on i n a

carbon ma trix afforded the grea t est pre c is i on for a number of the more vo latile elements. Anode exc i ta t i on provided generally better pre c is i on if a NaCl ma trix was used.

CaCl2 was a very unsat isfa c tory rn.a trix . li1or the more vola ti le elements ca thode exc i ta t i on provided ^a higher sens i t ivity than anode exc i ta ti on but with increased back

ground and cyanogen emiss i on .

The extra c t i on of the elements Au, Zn , Cd, Hg,

Ga� In, Tl, Sn, Pb , As , Sb and Bi from hydrochlori c a c i d into the three solvents cyclohexanone 9 cyclohexanol and

cycl ohexane was studied as a· func t i on of a c i d concentra tion.

Cyclohexanone is a more effic i ent, but less selective extrac t�nt , than cyclohexanol, Cyclohexane has l i t tle extrac t ing power for these elements.

Solvent extra c t i on of hydr ochl o r i c a c i d sol

uti ons of a ser i es of hi ghly sal ine Antarc t i c lake wa t ers int o cyclohexanone was used. to enrich the elements Zn, Pb, In1 Bi, Fe , Mn , Mo prior to spectrographi c ana lys is . For

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thi s , the perc ent extra c t i on of F e � rJn and Mo into cyclo-

hexanone from 3N hydrochloric acid wa s obta ined . Thi s

inves tigation has shown tha t one of the s e lakes 9 Lake Bonney 9 ha s mos t probably had ^a s ea w�ter origin o It i s also

po s s ible that another of the s e lakes9 Lake Fryxel l 9 may a l s o have conta ined s ea wa t er i n the pa st . From the rela t iv e abundanc e o f the vari ous elements in the o ther lakes , i t wa s possible t o c onduct a geochemical rec onna i s sance of the areas surrounding the lake s . Thi s sugges t ed trillt the two mo s t likely areas for minera l i sa t i on in the McMurdo Oas i s area of Antarctica are the regi on surrounding and feeding wa t er to Lake Hoare and the regi on surrounding Lake Joyc e o

A c ons idera t i on of the theory of di s c ontinuous c ount ercurr ent l i quid-liquid extra c t i on ha s shown that i t is pos s ible to s imultaneous ly determine the extra c ti on chara cteri s t i c s of a large number of element s for a given s olvent system o If thi s t echni que is c oupl ed with spec tro- graphic analys is the determina t i on is particulnrly rapi d o The extra c t i on of the elements Ti , V, er , _�Jn, Fe , Co , Ni 9 Zn9 Ga , As, Nb, M o 9 Ru, Rh, Pd , Ag, Cd, In, Sn, Sb , La , vv , Re, Os , Ir , Pt , Au, Hg 9 Tl , Pb and Bi from hydrochloric a c id into me thyl is obutyl ket one wa s s tudi ed a s a functi on o f a c id conc entra t i on . The da ta were obta ined b y s tudy- ing spectrographically the distributi on pa t terns of the elements after equi libra t i on on a di s c ontinuous c ount ercurrent l i quid-liquid extrac t i on appara tus . A c ompari s on

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of s ome of the da ta s o obta ined with results for the same sys t em as reported by other workers showed that the tech

nique is val id and ac curat e .

Us ing thes e da ta i t was pos s ible to devi s e a s cheme vvhich c ould s epara te Fe from the ma j or i ty of the

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trace elements extrac ted by cyclohexanone from a hydrochloric a c i d solut i on of a rocko By a c ombina t i on of ba tch extra c t

i on with cyclohexanone and c ountercurr ent di s tr ibut i on w i th methyl is obutyl ketone i t was possible t o ob tain quanti ta tive da ta for Zn and Ga and s emiquant i tative da ta for In in a

wide range of s i licate rocks by spec trochemi cal analys i s . By the us e of extra c t i on int o cyclohexanone c oupl ed w i th a t omic abs orpti on spectrome try i t wa s p o s s ible to det ermine the c onc entra t i on of Pb, Cd and Bi in the same sui t e of r ocks .

By the us e of thes e �echni ques i t wa s pos s ibl e t o obtain fresh abundance da ta for the above elements in the four s tandard r ocks , G-1J W-1 9 C�\S syeni t e and C�\S

sulphj_de .

The cyclohexanone

/

hydrochloric a c i d extra c t i on sys tem provides a sa ti sfa c t ory enrichment t echni que for the spectrographi c analys i s of trace elements in ma terial wi th a low Fe c ontent . For ma t er ial c onta ining a high

c oncentra t i on o f Fe.9 i t is neces sary to combine thi s tech

ni que with di s c ont inuous c ount ercurrent l i quid-liquid

extra c t i on t o s eparat e the_Fe b efore spectrographi c ana lys i s .

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However � Qnder these c ondi ti ons? c erta in elements can be de termined by direct a t omic abs orpt i on spectrometry o f the cyclohexanone extrac to

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PART IV

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Introduc t i on 61

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Development and applica t i on of a

quanti ta tive proc edure. 66

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Re sults and D i s cus s i on . 77 The Devel opment of D i s continuous Count er-

current Extrac t ion for Inorganic Sys t0ms .

89

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Introduc t ion

89

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PART V

(b )

(c )

(d ) (e )

The us e of di s c ontinuous c ountercurrent l i Quid-liQU�d extra c t i on for det er

mining the extra c t i on of the elements Cu, li.g� J�.u9 Zn9 Cd9 Hg, Ca 9 In, Tl, Sn, Pb 9 As , Sb , Bi 9 Ru9 Pd9 Ir and Pt from

3N

hydrochloric acid int o cyclohexanone A s tudy of the extra c t i on of certa in elements in the methyl i s obutyl ket one/

hydrochloric acid sys tem using

dis c ontinuous c ountercurrent l i Quid

l i Quid extra c t i on . Results and Discus s i on

Inves ti ga t i ons int o the us e of dis

continuous c ountercurrent extra c t i on for the s epara t i on of Fe .

The Det ermina t i on of Bismuth9 Cadmium9 Gallium, Lead and Z inc in Silicate Rocks .

PART VI

(a ) Tho development of QUant i ta tive proc edure s.

(b ) Results and Discus s i on . Conclus i ons and Cri t i cal Evalua t i on REFERENCES

96

99 101

107

112

1 26

13 7

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Solvent extraction in analytical geochemistry : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University of Manawatu

Copyright is owned by the Author of the thesis. Permission is given for

ACKNOWLEDGEMENTS

CONTENTS

PART IV

PART VI