AMMONIATED PEAT
I
I
I
Effect of Varying the Conditions of Ammonia
Treatment on Nitrogen Quality R. 0. E. DAVIS AND WALTER SCHOLL Bureau of Chemistry and Soils, U. S. Department of Agriculture, Washington, D. C.
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N AN EARLIER report (5') on the ammoniation of peat, it was shown that the amount of nitrogen contained in the final product was influenced not only by the character of peat but also by the variables of temperature, pressure, moisture present, and time of treatment. A further study has been made of the principal factors involved with a view to determining the effect on the product of varying the conditions, especially on the availability of the insoluble nitrogen in the ammoniated peat. Data, not yet published] obtained from a number of activity determinations and nitrification and vegetative tests, indicate that much of the insoluble nitrogen in ammoniated peat is of low activity and only slowly available for plant use. Nitrification in soil (S) showed a conversion of the insoluble nitrogen to nitrate a t a rate near that of the original nitrogen in soil and considerably less than the nitrogen contained in cottonseed meal. Because of differences in peat and of the number of factors involved, one type of peat was employed in these experiments, and certain limiting conditions for ammoniation were used in most cases. These conditions involved pressures up to 34 atmospheres, temperatures of 100' to 180' C., and time of treatment up to 24 hours. The water content of the peat used in the experiments was adjusted to the desired amount before ammoniation.
All analyses were made on ammoniated products dried to constant weight in vacuum desiccators over sulfuric acid at room temperature. Raw peat was dried a t 105" C., but the ammoniated products could not be dried a t this temperature, since preliminary experiments showed a loss of nitrogen. The activity of the insoluble nitrogen was determined only by the neutral permanganate test in most cases.
Time of Treatment with Ammonia The effect of time of treating peat with ammonia is shown in Table I for varying ratios of ammonia t o peat, in Table 11 for a constant ratio, and in Figure 1. The reaction of ammonia. with peat continues over a long period with a slow increase in total nitrogen; but after 2 t o 4 hours the changes in watersoluble and active insoluble nitrogen are considerably slower than during the first heating period. There is a slight increase in soluble nitrogen with extended heating period at 130' C., but there is a trend downward in the activity of insoluble nitrogen with the longer heating period.
TABLE I. EFFECTOF TIMEON AMMONIATION OF CAPAC PSAT WITH RATIOS OF AMMONIA TO PEATVARIED^ Aotive
Expt. Series
Apparatus and Method of Ammoniation In most cases the ammoniations were made in steel autoclaves, previously described ( 6 ) ,having capacities of 100 ml. A weighed quantity of peat of desired moisture content was added t o an autoclave. The autoclave was closed, and then the desired amount of liquid ammonia was introduced from an ammonia buret through a valve attached to the autoclave head. The charged autoclave was heated in an air-circulating electric oven for the desired period and then cooled immediately in running tap water. After excess ammonia was allowed to escape from the autoclave, the contents were removed and spread out to allow free ammonia to evaporate. Usually 24 hours were sufficient for the ammonia to escape. Then the product was ground to pass an 80-mesh screen and again aerated. Analyses were made to determine total, soluble, and active insoluble nitrogen according to the A. 0. A. C. methods (1). The time at which the charge attains the required temperature is designated "zero time," which is 165 to 160 minutes for temperatures from 100 to 180' C. During the heating period, the autoclaves remained stationary with no agitation of the charge. A smaller number of ammoniations were carried out in an autoclave of about 2 gallons capacity, provided with an agitator. This autoclave was electrically heated and was provided with a cooling coil for rapidly reducing the temperature. The peat employed in these experiments was a commercial product from Capac, Mich. As received it contained 38.8 cent water which was reduced in storage t o about 28 per cent. his material was ground to pass a 16-mesh sieve and moistened with distilled water to any desired higher moisture content. The dry peat contained 1.8 per cent of original nitrogen.
Ratio Temp. NHs:P&t
c. a
1.571
b
130
0.200
C
130
0.400
d
c
O
100
130
0.866
180
0.200
180
0.400
Time Yield
At?./sg
%
%
%
5.6 6.0
21 25
76 76
34
2
% 103 101
0 2 4 14 24
104 100 97 95 97
5.7 6.1 6.3 6.6 7.1
21 23 29 25 27
74 71 70 61 65
12
0
105 100 97 95 96
5.7 7.0 6.9 7.1 7.6
27 28 30 28 30
79 73 75 62 56
21
2 4 14 24' 0 2 4 14 24
102 98 104 102 102
6.6
26 30 29 30 31
75 67 72 71 70
34
6.9 7.5 7.8
0 2 4 14 24
97 93 93 88 85
6.8 7.2 7.4 7.6 7.4
29 25 25 21 21
67 63 57 55 62
17
HT. 0
0 98 2 92 4 92 14 88 24 88 Autoclave charge density, 0.209 gram raw eat, 40 per oent 6 fiy neutral KM& method.
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So!. N Insol. N in inTotal Calod. (Dry Total Insol. Gage BSsls) N Nb Pressure
TotalN
6.8
7.4 7.9 8.3 8.5 8.6 raw peat
an.
30 61 34 26 59 30 57 25 59 25 55 per ml.; moisture in
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Temperature Previously it was reported (5) that increasing the temperature in ammoniation of peat causes a greater input of nitrogen in the product. The data in Tables I and I1 show this to be true for the particular peat used, but the effect is less marked than in some peats, especially German moss peat. Curves in Fimre 2 were prepared from data inTable I, where the pressure was maintained a t approximately 34 atmospheres (500 pounds) per square inch gage by TIME - HOURS varying the ammonia concentra6 tion. The total nitrogen in the ~ ~ E ~ $ & oT F E ~ ~ ~~~o~~ ~ ~ w ~ H 100 I 20 140 160 180 TEMPERATURE- 'C, product is slowly increased with Treatment a t 130' C. and 34 atmospheres FIGURE2. EFFECTOF TEMPERATURE IN increasing temperature, but this pressure AMMONIATION OF PEAT greater nitrogen input is offset Treabment a t 34 atmospheres pressure for 165 minutes by a decrease in activity of the insoluble nitrogen from a maximum of about 76 per cent. Soluble nitrogen shows a tendency to increase with increase in temperature, although this may be changed by longer periods of treatment. Since the major portion of the nitrogen is in an insoluble form, it would seem advantageous to increase its activity
TABLE11. EFFECTOF TIMEON AMMONIATIONOF CAPACPEAT WITH CONSTANT RATIOOF AMMONIA TO PEAT" Expt. Seriea
Temp.
c.
Ratio NHs:P&
Time
Hr.
Active Total N .Sol. N Insol. N Calcd. in Total In Total Gage N Insol. N Pressure
%
%
%
Atm/ SQ. zn.
-
-TOT!L
~
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-
NITRFFN I
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Autoclave charge density, 0.624 gram raw peat per ml.; moisture in raw peat, 80 per cent.
by employing lower temperatures. Temperatures of 100' C. or lower, however, have the disadvantage of producing material of reduced total nitrogen content. On the other hand, temperatures above 180" C.cause too great a loss in the weight of product and a decrease in the activity of insoluble nitrogen.
TABLE111. EFFECTOF AMMONIACONCENTRATION ON AMMONIATION OF CAPAC PEAT" Expt.
Series
Temp.
The data of Table I11 and curves of Figure 3 indicate the effect of ammonia concentration on the nitrogen in the ammoniated products. While total nitrogen shows some increase with increasing ammonia concentration, the increase is not in direct proportion to concentration, so that high ammonia concentration would seem to be unnecessary. Moreover, soluble nitrogen is increased little or none at higher concentrations. The results for insoluble nitrogen show slight effect from variations in concentration on the activity determined by the neutral permanganate test but an upward tendency at higher concentrations by the alkaline test
$%&
c.
P
Sol. N in Total N
Neutral Alkaline KMnO4 KMnO4
%
%
%
%
120
0.297 0.933 1.784 2.973
5.3 5.7 5.7 5.6
16 19 23 17
79 79 77 77
47 47 51 4s
b
130
0.297 0.761 1.784 3.000
5.6 5.3 5.8 5.5
25 15 23 23
72 80 75 7s
49 51 54 55
C
140
0.340 0.933 1.784 2.973
5.7 6.0 6.1 6.1
20 l8 18
77 75 76 78
45 47 48 48
0.194 0.394 0,867 1.600
6.8 7.6 8.1 8.6
29 32 32 32
67 63 78 71
d
a
NHs:P&t
Active Insol. N in Total Insol. N
a
@
Ammonia Concentration
Ratio
Total N
180
16
Treatment a t zero time: 40 per oent moisture in peat.
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FEBRUARY, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
Effect of Water Content on Ammoniation The data of Table IV show variations in ammoniated products with different moisture contents from 10 to 40 per cent in the original peat. Over this range there is little effect on the total nitrogen fixed. Apparent increases in soluble nitrogen are obtained around 35 to 40 per cent moisture, but this may be partially due to the greater concentration of TABLE xv. INFLUENCE OF wATER ON A~~~~~~~~~~ PEAT" Moisture in peat
%
Q
Ratio p&t
pressure Atm./sq. in.
0.145 35 10 lo 0.219 20 28 0.228 20 0.509 35 40 20 28 0.388 40 0.867 35 20 1.000 50 25 1.000 29 1.000 47 45 35 1,000 41 39 1,000 38 Experiments carried out at 130'
OF
the basis of the output weight of the dried product divided by the charged weight of dry peat. In general, the data show that there is a small increasing loss with increasing time of ammoniation, and that some increase in loss is to be expected a t higher temperatures. No well-defined relation is shown between loss in weight and ammonia concentration, or other factors involved.
CApAC
Ac$;;af~;;f;,.I$in Total N 7 (Dry Sol. N in Neutral Alkaline ~ ~ Total ~ Ni K ~ ~ I ) ~ KOM ~~ O ~
%
%
4.9 8 6.0 6.0 l6 15 5.7 l8 5.7 27 6.1 23 6.0 25 6.0 5.5 25 21 5.9 5.8 26 17 C. and sera time.
% 72 75 81 78 79 76 74 74 75 75 79
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%
.. .. ..
.... ..
54 50 50 51 48
Aeration Effect on Ammoniated Peat Table VI gives data from several experiments in which the conditions of ammoniation were the same except with varying moisture in the peat. A ratio of 1 was employed for ammonia to dry peat; the heating was carried out a t 130' C. Each batch was cooled to 45" C. and subjected to partial vacuum to remove excess ammonia; then it was aerated. Products 529 and 525C were aerated 24 hours, when the moisture content was reduced to about 34 per cent. Additional aeration for 120 hours reduced the moisture t o about 10 per cent in the products, which are represented in samples 532 and 533, respectively. Analyses showed a loss of nitrogen, accompanying extended aeration, which was due principally to reduction in soluble nitrogen. This would indicate volatilization of ammonium compounds and low-boiling amines known (4) to be present in ammoniated peat. Sample 525, aerated to 11.6 per cent moisture, contained 39 per cent soluble nitrogen; the corresponding material, 533, aerated t o 10.7 per cent moisture, contained only 19 per cent soluble nitrogen. The difference in treatment consisted only in aerating sample 525 a short time after it was partly dried under partial vacuum with heat, whereas 533 was aerated from the wet stage over a long period. This would in-
ammonia where the pressure was kept constant. The indications are that moisture alone over this range has little effect on either the amount of nitrogen fixed or the activity of the insoluble nitrogen in the product. A high moisture content of 80 per cent, which occurs in wet peat, exerts a repressive influence on the amount of total nitrogen. The nitrogen fixed under these conditions (Table 11) is lowered by 1 to 2 per cent in comparison with that obtained in the products from treating peat conTABLEVI. EFFECTOF AERATIONON ACTIVE NITROGENIN AMMONIATED CAPACPEAT^ taining 10 to 40 per cent water. The percentage of water-soluble nitrogen when 80 per cent water Aotive Insol. N In Sol. Total Insol. N is present is about doubled, but the activity of W.ater Water Total N N in the insoluble nitrogen is apparently not influenced Pt; Pr;;uct );;)AI l$T ? Rem arks by this high moisture content. % % % % % % H r .
--
p;26: gk:; 2;;-
529
60
33.6
7.2
27
83
52
24
. . .... . ..
Autoclave Charge Density 532 60 10.0 6.4 19 78 44 144 529 aerated 5250 80 34.2 6.4 30 81 53 24 . . . . . . . .. Clark, Gaddy, and Rist sh0wed that the auto526 533 80 11.6 5.3 10.7 6,3 39 19 80 7o 47 45 144 24 525c aerated 525C & clave charge density (2) has an appreciable effect aerated on the conversion obtained in the synthesis of 525Ab 80 10.2 4.8 52 69 43 144 Superphosphate added urea. since peat contains Ammoniations were carried out at 130° C.for 135 minutes with a ratio "a: peat 1. a Wet roduot 528,78per oent water; after ammoniation neutralized with auperphoaghate and alr-&ed. urea (4),a few experiments were performed with different charge densities in the ammoniation of peat; the data are shown in Table V. The density a t which the autoclave is loaded in peat ammoniadicate that loss of nitrogen is not entirely due to volatile comtion does not change the resulting amount of nitrogen fixed pounds. The decrease in active nitrogen with extended or of soluble nitrogen to any appreciable extent, but a slightly aeration suggests a change in composition of some of the lower value is obtained for active insoluble nitrogen at the insoluble nitrogen compounds. higher densities. Nitrification Tests I Experiments on nitrification of several samples of ammoniOF AUTOCLAVE CHARGE DENSITY UPON ated peat in soil were carried out as a possible indication of TABLE V. EFFECT AMMONIATION OF CAPACPEAT^ their fertilizer value. It is recognized that this is only an Active Insol. indicator, but it is true that nitrogen compounds converted Charge sol. N in N in Total Density Yield Total N Inaol to nitrate are readily usable by plants. The tests thus G./mZ. % % % % serve as a means of giving positive evidence of value and as a 0 233 104 5.7 21 74 comparison in this regard with other known fertilizer ma0 467 106 5.6 25 67 0 588 99 5.4 21 69 terials. Data obtained from these tests are shown graphia 130' C.: zero time: 40 per cent moisture in peat; ratio "*:peat callyin ~i~~~~4. The results are with cottonseed (dry), 0.194. c meal, blood, ammonium sulfate, and raw peat. Though all the results were not obtained in the same series of experiments] the conditions were so similar that general comparison LOSSi n Weight during Ammoniation can be made. Data on loss in weight of peat under treatment with amCurves 1, 2, and 3 show results obtained on three samples monia are included in Table I. Yields were calculated on of ammoniated peat treated under the same conditionsI
INDUSTRIAL AND ENGINEERING CHEMISTRY
188
peat with 28 to 40 per cent water, heated to 130' C. with ammonia sufficient to produce 34 atmospheres pressure. The nitrogen is converted during the first 2 weeks t o nitrate in approximately the same amount as that from cottonseed meal, During the next 6 weeks the nitrate from ammoniated peat remains fairly constant, whereas with cottonseed meal there is a continuing increase up to 4 weeks and a somewhat slower rate conversion to the end of 8 weeks. Comparisons at the end of 8 weeks show that the nitrate conversion for ammoniated peat is 55 per cent of cottonseed meal, 45 per cent of blood, and 29 per cent of ammonium sulfate values. Comparison of results represented by curve 1 for previous tests (3) with the product from ammoniation at 180" C. (curve 4) shows conversion to nitrate of the 130" C. product about double that for the 180" C. product.
'
3' 4 l8D'C,
28% ' 4Hours. 40% '
60 50
z
8 40 8 t
*
30
3
2 Y
20 IO
o
1
2
3
4 5 WEEKS
TABLE
VII. POT TESTSWITH CARROTS, USING AMMONIATED CAPACPEATAND OTHERNITROGEN CARRIERS~ Dry Weight
Dry Weight
of Tops
RelaFertilizer Grams tive Fertilizer P-K 7.4 100 (NH4)aSOa Ammoniated peat 513 11.1 150 Ammoniated peat 524 Ammoniated peat 520 12 1 164 Cottonseed meal Urea 12.8 175 NaNOs dmmoniated peat 511 13.3 180 Values calculated to fifteen plants where fewer ,survived.
of Tops
Grams 13.4 14.5 14.5 14.6
Relative 181 196 196 197
Summary of Results
w
3
samples gave almost identical yields with those obtained from the tests with sodium nitrate and cottonseed meal, and the other two compared favorably in yields with those from urea and ammonium sulfate. The root development was low in these tests, their green weight amounting in some cases to less than the dry weight of the tops. Similar tests are in progress employing millet as indicator crop.
0.501 0 341
'
(34 Almorphares Prssure)
90
VOL. 31, NO. 2
6
7
8
FIGURE4. NITRIPICATION IN THE SOILOF AMMONIATED PEATAND OTHER NITROGEN CARRIERB The maximum values obtained for conversion to nitrate are 36 per cent in curve 1,32.5 in curve 2 , 2 6 in curve 3, and 17 in curve 4 for ammoniated peats, 45 for cottonseed meal, 56 for blood, and 85 for ammonium sulfate. The highest value for ammoniated peat (curve 1) is 80 per cent of that for cottonseed meal, 65 of blood, and 42 of ammonium sulfate; corresponding values for ammoniated peat with lowest conversion (curve 4) show 38, 30, and 20 per cent of the cottonseed meal, blood, and ammonium sulfate values, respectively. The sample represented by curve 1 gives a favorable comparison with three standard fertilizer materials. In general, the nitrification tests indicate that the nitrogen in ammoniated peat products becomes more readily available with treatment a t decreasing temperature. The highest results for conversion to nitrate were obtained from peats ammoniated a t 130' C., with 30-40 per cent moisture and a n ammonia-dry peat ratio of 1.
Vegetative Tests Results from a series of pot tests employing carrots as indicator crop are given in Table VI1 and Figure 5. These results are preliminary only and can be considered simply as supplementary evidence concerning nitrogen availability in ammoniated peat. Moreover, carrots may not be the most desirable crop for use with ammoniated peat. The peat samples included in these tests were ammoniated under conditions of 130" C. for zero time with an ammonia-peat ratio of 1 and with 40 per cent moisture. One of the ammoniated
In the ammoniation of peat, data were obtained on the influence of a number of factors on the character of the nitrogen in the products, employing one peat material. Total nitrogen in the products varied from 4.6 to 8.6 per cent of dry weight, depending on the conditions of treatment. In 3 to 5 hours of heating a t temperatures from 130" to 180" C., 90 to 95 per cent of maximum nitrogen is obtained with either wet or dry peat. Ammonia concentration and moisture content, with certain limits, appear to exert slight influence. The moisture content of 80 per cent in wet peat lowers the nitrogen fixed by 1 or 2 per cent. Water-soluble nitrogen ranges from 8 to 60 per cent of the total nitrogen. Extended heating periods increase soluble nitrogen a t 130' C. but decrease it a t 180" C. After 4 hours the increase is slow. Ammonia concentration or moisture content have little effect on the amount of soluble nitrogen in the product, except that with 80 per cent water the soluble nitrogen is increased. The activity of insoluble nitrogen in ammoniated peat, as determined by the neutral permanganate method, gives, in general, a value less than the A. 0. A. C. standard for highly active nitrogen and ranging from 55 to 82 per cent. Activity is lowered by longer reaction seriods and higher -temperatures. Higher concentrations of ammonia at 130' C. MMONIATED 'PEAT seem to raise the activity somewhat, as determined by both permanganate t e s t s , b u t more ,$SODIUM NITRATE ' /////////////// markedly by the alkaline test. Autoclave charge density shows no I I I I I I I I definite effect on 2 4 6 8 IO I2 14 DRY WEIGHT - GR the nitrogen fixed. FIGURE5. VEGETATIV~ TESTS Loss of weight WITH AMMONIATEDPEAT AND during ammoniaOTHERNITROGENOUS MATERIALS tion results from high temperatures and long heating periods. Maximum loss of 18 per cent was obtained a t 180' C., but a t 130' C. little loss was observed up to 4 hours of heating. Total conversion of nitrogen to nitrates in soil using am-
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FEBRUARY, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
moniated peats prepared a t 130' C., zero heating time, and 40 per cent water gave the following results: After 2 weeks the nitrate from ammoniated peat equaled that from cottonseed meal, but after 8 weeks it was only 55 and 45 per cent of that from cottonseed meal and blood, respectively. Maximum nitrate from ammoniated peat was 80 and 65 per cent of the maximum values for cottonseed meal and blood, respectively . These results indicate that some of the factors in ammoniation that tend to increase nitrogen content also reduce the activity of insoluble nitrogen, and others tending toward higher activity give lower total nitrogen. Of the products prepared from the peat employed, those having the most desirable properties were treated a t 130" C. from 2 to 4 hours with ammonia-peat ratios from 0.4 to 1.0 and moisture content of the peat from 28 to 40 per cent. The products contained from 5 to 8 per cent nitrogen, of which 18 to 25'per cent was soluble with activities of the insoluble portion from 70 to 78 and from 45 to 52 per cent by the neutral and alkaline permanganate tests, respectively. Nitrification tests on a few of these products gave maximum conversion to nitrate equal to about 80 per cent of that obtained from cottonseed
189
meal. Preliminary pot tests indicated favorable utilization of nitrogen in several of these products.
Acknowledgment The authors gratefully acknowledge the helpful assistance given by B. E. Brown and F. E. Reid of the Bureau of Plant Industry in making pot tests, and to Mrs. E. K. Rist of this laboratory in determining nitrogen on numerous samples and in carrying out tests on the conversion of nitrogen in ammoniated peats to nitrate. Literature Cited (1) Assoc. Official Agr. Chem., Official Methods of Analysis, 4th ed., p. 23 (1935). ENQ.C H ~ M . , (2) Clark, K. G., Gaddy, V. L., and Rist, C. E., IND. 25, 1092 (1933). (3) Davis, R. 0. E., Miller, R. R., and Scholl, W., J. Am. SOC. Agron., 27, 729 (1935). (4)Pinck, L. A., Howard, L. B., and Hilbert, G. E., IND.ENG. CHEM.,27, 440 (1935). (5) Scholl, W., and Davis, R. 0. E., Zbid., 25, 1074 (1983).
RECEIVED September 19, 1938. Presented before the Division of Fertilizer Chemistry at the 96th Meeting of the Amerioan Chemical Sooiety, Milwaukee, Wis., September 5 to 9, 1938.
RECOVERY OF OLIVE OIL BY
Giovanni Stradano (1 53 6-1605)
T h i s , No. 98 in the series of Alchemical and Historical Reproductions, is one of a set of twenty plates engraved about 1600 by the brothers Phillipp, Theodoor, and Joannes Galle of Antwerp, from original paintings by Stradano (van der Straet). We have previously reproduced one of Stradano's paintings as No. 58 in the series, and hope later to locate and reproduce another alchemical painting by him. This set of plates is known as "Nova Reporta" (New Discoveries) and deals with discoveries, inventions, and manufacture, all in the general technical field. We expect later to reproduce another plate from this collection on sugar manufacture at about the same period.
It is through the kind cooperation of Professor E. C. Watson of t h e California Institute of Technology that we are enabled to bring this reproduction of Plate 12 from his set of the "Nova Reporta," which represents the process of olive-oil extraction as practiced about 1570. Those interested in these plates are referred to an illustrated article by Professor Watson in "The American Physics Teacher," February, 1938, pages 25 to 27.
A complcte list of the first 96 reproductions appeared in our January, 1939, issuc, page 124. An additional reproduction appears each month.
D. D. BBROLZHEIMBK 50 East 41st Street New York, N. Y.
