Sept., 1913
T H E J O U R N A L OF I N D U S T R I A L
d a y s a n d then were placed in a solution containing 2 5 0 grams of sulfuric acid (HPSOI)t o t h e gallon. T h e solution was changed frequently a n d the briquettes broken a t regular intervals. T h e disintegration of concrete by such acid water is shown b y t h e following: Age in the solution.. 0 days 7 days 28 days 3 mos. 6 mos. Tensile strength.. . . . . 226 299 300 280 176
1 year Disintegrated
Several years ago the question of the action of oil on concrete was brought up a t one of t h e meetings of this society in connection with a paper by Prof. Carpenter. I n his experiments oil was mixed in with t h e concrete. I n t h e discussion which followed the reading of the paper, a number of gentlemen suggested t h a t what was needed most was information relative t o t h e action of oil on concrete which h a d already hardened, in view of the employment of concrete for machinery foundations, engine room a n d factory floors, etc., where i t is subjected t o t h e oil which leaks from t h e bearings of the machinery. I went home from this meeting a n d had a lot of s a n d briquettes made a n d allowed t h e m t o harden 2 weeks in air. These were stored in air, in engine oil, in cylinder oil, a n d in black oil. They were then broken a t stated periods with t h e following results: ACTIONOF OIL O S CONCRETE Age in air.. . . . . . . . . . . . . . . . . 14 days Age in o i l . . . . . . . . . . . . . . . . . . 7 days 28 days 3 mos. 6 mos.
TENSILE STRENGTHO F BRIQUETTES KEPT Engineoil . . . . . . . . . . . . . . . . . . 253 Cylinder oil . . . . . . . . . . . . . . . . . 235 . . . . . . . . . . 234
240 273 222
251 221 181
232 209 131
Air ........................
233
287
303
248
1. year
IN
23 1 203 Brokein clips 293
It will be noted t h a t t h e engine oil a n d the cylinder oil have practically no effect upon concrete. One would think t h a t as the latter has a considerable proportion of animal oil in its composition i t would be a p t t o effect appreciably concrete exposed t o it. On t h e other hand, t h e action of t h e black oil seems strange in view of the fact t h a t i t is a straight mineral product, All of these briquettes h a d absorbed considerable oil, t h e actual gain in weight of each set a t the end of t h e year being as follows: Per cent Set in engine oil . . . . . . . . . . . 10.6 Set in cylinder oil. .................... 10.0 12.0 Set in black o i l . . ......................
T h e briquettes in t h e black oil h a d not swollen perceptibly a n d seemed merely t o be weak. The experiments given above were all made upon very small test-pieces a n d hence t h e action of t h e solutions upon t h e m were much more rapid t h a n they would be upon a large mass of concrete, a n d while in most of t h e above cases a year was sufficient t o completely disintegrate t h e test-pieces, in a large body of concrete, such as a pier or wall, many years a t least would be required t o bring a b o u t this result. T h e experiments merely serve t o show t h a t even very dilute solutions of the salts of magnesium a n d the sulfates in general do have a destructive action on concrete a n d t h a t the generally proposed remedies do not appreciably retard this. T h e y indicate t h e desirability of
A N D E-YGIiX'E E R I N G CHE&fI S T R Y
72.5
employing low-alumina cements for sea-water construction. T h e experiments with the oils show t h a t n o destructive action is likely t o take place where cement is used for floors in machine shops a n d engine rooms. 202 NORTHCALVERT S T . BALTIMORE
THE DECOMPOSITION OF FELDSPAR AND ITS USE IN THE FIXATION OF ATMOSPHERIC NITROGEN By WILLIAMH.Ross' Received July 21. 1913 INTRODUCTION
T h e extensive search for sources of potash salts which has been undertaken in this country during t h e past two years has naturally led t o renewed efforts in devising methods for its extraction from feldspar a n d other silicate rocks. T h e investigations in t h e use of feldspar as a source of potash have, however, not been confined t o the past few years, b u t date back t o the time when t h e part played by potash as a fertilizer in t h e production of crops was first recognized. E v e n as early as 1847 a British Patent, No. 11,555, was issued t o Richard Albert Tilghman for a process of obtaining potassium sulfate from feldspar b y heating t o bright redness for 8 hours, z parts of feldspar with I part each of limestone and gypsum. Within a few years a number of other patents appeared in England a n d other countries outlining methods for obtaining potash not only from feldspar, but also from leucite a n d other eruptive minerals. T h e discovery of the importance of potash salts in agriculture took place also simultaneously with the discovery in 18j1 of the great salt beds a t Stassfurt, Germany, a n d in 1861 the first factory for refining crude potash minerals was established. T h e discovery a t this time of such a n enormous source of soluble potash salts naturally detracted from t h e interest which was being taken in t h e extraction of potash from t h e refractory silicates, a n d as a result n o investigations for obtaining potash from these minerals were patented for 2 9 years. The increasing demand in this. country for potash fertilizers has again turned attention t o t h e silicate rocks as a possible source. Owing t o t h e commercial application of a n y successful method which might be devised, most of the investigations have been carried on in secret, a n d before t h e publication of a n y results, patents have been applied for in almost every case covering processes which have been proposed for t h e extraction of potash from this source. T h e number of patents of this kind which have been issued during t h e past few years is surprisingly large. N o less t h a n seven have been issued during 1 9 1 2 alone, a n d i t is known t h a t a number of other patents have been applied for, b u t have not yet been issued, so t h a t t h e processes t o which they relate are still kept secret. PROCESSES F O R THE DECOMPOSITIOK O F SILICATE R O C K S
T h e total number of patents which are concerned with t h e extraction of potash from silicate rocks numScientist in Soil Laboratory Investigations, Bureau of Soils, U. S. Dept. Aar.
.
T H E J O U R N A L OF I A V D U S T R I A L A X D E,VGI-VEERI*\'G C H E M I S T R Y
726
ber a t least 40. T h a t s o - m a n y patents should relate t o processes all distinct from each other is not t o be expected, a n d it is therefore not surprising t o find t h a t many have been issued which describe essentially t h e same process for the extraction of potash from insoluble silicates. For convenience, these various processes may be considered in 3 groups as follows: ( I ) Processes which yield potash as t h e only product of value. ( 2 ) Processes which yield potash a n d some other salable material as a by-product. (3) Processes in which t w o or more operations are combined in one, yielding a fertilizer containing t w o or more of the essential plant foods-potash, phosphates a n d nitrogen in available form. Of t h e 40 patents which have been referred to, a b o u t j o per cent make no reference t o a n y products of value which can be recovered other t h a n t h e potash. From t h e results obtained in a previous publication' i t is safe t o conclude t h a t processes of this kind cannot prove economical for t h e reason t h a t the value of t h e product obtained, if based o n t h e percentage of potash present, as is now universally done in t h e fertilizer industry, could not cover the cost of t h e raw materials, a n d t h e expense of operation. T h e desirability of devising some method of treating feldspar which would produce a t the same t i m e some product of value in addition t o t h e potash was early recognized, a n d about one-half of t h e patented processes referred t o claim t o have met this requirement. Among t h e various by-products which are considered possible of recovery in these processes may be mentioned alumina, silica, pigment, r a w materials for t h e manufacture of glass, a n d hydraulic cement. It has been shown2 t h a t when I part of feldspar a n d 3 parts of calcium carbonate are ignited t o 1300-1400' t h e alkalies in t h e feldspar are completely volatilized a n d t h e residue has t h e composition required of Portland cement. Since t h e shale or clay used in t h e manufacture of cement contains small quantities of alkalies, it should follow t h a t t h e percentage of alkalies in t h e dust which escapes from t h e kiln during the process of burning should be considerably greater t h a n in t h e raw materials. This was found t o be t h e case in most plants a n d i n t h e case of several t h e concentration of t h e potash i n t h e flue dust was very marked. I n one plant examined the content of potash in t h e fine flue dust collected b y the Cottrell precipitators, recently installed, amounts t o as much as 40 per cent, mostly in t h e form of t h e oxide. Experiments are now being undertaken with a small cement mill t o ascertain t h e practicability of recovering potash as a by-product in t h e manufacture of cement by t h e substitution of feldspar for clay or shale. It has also been foundS t h a t when I part of feldspar a n d 1.68 parts of lime are digested with water under pressure of about 1 7 atmospheres, upwards of 90 per cent of t h e potash in t h e feldspar passes into solution I
Bureau of Soils, U. S. Dept. Agr., Circ. 11.
2
LOC.cif.
An article entitled "The Extraction of Potash from Sllicate Rocks." giving a more detailed account of the results here referred to, is expected to be published shortly.
Vol.
j, No. 9
in t h e form of t h e hydroxide. I n this form t h e potash is worth per unit about 1.8 times t h e value i t commands in t h e form of t h e chloride. T h e residue remaining insoluble has t h e composition required of Portland cement a n d would simply require ignition for its manufacture. T h e cost of t h e raw materials required for t h e process is estimated t o be about $6.70 per ton of feldspar, while t h e products obtained would have a value of about $13.90, assuming for the feldspar a n average potash content of I O per cent. T h e percentage of silica in feldspar is usually about double the combined percentages of potash and alumina present. When consideration is taken of t h e other reagents added in a n y treatment of t h e feldspar, i t therefore follows t h a t the insoluble residue remaining a t t h e end of t h e process will amount t o several times the quantity of potash, or potash a n d alumina present; consequently, in order t h a t t h e residual material may find a market, when a n y considerable amount of potash is produced, i t must be of such a nature t h a t i t can be used on a very large scale. Such may be said t o be the case of t h e raw materials used in the manufacture of glass, of which upwards of one a n d a half million tons are required annually, but t h e process which produces cement as a product in t h e extraction of potash from feldspar has t h e advantage in t h a t the quantity of cement used in this country is more t h a n I O times as great. Several of the patented processes of t h e second group which offer most promise are now being tested out on a comparatively large scale under t h e direction of t h e patentees. The results of these trials will determine conclusively t h e practicability of recovering potash from feldspar b y these methods. Some experiments have also been made in this laboratory on several of t h e remaining processes of this group, b u t t h e preliminary results obtained did not offer sufficient promise to justify continuing t h e work a n y further. T h e first U. S. Patent ( N o . 16,111)dealing with t h e decomposition of feldspar was issued t o Charles Bickell for a process which consisted in heating in a reverberatory or other suitable furnace t o a light red heat for about 2 hours, I part feldspar, 0 .j part phosp h a t e of lime, a n d 3 or 4 parts of air-slaked lime, all in a finely powdered condition. According t o t h e patent, both the potash a n d the phosphate become available b y this treatment. This process t h u s belongs t o t h e third group into which processes for decomposing feldspar have been divided, a n d a t first sight seemed t o be particularly attractive, for if both the potash a n d phosphoric acid were rendered soluble a s claimed by the patent, t h e method might be a n economical one since, when used as a fertilizer, no separation of t h e constituents would be necessary a n d t h e mixture would be of value for its phosphoric acid as well as for its potash content. It was found, however, t h a t t h e calcium phosphate has a passive effect in this treatment of the feldspar a n d t h a t no greater decomposition was produced in this way t h a n when it was treated with calcium carbonate alone. T h e process was further investigated by W. H.
Sept., 1913
T H E J O 1 7 R A Y A LOF I . Y D U S T R I d 4 L 4-YD E.YGI-\-EERI-YG
Waggaman of this laboratory who has shown in work soon t o be published t h a t when t h e ignition mas made in a n open vessel about 56 per cent of t h e potash mas lost b y volatilization, a n d of t h a t which remained very little was water-soluble. None of t h e phosphoric acid was lost b y volatilization under this treatment, b u t only 40 per cent was rendered citrate-soluble. X better result was obtained when there was added to t h e mixture about 0 . 2 part each of hematite a n d manganese dioxide for each p a r t of feldspar, a n d t h e whole ignited t o about 1400' for three-quarters of an hour. =1 limpid fusion resulted which, on cooling, was found t o contain all of t h e potash a n d phosphoric acid in a citrate-soluble state, b u t neither was water-soluble. FIXATIOS
OF
SITROGES
The object of t h e present in\-estigation \vas t o test the efficiency of ignited feldspar in bringing about t h e fixation of nitrogen through t h e agency of the combined alumina or silica present, while there was t h e possibility t h a t t h e potash would be set free a t t h e same time. This would t h u s constitute a process which: like t h e foregoing, belongs t o t h e third group. Experiments in t h e fixation of nitrogen m a y be said to date back t o t h e year 1;8j, when Cavendish first noted t h a t a n acid was formed when electric sparks were passed through a confined volume of air. T h e nature of t h e reaction, however! mas a t t h a t time unknown. Fifteen years later Sir H u m p h r y Davy observrd t h e formation of nitric oxide when air was passed over platinum wire heated b y an electric current. T h e function of t h e platinum in this reaction i n acting as a catalytic agent mas demonstrated by Gay-Lussac in 1864. Since then a n immense amount of work has been done along this line. The popular literature on the subject is very extensive a n d a surprisingly large number of patents have been issued i n Germany! Norway, United States, a n d other countries, on processes a n d equipment for fixing nitrogen b y different methods. T h e various processes recommended m a y be conveniently divided into four groups according as there is produced: ( I ) nitrates or nitrites; ( 2 ) ammonia; (3) nitrids; a n d (4) cyanids, or related compounds, as cyanamid. Processes representative of all these groups have been or are being carried out on a large scale. The first a n d fourth have already developed into large industries. Extensive experiments are now being carried out in this a n d other countries on processes n-hich relate t o t h e third group, a n d there is a possibility t h a t t h e fixation of nitrogen in t h e form of nitrids m a y ultimately prove more profitable t h a n in a n y other way. 'That certain metals, when heated. will combine with nitrogen t o form nitrids has long been known. Lithium is t h e most marked in its action in this respect, a n d takes u p nitrogen t o form Li,N even when exposed t o moist air. K h e n heat is applied in an atmosphere of nitrogen a violent reaction takes place. lfagnesium ranks next t o lithium in t h e tendency t o combine with nitrogen. This property of magnesium
CHEJfISTRY
727
is made use of in t h e well-known method of removing nitrogen in t h e preparation of argon from t h e air. ilmong other metals which possess a marked affinity for nitrogen m a y be mentioned calcium, titanium, silicon a n d aluminum. Instead of using t h e metal directly in t h e fixation of nitrogen, there m a y be used in preference a mixture of t h e oxide a n d carbon. I n this way reduction of t h e oxide and fixation of nitrogen may be brought about in t h e same operation. The most noteworthy experiments in this direction have been made b y Ottokar Serpek, who has worked out a technical process for fixing nitrogen on a large scale b y igniting bauxite with carbon a t I ~ O O - ~ O OinO ~a n atmosphere of nitrogen.' For this purpose a furnace was devised somewhat after the fashion of a rotary kiln having a n electric furnace inserted in one section. The rotation of the kiln: while conveying t h e mixture t o the electrical part of the furnace Tl-here t h e reaction takes place, acts also t o bring t h e bauxite a n d carbon intimately together. The current of nitrogen under slightly increased pressure is passed through t h e kiln in a n opposite direction t o t h e mixed alumina a n d carbon. ; I s t h e latter reaches t h e heated part of t h e furnace the reaction takes palce. whereby there is formed aluminum nitrid (,41S) a n d carbon monoxide. It is supposed t h a t t h e aluminum carbide which first has a tendency t o form reacts with t h e alumina t o form carbon monoxide a n d free aluminum which in t h e nascent state, a t t h e temperature used. readily conibines with nitrogen. T h e compound t h u s formed is of a bluish gray color a n d on issuing from t h e furnace may contain upwards of 2 6 per cent of nitrogen. When boiled with alkaline hydroxide or sodium aluminate solution, or with water under pressure, t h e nitrogen present m a y be liberated as ammonia, while t h e aluminum is changed t o hydroxide. This m a y be used over again, b u t a t present t h e use of fresh bauxite seems t o be more economical. I n either case t h e material is rendered anhydrous before passing into t h e electrically heated kiln b y calcining in a separate kiln with t h e carbon monoxide evolred from t h e reaction in t h e furnace kiln a n d which m a y be enriched with other combustible gases if necessary. I n some of his patents Serpek suggests t h a t there should be added t o t h e mixture of alumina and carbon about j peq cent of some metal such as copper or iron n-hich is capable of forming a n alloy with aluminum. I n other patents a n increased yield of nitrid is reported t o be brought about b y mixing with t h e nitrogen about 0 . I per cent of some acid gas such as hydrochloric acid or sulfur dioxide. I t is further stated t h a t instead of using pure or impure alumina, such :IS natural bauxite, aluminum borates or silicates may be used for carrying out t h e process, b u t no rcsults are given on t h e use of these minerals as in t h e case of bauxite. Experiments along t h e same line as those outlined in Serpek's patents on t h e use of alumina for fixing 1 'c. S. Patents 867.615; 884,423; 888,044; 987.408; 996,032; l , 0 0 7 , 4 ' 1 5 ; 1,016,326; 1,030,929; 1,040,439; 1,C44,?2i; 1,044,928; 1,037,28 O , S l l l j ; 1,060,6411.
T H E J O U R N A L OF Ii\-DUSTRIAL
728
nitrogen have been made by Tucker a n d Read.' T h e reactions were carried out in a stationary graphite electric resistance furnace. A t temperatures below 1600' the yield of combined nitrogen was small, amounting t o less t h a n 3 per cent. T h e addition of hydrochloric acid gas or of sulfur dioxide t o t h e nitrogen in the furnace gave lower results t h a n when pure nitrogen was used, from which i t was concluded t h a t these gases are harmful rather t h a n beneficial. The largest yield of nitrid, amounting t o 2 2 . 7 per cent calculated as nitrogen, was obtained a t a temperature between 1900' a n d 2oooo. E X P E R I hl E N T A L
RESULTS
In undertaking a n investigation on the use of feldspar in fixing nitrogen a cylindrical gas furnace was used in the preliminary experiments. This was provided with holes in opposite sides through which was passed horizontally a glazed Royal Berlin porcelain t u b e 6 0 cm. long with a n internal diameter of 2 cm. With this arrangement the portions of the tube inside the furnace could be repeatedly raised t o 1 2 0 0 O , inside temperature, b u t as t h e temperature was increased t o about 1400°, the tube soon became brittle a n d cracked. T h e tube was connected a t one end with a hard glass combustion tube containing copper gauze over which, when heated t o redness, the nitrogen was led under slightly increased pressure in order t o remove the last traces of oxygen. The other end of the tube was closed with a stopper through which passed a glass tube t h a t dipped into a flask containing water. This served as a trap t o prevent a n y back flow of air a n d also indicated t h e rate of flow of nitrogen through the apparatus. T h e nitrogen used in t h e experiments was prepared b y dropping a strong sodium nitrite solution into a hot saturated ammonium chloride solution. The gas t h u s formed was stored in a gasometer a n d before using was dried by calcium chloride a n d sulfuric acid. The feldspar used in the experiments was ground t o pass a I O O mesh sieve a n d analyzed as follows: Si02 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . AlzOa. . . . . . . ............... ............... FezOa. . . . . . . C a O . . ............................. MgO. . . . . . . . . . . . . . .
Kz0
.........................
NazO ..............................
64,32y0 19.64 trace 0.16 0.08 13.72 2.18
100.10
This was mixed with sugar cane carbon in different proportions, wrapped in filter paper a n d inserted in the portion of the tube within the furnace, a n d then ignited in a current of nitrogen a t temperatures up t o about 1400'. The fixation obtained in a n y case was slight, amounting a t most to about I per cent of the feldspar in the mixture. Since, as already stated, the potash in feldspar may be set free by igniting with calcium carbonite, a number of experiments were made in which this compound was added to the mixture of feldspar a n d carbon. When this was done, not only was potash set free by volatilization from the feldspar, but the amount of nitro1
Tba American Ferlilizev. 37, No. 9, p. 39.
A N D ENGINEERING CHEiWISTRY
Vol. 5 , No. 9
gen fixed a t the same time was greatly increased. The porcelain tube in which the ignition was made extended for about 13 cm. outside t h e furnace, a n d this portion was therefore comparatively cool. T h e volatilized potash, however, was found t o extend as a deposit not only along this length of the tube, b u t a portion even passed beyond the tube a n d was collected in the water trap through which the current was led; as the water contained a little phenolphthalein it acquired a deep pink color as t h e potash collected. The percentage of the total potash in feldspar which is volatilized when t h e latter is ignited in a n open vessel for a n hour a n d a half a t about 1400' with varying amounts of lime is given in the following table: Proportion of feldspar t o lime
Percentage of potash volatilized
5 t o 3 .................................. 5 to 4 .......... 5 to 5.................................. 5 t o 6 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 16 27 61
5 t o 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
95
When carbon, however, was added t o the mixture of feldspar a n d calcium carbonate, or its equivalent of lime, and the ignition made in a current of nitrogen, instead of in a n open vessel, t h e proportion of potash volatilized was found t o be very greatly increased. Thus, when a mixture of j parts of feldspar, j.4 parts of calcium carbonate, or 3 parts of lime, a n d 2 . j parts of carbon were ignited in nitrogen for one hour a t I zoo O, upwards of jo per cent of t h e potash i n t h e feldspar was volatilized, while a t 1400' the loss of potash by volatilization was found t o be complete. The amount of nitrogen fixed a t t h e same time in this a n d other mixtures was kindly determined b y Mr. T . C. Trescott of the Bureau of Chemistry, using t h e Kjeldahl method. T h e results given in t h e following table represent the mean of several determinations: 4 J
E
1. . . . . . . 4
2....... 3....... 4....... 5....... 6....... 7....... 8. . . . . . . 9....... 10 . . . . . . . 11 . . . . . . . 12
.......
6 4 2 4
2 4 4 4 4 4 2
2 3 2 1 4 4
2 2 2
2 2 4
0.0 6.4 4.3 2.15 4.3 2.15 2.15 12.0 0.0 2.15 4.3 6.0
about about about about about about about about about about about about
1200' 1200 1200 1200 1200 1200 1200 1200 1400 1400 1400 1400
;j
5.0
.., 55.7
.... .... 38.0
.,., 78.0 41.3 98.0 100.0 100.0
Nitrogen fixed in percentage of
0.20 0.83 1.27 1.44 1.40 1 45 0.50 0.44 1.00 1.68 6.10 5.21
1.9 8.0 12.2 13.8 13.4 13.9 4.8 4.2 9.6 16.1 58.5 50.6
I t mould seem from these results t h a t varying the proportion of carbon between the limits given does not have much effect, under t h e conditions of t h e experiments, on the amount of nitrogen fixed. T h e minimum quantity of carbon taken was sufficient t o combine with all the oxygen in the feldspar. Duplicate results, however, did not agree closely. This was no doubt due t o the fact t h a t it was not possible, with t h e arrangement in hand, t o maintain a uniform tempera-
T H E J O C R S A L OF I S D U S T R I A L A S D E - Y G I X E E R I S G C H E M I S T R Y
Sept., 1 9 1 3
t u r e at all times a n d a comparatively small rise in temperature produced a considerable change i n t h e a m o u n t of nitrogen fixed. T h e calcium equivalent t o t h e silica, as found b y analysis, in 4 parts of t h e feldspar is equal t o 4.3 parts of calcium carbonate. This proportion seems best suited in the fixing of nitrogen since smaller yields were obtained when t h e proportion of lime t o feldspar was increased or decreased beyond this limit. The same results were obtained starting with t h e oxide of calcium as with t h e carbonate. Only a very slight a m o u n t of nitrogen was fixed when a mixture of lime a n d carbon were ignited a t 1400’ in t h e absence of feldspar. T h e increase of fixation with time of ignition is shown in t h e following table, when J. parts of feldspar, 2 parts of carbon a n d 4 . 3 parts of calcium carbonate mere ignited for diffeqent lengths of time. T i m e of ignition Hours
. 2. . . . . . . 4........ 1. . . . . . . . 2 . . . . . .. . 1. . . . . . .
Potash Nitrogen fixed in volatilized in percentage of percentage of total feldspar aluminum in present taken feldspar
----
Temperature about 1200’
55,s
1.27
a b o u t 1200’
68.9
1.34
12.9
a b o u t 1200’
83.0
1 68
16 1
a b o u t 1400’
100.0
6 10
58.5
a b o u t 1400’
100 . o
7.44
71.5
12.2
Since t h e nitrogen in aluminum nitrid amounts t o j 1 . 6 per cent of t h e aluminum, i t follows t h a t t h e nitrogen fixed i n t h e last t w o experiments is greater t h a n what would correspond t o t h e aluminum in t h e feldspar. K O direct experiments have yet been made t o determine i n what form t h e nitrogen is combined, whether as nitrid or carbo-nitrid of silicon or aluminum. When boiled with water t h e material gave off ammonia very slowly, a n d even slowly when boiled with sodium hydroxide solution although in this case t h e ammonia was evolved more rapidly t h a n when t h e digestion was made with water alone. Equipment is now being installed t o carry on t h e experiments on a larger scale a n d at higher temperatures. I n t h e meantime i t was thought advisable t o publish t h e preliminary results obtained. BUREAUOF SOILS U. S. DEPARTMENT OB AGRICULTURE WASHINGTON
THE LEACHING O F POTASH FROM FRESHLY CUT KELP B y A. R. hlER2.l
AND
J. R. LINDEMUTH2
Received June 27, 1913
Drift, kelp usually has a very low content of potash
729
or’ rather potassium chloride. It has been currently reported t h a t t h e loss of potassium chloride from t h e freshly cut plant proceeds quite rapidly. Theoretically, there should be a distribution of t h e base between t h e plant a n d t h e water in which i t lies, a n d this redistribution might reasonably be expected t o commence at once, a n d even t o be much augmented or accelerated because of t h e relatively high content of sodium chloride in sea water. This problem is one of considerable economic importance, since i t has been proposed in t h e harvesting of kelp as a raw material for t h e production of potassium salts, t o tow the cut kelp from t h e groves t o t h e landing a n d t h u s avoid lifting t h e material upon a barge or boat. I n order t o obtain some information a n d d a t a bearing directly on this economic question, Professor W. C. Crandall, of t h e Scripp’s Biological Station, a t La Jolla, California, collected t w o large samples of M a c v o c y s t i s on a recent cruise of t h e yacht, “ i l g u x i ” , of t h a t station, towing these samples a n d taking subsamples from time t o time which were forwarded t o t h e laboratory of t h e Bureau of Soils, in Washington, for analysis. One of t h e large samples for t h e leaching espcriment was collected near Pt. Loma a n d t h e other near Coronado Island. T h e subsamples, on their receipt i n Washington, had commenced t o ferment. This fact, however, could not h a r e a n y particular influence on t h e d a t a here given. T h e tables which follow are self-explanatory. The analytical methods employed have been described i n THIS J O U R N A L , 4, 431 b y Turrentine, a n d acknowledgment is here made t o N r . T. C. Trescott, of t h e Bureau of Chemistry, who kindly made t h e nitrogen determinations for us. F r o m this examination i t is evidently a matter of considerable difficulty t o obtain a fair average sample of wet kelp. I t also appears t h a t freshly cut kelp, when immersed in sea water, does not, at least at first, lose i t s potash content very rapidly. Attention is called t o t h e analysis of “sea lettuce” in Table 11. This is not a kelp b u t a rock weed rather common on t h e Pacific coast. Algae other t h a n t h e giant kelps have not usually shown a high potash cont e n t , b u t this analysis indicates t h a t t h e matter is worthy of further investigation. ’rhe difficulties t o be apprehended in harvesting rock weeds, however, do not leave much promise for their economic importance a t present, even though they should be found t o have a high content of potash or other valuable
TABLE I-SAMPLE TAKEN NEAR CORONADO ISLANDS No. lm.. ... . . . . .. 1ex. . . . . . . . . , , 1A.. . , . . , . . . . 1B... . . . , . . , , 1 c . ., . . . , . . . 1 D . . . ... . . . . . 1E.. , . . . . . . . . IF.. .. . . . . . . 1 G . ., . . , . . , . .
T i m e exposed
;r:z
) fresh c u t
3 hrs. 6 hr5. 14 hrs. 1 7 1x5. 20 hrs.
Per cent Kz0 12.48 13.47 15.56 17.30 17.61 13.35 10 74 18.28 9.90
P e r cent Per cent P e r cent sol. salts org. m a t t e r ash 31.46 31.26 34.00 38.26 38.30 31.96 26.36 36.78 25.94
65.38 65.98 62.38 58.66 58.30 54.96 T0.66 60.86 70.18
3.16 2.76 3.62 3.08 3.40 3.08 2.98 2.36 3.88
1 Scientist in Soil Laboratory Investigations, Bureau of Soils, U. S. Dept. Agr. 2 Scientist in Fertilizer Investigations, Bur. of Soils, U. S. Dept. -4gr.
Per cent KC1 19.72 21.28 24.59 27.33 27.87 21.10 16.97 28.89 15.64
Per cent
Per cent
N
1
0.98 0.79 0.95 1.00 1,07 0 83 0.90 0.51 0.84
0.16 0.14 0.13 0.13 0.06 0 10
0.13 0.13 0.07
Remarks Dried and sent b y mail Wet, sent b y express in j a r Wet, sent b y express in jar Wet. sent by express in j a r \Vet. sent b y express in j a r Wet, sent b y express in jar Wet, sent by express in j a r Stems only, dried a n d sent b y mail Leaves only, dried a n d sent b y mail
constituent, and t h e importance of t h e matterprobably lies in showing that their occasional O r
