X-RAY FLUORESCENCE ANALYSIS OF THULIUM OXIDE/OXALATE A
Transcript of X-RAY FLUORESCENCE ANALYSIS OF THULIUM OXIDE/OXALATE A
B.A.R.C-1304
30O
X-RAY FLUORESCENCE ANALYSIS OF THULIUM OXIDE/OXALATEFOR RARE EARTH IMPURfTlES
A.r
!.. C. Chandoia and P. P. Kh.innaSpeciroscopy Division
1986
B.A.R.C. - I30K
GOVERNMENT OF INDIAATOMIC ENERGY COMMISSION
UOS<co
X - R A Y FLUORESCENCE ANALYSIS OP T H U L I U M O X I D E / O X A L A T E
FOR RARE E A R T H IMPURITIES
by
L .C . Chandola and P.P. KhannaSpectrosropy Division
BHABHA ATOMIC RESEARCH CENTREROMHAY, INDIA
1986
BARC-1304
INIS Subject Category,: B11.20
Descriptor 8
THULIUM OXIDES
OXALATES
IMPURITIES
RARE EARTHS
X-RAY FLUORESCENE ANALYSIS
QUANTITATIVE CHEMICAL ANALYSIS
BORIC ACID
ACCURACY
.SENSITIVITY
A B S T R A C T
An x-ray fluoraacenoa apactroaatrio Method for tha analyaio
of thulium oxide la described, tor tha analysis, the eample In
oxalate fora la mixed with borlo aold binding material and preaeed
Into a pallet over a eupportlng pallet of borlo aold. A wavelength
dlaperalTe fhillpe PW 1220 X-ray fluorescence apeetroaeter la uaed
for the experlaentai the minium determination llmlta are O.OO25C
for Hof £u and Tf 0.005/^ for Vj and Sr and 0.01^ for Tb. Calcula*
tiona for theoretical minlmua detection llmlta and percent atandard
deviation at each oonotntratlon of the atandard are carried out.
x<4UT ntrosEsoarci UALTSIS or THULHW antx/ounatJOB RABE BAMH IMPURITIES
by
£.0 . Chaadola and P.P. JQM&aa
I . IRBGDOOXIOV
Pura thullua (Xa) la l lkaly to oontaia Df, Re, Mr, l a , La and I
aa laBurltlaa l a I t . laara ara no aarlier raporta oonoandac Z>ray
fluoraaoaaoa (ZHf) analyata at Ta. Hcwarar, thara la ona optloal
aalaaloa •paotrographlt (OBS) oathod daralopad by Xnlaaly at a l '
for tha aaalyala of thullua oxld« to dataralna Ho, Kr, Tb, £u aid T
la tha ooaoaatratloB ranga 0.02-1^. Wa aanra m ooatlauimf profraaaa
of daraloplac aanaltlra XB9 aathoda for tha analyala of al«*
parity rara aartha ( H a ) . la oontlauatlon of thla pragraaaja aa
XBf aathod aaa aaaa daralopad for tha aaalyal nt thullua oxlda.
tha aathod bala( raportad la aora aanaltlva than tha aarllar raportad
CSS aathod. flia alalaua dataralnatloD limit (am) of tha aathod balaf
raportad la 0.002^ for Bo, Lu and T; 0.005^ tat Dy and *r aad 0.01)<
for Yb. OataralaatiOB of ly In thla aatrlx waa aot triad by
aarllar OBS workara and It la bain* raportad hara for tha Xtrat tlaa.
Apart froa battar aanaltlTlty la tha praaant oaaa, th* W aathod
haa an advaatafa orar CE3 mathod that It dlapanaaa wltfe tha ooatly
ooaauaablaa Ilka photographlo pl«t*a, aigb purity alaotrodaa ato.
ZZ.
II. 1 Mataod
Bi« toullua oxlda aaaple la eosTartad to thullua oxalata by
dlaaolutlon In altrlo moid and praolpltatlon with oxallo add. 450 ag
of 417 oxalata powdar la alxad well with 150 ag of boric aold powdar
binding aatarlal. Saa alxtura la praaaad to ton. a i£ lack dlaaatar
doubla layar ptllat orar about 4 ga of borio aold aaoklnc pallat.
Ska aaapla mataoa ia irradiatad with high lataaaitgr X-ra/a fro* a
tuofatan targat X-ray tuba aad tha fluoraaoani X-raya ara aaalyaad
by a Lif(200) exyatal. A < latanoltiaa of cfaaxaotariatie I . I-raya
of Ztf( Ha, Br, Ib aad £u ara seaaurad by a flow proportional ooimtar
whlla that of X X-ray of I la aaaaurad by a selntillatloa oountar.
Staadarda ara praparad aynthatloally by adding know* aawrtta of IX
ozida aolutiaa to thulium oxlda aolutloa aad praolpltatiag thaa aa
oxalataa. Iha baokgrouad iataoal»laa ara aaaaurad on a pura thullua
oxid* pallat at tha 2 ' anglaa of lapurlty alaacnt X-raya and ttiaaa ara
aubtraetad froa tha total oounta to arrira at tha aat oounta* Dia
nat oounta for at^jadarda ara plottad againat thair ooneantratloa to
obtain tha working ourraa for dlffarant alaaanta. tha oonoantratloa
of tha lapurity la a aaapla la obtainad by raadlng tn« T»1U» of nat
oounta fro* tha approprlata working ourra.
II.2 reparation of Standard* and Saaplaa
Bara aarth oxldaa of Iy» Ho, Er, Ybf Xu and T obtalaad froa
Sara Earth Produeta Ltd.* Chaahlra, England, ara dlaaolvad in altrlo
(3)
•Old (tt.H., llerck) an£ three standard eolutloee containing 500y/al,
50 V/al and 5 V/al of each rare earth oxide are prepared. Appropriate
aaounte act a-0* •*• wtigaed out separately sod dlaaolred la nitric
•old to VL&lch til* individual rare earth aolutlona are «dd«d« Bi«
atendarda prapared contalntd blank (no inpuritiae addad), 20,50,100,
200, 500, 1000, 5000 aad 10,000 ppa bjr weigjjt ot each raxa •arth oxlda
in *"2°3' nt«aa ataodard aolutions ar« than pr«cipitat»d aa oxalataa
by • aaturatad solution of oxalic acid. Th* preclpitataa ara filt«rad
and dried. 450 ag of dry oxalate ia mixed with 150 ag of boric acid
binding a»t»rial aid ground in aa agata aortar. SQila alxtura la
pre a«d at a praaaura of 20 tonsva to obtain a doubla layer pallet.
The oxld« aaapla la converted to oxalate aad treated aiailar to
the ataadarda to obtain a li inch dia. pellet.
11.3 Saapla to Binding Material Ratio and Saturation Bilolmeaa
Experlaenta
To ccmaerre the aaouat of »«unpl« needed for the asalyaia,
the double layer technique ia adopts. In order that the sample
doee not peel off from the backing pallet of boric acid, the eaaple
ia nixed with boric acid in the weight ratio 3s1. This ratio of
•ample to binder vraa found to be useful in our earlier worka '
and therefore retained for this analysis also.
(4)
Experiment* were dooe to find out the minimum weight of •ample-
binder mixture (3:1) vfclch will give saturation thickness when can-
Terted to a l i Inch diameter double layer pallet. Double layer
pellets over 4 g borio acid were prepared with 50,100,200,400,600,
1000 and 1500 mg sample-binder mixture of a 800 ppm ntandard*
Intensities of BK elements contained in the standard were measured
for 40 a (for Y-100 a) . The results of these studies are plotted
in Pig.1. From these studies i t was concluded that a 400 mg mixture
gives saturation thickness for the impurity X-rays. However, taking
a safety faotor, the minimum weight of the mixture waa fixed at
600 mg.
A fixed amount (4g) of borio aoid aa backing material 1B uaed la
the preparation of double layer pelleta since the quantity of backing
material contributes to the scattered X-raya for bard K^ l i sa of T.
II .4 Iaatruaent iwd Operate "f Conditions
A aeaiautooHtlo X-ray fluoresoenoe epeotreaeter Ihllipa model
Ft 1220 la use* for the analysis t out of the three crystals i t can
hold at a tine, fee 117(200) was found to ba suitable, tte Unatrument
haa a choice of two oolllmatore (480 *.m and 160MJI) and two deteotors
(flow proportional and sointi l lation). B»e inatrumant haa 4 portholea
for samples eaoh of which can hold a tablet of l i inch diameter. The
aaapla can be kept rotated or stationary and the X-ray path can be
(5)
evacuated If needed* Zhe conditions eelected for the analyst* are
given la Table-!. The wavelengths of selected analytical llnee are
given in Table II. It was possible to uee L A lines for Vy, Ho, Er, Tb
and Lu, «taereas for Y, the Ij line was used. A strip chart record
ot 1% standard is given in fig.2 where the impurity lines of analyte
elements are Marked.
III. HESD1TS
III.1 Workt«w Curves
The working curves relating the concentration of analyte
elenent oxide with net intensity (>L-*b) •*• eh own in figs. 5 sad 4.
The net Intensity is obtained by subtracting the counts obtained
froa a blank (*v) XTOM tot.nl oounts (l ) at 29 angle of each analyte.
A blank reading Is teken after every three readings so that any
variation la intensity with ti»e Is corrected for in the observations.
The average net oounts for different saalyte elements la each
standard are given in Table III.
III.2 Precision
The precision of the aethod was calculated la teras of percent
standard deviation (ss£). Initially the net counts (• - 5b) *re
obtained for 11 sete of reading, from these <rn t i* caloulated by
(6 )
2 4-using the foraula (£d /u-O" rtiere d la individual difference of aetoouat tram the average of a readings, finally SD$6 i s obtained ittiob.
Is equal to (<r .)HOO/(l - I . ) . The precision so calculated for sacknet p b
analyte element at each oonoentratlon of the standard la given ia
Table IT.
III.3 Theoretical Mjnlaun Detection Halts
A concentration which gives a signal equal 1>« three tiaes the
standard deviation of background ia taken as theoretical ainlaw
deteotion limit (TMDL). this i s calculated using the fornila.
1MDL - 3 ( l b ) x oan<j«ntrstton/(l-*b)« O»« ealouUtad
Taluta ara listed la Table V.
ACKHOWLEDQEMBHT3
the authors expreea their ainoera thanka to Dr. 8.1.1.6.
Head, Spectroacopjr DiTieion, for hie keen interest in the work sad
valuable guidanoe. Ifcenka are also due to Shrl B.M. Agrawal and
Dr. B.M. Dixit for help at varloua stages during the oourae of this work.
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RSfEEKIfCES
1. B.B» Khicely, V.A. Faseel, R.W. Tabeling, B.G. Hurd and B.B.Qulney
Determination of rare earth lapuritlea commonly aaaoclated with
purified TB, Yb, Xu and Sc.
Speetrochla. Acta JQ, 300 (1958).
2 . R.M. Dixlt and S.S. Deebpande
Deteradaation of C«f Pr, Nd and Sa in higfc purity laathanua dxld*
by X-ray fluoreac«nc«
Ctaaada inalitycwia 2 i , 1353 (1976).
3 . l . C . Chaadola, I . J . Machado and A.I . Mobil*
Deterattnatlon of rare earth impuri t i ta in cariu* diozida and
oxalate by X-rey fluoreeoenc* ttchnique
J. Radioanal. Gbea. %., 369 (1976).
4. L.C. Chandola and A.N. Mobile
Determination of rare earth impuritiea in praeeodjraluB oxide and
oxalate by X-ray fluorescence tedinique
Current Sc i . 46 , 299 (1977).
5. 1'C. Cbando7a and A.H. Mohile
X-ray fluoreacence spectroie tr io analyaie of neodymiua exlde
and oxalate for trace rare earth iapuritiea
Indian J. Pure & Appl. Ehyeico J 6 , 651 (1978).
6. R.M. Dixit and S.S. Seahpande
X-ray fluoreacence analyaia of Y, Ce, Pr, Sd t Eu and 6d
in high purity samarium oxide.
Treeeniua Z.Anal. Cbea. 29J2, 375 (1978).
- 8 -
7* R.M, Dixit and S.S. Deehpande
X-ray fluorescence determination of Pr, Nd, Sm, Qd» Tb, Jy end T
in high purity europium oxide
fieport BAfiC - 1275 (1985)
8* H.M. Dixit and S.S. Deehpande
X-ray fluorescence determination of Sa, Eu, Tb, Iy, Hot Ib and T
in hlgji purity gadolinium oxide
TreBcniua Z. Anal. Chen. 287.* 132 (1977).
9* l .C . Chandola, I .J . Katfiado and A.If. Uohile
X-ray fluorescence analypl* of terbium oxl4« and oxdate for
rare earth in^urities.
Mikrocbim. Acta (Wieu) I I , 399 (1976$.
10. H.M. Slxit and S.S* Deahpandc
X-ray fluorescence analysis of high purity dyaproaiua oxid«
for Y, Eu, Od, Tb, Ho and Er.
Vraaenius Z. Anal. Chem. OJ, 111 (i960).
11. fi.Jf. Sixlt and S.K. Kapoor
X-ray fluoreacence analysis of higji parity k«lstlu« oxide for
common rare earth iapurlties
£reseniua Z. Anal. Cbeo. 226, 394 (1979).
12. £ .0 . Cbacdola and P.P. Xhanna
X-ray fluoreecenoe spectroatrio analyala of erbiua oxide far
rare earth impuritieo
J. Badioanal. & Hud. Cbea. ^ 1 , 157 (1985).
13« ii.O. Chandola and P.P. KhannaX-ray fluor*se«ncs analysis of yttsrblua oxia«/Qnlat« for
rare earth iapuritita
Haport BXHO - 1176 (1982).
H . L.C. Chandol* and P.P. Xhanna
X-ra/ Xluor*ac«Doa analysis of lutatiua oxid«/onlat« for
rara sartb lapurltias
Rsport BAJRC > 1264 (1985).
1$. B.H. Dirtt and S.S. D*»hpande
As XBf asthod for ths detsrainatlon of ooousao rara sarth
iapuritiaa In hlgi purity yttriia oxida
Trsssnlua 2. inal. Ctasm. 2 ^ , 180 (1977).
- l o -
APPARATtfg Ajff qPKSAtiyQ COMIITIOMS JOB TffE ANALYSIS
1. Spectrometer
2 . Generator
3. X-ray tub*
4- Colllmator
5» X-ray path
6. Detector
7. Pulse Height•election
8. Counting tlae
Philips semiautomatic X~ray fluoreaceooe
Spectrometer P» 1220.
Philips ultrattable generator Ft 1140
Toltage and current regulated to O.OljC
3 kW tunget«a target tube operated
at 60 kV and 39 a*-
Pine (160Mm) for Dy, Ho, Er, Tb aid Lu
Ooarse (48CJU.») for Y.
Vacuum 0.$ tone*
H o w proportional operating on 90$ Ar
+ \O% CH. gaa for eleo«nt» By, Bo,
Scintillation Sal (Xl) type for Y.CH. gaa for eleo«nt» By, Bo, Br, Yb and 1Mi
for VPC; Base 300, Window 350
tor S.C.j Base 200, Window 450.
40s for Dy, Ho, Er, Tb «cd Xu
100B tor Y.
9. Analysiag Crystal Ll?(200). All element a in I order
10. Sample spinner On
-n-
BJUTOB J 0 1
or ram&w axxm
Ho
Ir
Lu
I
(Uf-200)
56.85
54.67
52.7
49.28
47.57
23.62
tawgjk*T
1.90881
1.84500
1.78425
1.67189
1.61951
0.63024
S
6
6
7
7
14
.494
.719
.947
.414
.654
.931
0.005
0.002
0.005
0.01
0.002
0.002
- 1.0
- 1.0
- 1.0
- 1.0
- 1.0
- 1.0
TABU-III
Standard%
1.0
0.5
0.1
0.05
0.02
0.01
0.005
0.002
122,955
62,355
13,822
9,550
4,139
2,046
869
-
MBAI NET
a*
200,919
102,456
36,683
16,507
9,751
4,731
2,348
1,003
COUNTS KB STASBABIS
Ueaa nat counts
Br
203,669
104,53$
35,784
17,940
9,043
4,374
1,988
m
92,066
46,557
15,009
7,349
5,211
1,987
-
Lu
165,312
64,166
28,147
14,324
7,101
3,652
2,099
1,141
r
319,882
161,605
59,786
29,135
15,235
8,027
4,211
2,215
-1 3 --
TABLE-IT
IKHCEHT STANDARD JEVIATIOg
Stand**! J r Ho Sr Tb Lu
1.0
0.$
0.1
0.03
0.02
0.01
0.003
0.002
0.3
0.5
1.5
1.8
4.0
7.5
18.2
-
0.5
0.6
1.0
2.7
3.3
4.4
12.5
20.9
0.4
0.7
2.0
3.4
6.4
13.3
28.1
-
1.5
1.6
3.9
8.7
13.3
26.8
-
-
1.3
1.4
1.3
2.4
4.7
9.4
17.2
31.1
0.4
0.6
1.8
2.5
4.5
8.8
16.1
34.6
9RB0RKTICAL SHBGIIOK LIMIT CALCIIIATICWS
—
*
I *
i r
Tb
X«
r
fat Cavartt*
9,550
16,507
17,940
7,349
14,324
29,135
Blank oauata
17,647
18,026
33,925
65,456
27,785
23,961
132.8
137.2
184.2
255.8
166.7
154.8
398.4
411.6
552.6
767.4
500.1
464.4
ppm
20.9
12.5
15.4
52.2
9.0
8.0
» 500 ppa •Undu4
« Yb
0 50100 200
Er
SAMPLE iBORiC ACID:: 3:1800 ppm STANDARD
400 600—SAMPLE mg -
FIG.I. SATURATION THICKNESS STUDIES ON DOUBLE LAYERPELLET OVER BORIC ACID
-u-
59 55 51 47— T W O THETA DEGREES
FIG.2. STRIP CHART RECORD OF 1%IMPURITIES IN THULIUM OXIDE
8
\0
20 50 100 200 500 1000CONCENTRATION IN ppm — —
FIG.3. WORKING CURVES FOR Dy,Ho ANO Y
5000 10000
io
20 50 100 200 500 1000 5000 10000CONCENTRATION IN p p m — • -
FIG. 4. WORKING CURVES FOR Er, Yb AND Lu
<• • •> v
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