COMMERCIAL ASPECTS OF NITROGEN CONTROL
Free nitrogen, it will be recalled, has no economic significance. To be available in the industrial arts it must be in a state of chemical combination. The form of compound is of secondary importance, since this may be modified more or less readily to suit the need, but its value is conditioned in terms of its availability in the form of nitrogen compounds. In consequence, the several sources are classifiable industrially under three heads:
Natural compounds—nitrogen occurring naturally in the form of marketable compounds.
By-product compounds—nitrogen rendered available incidentally in the course of operations otherwise directed.
Fixation compounds—nitrogen whose availability is dependent on special fixation treatment.
Natural Compounds.
—Chile nitrate is the outstanding representative of the natural compounds. The guano industry, or what there is left of it, and a few other odds and ends of production from organic sources, belong here as well, but their combined output is so relatively small that the Chilean industry comprises what amounts to a monopoly of the natural resources. It is not operated as such, however, but by private capital, which owns and operates the oficinas, paying the Chilean government a royalty or export tax amounting to about $11.20 per ton. British and Chilean interests share about equally in making up the far greater part of the capital invested. The balance is largely German and American. The total capitalization in 1909 amounted to approximately $134,000,000, representing an actual valuation of about $30,000,000. Various efforts on the part of the commercial interests involved to effect combinations for the purpose of stabilizing production have been attempted, but have not been entirely successful, and the general tendency has all along been toward overproduction.
The operations, as already outlined on [page 424], are crude, and the cost of production is correspondingly high, amounting to around $25 to $30 per ton at seaboard, inclusive of the $11 export tax. The nitrate is marketed largely through commission houses. The American situation is mostly in the hands of three companies, W. R. Grace & Co., E. I. du Pont de Nemours Powder Co., and Wessel, Duval & Co. The magnitude of the Chilean industry as a whole and its relative importance are shown in [Figures 16] to [18] and [Table 66].
By-product Compounds.
—To this class of compounds belong, with the few minor exceptions already noted, the nitrogenous products of organic derivation as a whole, and those from carboniferous sources such as coal and oil shale. From the former source comes a miscellany of organic refuse resulting from activities dealing with animal, vegetable, and fish products, and carrying nitrogen in the form of organic ammoniates commonly left as such for use in agriculture. From the latter the nitrogen recovered is all chemical nitrogen in the form of ammonia or ammonium salts, mostly ammonium sulphate, and is available in all capacities.
The organic production is impossible of definite analysis from any angle. The lack of systematically compiled records, and back of that the miscellaneous largely decentralized character of the output, along with the fact that the producing costs are for the most part indistinguishable, leaves altogether too much to the imagination. Much of the supply is derived from connections of sanitation, especially of local sanitation, such as the rural practice, for which there is no measure whatever. Another prominent source of supply is represented in what is known as tankage, the refuse from animal-rendering plants; but here too the issue is lost in the scattering of the production, the indefiniteness of composition, and the fact that not all of the product is used as a source of nitrogen, some of it going into the preparation of animal food. The same is true of cottonseed meal and various other less prominent forms of organic waste resulting from industrial activities. Fish scrap and slaughter-house refuse from meat packing also contribute prominently and at the same time rather more definitely to the supply of agricultural nitrogen; but even here adequate figures are not available. The Federal Trade Commission undertook to analyze the 1913 consumption, with results given in the following table:
Estimated Consumption of Nitrogen in Commercial Fertilizers for the Year 1913
| Materials | Fertilizing substance | Consumption (tons) | Content (per cent.) | Units consumed [157] |
|---|---|---|---|---|
| Nitrate of soda | Ammonia | 260,000 | 18.0 | 4,680,000 |
| Sulphate of ammonia | Ammonia | 130,000 | 25.0 | 3,250,000 |
| Cyanamid | Ammonia | 15,488 | 18.0 | 278,784 |
| High-grade tankage | Ammonia | 210,000 | 10.5 | 2,205,000 |
| Concentrated | Ammonia | 18,351 | 14.5 | 266,090 |
| Dried blood | Ammonia | 40,000 | 17.0 | 680,000 |
| Dried fish scrap | Ammonia | 50,000 | 11.0 | 550,000 |
| Cottonseed meal | Ammonia | 660,000 | 7.5 | 950,000 |
| Total | ... | ... | ... | 16,859,874 |
[157] A unit is 1 per cent. of a ton, or 20 pounds.
This estimate, however, takes into account only the more strictly industrial sources, leaving rural sanitation and the like out of the reckoning.
Aside from the conversion of organic ammoniates, which is practiced on a large scale only in a few instances, notably that of the Paris system of sewage disposal, four general types of industrial operation figure more or less in the production of by-product ammonia. They include coal distillation, bone carbonization, oil-shale distillation, and blast-furnace operations. The American production, however, is all derived from the first two types. Both the others are active producers abroad, especially in Scotland, but neither of them has as yet obtained a foothold in this country. The American recovery in connection with bone carbonization is of minor consequence. Practically the whole supply comes from gas works and by-product coking operations. [Figure 17], in the shaded area bearing the designation “ammonium sulphate production,” shows the magnitude and trend of the production from year to year since 1900.
The organic nitrogen recovered in all of the various by-product connections taken together probably constitutes 40 to 50 per cent. of the total supply. Coal product ammonia in this country adds another 12 to 15 per cent. So over half of our supply is of by-product derivation. The domestic output is supplemented in the case of the organic form by considerable importations from South America, and, until interfered with by the war, small amounts of ammonium sulphate were imported annually from Europe. Essentially, however, the by-product supply is of domestic origin. Despite its magnitude, it occupies an anomalous sort of position industrially. It is recovered incidentally for what it is worth, and sold for what it will bring. The cost of production is largely charged off against the major operations with which its recovery is associated, and the returns are credited in conformance, as a saving in the cost of the major operations. This is equally true whether the source be that of the domestic animal on the farm, a coke oven, or a packing house.
The industrial output is built up as a sequence to industrial concentration. This is evidenced all down the line, notably in the output of coke-oven ammonia from the steel industry and in that of organic ammoniates from the meat-packing industry. It is this influence of co-ordinated industrial concentration, along with the call for the major operations, that controls the supply of by-product nitrogen; so the development and handling of the industrial output comes naturally to be largely in the hands of trade combinations. Thus, the coal-product ammonia situation is largely at the disposal of the Barrett Co., the tankage and other animal-product ammoniates gather for disposal at the hands of the packing interests, and the nitrogenous fertilizers from cottonseed are for the most part prepared and marketed by interests subsidiary to the Cotton Oil Co.
The manufacturing interests involved are concerned primarily in the manufacture of other than nitrogen products. The by-product nitrogen recovered has to compete for its market against what comes from the other two industrial classes of supply, and its price goes just low enough to enable it to do so. The limits set in the incidental character of the output leave no special incentive to carry the price competition further. Whatever additional latitude of advantage as to cost of production it possesses goes not to promoting a further reduction in the price of nitrogen but to lowering costs with reference to the major theme of production. Gas-house ammonia, for instance, does not affect the nitrogen market so much as it does the cost of gas, and the organic ammoniates recovered in connection with meat packing have not lowered fertilizer costs so much as they have kept down the cost of meat to the consumer. Thus the by-product class of supply, though the leading one in the point of magnitude, and by far the cheapest to produce, has little to do with determining the price of nitrogen. The selling price of by-product nitrogen is determined by the price the product from competing sources brings. In this country it is controlled by the price of Chile nitrate, and not, as commonly imputed, by the trade combinations that develop and handle the output.
Fixation Compounds.
—Nitrogen has five general habits of combination: with oxygen, giving rise to nitric acid and its retinue of nitrate salts; with hydrogen, giving ammonia and the ammonium salts; with carbon, to form cyanogen and the cyanides; with basic elements, yielding nitrides; and organically, in the form of organic ammoniates. Various projects have been advanced for turning these to account in the fixation of atmospheric nitrogen. For the most part they have met with little or no practical success, but there are exceptions to the rule of failure in all five directions.
Direct Oxidation—Arc Fixation.
—Nitrogen does not oxidize at all readily under any ordinary conditions, but its natural indisposition to combine with oxygen may be overcome by passing a mixture of the two gases through an electric arc. The atmosphere furnishes the nitrogen and oxygen ready mixed, so all that is needed in the way of raw materials is an abundant power supply. Arc fixation was developed in Norway, where the possibilities in the way of hydro-electric power give the best setting to be found anywhere in the world. Efforts to introduce it elsewhere have resulted unsatisfactorily, and arc fixation has made relatively little headway, as may be deduced from [Table 66] and [Figure 18]. The reason is two-fold. So far, its use of power has proved uneconomical, and its product unsatisfactory. The former of these two objections depends for its force on the demand for power, but the latter is more decisive. The immediate end product is nitric acid, which is both difficult to transport and limited as to use. To be put in shape for agricultural use it must be neutralized in the form of a nitrate salt. Limestone is the only cheap neutralizing agent. This gives a salt, calcium nitrate, which absorbs moisture, cakes, and is thus unsuited to the American agricultural practice of machine drilling. An experimental plant near Seattle, Wash., aims to overcome this difficulty by turning out its arc product in the form of sodium nitrate, but the project is of no commercial significance as it stands.
Ammonia Fixation.
—Nitrogen is no more disposed to combine of its own accord with hydrogen to give ammonia than with oxygen to give nitric acid. In the case of the Haber process, the only synthetic ammonia process that has stood the test of industrial application, the native indisposition to combine is overcome by subjecting a properly proportioned mixture of the two gases to heat and pressure in the presence of a catalyzer. This process was instituted in Germany shortly before the outbreak of the war, and as shown in [Figure 16] and [Table 66] has developed steadily since then. Little seems to be known as to the efficiency of the German Haber practice. Apparently, careful manipulation is necessary to obtain results. This means a skilled attention, which is incompatible with mechanical volume production and is thus unsuited to American practice. What aims to be an adaptation to American conditions was worked out by the General Chemical Co., and a plant with a rated capacity of 60,000 pounds of anhydrous ammonia per day was projected at Sheffield, Ala., at the instance of the Government. The plant was completed, but before it could be tuned up for actual production the war ended.
Cyanide Fixation.
—Nitrogen, in passing through a red-hot mixture of finely divided soda ash, coke, and iron, reacts with the sodium and carbon to give sodium cyanide. This principle of fixation is being extensively experimented with, but has not been developed commercially, except in a small plant with a rated daily capacity of 10 tons of sodium cyanide at Saltville, Va.
Cyanamid Fixation.
—Hot calcium carbide will absorb nitrogen, forming a compound of calcium, carbon, and nitrogen, according to the formula Ca CN2, known as cyanamid. The cyanamid process, based on this reaction, has been extensively developed, far more so than any other of the various processes, as will be seen by referring to [Figure 16] and [Table 66]. Offhand, it looks to be the most adaptable and consequently the most promising of the lot commercially. In this connection, however, it is interesting to examine the several charts of its growth in the warring countries given in [Figure 16]. In none of these is the showing indicative of a strong, healthy development. Worst of all is the case of Germany, with the contrast offered in the Haber and cyanamid charts. Until the war, cyanamid manufacture was unable to obtain a competitive foothold in the United States, although a small plant has been in operation at Niagara Falls in Canada for some years. The problem it has faced is similar to that already chronicled for arc fixation, in that it draws heavily on power in the preparation of the necessary carbide, and the cost of power in this country has been prohibitive. Under the stress of the wartime demand for nitrogen, however, the Government contracted for the erection of three plants—one at Muscle Shoals, Ala., one near Toledo, Ohio, and one near Cincinnati, Ohio, with a total rated capacity amounting to 220,000 tons of ammonium nitrate per year. The work on all three was well under way, but none of the plants had reached the producing stage when the signing of the armistice brought the nitrate activities of the War Department to an end.
Nitride Fixation.
—The only process of any prominence aiming to fix nitrogen in the nitride form is one developed by the Aluminum Company of America. This has for its working principle the fact that a mixture of alumina and carbon, highly heated, will absorb nitrogen by reacting to give aluminum nitride. The nitride when heated with caustic soda gives its end product in the form of pure ammonia. The outstanding difficulty encountered in applying this process commercially seems to be that of providing a furnace capable of standing the temperature requirements. At all events the process has not succeeded in making good industrially.
Bacterial Fixation.
—The artificial attempts at fixation have been directed almost wholly toward employing chemical principles. In view of the difficulties experienced and the uncertain value of the results as a whole, it is interesting and perhaps highly significant to reflect that after all, as indicated in [Figure 15], inorganic chemical principles seemingly have little to do with developing the natural supply, probably because of the activities of nitrifying bacteria. Little attention has been given to the possibilities in this direction. This is only natural so far as commercially actuated research is concerned, since it does not lead in the definite direction of patent rights; but the failure to institute an adequate investigation governmentally can be attributed only to lack of comprehension with reference to the scope of the nitrogen issue as brought out under “General Aspects of Control” on [pages 425] to [433]. The subject has received just enough attention to show that bacterial fixation represents a tremendous field of grossly neglected possibilities.