I54
*
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
85 per cent potassium carbonate on t h e market, which in recent quotations was close t o one dollar per pound. Every t o n of fresh material will yield 2 7 pounds of this 90 per cent potassium carbonate. M E T H O D S OF HANDLING-By pressing the chopped stalks in a small cider press i t was found possible t o remove 7 3 per cent of t h e original moisture. This extracted juice was somewhat colored by dissolved organic matter, showed a specific gravity of I . 01 7 a n d contained I per cent potash. Since t h e original stalk contained approximately I per cent potash and 9 2 per cent water, t h e potash extracted b y pressing represents nearly 7 0 per cent of t h e total. Probably t h e most efficient method of recovery, however, is t o char t h e material. There are practically no difficulties encountered in this process. The nature of t h e material is a great aid in its own combustion. When heated, i t begins t o glow like charcoal and under a forced draft will burst into flame a n d support combustion, burning t o a n ash. I n t h e presence of a free supply of air, there is enough heat furnished after t h e first glow begins t o complete t h e charring without t h e further application of heat. This property can be made use of by placing t h e chopped raw material over a grating in a tall cylindrical heater, beneath which is a flame. The material in contact with t h e flame after drying begins t o char and with t h e forced draft arising from t h e height of t h e cylinder, will furnish heat from its own combustion sufficient t o dry t h e green material above it. Thus, by feeding t h e raw material in a t t h e t o p a n d drawing off t h e ash a t t h e bottom, a continuous yield of char can be obtained. This char can then be extracted with distilled water by a n y suitable means a n d t h e liquor evaporated t o dryness. T h e dried and ground salts are clean and white a n d only slightly hygroscopic. I n large cities where considerable amounts of these stalks are available, i t seems likely t h a t some scheme of collection or of segregation a t t h e garbage incinerators could be employed a t small expense. The subsequent recovery of t h e potash has already been shown t o be very simple and inexpensive, requiring no special or expensive apparatus. As stated above, one ton of fresh material should furnish in the neighborhood of $ 2 5 . 0 0 worth of salts a t t h e present market prices. This would seem t o justify a n expense for collection of about one cent per stalk (600 t o 700 stalks make a t o n ) , an$ still yield a fair margin of profit after deducting t h e nominal expense of treatment. The method of recovery lends itself readily t o small scale manufacture a n d would in all probability be most practicable under such conditions. S U M MARY
I-Dried banana stalks contain as much potash as kainit a n d compare favorably with dried kelp as filler for commercial fertilizer. 11-Charring and leaching of banana stalks yield 2 7 lbs. of 90 per cent potassium carbonate per ton. 111-The possibility of collection and treatment on a small scale is suggested DIVISIONO F AGRICULTURAL CHEMISTRY AGRICULTURAL EXPERIMENT STATION UNIVERSITY OF CALIFORNIA, BERKELEY
Vol. 9 , No. a
THE RELATIVE AVAILABILITY OF ACID PHOSPHATE AND RAW ROCK PHOSPHATE IN INDIANA FIELD TESTS1 By S . D CONNER
Approximately 80 per cent of t h e soils of Indiana are in need of phosphate fertilizers. T h e Purdue Experiment Station has been conducting field experiments testing t h e relative merits of acid phosphate and raw rock phosphate since 1904. Up t o t h e end of t h e 1915 season 8 2 tests had been carried out, in which acid phosphate could be compared t o raw rock phosphate. These tests were made on six different experiment fields in various parts of t h e state on a variety of soil types, a n d have been running from 2 to10 years. I n addition, tests were made in cooperation with farmers in five different counties on other soils. Table I presents a general summary of all these experiments. These tests are believed t o give a fair comparison of t h e use of t h e two phosphates under average Indiana field conditions, with various crops a n d during different seasons on a large number of soil types. The treatments have been t h e same for t h e various plots under investigation. except t h a t some have had acid phosphate, some have had raw rock phosphate and some have had no phosphate. As a result of t h e 8 2 tests i t shows t h a t without question i t pays t o use acid phosphate on these soils. R a w rock phosphate has also shown a profit, but much smaller t h a n for acid phosphate. The acid phosphate contained 16 per cent available phosphoric acid a n d has been valued at $16.00 per ton. The raw rock phosphate mas brown Tennessee rock containing 2 8 per cent total phosphoric acid and has been valued at $ 7 . 0 0 per ton. TABLEI-SUMMARYOF ALL EXPERIMENTS I N WHICH ACID PHOSPHATE AND RAW ROCKPHOSPHATE HAVRBEEN COMPARED (Average of Eighty two Tests with Various Crops in Indiana) 7 Averages per Acre per Year-Value . -.- - c-o.s.t. Phosof of Profit Crop or phate increase Phos( N o . of Tests) Phosphate Yield Increase (lbs.) (a) phate loss 43.04 bu. 5.49 bu. 190.5 $ 2 . 9 5 $1.52 $ 1 . 4 3 Corn (36). . , . Acid 0.66 Raw rock 42.20 bu. 4.65 bu. 532.0 2.52 1 .86 None 37.55 bu. Wheat (33). . . Acid 15.28bu. 4.31 bu. 190.5 4.63 1.52 3.11 Rawrock 12.88bu. 1.91bu. 5 3 2 . 0 2.12 1.86 0.26 None 10.97 bu. Legume hay Acid 2998 Ibs. 320 Ibs. 190.5 1.60 1.52 0.08 Raw rock 2773 lbs 9.5 lbs. 5 3 2 . 0 0.47 1 86 -1.39 (9) ivone 2678 ibs. Potatoes ( 4 ) , . , Acid 112.0 bu. 29.4 bu. 500 1 4 . 7 0 4 . 0 0 10.70 S.80 3.50 2.30 Raw rock 94.2 bii. 11.6 bu. 1000 None 82.6 bu.
__ -
-~ ~~
Average ( 8 2 ) . . Acid (b) Raw rock
205 545
$ 4.06 $1.64 $ 2.42 2 . 2 9 1.91 0.38
of increase inciudes value of corn stover and wheat straw. ( 6 ) Average length of time tests have been running. 3.47 yrs.
( a ) Value
The following crop values were used in calculating values of increase: Value (Per hu.)
.
Ear c o r n . , . , , . . . , , . . . . . $ 0 . 5 0 Wheat grain,, . . , , . . , . , , . , ! .OO Potatoes.. . , , . . . . . , , . , . 0 . 5 0
. .
-
Value (Per ton)
. ... . .. .. .. .. .. $ 32 .. 50 00 . . . ... . 10.00
Corn stover.. , Wheat straw.. . Legume h a y . . . .
This 1 Presented at 53rd Meeting of American Chemical Society. paper is based largely upon data published in Indiana Experiment Station Buil. 187, by A. T. Wiancko and S. D . Conner. Statistics of each crop and full particulars of the experiments may be found in that bulletin.
Feb., 1917
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
I n analyzing t h e crop results obtained, the following facts are noted: Acid phosphate has returned a crop increase over 6 times as profitable per acre as has raw rock phosphate. Acid phosphate has returned a c m p increase over 7 times as profitable per dollar invested as has raw rock phosphate. Each pound of phosphorus in acid phosphate has returned a crop increase valued a t zS1/3 cents. Each pound of phosphorus in raw rock phosphate has returned a crop increase valued a t 3l/? cents. A pound of phosphorus in acid phosphate has returned a crop increase over 8 times as valuable as t h a t returned b y a pound of phosphorus in raw rock phosphate, By taking t h e prices used in this paper for f a r m crops, t h e increases obtained by t h e application of phosphates would give a value of S 3 8 . 8 j per t o n for acid phosphate a n d $ 8 . 4 0 per t o n for raw rock phosphate. If t h e prices for farm products were reduced 2 0 per cent t h e acid phosphate would h a y e a value of $3 I . 08 per t o n a n d t h e raw rock phosphate a value of $ 6 . 7 2 per ton. T h e acid phosphate would still show a good profit a n d t h e raw rock phosphate would be used a t a loss. By calculating t h e phosphoric acid in all t h e crops grown, i t is found t h a t 2 2 4 lbs. of PzO6have been recovered in t h e total increase caused b y acid phosphate a n d 147 lbs. of P20s have been recovered in the total increase caused by raw rock phosphate. These amounts of P205are approximately 1/12 of t h e phosphoric acid applied in t h e acid phosphate and ‘/85 of t h e phosphoric acid applied in t h e raw rock phosphate. Nineteen samples of raw rock phosphate were taken on t h e Indiana market in 1 9 1 j b y the inspectors of t h e State Chemist. The analyses of these samples show a n average of 2 8 . 8 per cent total P z O j a n d a n average of I . 8 per cent ammonium citrate-soluble P206; 1 . 8 per cent of all t h e raw rock phosphate used in t h e 8 2 tests would indicate a n available phosphoric acid amount of 804 lbs. or over 5 times as much as was removed b y t h e increased crops caused b y t h e ram rock phosphate in 3 ] / * years. On t h e Scottsburg field,’ which has been running for IO yrs., raw rock phosphate came t h e nearest t o paying as large a profit as acid phosphate, t h e net returns per acre for t h e Io-yr. period being $31. j 2 for t h e acid phosphate a n d $19.51 for t h e raw rock phosphate. On t h e Scottsburg field, 88 lbs. per acre of citrate-soluble PsOr were added i n acid phosphate in I O yrs. and 2 6 lbs. oi Pz05were removed in t h e increased crops. If I . 8 per cent is considered t h e measure of t h e citrate-soluble phosphate in t h e rock phosphate used, then 7 2 lbs. of citrate-soluble phosphate were added per acre in raw rock phosphate in I O yrs. while 26 lbs of P206 were removed in the increased crops. IhDIAN.4
A G R I C U L T U R 4 L EXPERIMIBKT STATIO&‘
THE ACTION OF CALCIUM CARBONATE ON ACID PHOSPHATE’ By
EGBERT W. MAGRUDER
T h e reaction which takes place between calcium carbonate a n d acid phosphate is one of great interest both t o t h e farmer and t o t h e fertilizer manufacturer. I t has been generally taught t h a t calcium carbonate should not be mixed with acid phosphate because i t would act on the mono- and di-calcium phosphates and convert t h e m into t h e tri-calcium phosphate, which is insoluble in water and slowly available t o plants. Consequently t o find t h a t hlr. J. S. Burgest, State Agronomist of North Carolina, in Bulletirz 2 2 0 of t h e North Carolina Department of Agriculture, recommended t h a t ground limestone and acid phosphate be mixed in t h e proportions of 1 2 0 0 lbs. of t h e Eormer to from 400 t o 1000 Ibs. of t h e latter, was very much of a shock to me. hlr. Burgest says: “ N o a t t e m p t has been made t o leave t h e impression t h a t acid phosphate mixed with ground limestone will not revert to what is called di-calcium and, t o some extent, t o tri-calcium forms. But these forms of phosphorus are still available to t h e crops, while t h e iron a n d aluminum phosphates are entirely out of reach of t h e plants.” T o how great a n extent acid phosphate is converted into iron or aluminum phosphates in t h e soil I do not know, but in t h e Eastern and Southern states experimental results have uniformly shown t h a t acid phosphate gives much better results and is more profitable t h a n ground phosphate rock. Di-calcium phosphate is, of course, a valuable fertilizer, and tri-calcium phosphate which has been formed b y t h e reversion of acid phosphate would, without doubt, be more available t o plants t h a n ground phosphate rock on account of its fine subdivision. If reverted phosphate is better for crops t h a n acid phosphate, t h e fertilizer laws all need amending and t h e manufacturers of acid phosphate need t o change their methods of manufacture. They should p u t out no mono-calcium phosphate, b u t only di- a n d tricalcium phosphates. T h e only recent experiments on t h e reaction between limestone and acid phosphate I have seen are those of Dr. R. N. Brackett,2 of Clemson College, South Carolina. His limestone contained only a trace of phosphoric acid, a n d his acid phosphate was of t h e following composition: Total phosphoric a c i d . , .................... 16.84 Water-soluble phosphoric a c i d . , . . . . . . . . . . . . . 1 3 . 5 5 Insoluble phosphoric acid.. . . . . . . . . . . . . . . . . 1 .33
The following mixtures were used and results obtained : No.: 1 Lbs. acid phosphate., . . . . . . . . . . . . . . . . . . 1 4 . 0 Lbs. ground limestone., 6.0
................
2 15.5 4 5
3 17.0 3.0
1
10.0 10.0
LAPAVETTE 1
See Iodiaoa Bull 187, 1061
!Presented at 53rd Meeting of American Chemical Society, New York City, September 2 5 to 30, 1916. 2 THIS J O U R N A L , 7 (1915). 620.
