. THE 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
j80
conductivity method by a titration in which bridge readings were made simultaneously with E. M. F . readings. The results appear in t h e curves of Fig. 111, which show satisfactory agreement in t h e abscissae. SUMMARY
Vol. 6 . No. 7
vegetable ammoniates in commercial fertilizers is a subject of considerable interest a n d importance t o chemists who have charge of analytical work in connection with t h e enforcement of s t a t e fertilizer laws. T h e alkaline and neutral permanganate methods f o r organic nitrogen activity are now quite generally employed in many control laboratories. When properly interpreted t h e y are capable of making reliable differentiations between high a n d low grade organic ammoniates as regards their activity or availability as nitrogenous plant food. For several years past t h e writers have taken an active interest in these problems both as regards laboratory methods a n d their control by pot experiments. I n connection with these lines of investigation we have endeavored t o secure some satisfactory method for separating quickly t h e organic nitrogenous portion of commercial fertilizers from t h e mineral nitrogen, acid phosphate a n d potash salts. Several procedures have been tried b u t with indifferent success. T h e scheme about t o be described was perfected last year a n d employed as extensively as time permitted on many commercial fertilizer a n d crude nitrogenous stock samples.
With t h e aid of t h e hydrogen electrode a n indicator method for t h e preparation of tri-ammonium citrate has been developed.. T h e H + concentration given b y solutions of this salt of 1.09 specific gravity is shown t o be IO-'.^. This concentration is obtained in t h e preparation of t h e citrate by t h e use of a n easily prepared color standard, made by mixing HC1 a n d NaaHPOl solution. T h e results of a simultaneous determination of t h e “neutral point” with t h e electrode a n d conductivity methods are shown graphically, a n d t h e r e ’ a r e given results of several trials of the formula suggestcd. xom-It seems very likely t h a t t h e difficulties of t h e fertilizer chemist in determining available phosp h a t e are not due entirely t o lack of uniformity in t h e ammonium citrate solution used. I t may be impossible t o distinguish sharply between “reverted” a n d “available” phosphate by means of neutral ammonium citrate solution. For example, i t might be found t h a t available phosphate is barely dissolved by a citrate solution METHOD having a hydrogen ion concentration of IO-^: while Prepare the sample by drying from I O O t o 600 reverted phosphate is not greatly affected until a grams of t h e material, preferably unground, a t a hydrogen ion concentration of IO-^ is reached. Obviously t h e best solution for extraction would, in t h a t temperature of not over 170’ F. Cool a n d weigh. case, be one whose hydrogen ion concentration is T h e amount taken depends on t h e nature of t h e material IO-^, and remaiizs so duving the extractioiz. A solution a n d on t h e quantity of t h e organic portion desired. Nearly fill a suitable beaker with carbon tetrachloride whose hydrogen ion concentration varied between a n d a d d t h e sample in 2 5 t o 50 gram portions. Stir IO-^ a n d IO-^ would dissolve uncertain amounts of available phosphate. Furthermore, as mentioned in a n d allow t o settle. Skim off t h e portion t h a t floats t h e above paper, solutions of t h e normal ammonium . a n d throw on t o a dry filter. A t i n tablespoon is very citrate have a hydrogen ion concentration most sub- serviceable for this purpose. Continue this procedure ject t o variation, while solutions containing a n excess until t h e entire sample has been t h u s treated, using of acid or base would be changed much less by a n altera- more carbon tetrachloride a n d another beaker if necestion in t h e amount of t h a t excess. By reference t o sary. D r y t h e filter containing t h e organic portion t h e paper b y Hildebrand’ i t will be seen (Fig. IV) t h a t in a n air bath. Cool, weigh a n d preserve for microthe same considerations apply t o t h e proposal to use scopical a n d chemical analysis. T h e bulky residue t h a t sinks is transferred t o a z sodium citrate. The hydrogen ion concentration of liter flask, t h e filtrate from t h e organic portion is added, a n acid solution would be far less affected t h a n would t h a t of one nearly neutral by small variations in t h e a n d t h e carbon tetrachloride recovered by distillation a m o u n t of acid present. If a n acid solution will not in, a covered water b a t h . T h e residue remaining in .sharply differentiate available a n d unavailable phos- t h e flask can be removed easily after final drying in phate, then recourse must doubtless be had t o t h e a n air or vacuum b a t h a n d is then cooled, weighed and analyzed if desired. a m m o n i u m salt with a n excess of ammonia. I t has been found advisable in many cases t o screen It may also be found desirable t o maintain a definite t h e sample previous t o t r e a t m e n t , through a I mm. hydrogen concentration during t h e digestion b y means sieve a n d make t h e carbon tetrachloride separation of a suitable indicator, adding ammonia or citric acid on t h e two portions separately. If t h e odor of the as needed t o maintain a definite color. reagent proves offensive a small exhaust fan placed CHEMICAL LABORATORY o n t h e desk near t h e beaker with outlet pipe extending ~ I N I V E R S I T YOP C A L I P O R N I A , B E R K E L E Y outside is recommended, or the separation may be made under a hood. W PROCEDURE FOR SEPARATING ORGANIC AMMOT h e following ‘summary shows the behavior of many NIATES FROM THE MINERAL PORTION OF of t h e materials used in fertilizer manufacture. COMMERCIAL FERTILIZERS2 By C . H . JONESAND G. F. ANDERSON
T h e separation and identification of animal and 1
LOG.c i l .
2 Presented at the 49th Meeting of the .\rnerican Chemical Society, Cincinnati, April 6--10, 1914.
FLOATS O N CARBON TETRACHLORIDE-Dried blood, fish, tankage, hoof meal, horn meal, leather, kanona tankage, morocco clippine, azotin, cottonseed meal, castor meal, castw pomace, beet refuse mmpoand, nitrogenous manure, casein, peat, garbage tankage, tartar pomace. moarah meal, rape meal, soja bean meal, wheat gluten, tobacco stems, fillerine (partly), cinders (rertain types).
.
A S D E SGIA\7E E RI N G C H E M I S T R ISINK^ 1s C A R B O N TsTRAClILoRIDE-Ground bone, nitrate of lime, cyanamid. grape pomace, aluminum nitride, nitrate of soda, sulfate of ammonia. acid phosphate,, rock phosphate, basic slag, dissolved bone black. a n i m a l charcoal, muriate and sulfate of potash. kainit.
Tabie I s h o w s t h e separation as regards t h e organic portions of 1 3 commercial fertilizers a n d z tankages. T h e y have been selected from some 3 j samples as being representative of t h e extremes a n d averages t h u s i:rr found. L -An inspection of t h e table shows large variations in the nitrogen content of t h e mixtures t h a t contribute to furnish t h e organic nitrogen found i n commercial fertilizers. I t varies from 2 . j 4 per cent in No. 1 2 t o 1 1 . 6 5 a n d 1 2 per cent in Nos. 9 a n d 13. The water - in sol u ble ni t r og e n indicates si mil a r ranges . The inorgctnic portions from t h e samples above enumerated h a w been tested as t o their insoluble nitrogen contcn: a n d its activity determined. The activity fount1 coinpares favorably with t h a t shown in Table I in n i l '>ut two cases. I n other words a high activity 'I.
;8
I
N o claim is made t h a t t h e separation is absolute. T h e scheme, however, serve8 t o separate readily t h e major portion of t h e organic nitrogen present, in a m o u n t s sufficiently large t o enable one t o conduct microscopical a n d chemical analyses a n d pot experiments. Numerous other applications suggest themselves, among t h e m being t h e separation of s a n d , dirt a n d mineral salts from organic drugs, feeding stuffs a n d condimental feeds. CLASSIFICATION FOR ORGANIC ~ - I T R O C . E V ACTIVITY AS DETERMINED BY ik,KALINE
PERMANCIVATE
THE
?vfE'CHOD
PORTIOS-FLOATS o s CARBONTETRACHLORIDE
i i i ~ i : I--ORGANXC
T h e aboi-e classification of materials used in t h e manufacture of commercial fertilizers may prove of interest in this connection.
Per cent nitrogen 7 -
EXPERIMENT STATION BURLINGTON, VERMONT
.&ORICULTURAL
-
REMARKS Indicated by visual inspection a n d analysis
,2
F
4.....
7.86 9.48 6.80 9.I 6
3
9 48
l... ?..... s.... .
.
b
Tankage 15. 16.
4.28
4.ii
2.Oi
3.03 1.40 3.02 2 18 0.84 I .4; I .9i 1.26 1.12
5.79 6.45 5.40
6.14 7.30 3.44 3.30
3.96 10.39
69 75 66 68 75 45 61 55
5.93 11.65 5.12 4.70 2.54 12.00 4 50
l.4i
3.23
2:
0.7Y 0.00 1.62
1.75 12.00 2.91
44
7.58 10.24
0.65 0 57
6.93 9.67
73 76
4.00
78 45
74
1('
THE AVAILABILITY OF N I T R O G E N I N K E L P By J O H S A . CPLLEK
Base mix, castor pomace and hoof meal
Tankage, castor pomace Garbage tankage present Dry mix, cinders, tankage Tankage, garbage tankage Dry mix. dried blood, tankage Garbage tankage present Garbage tankage Dry mix, kanona tankage Tobacco stems, castor pomace and tankage
in t!ie separated organic portion as determined by laboratory methods was nearly always accompanied by a similar activity for' t h e water-insoluble nitrogen carried down with t h e mineral portion of t h e sample. I t should be noted t h a t ground bone sinks in t h e reagent employed. The sunk portion, therefore, in the t w o tankages was largely bone. This was indicated not only b y visual inspection b u t by i t s nitrogen content oi 2.32 a n d 2 . 1 7 per cent, respectively, as well as by t h e PnOapresent. .I relatively high water-insoluble nitrogen percentage in t h e mineral portion of a fertilizer t h a t sinks b y this procedure is indicative of bone especially if t h e acti\.ity b y t h e alkaline permanganate method is over 60 per cent. Certain materials other t h a n those listed under t h e column headed "Remarks'! have been noted i n m a n y of t h e samples examined. Their n a t u r e will be further studied when time permits. One in particular is worthy of mention. I t occurs as small black pellets, which crumble easily between t h e fingers. Analysis shows these pellets to contain 3.12 per cent t o t a l nitrogen a n d ' 1.60 per cent water-insoluble nitrogen with a n activity measured b y t h e alkaline permang a n a l e method of 5 1 per cent.
Received April 14, 1914
I n view of t h e widespread interest in kelp as a possible source of American potash, some information as ' t o t h e value a n d nature of t h e nitrogen present becomes a factor of considerable importance. T h e average of a large number of analyses made b y Mr. T. C. Trescott,' of t h e Bureau of Chemistry, shows a n average of approximately 2 . per cent of nitrogen. If i t is proposed t o market dry kelp t h e value of this a m o u n t of nitrogen present is apparent. I n t h e experiments by t h e a u t h o r different methods were followed in order t o determine t h e availability of t h e nitrogen. Briefly t h e y consisted in following t h e official alkaline permanganate method,%a n d later with modifications of t h e same. ,4n a t t e m p t was also made t o secure availability percentages b y using t h e neutral permanganate method b u t this was found impractical because of a bulky residue a n d i t s resistance t o filtration. T a b l e I gives t h e results obtained in .the various experiments. I t will be noticed t h a t b y using t h e official method which provides for a n a m o u n t of t h e sample equivalent t o 5 0 mg. of total nitrogen, t h e availability percentages range from 13.44 per cent in sample number 40 t o 44.So per cent in sample number 19. By pursuing t h e column farther i t will be observed t h a t t h e per cent of availability generally increases with a decrease in t h e a m o u n t of sample used. I n other words i t appears t h a t t h e per cent of availability is inversely proportional t o t h e a m o u n t of sample. Kelp contains on t h e average about 60 per cent organic matter. Assuming t h e average nitrogen cont e n t t o be a b o u t 2 per cent, t h e a m o u n t of sample 1
TIIISJOURNAL, 4, 431; 6 , 28i and i ? 9 ; 6, 19.
2
Report on nitrogen Bull. 162, Bur. of Chem.
