December, 1924
INDUSTRIAL A N D ENGINEERING CHEilfIXTRY
nicotine sulfate with dusts always results in a loss of the nicotine content. Lloyd's reagent (an aluminium silicate) gave the best results, but even this showed a heavy loss on standing six months. Such powders should apparently be prepared not longer than a few weeks before consumption and if marketed should be dated and recalled after a definite period of time. Alkali is not a necessary part of poultry dusts, as the duodenum of the fowl near the cecum has an alkaline secretion, and it is a t this point that the roundworms are usually found. Suspensions of the prepared nicotine dusts in solutions of this pH value were found to release a large part of the nicotine.
1277,
TOXICITY OF NICOTINE TO CHICKENS Free nicotine was found to be very much more toxic to chickens when administered orally than was nicotine sulfate. One hundred milligrams of nicotine sulfate could be given with impunity in distilled water, but 10 to 65 mg. of free nicotine produced immediate death or collapse and death xithin a few minutes. A dosage of 3 mg. of free nicotine was found to be the minimum a t which death might or might not occur.
Trend of Developments in t h e Nitrogen Problem' By J. M.Braham FIXED NITROGEN RESEARCH L A B O R A T O R Y , WASHINGTON. D. C .
T
HE problem of meeting the rapidly increasing demand for
annually, a quantity equivalent in nitrogen to about 3,300,000 tons of Chilean nitrate and nearly half of the world's inorganic nitrogen output. The part nitrogen fixation has played from 1913 to 1922 in meeting the world's nitrogen needs is shown in Fig. 1. It is seen that in 1922 Germany produced about 75 per cent of the total nitrogen fixed, and met the greater part of her nitrogen requirements in that manner. The fixation in this country, on the other hand, was very small. The situation a t present is essentially the same as in 1922. There are three processes now in operation on a large scale for the fixation of atmospheric nitrogen. These are commonly referred to as the arc, the cyanamide, and the direct synthetic ammonia processes. A fourth process is now in operation in this country on a small scale, producing sodium cyanide and hydrocyanic acid. Although ammonia can readily be produced from cyanide, it does not now appear likely that this process will be able to compete with the direct synthetic ammonia process in the manufacture of ammonia. ARC PROCESS-The arc process, in which nitrogen - becomes chemically combined with oxygen by passing air through an electric arc, was put into operation in Norway in 1905. It was the first air-fixation process to be commercially d e v e 1o p e d The present annual rate of fixation by this process is about 36,000 metric tons of nitrogen, and although there are arc plants in six different countries, over 95 per cent of the total is produced in the two plants in Norway. The main handicap of this process is its enormous power requirement, about 68,000 kilowatt-hours per metric ton of nitrogen fixed. Its commercially successful operation for fertilizer production is therefore limited to UNITED 9TATES countries having very cheap water power. There is a small arc plant in this country, located a t La Grande, Wash., but its 1913 1322 - consumption main product is sodium nitrite. - F i x e d atmospheric production No outstanding improvements in the arc process have been FIG. GELATION O F FIXEDATMOSPHERIC NITROGEN PRODUCTION made during the past ten years, TO TOTAL INORGANIC NITROGEN CONSUMPTION
nitrogen in combined form is now engaging the attention of all the important and progressive countries. The reason for this is that nitrogen is not only the heart of explosives, and hence of prime military importance, but it is also the key element in the fertilization of crops and consequently of utmost importance in meeting the fertilization of crops and consequently of utmost importance in meeting the food requirements of the world. A consideration of the principal sources of combined nitrogen suitable for both agricultural and military uses--namely, ammonia from coke and gas manufacture, Chilean nitrate, and the products of atmospheric nitrogen fixation-leads to the conclusion that the latter must be largely relied upon to meet the constantly growing demands. While this method of suppIying fixed nitrogen may not be the ultimate solution of the nitrogen problem, it will in all probability be the main contributor of fixed nitrogen for several decades. This general conclusion has been reached by workers in this field both in this country and abroad and as a consequence nitrogen fixation processes are now and have been for a number of years the subject of intensive investigation and development in many countries, particularly in Germany, France, Italy, England, Norway, Japan, and the United States. The outstanding developments in the nitrogen problem are in the nitrogen fixation processes and in the new materials which are being made available to agriculture by these processes. COMMERCIAL FIXATION OF NITROGEN Nitrogen fixation on a commercial scale was first accomplished less than twenty years ago, yet a t the present time air fixation processes produce nearly 500,000 metric tons of nitrogen 1
Presented before the Division
of Fertilizer Chemistry at the 68th Meeting of the American Chemical Society, Ithaca. N. Y., September 8 to 13, 1924.
0
4
.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1278
and unless means of reducing the power requirement can be found, the process will play only a minor part in the air-nitrogen industry of the future. CYANAMIDE PROCESS-The cyanamide process, in which nitrogen is fixed by combination with finely powdered calcium carbide a t relatively high temperature, was developed in Germany shortly after the arc process was put into operation in Norway. It requires less than one-fourth the electric power of the arc process per ton of nitrogen fixed, and hence it has been much mo2e widely employed. In 1913there were cyanamide plants in operation in nine countries, with a combined capacity of approximately 34,000 metric tons of nitrogen. Owing to the great demand for nitrogen during the war there was a tremendous increase in the production of cyanamide, and in 1918 there were in operation or under construction thirty-six cyanamide plants, with a combined capacity of nearly 325,000 tons of nitrogen. One of these was U. S. Nitrate Plant No. 2 , a t Muscle Shoals, Ala., with a capacity of 40,000 tons of nitrogen per year-the largest cyanamide plant in the world. A number of war-built cyanamide plants have since been scrapped, and others have remained idle, as in the case of the Muscle Shoals plant. The present annual rate of fixation by the cyanamide process is about 140,000 metric tons. This is somewhat more than four times the production for 1913, but represents less than half of the productive capacity of existing plants. The chief disadvantage of the cyanamide process is that the product, calcium cyanamide, has not proved entirely satisfactory as a fertilizer material for general use. In this country, another limitation is that the product cannot safely be used except in small quantities in mixed fertilizers containing acid phosphate. Although cyanamide can be converted into other forms of fertilizer nitrogen, such as ammonium sulfate, and urea, the conversion costs have thus far been too high to enable the product to compete with by-product ammonium sulfate and Chilean nitrate. The quality of calcium cyanamide, as measured by the nitrogen con-
$
HF
5-00.000
”/
metric tons of nitrogen per year, and one a t Merseburg, with a 200,000-ton capacity. It will be noted that the annual output of these two plants alone is nearly equivalent in nitrogen to that produced in Chile a t the present time. There were no direct synthetic ammonia plants in successful commercial operation outside of Germany during the war, but in the latter part of that period investigations were begun on this process in a number of countries, and there are now several forms of the synthetic ammonia process in operation. Thus, there is the Haber-Bosch process in Germany, the Claude process in France, the Casale process in Italy, the General Chemical Company and American processes in this country, and also a process recently put into operation in England. All of these are based on the same fundamental reaction, but differ mainly in the operating conditions, especially in the pressure and in the source and method of purification of the hydrogen. There are now fourteen synthetic ammonia plants in operation in the various countries (three in the United States), with a combined capacity of about 320,000 metric tons annually, and several are under construction. The two large German plants previously mentioned produce more than 90 per cent of the total output by these processes. The production and purification of hydrogen is the main problem in the synthetic ammonia process, and is the chief item of cost. In the Haber-Bosch process the hydrogen is obtained through the production of water gas from coke; in the Claude process it is obtained by fractionation of coke oven gas; and in the Casale process by the electrolytic decomposition of water. The power requirement of synthetic ammonia processes depends upon the method of hydrogen production, but as ordinarily operatedi. e., water-gas hydrogen-it is only about one-fourth that of the cyanamide process. During the past three years important advances have been made in the synthetic ammonia processes not only in hydrogen production and purification, but in the simplification in plant design and operation and also in the catalysts required. It appears probable that with these improvements ammonia can be produced in this country in a large installation a t 5 to 6 cents per pound. This, it will be noted, is much below the present market level for by-product ammonia, for example. The growth of the nitrogen fixation industry and present status of the various fixation processes are shown in Fig. 2. OTHER FIXATION PROCESSES-In addition to the four fixation processes that have been mentioned, there are several others now under investigation, but a t present none of them gives promise of displacing in the near future the methods now in commercial operation. POWER
I910
I913
/9/7
I920
I923
YEARS F I G . %-GROWTH
OS THE
REQUIREMENTS O F FIXATION PROCESSES
The power requirements of the various fixation processes, together with the relative output of nitrogen by each process, are shown in round numbers in Table I.
NITROGEN FIXATION INDUSTRY
tent, has been very materially improved during the past few years, but there have been no decided improvements in the process in the last ten or twelve years, and it is gradually being superseded by the direct synthetic ammonia processes. DIRECTSYNTHETIC PRocEss-The outstanding developments in nitrogen fixation a t present are in the synthetic ammonia process, and it is in this direction that a reduction in the cost of fixed nitrogen can be confidently expected. This process, which consists in forming ammonia directly from the elements under conditions of high pressure and relatively high temperature in the presence of a catalyst, was first operated on a commercial scale in 1913 in Germany. The urgent need for nitrogen by Germany during the World War led to the construction of two huge fixation plants, one a t Oppau, with a capacity of 100,000
Vol. 16, X o . 12
TABLE I-POWER REQUIRED PROCESS Arc Cyanamide Direct synthetic ammonia: Electrolytic hydrogen Water-gas hydrogen
Kw.-hrs. per metric ton nitrogen 68,000 15,000
Total fixed nitrogen produced Per cent 7.3 28.2
20,000 4,000
2.0 62.5
As previously indicated, the order of development of the processes is arc, cyanamide, and synthetic ammonia. It will be noted that the power requirement of the cyanamide process is only about 22 per cent that of the arc process, and that for the synthetic ammonia process, obtaining hydrogen from coal or coke, only 6 per cent. These figures, together with those for relative production by the various processes, show very clearly the trend in the fixation of atmospheric nitrogen in the direction of smaller and smaller electric power requirements. In other words, nitro-
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INDUSTRIAL A N D ENGKNEERING CHEMISTRY
December, 1924
gen fixation is changing from what may be termed an electrochemical industry to a chemical one. FIXAT1oN PRocEssEs
FERTILIZER PRoDUCTs OF
The direct products of the arc, cyanamide, and direct synthetic ammonia processes are dilute nitric acid, calcium cyanamide, and ammonia, respectively. All of these require processing or conver-
the atmosphere so readily that i t is difficult to handle or use, particularly in mixed fertilizers. Various methods have been devised t o overcome this dficulty. In Germany a double salt consisting of nearly equal parts by weight of ammonium nitrate and ammonium sulfate is now being extensively used. This material is commonly referred t o as ammonium sulfatenitrate. Ammonium nitrate is also mixed with potash salts,
,Cyanam /de Process,
D f e c f Syn#hetic Ammonia Processes t
JI
L
CALC/UM CYANAMIDE Cyanamide Fertilizer
AMMONIA = Ammonium Sulphafe
Ammonium Phmpate
c
Ammonium Nifra i e
c
Ammonium Ammonium Sulphate -Nitrate Chloride
4
Urea
Sodium Nifra fe (Synthetic Chilean Nitrate)
Calcium Nifm t e (Nor weqian Sal fpe te$
FIG.3
sion to other forms before they are suitable for fertilizer use. These conversion processes are indicated in Fig. 3. Consideration of the ammonium compounds suitable for fertilizer use is of special interest because of the large output ef fixed nitrogen in the form of ammonia. Of the ammonium compounds indicated in Fig. 3---namely, the sulfate, phosphate, nitrate, sulfate-nitrate, chloride, and urea-only the first in the form of by-product ammonium sulfate is entirely familiar to the fertilizer industry of this country. A small quantity of ammonium phosphate has, however, been marketed in this country under the trade name of Ammo-Ph os. AMMONIUM PHosPHATE-!t+here is but little doubt that monoammonium phosphate will become a very important fertilizer salt in the very near future. It contains 14.7 per cent ammonia and 61.7 per cent Pz05,or a total of 76.4 per cent of what is termed “plant food;” it is very stable and nonhygroscopic, and although it has been used as a fertilizer only to a very limited extent, the results in general have been satisfactory. Its commercially successful manufacture is dependent on the cheap production of liquid phosphoric acid. The important advances now being made in this country’in the thermal process for the production of this acid make it appear probable that it will be available for the manufacture of ammonium phosphate in a short time at fertilizer prices. AMMONIUM NITRATEAND AMMONIUM SULFATE-NITRATE-The demand for enormous quantities of ammonium nitrate during the World War for use as a high explosive ingredient resulted in the development of processes by which this material can be produced from the atmosphere a t a cost per unit of nitrogen comparable with that of Chilean nitrate and by-product ammonium sulfate. Ammonium nitrate has been shown to be an excellent fertilizer material, but unfortunately it absorbs moisture from
particularly the comparatively high-grade potassium chloride, yielding a mixture of ammonium chloride and potassium nitrate through double decomposition. While both the double and mixed salts of ammonium nitrate thus obtained are somewhat hygroscopic, they are being successfully used in Germany; in fact, the main source of nitrate nitrogen in German agriculture is now ammonium nitrate applied chiefly in the mixtures mentioned. The hygroscopicity of ammonium nitrate can be reduced by producing the material in the form of grains and oilcoating them. The cost of this treatment is by no means prohibitive, and a product which is very much less hygroscopic than calcium nitrate or Norwegian saltpeter can be produced. AMMONIUM CHLORIDE-The development of the synthetic ammonia process, particularly for operation in conjunction with the Solvay soda process, is opening up new possibilities for the cheap production of ammonium chloride, and developments along this line are now under way in several countries. The fertilizer value of this material is being investigated a t numerous experiment stations in this country and abroad. I f it can be demonstrated that ammonium chloride is a satisfactory fertilizer material, it will undoubtedly become one of the important nitrogen materials. UREA-Urea is perhaps the most interesting of all the newer nitrogen materials being made available through nitrogen fixation processes. It is the most concentrated nitrogen material thus far considered as fertilizer-46.6 per cent nitrogen, or 55.6 per cent ammonia-and possesses good physical properties. It has given splendid results in all tests of its fertilizing value. As indicated in Fig. 3, urea can be produced directly from calcium cyanamide and also from ammonia. Heretofore, the cost of producing urea from cyanamide has been too high t o permit its use as a fertilizer, but recently a process has been developed in
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
Switzerland for the production of a fertilizer material called Phosphazote, which contains urea and acid phosphate. The most promising method of urea production, however, is the direct combination of ammonia and carbon dioxide under conditions of relatively high temperature and pressure. This process is being developed in a number of countries and in Germany a small plant is already in operation. It can be operated to particularly good advantage in conjunction with a synthetic ammonia plant obtaining its hydrogen from water gas, since more than ample quantities of waste carbon dioxide are then available in concentrated form. There is but little doubt that urea will be on the market a t fertilizer prices in a few years. CALCIUM AND SODIUM r\iITRATES-cakiUm nitrate for use as fertilizer is now being manufactured in Norway at the rate of about 160,000 tons annually, nearly all of which is exported. Although the material has been regarded as a very satisfactory form of nitrogen in Europe, it has the disadvantage for general use in this country of being very hygroscopic, and furthermore it contains only 13 per cent nitrogen. Sodium nitrate is now being produced through nitrogen fixation on a somewhat limited scale for use as fertilizer. The main obstacle to its manufacture in large quantities is the high cost of the neutralizing agent, soda ash.
Vol. 16, No. 12
Extraction of Cesium from Pollucite’ By Victor Lenher, George Kemmerer, and Earl Whitford UNIVERSITY OF WISCONSIN, MADISON, Wrs.
H E existing methods for the extraction and purification of T cesium from pollucite, cesium aluminium silicate, are largely the work of Wells.* The essentials of the procedure of
Wells consist in dissolving the mineral in hydrochloric acid, dehydrating the silica, and precipitating the cesium as cesium plumbic chloride, CszPbClB, or with antimony trichloride as 3CsC1.2SbClS. The antimony salt is suspended in water and decomposed by hydrogen sulfide, which according to Wells is a slow and laborious operation, or the antimony is precipitated from the double salt by ammonium hydroxide, in which case the resulting cesium chloride contains large quantities of ammonium chloride. Wells suggests the removal of the ammonium chloride by repeated evaporation with concentrated nitric acid. This also is a long and tedious operation when large quantities of material are being used. Ammonium chloride must not be sublimed from this mixture of chlorides, as it sublimes so near NITROGEN FIXATION AND CONCENTRATED FERTILIZERS the temperature of volatilization of cesium chloride that a large part of the cesium is lost. The nitrogen content of materials being made available to I n extracting cesium from 5 kg. of pollucite, several important agriculture by nitrogen fixation is shown in Table 11. changes in procedure have been introduced which are deemed of sufficient interest to those working with cesium to record. TABLE11-NITROGENCONTENT O F NITROGEN FIXATION PRODUCT8 About 5 kg. of pollucite from Hebron, Me., were ground to a Nitrogena Nitrogena MATERIAL Per cent MATERIAL Per cent h e powder and passed through fine-mesh bolting cloth. I n Urea 46.6 Cyanamid fertilizer 22.0 this state of division pollucite i s slowly but completely de35.0 Ammonium sulfate 21.2 Ammonium nitrate Ammonium phosphate 1 2 . 2 (61.7% composed by concentrated hydrochloric acid. The silica was rePzOd Sodium nitrate 16.4 Ammonium sulfate-nimoved by evaporation t o dryness and dehydration at 110’ C. 13.0 trate 28.8 Calcium nitrate The dry residue can best be extracted by hydrochloric acid of Ammonium chloride 26.2 a Percentage for pure material except cyanamide and calcium nitrate. such concentration as will render the cesium antimony chloride least soluble; this in the writers’ experience is 3 N . Wells’s It will be noted that most of the compounds listed are much more suggestion is one-third t o one-half the total volume of concenconcentrated than those now employed [Chilean nitrate 15.6 per trated hydrochloric acid. Antimony chloride dissolved in 3 N cent nitrogen). By suitable combinations of these materials with hydrochloric acid, when added in slight excess t o the acid exhigh-grade potassium-phosphorus and potassium-nitrogen com- tract from the silica, yields practically all the cesium as crystalpoundsvery concentrated and complete fertilizers can be produced. line 3CsCl.2SbCl8. The small amount remaining in the soluThe fixation of nitrogen in this country is only in its beginning, tion can be removed by evaporating the filtrate and diluting but there is every reason to believe that within the next ten years to 3 N . When this strength of acid is used, further treatment this country will be supplying a large part of its rapidly increas- with lead chloride and chlorine to get CslPbCls is unnecessary. ing nitrogen needs through the fixation of atmospheric nitrogen. Hydrolysis of the antimony cesium salt by boiling with water The change from the use of dilute to concentrated fertilizers gives a product which contains only small quantities of antiinvolves the solution of many problems and it will undoubtedly mony along with traces of iron and aluminium. This can be come gradually, but there is no doubt that the era of really con- treated with hydrogen sulfide to remove the antimony, after centrated fertilizers in this country is already here. which the chlorides are converted t o nitrates by evaporation with nitric acid. District of Columbia Chemistry Teachers Organize The cesium nitrate is then converted to carbonate by disChemistry teachers and those interested in the teaching of solving and mixing with twice its amount of oxalic acid and chemistry organized the District of Columbia Chemistry Teach- igniting. The reaction between cesium nitrate and oxalic acid ers’ Association a t a meeting a t the Cosmos Club on hTovember is attended by considerable frothing, so can best be accomplished 20. The meeting was called by the Washington Section of the at relatively low temperatures in a porcelain casserole which AMERICAN CHEMICALSOCIETY as a part of Education Week program. Addresses were made by N. E;. Gordon, C. E. Munroe, can be covered by a watch glass. The final heating is conducted in a platinum dish. The cesium oxalate breaks down completely Louis Mattern, and R. S. McBride. The purpose of the new organlzation is to increase interest in at redness into cesium carbonate. The fused carbonate is the teaching of chemistry in the high school and college and to next dissolved in water, when the insoluble traces of iron, alusee that chemistry takes its place in the curriculum. Other matters which the organization proposes to consider are the general mina, antimony, together with carbon, can be filtered off and conditions surrounding the teaching of chemistry in Washington the cesium carbonate obtained in pure form. Further purificaand the conditions under which the teachers have to labor. tion can be effected by crystallization from absolute alcohol George I,. Coyle, professor of chemistry a t Georgetown Uni- according to the method of Bunsen. versity, was elected president; H. C. McNeil, of George WashingBy following the procedure described above 37 per cent yield ton University, vice president; Miss Elizabeth Gatch, of Central High School, secretary; and H. A. Lepper, professor of organic of the original material in terms of cesium carbonate was chemistry at George Washington, treasurer. The executive obtained. committee consists of the officers and Hardee Chambliss, pro1 Received October 9, 1924. fessor of chemistry a t the Catholic University, and E. A. Hill, * A m . J . Sci., 46, 180 (1893); Am. Chem. J . , 26, 265 (1901). of George Washington University.
