Sodium Metaphosphate 0
1
T
0
in Laundering U
A Modified Application B. H. GILMORE Mellon Institute, Pittsburgh, Penna.
C. J. MUNTERAND E. R. BURNETT Calgon, Inc., Pittsburgh, Penna.
Test Methods -HEX g l a s s y s o d i u m A new method is proposed for applying metaphosphate was first glassy sodium metaphosphate in washThe test sets used were deproposed for laundry use room practice. When metaphosphate is signed to demonstrate in three in 1933 (b), a study of its properdifferent ways the quality of added as an adjuvant with soap and alkali in ties indicated that the most the work produced with regard the soap tank, its usage on all sudsing appropriate place for its introto maintenance of whiteness, soil duction into the standard operations effects substantial savings in removal, and tensile strength multiple-suds washing formula supplies without sacrificing quality. The loss. was the bleach suds. At this results obtained are due partly to the waterpoint in the formula, conditions softening properties of the metaphosphate For the determination of mainof p H value and temperature tenance of whiteness and tensile and partly to detergent properties, which were such as t o facilitate the s t r e n g t h l o s s , t e s t pieces of solvent action of the metaphoshave not been previously apparent. bleached white Pequot sheeting phate in removing deposited lime were taken from the same bolt of soaps from fabrics. Furthercloth. This sheeting had a count of 77.5 warp threads and 68.5 fill threads per inch. Two pieces of more, the carry-over of metaphosphate into the early rinses sheeting-were required for each test s&t, one for the one-wash served to prevent the formation of additional lime soaps in those piece and the other for the twenty-wash piece. These pieces were early rinses where their formation is likely. At that time it was so cut from the cloth that the warp threads of one piece were the also shown that, when metaphosphate was applied in the last or direct continuation of the warp threads of the other piece. This manner of cutting the test pieces was essential if consistent rebleach suds, an improvement in rinsing could be expected, and sults were t o be obtained in the tensile strength tests, since pieces that metaphosphate was harmless to textiles and to colors. cut indiscriminately from the cloth might have tensile strengths The benefits of these properties of metaphosphate have been differing initially by more than the allowable error of the test. obtained in many laundries throughout the country. By taking adjacent pieces, the chances for variation in the tests because of cloth variations were cut to a minimum. Each piece At the time of that investigation the possibility of using of sheeting taken for a test set was 9 inches in the direction of the metaphosphate throughout the sudsing operations of the warp threads and 27 inches in the direction of the fill threads. multiple-suds formula was considered, but the practice did not During washing tests each piece was pinned in a net by two corappear t o be economically feasible. Since then it has been ners so that the sheeting hung 9 inches down in the net; the 27inch length ran across the net in loose folds. With this arrangeobserved frequently in commercial laundries that, by adding ment there was no chance for the piece to be pulled taut in the net glassy sodium metaphosphate to the sudsing operations, or t o be subjected to any strain greater than might be exerted on marked reductions in the amounts of supplies necessary for a piece of cloth loose in the net. At the same time, the cloth good washing followed. I n practice, quality of the work apcould not ball up and fail t o be subjected to washing action. For measuring soil removal, each test set contained two pieces parently was not impaired, b u t such qualitative observations of soiled cloth prepared by the method described by Morgan (4). could not be accepted without definite quantitative data to Pequot sheeting, such as was used for the maintenance of whitesupport them. This investigation was undertaken t o obtain ness test pieces, was also used for this purpose. The two soiled these data, as well as to determine whether or not actual pieces in each set were always taken from the same lot of soiled cloth so that any possible variation from lot to lot would not afeconomies could be shown. fect the test results. The reflectance on each piece of soiled T o obtain the information desired, arrangements were made cloth was obtained before it was washed, a Zeiss Pulfrich photomto carry out the tests in the regular production work of a cometer being used for this determination. The average reflectance of the soiled pieces used in this work before washing was 11.4 mercial laundry. Each formula to be tested was checked for a per cent. In washing tests each piece of soiled cloth was pinned twenty-wash run, and a complete record of the formula was in the net by all four corners; this arrangement kept the cloth kept for that run so that the averages for the various condiopen t o the action of the wash liquor. tions existing during the tests could be obtained and tabuWhen preparing a net of test pieces for a test, the net was lated, as shown in the typical formulas in Table I. I n additurned inside out and the pieces were then pinned to the net. By reversing the net the pieces could be obtained on the inside in the tion, the work produced was examined in the washroom to see proper manner without trouble. Two such nets were used to whether or not i t met the plant’s standards. T o supplement check each formula-one net in each pocket of the machine. these observations, test sets were also washed so that quantiAt the conclusion of the first wash the nets were removed from tative estimates of the quality of the work could be obtained. the wheel and extracted, and the one-wash pieces removed.
W
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INDUSTRIAL AND ENGINEERING CHEMISTRY
VOL. 32, NO. 9
found to vary markedly in appearance; some appeared yellow and others blue. This difference in color made the matching of samples difficult and OperaWater as a result introduced some uncertainty into the Level Titration tion Temp. Time PH Supplies reflectance readings taken without a filter. It Inches Drops F. Min. Gallons was found after some experimentation that conA . Regular Formula sistent results on blued test pieces could be ob1 8.0 0.0 /0.4 6.1 ........ 95 5.6 tained only by employing a blue LIII filter. As a consequence all reflectance measurements reported 5.8 4.4 /6.5 124 2 11.2 11.3 { f&li ; : in this study, both in whiteness and soil removal, 5.5 11.2 141 3 3 . 3 /4.0 Soap 2.15 10.0 4 152 5.7 2 . 5 /4.0 11.1 were made with a n LIII filter. Soap 1.80 9.8 5 159 10.0 5.2 2.0 /3.3 11.1 Soap 1.70 For the determination of soil removal, the reBleach 1 . 5 1.9 /2.9 6 5.2 161 15.2 11.1 flectance of the washed soiled pieces was deter{Soap 1.5 173 10.1 0 . 7 /1.4 4.3 10.8 7 mined with the photometer just as for the white 10.1 0.4 /0.7 8 180 5.0 10.1 pieces, except that four thicknesses were used 9 0.2 /0.5 10.1 182 5.4 9.5 instead of eight. To estimate the washing power 0 . 1 /0.3 10 ........ 5.0 10.1 185 8.8 0 . 05/0. 2 ........ 10.3 129 11 7.8 5.0 of the formula, the ratio of the reflectance of the 12 111 ..... twenty-wash piece to that of the one-wash piece 5.0/10.0 4 . 5 / 1 2 .O 5.1 {E:: 21 . 4 0 2 . after washing was used. This ratio represents a B. Low Metaphosphate Formula measure of the detergent power of the formula after both soiled cloths had been brought to the 4.6 7.9 0 . 0 /0.5 6.1 ........ 1 90 Alkali 2.93 same condition by the first wash. In this way any 11.4 5.4 4 . 8 /7.2 119 2 11.4 {Soap 5.90 variations due to slight differences in cloth prepa10.5 5.0 3.5 /5.3 11.3 Soap 2.1 138 3 ration could not affect the results. 10.1 5.0 2.6 /4.1 11.2 Soap 1.1 4 150 1 0 10.0 4.9 1 . 8 /3.0 11.1 Soap 157 5 For the tensile strength determination the sheets Bleach 1 5 15.3 4.7 1 . 2 /2.1 161 6 examined for the maintenance of whiteness were 1 1 ' 0 {Soap 0.89 175 5.1 10.1 0.5 /1.0 10.5 ........ used. Before they were prepared for testing, a 7 5.2 10.0 0.2 /0.5 180 9.6 ........ 8 thread count was made according to the recom5.3 10.0 0.1 /0.3 9.1 ........ 182 9 mended A. S. T. M. method for woven textile 5.0 10.0 0.05/0.25 8.5 ........ 185 10 fabrics ( 1 ) . Both warps and fills were counted. Sour 1.3 4.4/12.5 ..... 5.6/6.1 181/137 4.4/6.3 11 Blue The cloth was then cut into 4 X 6 inch swatches 6.4 10.3 ..... 5.1 .... 2 . 8 01. 115 12 for the A. S. T. M. grab method of determining C. High Metaphosphate Foirmula the tensile strength of woven textile fabrics (1). The swatches were so cut that warp threads only 7.8 0.0 /0.4 6.4 ........ 5.1 1 81 were tested. At least six swatches could be obAlkali 3.0 11.4 5.5 /7.8 5.3 114 11.5 2 Soap 4.54 tained from each test piece if the 6-inch edge of 5.2 3.7 / 5 . 5 11.4 Soap 1.55 10.2 133 3 the swatches was taken along the 9-inch edge of 11.2 5.1 2.5 /4.0 Soap 1.48 145 4 10.0 the test piece. The 4-inch edges were then taken 5.0 1.7 /2.9 10.1 152 Soap 0.90 11.1 5 Bleach 1 . 5 along the 27-inch edge of the test piece. After 5.0 1.1 / 2 . 2 15.6 11.0 157 6 Soap 0.64 the swatches were cut, they were placed in a con10.4 ........ 9.8 0.4 /1.0 166 5.2 7 ditioning chamber having a humidity of 65 per 10.1 0 . 2 /0.4 9.0 175 5.2 8 1 0 . 1 0 . 1 /0.4 9 . 0 178 5.1 9 cent a t 75" F. for at least 4 hours. When 10.1 0.05/0.3 , ........ 8.5 5.0 180 10 thoroughly conditioned the pieces were pulled in 4.1/5.3 4.3/12.0 ..... 5.2/5.9 178/133 11 a Scott tester t o obtain their tensile strengths. 5.3 10.2 ..... 6.3 ........ 108 12 Before computing the tensile strength loss for a given set of test pieces, the average tensile strength D. Reduced Regular Formula of the twenty-wash piece was corrected for the 5.0 7.9 0.0 /0.3 6.4 ........ 76 1 difference in thread count between the one- and 11.8 6.2 5.4 /7.2 11.3 {g$i 2 101 twenty-wash pieces, so that both would be re3 . 5 /4.9 Soap 1.65 9.9 5.2 11.2 126 3 ported on the same basis. The difference between 2.3 /3.4 11.1 Soap 1.35 10.3 5.2 4 138 the tensile strengths after the correction is the Soar, 1.18 5.2 1.6 / 2 . 5 11.0 146 10.2 5 Bleach 1 . 5 tensile strength loss for the twenty-wash run, and 150 6 15.9 5.2 1.0 /l.9 11.0 {Soap 0.93 the ratio of this loss to the strength of the one0.4 /0.9 10.6 ........ 5.0 10.2 162 7 wash piece will, when multiplied by 100, give the 0.2 /0.6 9.7 ........ 4.9 10.2 167 8 percentage of tensile strength loss. 0.1 /0.4 9.0 ........ 5.0 10.2 169 9 0.05/0.4 8.5 ........ 4.6 10.1 170 10 I n this work 42 X 84 inch Monel metal wheels 5.1/5.2 4.2/12.0 ..... 4.5/5.1 :,$ o a , L69/ 115 with two Dockets were used. The loads washed in 11 5.9 11.7 ..... 5.6 ........ these wheds consisted of netted work covering the 91.4 12 white finished, white rough-dry, and white damp wash classifications. No shirts or starched materials were washed in the tests. The soil content These pieces were ironed and stored in a protected place until the of the clothes was heavy, and the weight washed per load varied between 300 and 325 pounds. run was completed. The remainder of the set underwent nineteen more washes, a total of twenty in all. Between each wash All water supplied to the washroom was zeolite-softened; the the test nets were extracted and the test pieces that had become hardness ranged between 0.06 and 1.7 grains per gallon of calcium rolled up were opened. After the washing the pieces were recarbonate, the average hardness being 0.4grain per gallon. The moved from the wheel, extracted, and ironed. They were then hot water was supplied a t 180" F. The supplies used were proready for the tests. vided in stock solutions, and consisted of break alkali, soap, For the maintenance of whiteness tests the reflectances of the bleach, sour, and blue solutions, all prepared with softened water. sheets were determined with a Zeiss Pulfrich photometer. I n this test the sample was folded so that measurements were made The break solution was prepared by dissolving 44 pounds of upon eight thicknesses of the cloth; this was done to eliminate alkali in water and making the solution volume up to 100 gallons. the effect of the black background of the sample holder. Thus This alkali yielded high pH values in the sudsing operations; variations in the sample thickness could not affect the results. supplementary experiments showed that, when the pH value was Four sets of five readings each were taken on different quarters maintained in the vicinity of 11.0 in the suds, similar results were of the cloth by each operator. All samples were examined by two obtained with other alkalies than the one used in the reported different operators, and some were examined by three. The experiments. The stock soap was prepared by dissolving 110 average of all observers' readings was taken as the reflectance in pounds of chip soap and 22 pounds of alkali in water heated with percentage of barium sulfate white. To obtain the maintenance live steam, and making the volume of solution up to 400 gallons. of whiteness after the reflectances had been secured, the ratio of The chip soap was of 42" titer, containing 88 per cent of anhythe reflectance of the twenty-wash piece to the reflectance of the drous soap, and the alkali was the same as that used for the break one-wash piece was multiplied by 100. The result is the maintesolutions, The stock bleach solution was prepared by diluting nance of whiteness in per cent. concentrated sodium hypochlorite, having 14 per cent available chlorine, with sufficient water to give a solution with a n available Test pieces examined for maintenance of whiteness with white chlorine content of 1.2 per cent. The sour was prepared by dislight (or without a filter) in the Zeiss Pulfrich photometer were
TABLEI. FORMULAS
;.poz,
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{z::
SEPTEMBER, 1940
INDUSTRIAL AND ENGINEERING CHEMISTRY
solving 9 pounds of a proprietary sour in water and making the solution up to 50 gallons. The blue was prepared by adding 1 fluid ounce of a proprietary blue to 1 gallon of water. Each ounce of this stock blue was diluted to 1 gallon for use on the wheel,
Regular Formula As a basis to work from, the regular formula of the plant was checked first. Because of the heaviness of the soil characterizing the white work regularly done, the standard formula in use at this plant (which was taken as the basis of comparison) was approximately 95 minutes long, of which time about 24 minutes were consumed in filling and dumping. The results of the test run indicated that the formula could be modified in the direction of saving time and operations, but only one rinse was eliminated in the subsequent tests. No other change was made, so that changes in supplies and supply dosages made in the subsequent tests would be the only variable factors during a test run. It would then be possible t o determine just what changes in the test results had been produced by the supply changes without the complicating effect of marked changes in formula, which might confuse the interpretation of the results. I n the test run on the regular formula a good suds was maintained in all sudsing operations. A complete record of conditions maintained in each wash was kept, and the average conditions for twenty washes compiled from those records a r e given in Table IA. The temperatures represent those immediately determined on samples taken as the wash wheels were dumped. The times include filling and dumping time, so that the sum of the times given represents the total time of t h e washing procedure. Titrations were made on 25-ml. samples with 1.0 N hydrochloric acid solution. The value above the line represents the number of drops of normal acid required to titrate the sample to the phenolphthalein end point. The number below the line represents the titration to t h e methyl orange end point and includes the phenolphthalein titration. The tenths of drops reported were obtained b y using 0.1 N hydrochloric acid when 1 drop of the stronger acid would have carried the titration past the indicator change. Each drop of normal acid required for the size of sample used represents 100 p. p. m. of alkalinity as calcium carbonate. The zeolite-softened water titration was 0.0/0.2 throughout this work. I n the case of the sour and blue operation, under temperature, time, and water level, the values above the line represent the level while the sour was in the wheel alone. After approximately 5 minutes of souring, the water level was raised t o 12 inches and the blue added. The wheel was then allowed to run for an additional 5 minutes for bluing. The values under the lines represent conditions as the wheel was dumped. The quantity of supplies used on the average for a wash with the regular formula is given in Table 11. With these supplies, work of a satisfactory quality was produced, according to observations in the plant. During the twentywash run no increase in the number of wash-overs was noticed. T h a t the work was of good quality is indicated by the maintenance of whiteness and soil removal given in Table 111. Tensile strength loss for this formula (11.9 per cent) was close to the average for all formulas (10.9 per cent).
1235
number of preliminary experiments were made in the washroom by adding metaphosphate to the suds before the soap and alkali were introduced. It was found in one trial that b y adding 1.5 ounces of metaphosphate by weight to the first suds, 0.35 ounce each to the second and third suds, and 0.2 ounce each to the fourth and B t h suds, the stock soap consumption dropped from 14.8 to 10.5 gallons on a typical load. By doubling these dosages the stock consumption dropped t o 7.7 gallons per load. These experiments indicated that a reduction in soap stock consumption would follow from the addition of metaphosphate to the suds, but they did not indicate whether the quality of work would be satisfactory. Such a marked reduction in the amount of soap stock used per load might easily have affected adversely the quality of work produced. This, however, could be ascertained only by a trial covering a number of washes.
Low Metaphosphate Formula A series of twenty experimental washes was therefore performed in which 9 pounds of metaphosphate were added to the 400-gallon tank of soap solution built according to the regular formula. This solution was applied so as to maintain the same type of suds that prevailed during the regular formula. The washing formula deviated from the regular formula only in that one rinse was eliminated before souring, and as a consequence souring was conducted a t a somewhat higher temperature. A cold water rinse followed the souring and bluing to make i t possible to handle the clothes. The same rinsing procedure was followed in the subsequent experimental washing formulas. The average conditions prevailing during this series of washes are presented in Table IB. The quantity of supplies used is given in Table 11. By the addition of 0.248 pound of metaphosphate per load, a saving of about 5 per cent in alkali and about 24 per cent in soap was made. With this reduction in supplies the quality appeared to be satisfactory in the plant, but the results on the test pieces given in Table I11 show that it would have been affected adversely over a period of time. The maintenance of whiteness dropped from 98.2 per cent for the regular formula t o 94.2 per cent for this experimental formula; the soil removal dropped from a ratio of 1.61 to 1.39. Superficially it might be concluded that the reduction in the quantity of soap solution used had lowered the washing power of the formula to such an extent that the whiteness of the work was impaired. That is what would be expected with a marked drop in soap consumption. However, the possibility also existed that insufficient metaphosphate had been
TABLE11. AVERAGESUPPLIESCONSUMEDPER LOADIN FOUR FORNULAS Formula Alkali, lb. Soap, lb. Rletaphosphate, lb. Bleach, gal., Sour, lb. Blue, o z .
Regular 2.014 3.955
...
1.5 0.1s 2.4
THE
Low High hfetaMetaReduced phosphate Regular phosphate 1.895 3.025 0.248 1.5 0.23 2.8
1,820 2.500 0.456 1.5 0.23 2 6
1.941 3.105
...
1.5 0.26 2.8
TABLE111. RESCLTS ON TESTPIECES
Experimental Formulas I n order to determine approximately what could be expected t o occur when glassy sodium metaphosphate (“Calgon”) was used in the sudsing .operations of the formula, a
Formula Regular Low metaphosphate Highmetaphosphate Reduced regular
hlaintenance of Whiteness Reflectance, “A Bas01 1 20 Per wash washes cent 83.1 85.7 86.4 87.4
81.6 80.7 84 1 82.9
98.2 94.2 97.4 94.7
Soil Removal BaSOc
Tensile Strength Loss 1 wash, 20 washes, Loss, ~
1 wash
washes
Ratio, Rm/Ri
43.8 53.7 49.6 51.1
70.4 74.4 79.4 77.7
1.61 1.39 1.60 1.52
20
lb.
lb.
5%
63.2 67.1 63.6 61.2
55 7 59 5 56.6 55 4
11.9 11.3 11.0 9.5
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INDUSTRIAL AND ENGINEERING CHEMISTRY
used t o allow the soap and alkali to function to the best advantage.
High Metaphosphate Formula To ascertain whether the fall in whiteness was related to the concentration of metaphosphate employed in the soap solution, a n additional series of twenty washes was performed, in which 20 pounds of metaphosphate were added to each 400 gallons of soap and alkali. This stock soap was added to the wheel to maintain a good running suds, and the average results of the twenty-wash series are summarized in Table IC. Table I1 shows that b y increasing the metaphosphate dosage in this manner, a still further reduction in soap and alkali consumption was made. By using 0.456 pound of metaphosphate per load, a saving of 9 per cent in alkali and 37 per cent in soap was made as compared to the regular formula. Compared t o the low metaphosphate formula by an increase in the metaphosphate used by over 1.8 times, a saving of 4 per cent in alkali and 17 per cent in soap was effected. Here again the quality as judged in the plant appeared to be good. The test data in Table I11 show that the plant conclusions were correct in this case. The maintenance of whiteness was elevated from the low value of the previous formula t o a point almost equivalent to t h a t obtained by the regular formula. At the same time the soil-removing power was increased t o t h a t of the regular formula; thus there was no danger of a fall in quality from inadequate washing with this higher metaphosphate dosage. These results show plainly that with the proper dosage of metaphosphate a definite reduction in supply requirements could be made without reducing whiteness to a significant extent.
Reduced Regular Formula There remains the question as to whether similar reductions in the quantity of supplies used for the regular formula, without any other changes, might not also give equally good work with a saving in supplies. This was checked by a test on the regular formula in which a light suds was maintained in the wheels instead of a good running suds. The conditions maintained during this run are given in Table ID. The supplies consumed in this test are given in Table 11. A reduction in alkali of 3.6 per cent and in soap of 21.5 per cent in comparison to the regular formula was made. With this reduction there was no indication of poorer quality, in so far as the plant operators were able to observe. However, the data in Table I11 show t h a t the maintenance of whiteness dropped t o a marked degree, as did the washing power. Over a period of time this formula would bring about a harmful reduction in the quality of the laundry work, even though savings could be effected with it. It has been shown that good quality work can be produced with soap and alkali if proper quantities are used. If the amounts of supplies are insufficient, retention of whiteness falls off. Although this may not be immediately apparent in the plant, the test results show that the change will become obvious in time, so that a choice must be made between economy and work quality.
Function of Metaphosphate The experimental results indicate that metaphosphate may be used to considerable advantage by introducing it into the soap tank in building the soap. This practice enables a considerable economy in washing supplies, b u t the metaphosphate dosage must be correct; otherwise the whiteness of the finished work would suffer. The necessity for the proper metaphosphate dosage may be partially explained by simple calculations. Approximately 500 gallons of zeolitesoftened
VOL. 32, NO. 9
water are required per load for saturating the clothes and putting on the sudsing operations u p to and including the bleach suds. For the complete softening of this volume of water, with an average hardness of 0.4 grain per gallon a t a pH between 10 and 11, about 6.6 ounces of metaphosphate by weight would be required. I n the low metaphosphate formula only 3.97 ounces were introduced during sudsing. As a result of only partial softening, some of the soap must have been consumed in precipitating the residual hardness of the zeolite-softened water and was therefore not available for washing purposes. The whiteness might be expected t o suffer, as was observed. I n the high metaphosphate formula about 7.3 ounces of metaphosphate were used per load, which is slightly more than is required to soften the water used in sudsing. Attention has already been called to the improved results obtained with this formula, and i t is believed that they are related to the degree of softening produced by the proper metaphosphate concentration. The best method of ensuring the proper dosage of metaphosphate in the wheel is to base the amount of metaphosphate added on the amount of soap, since it is essential to get enough soap in the wheel to wash even with most completely softened water. On this basis, for a water of 0.4 grain per gallon hardness, 1 pound of metaphosphate would be needed for every 6 pounds of soap. However, it is desirable to provide a n excess of metaphosphate in order to allow for variations in water hardness rather than set the dosage too close to average softening requirements. The proportions used in 0.4-grain-per-gallon water in the high metaphosphate formula seem to provide the desirable results-namely, 1 pound of metaphosphate for every 5.5 pounds of soap. These proportions should neither be affected by the concentration of soap stock nor be influenced by the nature of the alkaline builder, so long as it yields a sufficiently high p H value. If water hardness increases or decreases, the metaphosphate poundage should be raised or lowered, respectively, in proportion to t h e hardness change.
Detergent Properties of Metaphosphate Although it is necessary to provide sufficient metaphosphate to remove completely the residual hardness of zeolite-softened water in order to maintain proper whiteness, this softening action alone is inadequate to explain the economies effected by this usage. For example, on a basis of the chemical equivalents involved, metaphosphate, considered only from the standpoint of water softening, can save no more soap than &Is amount equal to its own weight. Thus a maximum saving of 7.3 ounces or 0.45 pound of soap might be expected on t h e high metaphosphate formula. Instead, the saving amounts to 1.45 pounds (3.95 - 2.50 pounds). This is three times the theoretical savings. Obviously metaphosphate must contribute more to the washing process than its water-softening power; this further evidence suggests t h a t metaphosphate possesses some detergent properties. Other evidence in this direction has been accumulated. For example, it is a n excellent dispersing agent for clays and proteins. Some emulsifying action has been demonstrated by its effectiveness in cleaning greasy fabrics (2). I t s surface-active properties have been pointed out in other fields (3). More recently metaphosphate has been introduced into the manufacture of toilet soaps in Germany where it replaces as much as 5 per cent of fat (6). Altogether it seems not unreasonable t@ attribute some of the effects obtained in this study to detergent properties of the metaphosphate.
Relative Economies of Experimental Formulas With respect to the possible saving obtained b y these formulas, the greatest saving resulted with the reduced regu-
SEPTEMBER, 1940
INDUSTRIAL AND ENGINEERING CHEMISTRY
lar formula. Table I1 shows the extent of these savings, which on the basis of current market prices amount to about 7.4 cents per load. As pointed out, a choice between savings and work quality must be made here, if such savings are to be realized. With the high metaphosphate formula sufficient supplies were saved to reduce the cost per load by 4.7 cents over and above the cost of the metaphosphate without any deleterious effects on work quality.
Acknowledgment Acknowledgment is made of the cooperation of John A.
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Fullerton who made the facilities of the United Laundries of Pittsburgh available for this study.
Literature Cited (1) Am. SOC.Testing Materials, Standards, Part 11, Non-Metallic
Materials, pp. 1224-8 (1933).
(2) Gilmore, B. H., Starchroom Laundry
J.,40, 24 (1933). (3) Hatch, G. B., and Rice, Owen, IND. ENQ.CHEM., 31, 51-7 (1939). (4) Morgan, 0. M., Can. J . Research, 6, 292-305 (1932). (5) Seiden, R., IND. ENQ.CHEM.,News Ed., 15 496-7 (1937). PRESENTED before the Division of Industrial and Engineering Chemistry a t the 99th Meeting of the American Chemical society, Cincinnati, Ohio.
Vitamin Content of Distillers’ C. S. BORUFF AND A. F. LANGLYKKE Hiram Walker & Sons, Inc., Peoria, Ill.
By-Products d
SIMON BLACK University of Wisconsin, Madison, Wis.
In this process for the complete recovery of distillers’ residues, a feed product is prepared which is composed of the insoluble portion removed on screens, a second insoluble fraction removed by centrifuges, and a sirup or soluble fraction recovered by evaporating the effluent thin slops. The composite distillers’ grains and the fractions of which it is composed were commercially dried and assayed by chick methods. The composite feed contains only small amounts of vitamins A and D, but 13.3 to 15 micrograms of riboflavin and 1.0 to 1.3 I. U. of vitamin B1 per gram, as well as sufficient chick antidermatitis factor to protect chicks at a feeding level of 30 to 40 per cent. The dried centrifuge sludge which is composed mainly of yeast solids, as well as the dried screenings, is relatively poor in water-soluble vitamins. The dried sirup contains 26 to 40 micrograms of flavin per gram, 2.0 to 3.0 I. U . of vitamin B1 per gram, and chick antidermatitis factor sufficient to protect at feeding levels of 10 to 20 per cent. This product is also a good source of factor W.
D
R I E D distillers’ grains have long been considered with favor as an ingredient in dairy feeds (11). This is particularly true of Corn Distillers’ Dried Grainsi. e., the product recovered from distillations in which corn is the predominant grain mashed. The type and quantity of protein, fat, and, probably to some extent, the vitamin content of these grains have played their parts in making these grains a favored constituent in dairy feeds. Quantitative
data on the vitamin content of these grains have only recently become available in the publication of D’Ercole et al. (7). The old type distillers’ grains, as described by Morrison ( I I ) , were composed only of the suspended grain solids t h a t could be recovered by screening the spent mash (stillage) discharged from the stills. The finely suspended solids and solubles were run to waste or fed in the liquid form to hogs and cattle. This old type of distillers’ grains, which is a t present recognized in the trade as Light Distillers’ Grains, is referred to in this manuscript as Dried Screenings. The large and modern distillery now recovers the fine suspended solids and solubles t h a t pass the screens, concentrates this material in multiple-effect evaporators, mixes the sirup so produced with the wet screenings, and then dries the combined materials in rotary dryers. This newer type of distillers dried grains is referred to commercially as Dark Distillers’ Grains or Distillers’ Dried Grains Containing Solubles. If all of the solubles are recovered and dried with the screenings, the final product will be composed of about equal quantities of each by weight on a dry basis. A variation in the standard method of complete recovery of distillers’ stillage as developed and patented by Hiram Walker & Sons, Inc., and described by Boruff and Miller (4) and Cooley (6), permits the removal of suspended grain fines, coagulated proteins, dead yeast cells, etc., from the screened stillage by the use of centrifuges. The centrifuge cake when dried is referred to as Dried centrifuge Sludge. The use of this process also permits the production of a sirup in the multiple-effect evaporators which is free of coarse material and concentrated in water-soluble grain fractions, as well as the watersoluble vitamins derived from the yeast and grain used in the fermentation process. This sirup can be dried on drum dryers to give what is referred to in this manuscript as Dried Distillers’ Solubles We also have available a solvent extraction plant through which may be passed part of the distillers’ by-products for removal and separate sale of the corn oil found in these grains (6). The Oil-Extracted Corn Distillers’ Dried Grains Containing Solubles have the same water-soluble nutrients as did the original dried grains from which they were produced. The protein level is enhanced by such treatment. For some time the research department of Hiram Walker & Sons, Inc., has considered the possibility of the use of distillers’ by-products in feeds other than dairy feeds, espe-
