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animal tankage, and cottonseed meal were added in amounts equivalent to 1, 2, and 3 per cent nitrogen, respectively. The close agreement of columns (A) and (B) by the proposed method indicates that any action of hydrogen on these materials is insufficient to offset the effect of the concentrated soda solution used. The differences found are stated in the third column, the apparent nitrate present being 0.03, 0.07, and 0.11 per cent in the samples containing cyanamide. I n four of the remaining samples the (B) column shows that the action of sulfuric acid and soda alone was even slightly greater than the iron, sulfuric acid, and soda treatment. All, however, are well within the limits of error. Against this showing compare the results obtained by the official reduced iron method, particularly in the samples containing cyanamide, where 0.56, 1.12, and 1.65 per cents
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of nitrate nitrogen are indicated where none exists. I n the remaining samples no such variations are noted, though all show increases over those obtained by the proposed method. It seems probable that during the curing of acid phosphate, to which either cyanamide or urea has been added, these organic ammoniates may be partially converted to ammonia. This portion, if held in the mixture in the form of ammonia salts, should now be classed as mineral nitrogen, for it so exists in the material regardless of its original source. Thus far this method has been applied to laboratory mixes only, where well-cured acid phosphate was used. The writer desires that fertilizer chemists give it a thorough trial on factory mixed goods containing known amounts of nitrate nitrogen together with cyanamide and urea.
Some Economic Aspects of Texas Potash' By J. W. Turrentine BUREAU OB SOILS,WASHINGTON, D. C
T
HE establishment of unmistakable evidence of the presence of segregations of potash in the saline strata underlying a large area in western Texas and south-
eastern Ken- Xexico has again aroused the popular interest in American potash. It has long been the dream of those of us who have devoted our energies to the establishment of American independence with respect to this important agricultural and industrial essential that some day we should find within our own boundaries subterranean deposits of potash similar to or a t least comparable with the great German deposits. I n the days when national potash surveys were inaugurated, potash production in Germany was largely a simple mining operation, potash salts being mined and crushed and shipped to market without refining, pretty much as coal is mined and shipped in this country. A simpler or cheaper source it was hard to imagine. And i t was because of this dream of natural deposits of water-soluble potash that we were discouraged in our study of the abundant potash-bearing raw materials which we found in America, all of them requiring more or less elaborate chemical processing to render the potash merchantable. Now that we are apparently approaching the realization of our dreams, is our problem about to be solved or are we confronted by fresh disappointments? Is it not better to anticipate these than to meet them unprepared? Geological Considerations
The C . S. Geological Survey have provided many reliable data relative to the newly discovered Texas deposits. Unfortunately, these data are still largely qualitative, but even so are highly significant. I n drilling for oil in the region mentioned strata of rock salt and anhydrite have been encountered over a wide area. An examination of the balings obtained in penetrating these strata has revealed occasional high percentages of potash, first reported by J. A. Udden, of the Bureau of Economic Geology and Technology of the TJniversity of Texas, and later in more complete form by Mansfield, Hoots, and Lang, of the Geological Survey. With the churn drill there employed and with fresh water lubrication, material 'Received August 19, 1926. Presented before the Division of Industrial and Engineering Chemistry at the 72nd Meeting of the American Chemical Society Philadelphia P a , September 5 t o 11, 1926
from the strata penetrated is mixed and so affected by the solvent action of the water that it is impossible to tell whether the thickness of the potash-bearing strata is to be measured in feet or inches, or what their potash content is. However, fragments of the definite potash mineral, polyhalite (KzSO4.MgS04.2CaS04), have been obtained from Texas wells, and more recently there has been obtained a core from a continuation of the same deposit underlying southeastern New Mexico, showing, in addition to several strata of polyhalite, also sylvinite (KC1. zKaCl), kainite (KC1. MgSOa.3H20), and langbeinite (KzS04.MgSOJ. These discoveries definitely establish the presence of segregations of potash salts brought about by evaporation and crystallization processes. These segregations are found at intervals in the Permian beds and a t depths ranging from 700 to 2200 feet. The rock-salt deposits here underlie a region of an average length of 360 miles from north to south and width of 275 miles from east to west,2 embracing approximately 70,000 square miles in Texas and New Mexico. The maximum recorded thickness of the salt series is 1391 feet. Associated strata of anhydrite are encountered which increase in thickness a t the periphery of the deposits, as the thickness of the salt decreases. The borings from which potash has so far been obtained are confined, for the most part, to an area of 20,000 square miles and the potash strata penetrated are located in the upper part of the saline deposits. Under date of June 21, 1926, the Geological Survey summarizes their data in the announcement of
* * * the discovery of potash in 15 additional wells, distributed in 7 counties in the Western Texas region and in one county in New Mexico.***There are now 48 wells in 17 counties of Texas and 2 wells in 1 county in New Mexico, or a total of 50 wells in 18 counties in the two states named that have furnished potash data. * * * The laboratory examinations of the cuttings from these 15 new wells include***quantitative determination of 217 samples*** showing more than 1.5 per cent of potash (K20) while 11 yielded more than 5 per cent.***The richest sample, which contained 13.6 per cent of potash (KzO)***was taken a t a depth of 1515 feet From the geological data at hand the conclusion that these deposits are the result of the evaporation of sea water seems justified, since they appear to be comparable with or analogous to the German deposits whose marine origin is generally Hoots L; 3 Geoi Surzey Bull 780-B (December 29 1925)
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accepted. I n both deposits anhydrite, halite, and polyhalite occur at the bottom of the series and from the bottom upward, in the order mentioned. I n the evaporation of brines of oceanic character, anhydrite is the first salt to precipitate. It is therefore found at the bottom of the crystalline series. The recurrence of anhydrite strata may be taken as evidence of recurrent freshening, induced by recurrent periods of humidity during the general and prolonged period of aridity inducing eraporation, with the influx of the leachings of sedimentaries or of fresh influxes of sea water-both indicating the redilution of the accumulating mother liquors and possibly their partial dissipation. The next salt to be precipitated would generally be sodium chloride, and with the further evaporation of the solution and the increase in concentration of the other common sulfates, polyhalite would be the next compound precipitated. It would be precipitated from a solution containing only a small percentage of potassium. I n substantiation, syngenite, a hydrated potassium-calcium sulfate, may be formed artificially and has been encountered and caused much grief in the concentration of potash solutions obtained by leaching cement dust. Here it is formed in solutions containing only 4 to 5 per cent KzO. I n contact with concentrated solutions of magnesium salts it is converted into polyhalite.3 I n European deposits these two compounds occupy corresponding positions near the bottom of the salt series and both are distinctly products of low concentration in potash. They are accordingly primeval potash deposits. The penetration of polyhalite strata in the salt series of Texas might be taken to indicate that the bottom of the potash deposit had been reached and that potash salts of other compositions and greater concentrations should be looked for above the polyhalite, and not a t lower positions in the series. This does not hold, however, since the deposition of saline strata frequently takes place in cycles, owing to recurrent periods of humidity and aridity or of freshening and concentration, and resulting changes in the composition of the brine undergoing evaporation. This stratification may be repetitive. As a consequence one cannot be sure that the bottom of a potash deposit has been found until the floor of the basin in which deposited has been reached. However, it may be concluded that a t the time the polyhalite strata were formed, desiccation and concentration in potash salts had not gone very far. It is fortunate indeed that from a great body of brine containing less than 5 per cent of potash a compound could be precipitated containing 15 per cent. Concentration of Polyhalite I n the refining of polyhalite, the potash salt so far discovered in greatest abundance, when this mineral is redissolved the resulting brine will contain potassium and magnesium sulfates in equimolecular proportions and, although the calcium sulfate will be practically eliminated, the solution will be saturated with that salt. Polyhalite in the pure state, containing 45.2 per cent CaSO4, 19.9 per cent MgSO4, 28.9 per cent KzSO~,and 6 per cent HzO, in contact with water will give a solution which when saturated a t 25’ C. will contain 21 per cent of soluble salts, of which 6.6 per cent is KzO. This may therefore be taken as the maximum concentration in potash of a brine obtainable directly by leaching polyhalite. The possibility of obtaining a brine so rich in potash suggests dissolution in situ of the potash strata instead of mining, following the method in common use in the salt works of New York State, where fresh water is admitted a Basch, Siteb. kgl.
Akad. Wiss. Berlin, 1900, p. 1084.
Vol. 19, No. 2
to the strata and a saturated brine is pumped out. This procedure would obviate expensive mining operations and would constitute a preliminary step in refining operations. Unfortunately, polyhalite is slowly and difficultly soluble on account of the large percentage of calcium sulfate present. This constituent, being only slightly soluble, would remain as an insoluble crust on the exposed faces of the polyhalite, thus forming a protective coating and slowing up if not completely stopping the dissolution process. Furthermore, the calcium sulfate going into solution a t the beginning of the operation subsequently recrystallizes on exposed surfaces, thus increasing the protective action of the surface coating. Unless very thick beds of polyhalite were located, contact with rock-salt strata would soon be effected as the cavity developed by the solvent action of the water enlarged, which being more readily soluble would likewise be dissolved and would burden the brine with a constituent that would subsequently have to be removed from a very complex physico-chemical system. This simple expedient therefore does not, from a priori considerations, appear to be feasible. Concentration vs. Shipment of Crude Material The only alternative seems to be mining, as is also practiced in the salt measures of New York. The choice is offered of shipping the salts as mined or refining to yield a higher grade product. Since pure polyhalite contains 15 per cent KzO, this concentration will be the highest attainable without refining. This would compare favorably with the German kainite, formerly in popular and widespread use but now largely replaced by high-grade products. Transportation costs will be the determining factor. It has been shown by Holmes, of the American Potash and Chemical corn pan^,^ how freight rates per unit of potash decrease with increased potash content. Freight is paid for on the basis of weight, while potash is paid for on the basis of analysis. To illustrate, a freight rate of $7 per ton of potash salts represents a charge of 70 cents per unit of potash in a salt analyzing 10 per cent KzO, but only 14 cents per unit in one analyzing 50 per cent KzO. Distances entailing a higher transportation cost show a greater differential in favor of the more concentrated salts. Here is the telling argument in favor of concentration as opposed to the shipment of the crude salts. When polyhalite is dissolved in water to concentrated solution the calcium sulfate is practically eliminated, which leaves a solution essentially of potassium and magnesium sulfates. Since the formation of a protective coating of calcium sulfate on the surface of the polyhalite fragments will greatly decrease the rate of solution, leaching with agitation or grinding to remove the coating will be necessary. On evaporation, at ordinary temperatures, this solution will yield artificial schoenite, potassium-magnesium sulfate with six waters of crystallization, or artificial leonite with four waters; a t higher temperatures langbeinite, the anhydrous double salt, is formed. Thus, from polyhalite containing 15 per cent K20 can be produced the double sulfate of potash-magnesium with six waters of hydration in which the potash content will have been raised to 23 per cent KzO, or the anhydrous salt, to 30 per cent KzO. This appears to be the maximum concentration obtainable by simple crystallization methods. While a freight rate of $7 per ton on the crude salt (15 per cent KzO) would represent a charge of 47 cents per unit, on the refined, hydrated potassium-magnesium salts, containing 23 per cent KzO, it would be only 30 cents per unit; and on the dehydrated salt, containing 30 per cent Kz0, 2 3 4
Turrentine, “Potash,” p 170, John Wiley & Sons, Inc
, 1926
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cents per unit. It is obvious that while the polyhalite itself would constitute a desirable fertilizer salt for direct use, its slow solubility being a distinct advantage rather than otherwise, economic consideration will impel refining and concentrating if Texas potash is to enter a market within reach of the European commodity. The Transportation Problem
Transportation charges borne by German potash salts from the mines to the Atlantic seaboard of the TJnited States are approximately $5 per ton, equivalent to 17 cents per unit KzO in a 30 per cent salt. From the seaboard inland they have to carry an additional charge for reloading and rail transportation. While the bulk of the potash used in America is employed in the East and South Atlantic states, large and increasing amounts are used farther inland. A line is reached, therefore, where the European and the Texas potash would meet on an equal footing, inside of which the advantage would be on the side of the Texas product. Undoubtedly, cheap potash in the Southwest would greatly stimulate potash use. The great agricultural activities of that region could be developed into a very important market for the local product. And to the northeast lies the great agricultural Middle West, where cheap potash is demanded if its prosperity is to be restored through the adoption of labor-eliminating and therefore the more economical intensive methods of agriculture in which liberal fertilizer use is a prime essential. I s there no way to escape the handicap of high transportation costs to be borne by this possible new industry? Railroads serving this locality are alive to the importance of this potential industry and apparently are prepared to make all possible concessions. A rate is suggested of $4.10 per ton of potash salts, Midland, Texas, t o Galveston on shipments going beyond, t o which must be added port handling charges. Rates on crude sulfur from Freeport, Texas, to Chicago ($7 per ton), Memphis ($6.50), and St.Louis ($6.50), it is assumed would be applicable to potash, relatively favorable rates though still constituting a charge of 42 to 47 cents per unit of potash in a 15 per cent (KzO) salt and 21 to 23 cents in a 30 per cent salt. If Texas potash could be gotten to the Gulf Coast, its delivery therefrom by water transportation to the Middle West and South and even the Atlantic Coast states would be greatly facilitated. IJnfortunately, the area underlain by potash is over 300 miles distant by straight line from the nearest seaport and by rail considerably farther. This would appear to be the inescapable minimum of rail transportation. The Texas potash area a t its lowest altitude is 2500 feet above sea level. Could pipe-line transportation employing gravity flow be used to deliver a concentrated brine to the seacoast, there to be processed for the preparation of concentrated potash salts? Crude petroleum is economically transported by pipe-line distances as great as 1400 miles a t rates of from 15 to 77 cents per barrel, or an average of 4 2 cents per barrel, depending on variables such as distances, size of pipe, topography of country traversed, and climatic conditions. A concentrated potash brine as obtained from the leaching of polyhalite would contain a maximum of 6.5 per cent, or 28 pounds KzO, of a fabricated value a t 50 cents per unit or 70 cents per barrel. The average charge for pipe-line transportation being approximately 0.09 cent per barrel per mile, this rate applied to a 6.5 per cent potash brine is equal t o 0.06 cent per unit K20. On this basis the cost of pipe-line transportation from the Texas field to the Gulf Coast, a distance of 300 miles, may be estimated at about 18 cents per unit KzO. This estimate is based o n the average of rates charged and not on costs.
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Unless this highly unfavorable figure can be reduced by substituting a lower rate for pipe-line transportation in view of the lesser viscosity of the brine as compared with crude petroleum, and gravity flow, which apparently could be employed with the elimination of pumping, or compensated for by advantages due t o more fax-orable manufacturing conditions a t a seaport as contrasted with an isolated inland situation, resulting in lower manufacturing costs, its further consideration would not seem justified. Possibility of Solar Evaporation
The Texas potash area is a semi-arid region with high summer temperatures. In the more favorable section there are no permanent streams. Fresh water is obtainable from wells sunk to the bottom of the surface deposits of sand where such are not less than 50 feet thick. “Otherwise, it is usually necessary t o penetrate the Triassic red clay to a depth of 500 to 750 feet, where fresh water is in many places encountered in sands within the Triassic.”2 An adequate supply of fresh water for processing a large tonnage of potash salts may therefore present a problem, offset, however, by the opportunity which the climatic conditions offer for solar evaporation. The numerous salt playas in this region bear testimony to the feasibility of that method. Solar evaporation would make unnecessary the purchase of fuel for other than power purposes and the installation of the equipment required by artificial evaporation. d Competition with German Potash
When an adequate market for Texas potash shall have been developed in the agricultural Southwest, Texas potash, by virtue of its protection due to high freight rates from seaports into that region, need not fear the competition of cheap German labor and the highly efficient and experienced German potash organizations and elaborate chemical plants. It is estimated that production costs of German potash range from 8 to 14 marks per 100 kg. of K20,which in American currency is from 20 to 35 cents per unit. Wages constitute about 50 per cent of this, the experienced German miner receiving only 4.8 marks, or $1.20, per day. Freight from the mines to Hamburg is 9 marks or $2.25, and from Hamburg to Kew York, $2.50 to $3 per ton of salts. On the basis of salts analyzing 40 per cent KzO, this is a cost of about 12 cents per unit. I n Texas, Mexican and negro labor will be available, which will be cheap from the American point of view though probably not very efficient. By-products
Potash production, it is reiterated, is a chemical problem.
It is no longer purely a mining operation. Even in Germany, where in the famous Stassfurt region the deposit is nearly 1000 meters thick and the individual strata of workable salts are from 50 t o 60 meters thick, only those shafts most economically worked and yielding salts of the most desirable composition are in operation. Thus only 43 out of a total of 225 shafts are now being operated in Germany. Various determining factors enter into this situation, conspicuous among which are by-products. Other things being equal, those salts are chosen which yield the most valuable byproducts, for little potash is now exported which is not first subjected to a refining process with a concurrent output, of other values. By-products, a t best low-grade materials, are of great importance as bearing in part the manufacturing costs of the potash. This realization of the value of byproducts, coupled with the necessity of reducing transportation costs by increasing the purity of the product, has transformed potash production from a mining t o a chemical
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basis. German potash is now turned out by a small number of large chemical refining plants instead of the former large number of small mechanical crushing and sorting plants. The advent of the chemist into the potash industry has effected a revolution which has attracted little attention and is therefore insufficiently appreciated. He has brought about a state of affairs where the economics of potash production is more concerned with the value of the side products obtainable than with the potash content of the raw material. This is most perfectly illustrated by the leading American potash industry, the American Potash and Chemical Company. Here through the ingenuity of American chemists potash almost of the purity of a chemical reagent is manufactured from a raw material containing only 4 per cent KzO and is offered as a fertilizer salt in competition with the European products, by virtue of the equally excellent grade of borax there yielded as a by-product. Here also by the newly developed process for extracting potash from the great New Jersey greensand deposits, containing only 6 per cent Kz0, three side products, ferric oxide, alumina, and activated silica, are yielded, the last named of which i t is estimated can carry all the manufacturing charges and
yield a profit besides, thus in effect placing the potash and the two other products on a basis of zero production cost. Lnfortunately, we Americans do not possess the byproduct type of mind. By-products mean complications both in manufacturing and selling. They are too much trouble. There is more romance in tonnage of output than in cost of production. That is why we are more enticed by the vision of potash mines in Texas than of chemical plants in New Jersey. Both have their function. It is not a plausible assumption that the great, continent-wide agricultural industry of America will ever be supplied with potash from a single source, even should a source large enough ever be discovered. Smaller potash plants, situated strategically with respect to the agricultural areas to be served, and operating on near-by raw materials, each supplying its quota and all producing side products to share the costs of the potash produced, would appear to offer better promise of cheap potash and a stable industry. I n such a scheme Texas potash will play an important role. Only in this way can we hope to effect our complete emancipation from the GermanFrench monopoly.
Significance of the Occurrence of Manganese, Copper, Zinc, Nickel, and Cobalt in Kentucky Blue Grass‘ By J. S. McHargue KENTUCKY AGRICULTURAL EXPERIMENT STATION, LEXINGTON, K Y
R E V I O U S to its in-
P
The soils of the blue-grass region of Kentucky are
t r o d u c t i o n into this richer in copper, manganese, zinc, nickel, and cobalt country, Poa pratensis than the soils of other parts of the state. Therefore, (Kentucky blue grass), was Kentucky blue grass makes a more luxuriant growth known by the more common here because it can absorb all the elements that are names of “ E n g l i s h s p e a r necessary for its maximum growth. Hence the blue grass,” “June grass,” and grass of the pastures of this part of Kentucky becomes ‘ g r e e n s w a r d .” However, a more adequate source of all the necessary vitamin with its introduction on the factors for the growth and development of fine livestock fertile soils of central Kenfor which the region has long since attained a worldtucky it was r e c h r i s t e n e d wide fame. “Kentucky blue grass,” preTable I-Analyses of sumably because of the superior luxuriance and development it attained in the soils of this region. Kentucky blue grass is YOUNGBLADES primarily a pasture grass and as such is far superior to any CONSTITMoistureAsh UENT other grown in this part of the state. When once seeded to free the soils of this region and a good sod is formed, it makes a permanent pasture thereafter and the soil is apparently imPer cent Per cent proved by its continued growth. The grass grows rapidly in Ash Silicon the early spring and undoubtedly contains its maximum Copper nutritional properties when the young blades are 2 or 4 inches Iron Manganese in length. At this stage it presents a beautiful deep green Zinc color to the landscape and affords a rich, succulent food which Nickel Cobalt contains all the necessary elements for the development of Calcium Magnesium some of the world’s finest specimens of livestock. Phosphorus Analysis of Kentucky Blue Grass
For the purpose of determining more definitely the mineral constituents of Kentucky blue grass a t a stage in its growth when it is best suited for grazing, a good-sized sample of the young blades that were about 3 inches long and were 1 Presented before the Division of Agricultural and Food Chemistry at the 72nd Meeting of the American Chemical Society, Philadelphia, Pa., September 5 to 11, 1926.
Sulfur Potassium Sodium Nitrogen Protein
3.83 23.80
... ...
the first to grow in the spring of 1925 were collected, airdried, and analyzed for the various elements contained in the grass. The usual methods of a s h a n a l y s i s were followed,*J but sulfur was determined in the dried grass by the method of Benedict.4 The percentages found are reported in Table I. K e n t u c k y Blue Grass ASH OP ALCOHOLIC
SEEDS
EXTRACT Moisturefree
OF
GREEN
Ash
BLADES Per cent 5.79
Per cent
Per canf
0:315 0.197 0.850 0.201 0.670 0.250 4.35 27.18
4.05 2.79 12.09 2.86 9.47 3.58
o:oii
0.086 0.005 0.086
...
Nine 2.340
0.045
1.770 4.960 2.380
...
... ...
2 Scott, “Standard Methods of Chemical Analysis,” 1917; copper. xanthate method, p. 165; zinc, ferrocyanide turbidity method, p. 487; nickel, glyoxime method, p. 287; cobalt, nitroso-&naphthol method, p. 143. a Willard and Greathouse, J . A m . Chem. Soc., 39, 2366 (1917); manganese. 4 J. B i d . Chem., 6, 363 (1909); sulfur.
