CHEMICAL SCIENCE HAS AIDED MATERIALLY IN THE IMPROVEMENT OF EXISTING PROCESSES FOR THE MANUFACTURE OF FERTILIZERS
with then-known analytical methods was enacted in 1872. Today all 48 states have such laws. The literature shows that much of the guano imported during the early years was heavily leached, with practically no plant-food content remaining. To establish fraud in such cases and prevent further importations of worthless material, it was necessary t o develop analytical methods sufficiently accurate t o stand up in court and assist in protecting the consumers. The formation of the Association of Official Agricultural Chemists in the early 1880’s and their subsequent research in developing accurate methods of chemical analysis have been of incalculable value t o agricultural chemistry in all of its branches.
T
HE use of various natural materials t o increase crop produc-
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tion has been recorded since the days of early Rome. I n the United States such practices were recommended in the diaries of Washington and Jefferson. As early as 1830, Chilean nitrate of soda was imported and 2 years later commercial importation of guano from Peru was established. The years 1849 and 1850 mark the actual beginning of chemical fertilizers in this country. The first of these years saw the initial manufacture of superphosphate in the United States in Baltimore, and the issuance t o the Chappell brothers of the first chemical fertilizer patent, U. S. Patent 6234. This patent covered the production of a compound or mixed fertilizer in a combined acidulating and mixing process. The components of the mixture included bones, sulfuric acid, “gas or ammoniacal liquor,” and a number of “residues” from other chemical operations. These residues contained, among several other things listed, carbonate of potash, calcium sulfate, and magnesium sulfate. From their nature, no doubt, they also contained a t least traces of the minor plant-food elements. I n this century-old patent are mentioned all the now-known primary and secondary plant foods and probably some of the minor ones. Some processes described in the patent are standard practice today, though in considerably more mechanized form. I n 1850, in Baltimore, mixed fertilizers were produced for the first time in this country. By 1856 it is believed that production reached 20,000 tons. Even so, three times t h a t much Peruvian guano was imported the same year. From then until the late sixties, production seems t o have increased slowly and steadily as more plants were built and demand increased, but by-product materials were the main source of the ingredients used in the mixtures. The phosphoric acid came mostly from bones, packing house tankage, and fish scrap. These materials, along with imports of Peruvian guano and Chilean nitrate of soda, furnished the nitrogen. Potash was just being exploited as a plant food by Liebig. Imports of potash from Germany started in 1869. Shortly after the end of the Civil War, the value of the phosphate rock deposits near Charleston, S. C., was recognized and their development undertaken. Treatment of this rock with sulfuric acid produced superphosphate, which soon became the principal source of phosphoric acid in fertilizers. The development of fertilizer manufacture from a scavenger industry into a chemical industry began in this era. By 1875, about the time the AMERICAN CHEMICAL SOCIETY was founded, annual consumption of fertilizers and fertilizer materials had increased t o nearly a million tons, and the chemical problems involved in fertilizer manufacture became important. It had been realized almost from the first that the agricultural value of a fertilizer was in direct proportion t o its content of certain chemical compounds, notably those carrying nitrogen and phosphates. The first record of a fertilizer analysis by a state official appears in 1851. Little was then known of satisfactory chemical methods for quantitative measurement. As early a s 1856, a state fertilizer control law was enacted in Massachusetts, but its requirements were so rigid and exacting that it could not be enforced. A revised law more in keeping
C H E M I C A L PROCESSES USED IN P R O D U C T I O N O F FERTILIZERS
Discovery of the phosphate rock deposits of Florida and Tennessee in 1881 and 1893, respectively, and their development mntributed additional impetus t o the expansion of the chemical side of the fertilizer industry. In the early 1890’s the first concentrated superphosphate was produced in this country and by-product sulfate of ammonia was first recovered from the coking of coal. During the first 50 years of the industry’s progress, the nitrogen used came almost entirely from the organic wastes of other industries. The principal sources were the oilseed meals, packing house by-products (such as tankage, blood, and bone), fish scrap, garbage tankage, and peat. In 1900, over 91% of the nitrogen was in the natural organic form and only 9% came from chemical salts. Increased production of by-product sulfate of ammonia and additional imports of nitrate of soda, together with better knowledge of formulation possibilities, rapidly increased the use of the chemical forms until by 1920 about equal percentages of organic and chemical forms were used. In 1949, less than 5% of the nitrogen consumed as fertilizer was in the organic form. Practically all these previously used organic by-products were diverted t o use as animal feeds. About 1926 the processes of using aqua and anhydrous ammonia directly in fertilizers were introduced and the later use of ammonia solutions containing ammonium nitrate or urea contributed greatly t o this development. Production of cyanamide a t Niagara Falls, Canada, in 1909, followed by the production of synthetic anhydrous ammonia in 1921, added t o our nitrogen resources. The synthetic ammonia plants built by the Government in the World War I1 program and later released t o private ownership and management ensured an adequate supply for all peacetime needs. One of the greatest chemical achievements of the fertilizer industry was the establishment of a nationally self-sufficient potash industry. The chemical process problems and chemical engineering details worked out in connection with the production, through fractional crystallization, of potash from the brines of Searles Lake, Calif., and the salt flats near Wendover, Utah, and the recovery and concentration of potash from the solid deposits of low grade salts beneath the New Mexico desert near Carlsbad, N. M., have been outstanding contributions t o industrial chemistry.
F. S. Lodge, National Fertilizer Association, Washington, D. C. 311
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 43, No. 2
Although the chemistry of superphosphate manufacture has inexhaustible supply in the air. Deposits of phosphate rock been changed little in the last 100 years, there has been much already surveyed t o last an estimated 3000 years, together with refinement in the technique of its application. The techniques sufficient mining and processing capacity t o produce our needs of have advanced from hand-stirring in mortar boxes with hoes available phosphoric acid, are available. We have enough t o almost automatic mechanical installations for Iveighing and capacity already installed t o produce and refine our needed potmixing the ingredients, and from hand-digging of dens of superash, with reserve deposits mapped out t o last a t least 200 years. phosphate t o mechanical dens t h a t excavate themselves and Consumption of fertilizers had increased to 2,200,000 tons by deliver the crumbled and aerated superphosphate t o storage. 1900, with an average plant-nutrient content in mixed goods of The manufacture of a higher grade superphosphate or con13.9’%. By 1930, it had reached 8,200,000 tons, with an average centrated superphosphate began in 1872 ( 4 ) . This process nutrient content in mixed goods of 17.90%. The approximately 50% drop in consumption reached in the depression of 1932 was was essentially an acidulation of phosphate rock with somewhat all recovered by 1940, and steady increases continued until 1949 weaker sulfuric acid than was used t o make normal superphosregistered a consumption of 16,500,000 tons with an average phate. The sulfuric acid converted the phosphorus content t o phosphoric acid. The product was leached t o obtain the phosnutrient content of over 22%. phoric acid in dilute solution, which was then concentrated and S s these many improvements and advances in fertilizer chemused t o acidulate more ground phosphate rock. The resulting istry came t o pass. the attention of the industry was brought more uroduct. known as concentrated superphosphate (also called and more to the supreme importance of chemical science t o its double superphosphate, triple welfare. The functions and superphosphate, and treble significance of chemical consuperphosphate), contains 40 trol in the industry became Officers of the Division of Fertilizer Chemistry, recognized, and the fertilizer t o 48% available phosphoric 1909-1 950 acid. The phosphoric acid for chemist became a man of imChairman Secretary Year portance and value rather than the acidulation may also be a necessary eviI. Fertilizer F. B. Carpenter J. E. Breckenridge obtained by smelting phos1909-1910 chemistry became recognized Paul Rudnick J. P. Street phate rock in an electric fur1911-1912 J. E. Breckenridge Paul Rudnick nace, recovering the volatilized as a separate branch of the 1913 profession, J. E. Breckenridge E. L. Baker phosphorus, which is then 1914-1915 burned and collected in the J. E. Breckenridge F. B. Carpenter 1916 FERTILIZER CHEMISTRY AND THE J. E. Breckenridge form of concentrated phosL. L. Van Slyke 1917 A M E R I C A N C H E M I C A L SOCIETY J. E. Breckenridge F. B. Carpenter phoric acid. Officially, super1918 F. B. Carpenter H. C. Xoore The Division of Fertilizer phosphates containing up t o 1919-1920 Chemistry of the AMERICAN F . B. Carpenter H. C. Moore 1921-1922 25% available phosphorus CHENICALSOCIETY was authorF. B.Carpenter H. C. Moore pentoxide are knom n as normal 1923-1924 ized in 1908, shortly after the F.B.Carpenter H. C. Moore 1925-1 926 superphosphate and those conSociety inaugurated the diviF.B. Carpenter H. C. Moore taining above 25% as concen1927 sional system, being one of the H. C. Moore 1928-1 929 trated superphosphate, E. W. Magruder four divisions authorized that E. W. Magruder H. C. Moore 1930-1 93 1 The processes for converting first year. E. W.Magruder H. C. Moore 1932-1933 the comparatively insoluble The organization of the E. W.Magruder H. C. Noore 1934-1935 and unavailable phosphorus Division of Fertilizer ChemisH. C. Moore 1;. W.Magruder 1936-1937 content of phosphate rock into try was perfected in 1909 with E. W. Magruder H. B. Siems 1938-1939 compounds which carry the F. B. Carpenter, chairman, C. A. Butt H. B. Siems 1940-194 1 phosphorus in forms which can and J. E. Breckenridge, sec€I. B. Siems C. A. Butt be utilized readily by plants 1942- 1943 retary. H. B. Siems C. A. Butt have perhaps undergone more 1944-1 945 C. A. Butt H. B. Siems An executive committee, research effort than have all 1946 J. B. Hester selected from chemists in state C. A. Butt the other fertilizer chemical 1947 and government service and J. B. Hester Vincent Sauchelli p r o b l e m s . T h o u s a n d s of 1948-1 949 from the fertilizer industry, S. F. Thornton Vincent, Sauchelli dollars have been spent on this 1950 has functioned throughout the research problem. I t is still years, particularly in program perhaps the most vital chemiarrangements and in deciding matters of policy. cal problem facing the industry because of the impending shortAlthough the division held meetings between 1909 and 1916, age of sulfur required by the supeiphosphate manufacturers for no record of the attendance or programs seems t o have been their production of sulfuric acid. h n o n g the many processes published; in fact, the attendance was usually small and the that have been investigated in this research which have reached papers presented were few. I n 1916, for instance, a t the spring a t least the pilot plant stage, if not even the production stage, are meeting held at the University of Illinois, Urbana, Ill., only three the follow-ing: members were present-J. E. Breckenridge, then chairman, 1. Calcination of phosphate rock in rotary cement kilns with F. B. Carpenter, and the author of this history. At that meeting, and without such reagents as soda ash, silica, or water vapor. 2. Production of calcium metaphosphate by burning elefree, informal discusaion of the chemical problems of the fertilizer mental phosphorus in the presence of phosphate rock. industry resulted in a definite outline for future meetings of the 3. Fusion of phosphate rock with serpentine or olivine. division. 4. Acidulation of phosphate rock with hydrochloric or nitric Inasmuch as the spring meetings of the Society generally take acid. place a t the height of the fertilizer shipping season tvhen it is THE FUTURE OF THE FERTILIZER INDUSTRY very inconvenient, if not impossible, for industry chemists t o be absent from their laboratories, it was proposed that meetings These various advances in chemical technology in the fertilizer of the division should be held only during the fall meetings of the industry have placed our nation in an independent position as Society and this policy has been maintained. to its necessary requirements of plant food. Sufficient capacity I n order t o stimulate interest in the meetings of the division is available in the form of synthetic ammonia plants t o produce and ensure larger attendance, it seemed desirable, as far as all o m conceivable agricultural needs of nitrogen from the
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possible, t o have one topic predominate a t each meeting. Believing that the question of obtaining representative samples of fertilizer shipments for the purpose of analysis by state officials administering fertilizer laws was of the first importance, this subject was decided upon as the major topic for discussion a t the 1916 fall meeting. The availability of the nitrogen in organic fertilizer materials was t o be a secondary topic for discussion. At the 1916 fall meeting, a report (3) was made on the sampling devices and methods used by the control officials of practically all of the fertilizer-consuming states. I n many cases, the methods and implements used were so crude and so inadequate t h a t representative samples could not be obtained by their use. Approximately 100 people were present at the 1916 meeting, including many state control officials. As a result of this meeting, a committee composed of control officials and industry chemists was awointed t o carry out collaborative work on -sampling for the purpose of developing standard methods of sampling fertilizers that might be designated as “official” by the Association of Official Agricultural Chemists. A similar committee was appointed by the Association of Official Agricultural Chemists t o cooperate with the AMERICAN CHEMICAL SOCIETY committee. Such methods were reported and approved a t the 1917 meeting of the Division of Fertilizer Chemistry and were later, in 1920, adopted in substance by the Association of Official Agricultural Chemists. Many states adopted these methods and sampling ceased to be a major problem. Attendance was light a t the division meetings during the World War I period, and papers and discussions generally centered around analytical methods and technique. Since 1920 the meetings of the division have been uniformly well attended when held in the eastern half of the country. No meeting of the division was scheduled in 1925, when the fall meeting of the Society was held in Los Angeles. Meetings of the division, attended as they are by scores of industry chemists and official state and government chemists, provide a forum where problems of fertilizer chemistry may be discussed. The results growing out of such discussions have been of incalculable benefit t o agricultural and fertilizer chemistry and hence t o agriculture itself. I n addition, such meetings of official chemical workers and researchers on common ground with chemists from industry faced with practical problems have established cordial, friendly relations and have broadened the viewpoints of each with advantage t o all. Meetinrrs of the division, comina as thev’do usuallv a few weeks prior to the annual meeting of t h e Association of Official Agricultural Chemists and the annual meeting of the American Association of Fertilizer Control Officials, afford an opportunity t o present and discuss pressing problems for consideration by those organizations. Technical workers in fertilizer manufacturing processes and scientists engaged in agronomic and chemical research on plant foods find in the meetings of the Division of Fertilizer Chemistry interested and sympathetic audiences t o whom they are welcome to present their problems and research findings and with whom such matters may be discussed with mutual understanding and advantage. In addition t o sampling, many other subjects originally presented and discussed before the division have later received consideration and final action by the Association of Official Agricultural Chemists. They include: 1. Chemical methods for evaluating the activity of organic nitrogen in fertilizer materials. Adopted 1927 (1). 2. A change in the size of sample used in the determination of available phosphoric acid, so as to measure more accurately the phosphoric acid content available to plants as food. Official 1931 ( 1 , 2 ) . 3. Method for the determination of the amount of potash in fertilizers that is available as plant food, in place of the amount that is water-soluble potash (1). 4. Recognition of the role of the so-called minor plant food elements in plant nutrition and their determination in fertilizer materials and mixtures. Adopted 1938 ( 1 ) .
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Commercial mining of phosphate rock in the United states had its origin at Charleston, 8.C., in 1868
Flotation cells and tables for phosphate processing at International Minerals and Chemical Corp., Mulberry, Fla.
T h e size of modern plants i s typified by this view of American Potash and Chemical Co., Trona, Calif,
T h i s $1-cubic-yard dragline excavator used in phosphate mining i s appropriately named the Bigger Digger 5 . Discussions resulting in the establishment by the Association of Official L4gric~~ltural Chemists of its Committee on Definition of Terms and Interpretation of Results on Fertilizers and Liming Rlaterials. Appointed 1920 ( 1 ) . 6 . Study of the problems involved in producing fertilizers of predetermined residual reaction 111 the soil, not spoken of as “acid-forming” and “nonacid-forming” mixtures. Adopted 1936 ( 1 , 6). Following the idea of having one subject predominate a t each meeting of the division, beginning about 1940 a symposium on some prominent phase of fertilizer chemistry has bern held each year. In addition, a t least one session a t each meeting is devoted to papers pertaining t o the broad field of fertilizer technology but not appropriate for the symposium. Some of these symposia have been held jointly with one or more other divisions of the Society. Symposia on the tollowing subjects have been conducted over the last 10 years, and thc plan has been most successful: 1940 Joint Symposium on Liebig and Hi. Contributions to Agricultural Chemistry 1941 Joint Syniposium on Phosphates 1942 Potash 1943 Boron in Agriculture 1944 Nitrogen in Agriculture 1945 I\To meeting of the dociety 1946 Magnesium in Agriculture 1947 Calcium in Agriculture 1948 Processing of Phosphates 1949 Sulfur in Agriculture
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Attendance a t the divisional meetings during the last 10 years has been very good, from 100 t o 250 being present. Through the years, the organization of the division has been somewhat informal in character. KO divisional dues have been assessed and no formal membership requirements have been adopted. The close relationship between fertilizer chemistry, soil chemistry, and agronomy in general has made it desirable for many papers t o be placed on the division programs t h a t a t first thought might
seem inappropriate for presentation before the AMERICANCHEWc.4~SOCIETY. However, fertilizer chemistry in its broad aspects goes far beyond the reactions within fertilizer mixtures. The chemistry of the soil, the chemical content and physical characteristics of food, feed, and fiber are all vitally concerned with and affected by the utilization of fertilizers. As a result, fertilizer chemistry and agronomy go hand-in-hand, and many official and commercial agronomists and soil scientists attend the division meetings. Some 600 members of the AMERICAN CHEMICAL SOCIETY are n o y listed as members of the Division of Fertilizer Chemistry. Members who have held positions in state or federal laboratories or other official organizations have generally preferred not t o accept election as a division officer but have at all times served 011 the Division Executive Committee. Chemists and agronomists representing commercial organizations have consequently accepted such officer assignments and have attempted t o manage the division meetings and programs so t h a t they would be useful and interesting t o all segments of the membership. The continually increasing interest and attendance noted a t the annual meetings reflect the divisional officers’ success along these lines. Many factory and field problems in fertilizer chemistry remain unsolved and many presently uqed processes are open t o improvement and refinement. It is hoped t h a t the divisional meetings of the future, by revealing the latest in research findings, will be as helpful as those of the past. LITERATURE CITED
(1) Assoc. Official Agr. Chemists, “Methods of Analysis,” 5th ed., pp. 20-40, 1940.
(2) Jacob, X. D., et al., IND. ENQ.CHEY., 22, 1385 (1930). (3) Lodge, F. S., Am. Fertilizer, 45, 26 (Oct. 14, 1916). (4) Mehrins. A. L.. U. S. DeDt. Am., Circ. 718 (December 1944). i5) Pierre, H., Am. F e r t i t i h , 75, 18 (Sept. 12, 1931).
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