T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
78
Vol.
12,
No. r
TABLEI-EXTENT
OF Loss IN VOLUMETRIC METHOD,USING FILTER TABLE 11-RESULTS B Y THE VOLUMETRIC ASBESTOSGOOCHMETHOD. WITH USUALCHARGE AND WITH SMALLCHARGE (l/s) PAPER;AMOUNTOF IRONOCCLUDED B Y GRAVIMETRIC VOLUMETRIC METHOD Grav. Calc. Det. Charge Calcium SAMPLE No. Gram Gram Per cent Per cent Bone Ash 7 0.0750 0.02897 38.627 .... a-
--.
.cI av
E i o
8 3
d
, M 2 : $ - - - - - - -
c)
SAMPLE
n
Bone Ash 1 1454
d
6
VOLUMETRIC Calcium Gram Percent
0.25 0.1348 0.09634 0.0962 38.484 0.25 0.1352 0.09662 0.0961 38.440 0.25 0.1346 0.09619 0.0959 38.340 0.25 . . . . . . . . . 0.0961 38.440
1440
5 6
7
S$
T &”
r’
20.0 20.0 20.0
ab.
....
38.426
11 12 13 14 15
38.534 0.050
-
-__
AVERAGB 0.095 0.103 0.008 1 The precipitates had an iron oxide color. * The Gooch filter, not filter paper, was used in this reprecipitation.
b y representative results in Table I. The lower result obtained by t h e use of filter paper is probably due t o t h e loss of a small quantity of t h e p r e c i p i t a t e enmeshed in its fibers. Placing t h e filter paper in t h e hot sulfuric acid when almost at t h e end-point in titration is not feasible when t h e quantity of calcium oxalate is small. This interferes with t h e definiteness of the end-point. Therefore i t is proposed t o use non-reducing ignited asbestos in place of t h e filter paper in a Gooch crucible, as shown in Table 11. The results then closely check t h e gravimetric procedure, BY THE
0.02908 0.02908 0,02897
0.3500 0.3500 0.3500 0.3500 0.3500
0.13512 0.13512 0.13527 0.13504 0.13516
Charge Grams
CaO Gram
Gram
Swine Feces1 1530
16 17 18
4.9474 5.0150 4.8630
0.0302 0.0310 0.0300
0.0216 0,0222 0.0214
..........
4.6357 3.9106 3.5862
0.0198 0.0168 0.0156
0.0142 0.0120 0.0112
AVERAGE 1532
22 23 24
AVERAGE
Swine Urine2 1549
28 29 30
cc.
.
0.0126 0.0126 0.0123
200 200 200
0.0092 0.0094 0.0092
0,0066 0.0067 0.0066
AVERAGE 1552
34 35 36
AVERAGE 1 Feces ashed in both methods.
2
0.0063 0.0063 0.0062 0.0063 0.0033 0.0034 0.0033 0.0033
38.688 38.616
+o. 12 +0.05
WITH THE
’
--
GRAVIMETRIC PROCEDURE VOLUMETRIC
Charge Grams
Calcium Gram Per cent
19 20 21
4.4124 4.6182 4.3290
0.0178 0.0185 0.0177
AVBRAGE 25 26 27
5.2118 4.9386 4.2078
0,0152 0.0145 0.0124
AVERAGE 31 32 33
100 cc.
0.0118 0.0119 0.0119
AVERAGE 37 38 39
0.403 0.400 0.408 0.404 0.291 0.293 0.295 0.293
G . per
cc. 200 200 200
200 200 200
0.0062 0.0062 0.0059
AVERAGE Aqua regia digestion used in both methods, followed by ashing.
t h e difference being 0.05 per cent higher, or a n error of 0.13 per cent. For small quantities of calcium oxalate t h e difference is slightly greater, as shown in Table 11. The volumetric results on bone ash (Table I) are one- t o two-tenths of a per cent lower t h a n t h e gravimetric, or a difference of one-third of a per cent. This percentage in samples containing less calcium would of course be greater. I n the gravimetric method approximately one-tenth gram of CaO was weighed. T h e gravimetric CaO precipitate containing iron oxide, from t h e wheat bran sample, was dissolved in acid, filtered, and t h e calcium reprecipitated and determined volumetrically, using the asbestos Gooch pad for filtering off t h e calcium oxalate which was transferred with the pad t o t h e sulfuric acid and titrated
......
-0.14
No.
100 cc.
0.0176 0.0176 0.0172
Diff. bet. Vol. and Grav. Methods
38.553 38,426
Det.
G Der
200 200 200
38.565
with potassium permanganate withthe following results: an average of 0.0021 g. iron oxide was present in t h e CaO precipitate. This gave a high result, amounting t o 8.2 per cent. Table I11 gives results on urine and feces, compared with gravimetric results on t h e same samples. T h e volumetric results are taken from our daily records. The results on feces of both methods agree within a n average of 0 . 0 2 6 per cent. For urine, t h e modified method checks t h e gravimetric within an average of 0 .2 j mg. calcium per I O O cc.
Calcium Per cent 0.436 0.442 0.441 0.440 0.305 0.307 0.311 0.308
38.688 38.612 38.612 38.649 38.584 38.616
-
38.616
METHOD Gravimetric.. . . . . . . . . . . . . . . . . . . . . . . . . Volumetric with Filter Paper. Volumetric with Gooch Filter small charge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Volumetric with Gooch Filter, usual charge
MODIFIED MCCRUDDEN METHODCOMPARED GRAVIMETRIC
Det.
.... .... .... -
SUMMARY Calcium Per cent
_ . A
SAMPLENo.
38.779 38.779 38.627
AVERAGE
38.565 0.139 0.101 0.006 0.109 0.014 0.009 0.003
0,0750 0.0750 0.0750
AVERAGE
H
0.02821 0,0202 0.01892 0.095 0.0012 0.0306 0.0219 0.0189 0.096 0.0029 0.0276 0.0197 0.0192 0.096 0.0006
TABLE111-RESULTS
8 9 10
gss
. . . . 38.684 0.244 . . . . 38.477 0.137 - . . . . --
2 3 4
AVERAGE Wheat Bran
1454
1-
0.0059 0.0060 0.0060 0.0060 0.0031 0.0031 0.0030 0.0031
Difference Per cent 0.033 0.042 0.033 0.036 0.014 0.014 0.016 0.015
G. 9er 100 cc. 0.0004 0.0003 0.0002 0.0003 0.0002 0.0003 0.0003 0.0002
,
CONCLUSION
The volumetric method of estimating calcium in t h e McCrudden method, substituting t h e treated ignited asbestos Gooch for filter paper, gives a l z o s t identical results with t h e gravimetric procedure. The method is rapid and t h e treated ignited asbestos does not tend t o reduce K M n 0 4 in t h e presence of H&04 ( I : 5) a t 65’ C. The authors wish t o thank Dr. E. B. Forbes who made this work possible. THE EVALUATION OF ALUMINUM DROSS By F. IS.Bezzenberger LYNITELABORATORIBS, THE ALUMINUM CASTINGS COMPANY, CLEVELAND, OHIO Received June 30, 1919
The necessity for t h e recovery of metal from t h e relatively large quantities of skimmings and dross
Jan., 1920
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
which occur in t h e fabrication of aluminum and its alloys has led t o t h e following method for t h e evaluation of this waste material. Besides t h e metals with which aluminum may be alloyed, such as copper, zinc, and iron, this dross contains a high percentage of aluminum oxide, formed b y t h e ready oxidation of t h e molten metal, and also t o a large extent b y weathering, t h e degree of t h e latter varying with t h e size of particles and t h e conditions t o which they are subjected. The solubility of this finely divided oxide in all solvents commonly used for t h e preparation of alloys for analysis necessitated finding some reagent which will enable t h e quantitative separation of t h e metal from i t , preferably by taking t h e latter into solution t o facilitate its final determination. For t h e purpose of testing various reagents which seemed promising, pure aluminum oxide made by t h e ignition of t h e washed hydroxide was used. This material was found t o be insoluble t o a detectable degree in boiling water, b u t soluble t o a prohibitive degree in acids and alkalies of a strength suitable for the solution of t h e metal. The well-known activity of t h e free halogens with aluminum led t o t h e trial of a saturated water solution of bromine for t h e purpose, which proved satisfactory, inasmuch as it attacks metallic aluminum vigorously, b u t does not dissolve t h e oxide t o a detectable degree. This insolubility of t h e oxide in bromine water, conrtrasted with its solubility in dilute acids, is explained iby t h e low degree of hydrolysis of bromine in saturated solution, the constant a t 2 5 ' being 2.4 X IO-*,^ which is equivalent t o 0.013 per cent hydrobromic acid. On 'the basis of these qualitative results, a procedure f o r analyzing aluminum waste was outlined, as follows: I-Weigh out a representative (0.8 to 1.3 g.) sample of the mixture to be analyzed. 1
I
Bray, J . Am. Chem. Soc., 32 (1910), 932.
79
2-Treat with saturated water solution of bromine and add a few drops of free bromine as long as the reaction continues, which depends upon the amount and nature of the sampIe. 3-If the red color 01 bromine remains after stirring, the reaction is complete. Drive off free Brz, digest on a hot plate until color changes to brown, filter, and wash. 4-Precipitate with NH40H, wash by decantation three times, filter, and wash with I per cent NH40H. Ignite and weigh as usual in this determination.' ,
This gives total aluminum, iron, and adsorbed impurity of copper as oxides. T h e latter was found in some cases t o be as high as 2 per cent. To correct for this, proceed as follows: I-Treat the oxides in the crucible in a beaker with sulfuric acid, 5 to I O cc. acid to IOO cc. solution. This dissolves Fez03, CuO, and some & 0 3 . a-Electrolie for copper. 3-Reduce the iron by passing the solution through a Jones reductor and titrate with permanganate. 4-Calculate CuO and Fe as FezOs, and subtract from the total oxides. 5-This gives AlzOa. Calculate as aluminum.
Following this procedure, a number of synthetic samples consisting of metallic aluminum and aluminum oxide in amount from zero t o 45 per cent, of t h e sample, were analyzed. The results are given in t h e following table: W t . of Sample 0.6160 0.5642 0.4104 0.3063 0.5791 0.3538 0.4098
Percent A1208 0 0 5 7 18 30 45
A120 in Sample 0 0 0.0231 0.0230 0.1038 0.1013 0.1847
Aluminurn in Sample 0.6160 0.5642 0.3873 0.2833 0.4753 0.2525 0.2251
Aluminum Found 0.6177 0.5633 0.3880 0.2830 0.4768 0.2517 0.2257
Error Based on Aluminum Per cent f0.27 -0.16 + O . 18 -0.11 f0.32 -0.32 f0.29
The results indicate t h a t t h e method is entirely satisfactory for t h e purpose and it has been adopted and used in our laboratories. 1
Bureau of Standards, Bulletin 286.
ADDRESSES AND CONTRIBUTED ARTICLES THE VALUE OF COST ACCOUNTING I N COMMERCIAL LABORATORIES1
By William W. Caswell TREASURER, ARTHURD. LITTLE, INC.,CAMBRIDGE, MASS.
I truly appreciate the honor of being invited to present this paper before you to-day, and it is with diffidence that I approach the subject of cost accounting as applied to chemical laboratories, but I have found the knowledge of costs of the greatest value in every line of business with which I have been connected, and not by any means the least in a commercial laboratory. &Tot so very long ago cost accounting was practically unknown, and in the business where it was not employed it was considered a frill and just so much red tape; in fact it was looked upon by the executive of the average corporation as one of the black arts, and most executives had as much knowledge of cost accounting as they had of quadratic equations. The men of sound business principles, however, and those forced by com1 Presented before the 58th Meeting of the American Chemical Society, Philadelphia, Pa., September 4, 1919.
petition or through the nature of their business to make only a small margin of profit on a large output, soon realized the danger of treading an unknown way without a light to guide them. The haphazard methods of guess-work as to what is manufacturing cost may be all very well for a concern making only one article and that of the simplest variety, but take, for instance, the manufacture of automobiles with all the different parts both made and purchased, and the man who attempted to run such a business without a n adequate knowledge of the costs would commit financial suicide. We all look upon the government supervision of our incomes, both individual and corporate, as a necessary evil, but in reality it has not been a n unmitigated evil, for this supervision which has been brought about by control of prices and the collection of taxes has taught a great many of us not only the value of keeping accurate accounts, but also the necessity of knowing exactly what our costs are in order to arrive with some degree of definiteness a t our profits. Government statistics show that out of over 250,000 corporations in the United States less than half are making money and that only about 5 per cent have any accurate idea of what their costs are. This is a sad showing,
