Determination of Bismuth in Tungsten Ores Application of a Colorimetric Method f o r Determining Bismuth in Biological Materials C. L. SOLLENBERGER A N D JANIS SMITH1 Research Laboratories, Allis-Chalmers Manufacturing Co., Milwaukee, Wis. BISMUTH mineral, which occurred as a secondary value in a Korean scheelite ore from a contact metamorphic deposit, was slated for recovery in a recent ore-testing investigation conducted by the Process Laboratory. A fast, accurate chemical method for small amounts of bismuth was required to expedite the work. I t was believed that a colorimetric method using an electrophotometer for color comparison would be most mtisfactory. A method for determining bismuth in biologcal materials ( 9 ) was successfully adapted to the determination of small amounts of bismuth in this ore. The procedure has also been successfully applied to seven different scheelite and wolframite concentrates, containing small quantities of bismuth, supplied by Ledoux and Co., New York, N. Y.
A
Table 1.
a
b
Gravimetric and Colorimetric Determination of Bismuth
Head sample Flotation tail Flotation tail Scheelite concentrate Sulfide float Sulfide float Bismuth concentrate Basic chloride method. Bismuth oxide method.
Gravimetric, 0.213a 0.068'' 0.052a
Colorimetric, % 0.208 0.040 0.036
0.4614 6.62b 6 . lob 61.46
0.432 6.50 6.13
SOLUTIONS
All reagents were prepared from chemicals conforming to ACS specifications. Sodium Sulfite. Add 1 gram dissolved in water to 0.8 ml. of concentrated sulfuric acid, and dilute to 200 ml. Make up fresh every day. Potassium Iodide. Dissolve 17 granu in 1 liter of water. Bismuth Standard. Dissolve 1 pram of Dure bismuth metal in 20 ml. of 1 to 1 nitric acid and &lute in volumetric flask to 1 liter. One milliliter then equals 1 m4. of bismuth. Dilute 100 ml. of this solution to 1 liter to obtam a second solution in which 1 ml. equals 0.1 mg. of bismuth. CALIBRATION CURVE
Aliquots of various concentrations should be made up from the latter solution to obtain a calibration curve for the electrophotometer. Standard colors for the calibration curve may be developed by the procedure for ore samples described below.
66.00
SELECTION OF METHOD
'
The original Sproull-Gettler procedure used reagents meaeured to 0.1 ml., and color was developed in 100 ml. of solution. Because the electrophotometer cells used in this laboratory have a capacity of only 23 ml., color was developed in a solution having a final volume of 50 ml Varying the milliliters of reagents to whole numbers did not affect the accuracy of the method.
An investigation of the literature revealed numerous colorimetric methods for determining bismuth in a variety of materials. The cikhonine potassium iodide and the bismuth iodide methods described by Scott ( 1 ) were said to be suitable for analysis of ores, but were found unsuitable for use with the electrophotometer, because a colloidal precipitate formed a few minutes after the addition of specified reagents. The great advantage of the method described here was that the color, once developed, wrts stable for a t least 14 days, and consequently could be used with an electrophot,ometer. Preliminary gravimetric analyses of the head samples showed an average content of 0.2% bismuth. Mineralogical examination revealed that this element occurred in the form of bismuthinite. It was found that the bismuth could be complet.ely extracted by digestion with nitric acid from samples ground to pass 100 mesh; a qualitative test for bismuth in the residue after such a digestion was negative. I n the following procedure, the solution contained bismuth in the form of the subnitrate and when diluted to appropriate concentration was ready for color development. The method was finally adapted from that described by Sproull and Gettler (9). The Lambert-Beer law was valid up to concentrations of 2.00 mg. of bismuth per 100 ml. of solution. In the bismuth nitrate solution obtained from the ores tested, interfering ions were within the tolerances indicated by Sproull and Gettler (2). Ore samples containing excessive amounts of interfering elements could undoubtedly be subject,ed to the necessary separations for their removal prior to color development (1). 1 Present address, hletallurgy and Control Division, Hanford Works. Richland, Wash.
All color measurements in this laboratory were made in a Fisher AC model electrophotometer. The per cent color absorption was read directly from a built-in logarithmic scale. The calibration curve was plotted for concentrations up to 0.7 mg. of bismuth per 50-ml. aliquot and was found to be a straight line. The No. 425B filter was used. Wiegand, Lann, and Kalich (3) have shown that the light absorption of the yellow iodobismuthite solution is at its maximum at 4600 A. Although the No. 425B filter had ita maximum transmittance in the 4250 A. spectral region, it proved entirely satisfactory. PROCEDURE
Digest 1 ram of pulverized sample in 20 ml. of 1 to 1 nitric acid a t low %eat for 1.5 to 2 hours or until fuming ceases. For samples of higher concentrations than 1% bismuth, use more acid and a longer digesting time. For samples containing oxy compounds of bismuth, a more vigorous digestion may be required. The use of bromine, hydrochloric acid, or sulfuric acid during the digestion was not necessary with the Korean ore, but when these reagents were used in the quantities recommended by Scott ( I ) , no interference was obtained. Bismuth is extracted as bismuth nitrate. Filter into a 100-ml. volumetric flask and dilute to the mark with distilled water. For ore samples assaying less than 0.5% bismuth, use a 10-ml.
Table 11. Bismuth in Tungsten Concentrates Modified SproullGettler Method,
%
Tungsten Ore Concentrates (Ledoux and C o . ) ,
%
Scheelite 0.58 0.08 0.35 0.02 Wolframite 0.03 0.11 0.18 (8). Analyzed spectrographically. (0). Thiourea colorimetric method after fusing 5 to 10 grams of original material in assay crucibles with necessary fluxes to obtain a lead button weighing 20 grams and containing all the bismuth.
1490
V O L U M E 2 3 , NO. 10, O C T O B E R 1 9 5 1
1491
aliquot of the original 100-ml. volume. If the ore contains a higher percentage, dilute the 10-ml. :diquat to the appropriate concentration rangc and test an aliquot of the diluted solution. Pipet the 10-ml. aliquot of appropriate dilution into a 50-nil. volumetric flask. .kid from buret 7 nil. of sodium sulfite solution :tnd 8 ml. of potassium iodide solution, and dilute to the mark. Mix xell. The color develops inimediately and is stable for sevcral days. Sample4 ma> I x read in the elcctrophotometer nt once uqing a 42,513 filter.
LITERATURE CITED
PRACTICAL APPLICATION
This procedure
MR
quired to obtain 811 aliquot of bismuth concentration in the range for color that accuracy was impaired. The proceduie was checked using seven tungsten ore concentrates that had been analyzed by Ledous and Co. by other methods (Table 11). It can be concluded that this method is applicable for the determination of bismuth in tungsten ores.
used for ore products varying from 0.03 to
60% bismuth. Excellent material balances were consistently obtained when the products from ore beneficiation all contained IPPS than 10% bismuth. JJ-hen higher grade bismuth concentixtes n-cre produced, hon-evw, such great dilutions were re-
(1) Scott. IV. W..“Standard Methods of Chemical Analvsis.” Voi. ’ 1, PP. 15O-61,Kew York, D. Van Sostrand Co., 1939:
( 2 ) Sproull, R. C., and Gettler, A. O., IND. ENG.CHEM.,ANAL.ED.,
13,462 (1941). ( 8 ) IT-iegand,C. J. JV,,Lann, G. H., and Kalich. F. V., Ibid., 13, 912 (1941). R~~~~~E D l I a r c h 6,10:0.
New Color Reaction for Detection of the Methyl Ketone Group JIRO ADACHI Chemical Laboratorj; T o k y o Bunrika Cniaersity, Tokyo, Japan l 0 I i the detection of the CH3CO- or CH$CH(OH)- groups Lieben’s iodoform reaction ( 7 ) has been widely used. This reaction, however, which relies upon smell, often give?;m i Iiguous rcsulte, TThich are attributed to the anesthetic action of the iodoforni formed upon the olfactory nerve. The color renc-
’ (d),
HOCHz-CHz-CH2
tiori proposed hj- Lustgarten or Klar ( 7 ) , which develops :I red coloration when the Lieben’s mixture-a methyl ketone and potassium hypoiodite solution-is heated with the addition of resorh o l , seems to be a disagreeable procedure. Fujin-am ( S ) ti,e:ited a guinea pia with chloroform, hy inhaln-
CH.&OO-CHz-CHr-CH,
p
c
1
H
/“‘CH,
/
’0‘
I,,, ‘0
.4cetylation
A _ T I
Egonol ( 6 ) .
\
HOCH -CHz-CH2 Reimer Tiemann reaction CH3COOCH2-CHz-CH
Saponify Styraxinolic aldehyde
acid CH1COOCHzCHzCHz
HOCHZ-CHI-CH~
Styraxinolic
acid
Figure 1.
VI
4
Acetic acid ++ Piperonylic acid
Saponify
Acetyl styraxinic acid
Conipounds Containing Neither .\Iethj I Ketone S o r .\leth\ I Carbinol Groups, But Showing Positive locloforni Heactions
