Potash from Greensand (Glauconite) - ACS Publications - American

of potash-bearing material known as “greensand” Delaware River offer ... Largely on account of the obtainable by open-pit methods or within reach ...
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I N D U S T R I A L A N D ENGINEERING CHEMISTRY

November, 1925

Potash from Greensand (Glauconite)’ By J. W. Turrentine, C. W. Whittaker, and E. J. FOX BURBADOF SOILS, WASHINGTON, D. C.

T

HE great, conspicuous, and easily accessible deposits a t many points, and streams flowing across them into the of potash-bearing material known as “greensand” Delaware River offer sources of ample water supply and as they occur in New Jersey, Delaware, Maryland, and opportunities for water transportation facilities. Virginia have long been the object of study of the chemists As has been stated, p?tash sufficient to supply this country’s and engineers seeking the utilization of American raw materials needs for 1000 years is here available in this raw material for the production of potash. Largely on account of the obtainable by open-pit methods or within reach of the steam relativelv low Dotash content of this material. these re- shovel. Its availability may be further emphasized by the searcheshave sd far been unsuccessful from the point of view estimate of chemical engineers that greensand may be delivered into a plant a t a cost of the establishment of perof 25 cents per ton. manent commercial operations. However, the soluThe greensand beds of New Jersey, Delaware, and Composition and tion of this problem might Properties Maryland constituting America’s greatest deposit of easily mean the solution of potash mineral so far surveyed, a feasible process for Greensand has a marked the entire American potash the recovery of potash therefrom might easily mean advantage over most of the problem. I n any comprethe solution of America’s potash problem. The profitother potash-bearing minhensive program of investiable recovery of potash from present known American erals in that it occurs natugation of American potash sources depends on by-products. The study of greenrally in a finely divided r e s o u r c e s , therefore, the sand as a source of potash has therefore been the study c o n d i t i o n , s u i t a b l e for greensands must have a conof by-products, and researches have been directed d i r e c t treatment usually spicuous place. As is the toward the elaboration of side products of sufficient without grinding. If grindcase with the other potash value to carry the cost of the potash extraction. In ing is necessary it can be prospects, the problem can the new process here described, practically all of the accomplished with ease, as only be solved by a considerconstituents of greensand are converted into useful the material is soft and ation of by-products. From products by simple and economical procedures. readily pulverized. Genthe point of view of the deerally speaking, it is more velopment of a large and readily attacked and decompermanent potash industry, the New Jersey greensand beds may be regarded as the most posed by chemical reagents than are the other potash-bearing promising among the present known deposits of potash-bear- silicates. The uniformity of the deposits is such that for the present i t ing mineral, because of the advantages which they possess, particularly their great size and uniformity, the ease with will not be necessary to consider preliminary purification. which they may be mined and with which their potash may When purification becomes necessary the magnetic properties be extracted, their proximity to market, and the possibilities of the glauconite may afford a ready means. As applied to the run of mine material, magnetic concentration, it is stated, which they offer for useful by-products. increases the potash content about 40 per cent. Occurrence and Quantities Greensand is composed of unconsolidated mineral particles Although greensand deposits have been found in other of a fairly uniform appearance, composition, and size, passing states, the New Jersey deposits are considered the most im- a 20-mesh sieve. Its green color is due to the presence of portant in point of extent, situation, uniformity, purity, and glauconite, a supposed mineralogical entity represented by ease of mining. Mansfield,* in his excellent description of the formula, KFe”’ Si2OS aq.; but the particles themthese deposits, estimated that the greensand here available selves are not definitely crystalline, which gives rise to conby open-pit mining methods alone would supply 257,000,000 siderable doubt as to their true constitution. Among short tons of potash (basis KzO). “At the rate of importation the physicochemical properties of the mineral the colloidal for the five years preceding the World War, including 1914, characteristics are outstanding. Typical analyses of greensand are shown in Table L 4 this quantity could supply the United States for nearly 1000 years. ” If consideration were given the additional quantities Table I-Analyses of Greensand obtainable by underground mining, these figures would be 1 2 3 4 greatly increased. Washington3 has estimated the content SAMPLE 7.88 7.4 KzO (potash) 6.60 6.68 of the New Jersey beds a t 2,034,000,000 metric tons and the SiOa (silica) 50.32 49.8 51.83 50.74 18.0 18.38 17.15 17.36 dimensions at 160 km. (99 miles) in length, with an average FezOa 3.02 FeO 2.93 3.34 ... 7.53 6.23 1.93 9.8 width of 16 km. (10 miles), and an average thickness of 6 AhOs (alumina) 0.52 0.65 2.86 0.9 CaO meters (20 feet); and states that in point of the potash which 3.82 7.7 3.66 3.76 0.76 1.53 0.22 g,200 0.4 they contain these deposits rank second only to the Italian Z 0.88 ... 0.15 0.36 coz 0.31 1.79 0.34 0.25 PZO3 leucites. 0.24 &So4 The New Jersey deposits are located contiguous to the H*O Loss on ianition 5.6 9.9s 9.08 8.58 country’s center of industrial activity. Railroads cross them 100.1 100.33 99.95 100.89 “

I

+

1

Received July 8,1925

Presented a t the Joint Meeting of the Division

of Industrial and Engineering Chemistry, Section of Paint and Varnish

Blair5 shows the averageK20 content of twenty specimens

Chemistry, and Division of Cellulose Chemistry a t the 70th Meeting of the American Chemical Society, Los Angeles, Calif., August 3 t o 8, 1925. 2 U.S.Geol. Survey, Bull. 737 (1922) 3 J l e l . Chem Eng , 18, 17 (19181.

4 Samples 1 , 2 , and 3 quoted from Mansfield, loc. c i L , Sample 4 quoted from Shreve, THIS JOURNAL,13, 693 (1921). 5 N. J. Agr. Expt. Sta.. Circ. 61, 12 (1916).

I K D USTRIAL A N D ENGINEERING CHEMISTRY

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of greensand from various localities to be 4.57 per cent. Shrevee states: Commercial beds of greensand contain around 7 per cent potash, 50 per cent of silica, 18 to 23 per cent of iron oxides (as Fez&), 7.5 to 10 per cent of alumina, 3 to 7.5 per cent of magnesia. The commercial beds carrying 5 t o 7.5 per cent potash, however, are chiefly within the state of New Jersey.

By magnetic concentration, in the opinion of some, the potash content may be raised to 8 per cent, and by applying this method to the low-grade greensands their potash content may be raised to 6.5 to 7 per cent. Patent Literature on Greensand

I n the study of methods of obtaining potash from natural silicates greensand has received a liberal share of the attention of inventors. A long series of patents covering processes is to be found, which may be classified into the following six groups to show the more popular lines of attack employed by those studying the extraction of potash from greensand: (1) Processes employing autoclaving with subsequent recovery of potassium salts. (2) Processes employing roasting or heating without volatilization of potash, followed by leaching for the extracting of the potash. (3) Processes in which potash is volatilized and subsequently recovered. (4) Processes using reagents in water solutions a t low or moderate temperatures. ( 5 ) Processes for the direct production of fertilizer without the extraction of potash. ( 6 ) Miscellaneous processes. Commercial Utilization of Greensands

Desultory efforts a t various times to develop the practice of direct application of greensand as a low-potash fertilizer have not resulted in its general use for that purpose. Several attempts have been made to process greensand for the manufacture of useful products, but to date with only indifferent success. During the war years of potash famine efforts were especially made to develop a potash industry on the basis of this raw material, and several showed decided propise of being about to result in successful commercial processes. But the end of the war and the attending decrease of prices obtainable for potash coupled with the uncertainties of the years that followed resulted in the suspension of most of this work. The essentials of two of the methods employed will be pointed out briefly. TSCHIRNER PROCESS-Aprocess involving the mixing of greensand with “limesand” and salt followed by heating was attempted with very encouraging results by the R . S. Ryan Company. “Limesand” is a natural material occurring in large tonnage near the greensand deposits in certain areas, sometimes constituting the overburden of the greensand beds. It contains about 48 per cent calcium carbonate and is a convenient and inexpensive source of lime for such a process. The three ingredients in the proportion of 10 parts greensand, 12 parts limesand, and 3.5 parts salt were mixed wet in a pug mill and heated in a rotary kiln t o about 800” C. The resulting mass was leached to recover the potash, as potassium chloride, and that portion of the salt (about 66 per cent) which had not entered into insoluble combination. The two were then separated by crystallization methods, the recovered salt being returned to the process. The potash recovery in a pilot plant was about 80 per cent efficient. Some potash was volatilized by the heat of the kiln which in a completely equipped plant would be recoverable. I n such a plant it was estimated the process wouId be about 90 per cent efficient. ‘Am. Frrfilien. 66, 35 (1921).

Vol. 17, S o . 11

SHREVEPRocEss--Noteworthy among the attempts to produce potash from greensand is that of the Eastern Potash Corporation under the technical direction of R. Norris Shreve. Experimentation was carried on a t Jones Point, N. Y., for a number of years, particularly along lines suggested by the Charlton patents.’ According to Shreve? In outline, this process as now employed consists in heating a slurry made from 1 part of ground greensand, 1 part of lime, and 5 parts of water or weak washings in a digester for about 1 hr., a t a temperature around 470” F., and under sufficient pressure to keep the water in the liquid phase. This will be somewhat over 500 pounds pressure. The chief reaction which takes place is that of the lime upon the greensand, which on the one hand liberates the potash in the form of a very pure caustic potash, and on the other hand produces a material high in lime which possesses valuable cementitious and liming properties.

From the latter product it was proposed to manufacture building brick as the by-product of potash extraction. The action of lime on greensand was studied with the following variables: (1) state of subdivision, (2) temperature of digestions, (3) ratio of water used, (4) the substitution of KOH solutions for water, ( 5 ) ratio of lime used, and (6) addition of various salts. Among the many interesting observations made in these researches is the particularly valuable one that if sodium nitrate is added to the charge the potash rendered soluble is increased from 61 per cent to 81 per cent, and upon evaporating the solution resulting from this digestion high-grade potassium nitrate is recovered while the equivalent of caustic soda remains in solution. Caustic potash is the normal product of the action of lime on greensand. I n this compound both the potash and the hydroxyl radical are valuable. However, there may be applications where the one is of value and the other is not. In such cases the two may be separated and used individually, as illustrated by the two equations:

++NaNOs = KNOB+ NaOH NazSOn = &SO4 + 2NaOH

KOH 2KOH

These considerations add materially to the value of the Shreve process. The results of the Shreve researches are summarized in the statement that to secure the economic recovery of potash from greensand the following conditions should be observed:g (1) Fine grinding-that is, 90 per cent to pass 200 mesh. (2) Digestion for 1 hour a t 470” to 480” F. (3) A charge made up of greensand, quicklime, and water in the proportion of 1:0.9 :5 . (4) Addition of various salts for the purpose of: ( a ) Accelerating the reaction (increasing the percentage recovery). ( b ) Changing .the potassium hydroxide to other potassium compounds, or a combination of ( a ) and (b).

Experimental Extraction of Potash f r o m G r e e n s a n d

Favorable results obtained from the direct use of greensand as a fertilizer have been interpreted as meaning that its potash is somewhat water-soluble-a conclusion substantiated by laboratory tests. Many methods applied to the extraction of the potash show that it is loosely combined. There is, in fact, considerable evidence that the greensand aggregate is formed as the result of colloidal adsorption. At any rate, the mineral is radically different from and is much less refractory than the other common potash silicates. Accordingly, as preliminary activities in the investigation of greensand in these laboratories, some attempts have been made to effect the liberation of the potash in, or its conversion to, a water-soluble form by methods much more direct and THIS JOURNAL, 10, 6 (1918). Ibid., IS, 683 (1921). @ Shreve, Concrete (Cement Mill Ed.), 80, 43 (1922); see also Ruckmaa, “Putting New Jersey’s Potash Works on a Paying Basis,” Rock Producls, July 29, 1922. 7

8

November, 1925

INDUSTRIAL A N D ENGINEERING CHEMISTRY

simple than those required by the other silicates. Since they resulted negatively, they will be merely outlined. ROASTING-TVith a view to the possible loosening of the combination by which the potash is held in the glauconitic aggregate, greensand was roasted over a range of mild temperatures and the effect on solubility of the potash noted. The result was a gradual increase in solubility with rise in temperature, from 0.45 per cent of the total potash present in the unroasted control to 0.9 per cent a t 500' to 550" C. E L U T R I A T ! O N - A C C ~as ~ ~a ~working ~~ hypothesis the view that greensand is not homogeneous but merely an aggregate of glauconitic material adsorbed on siliceous nuclei, it was hoped that by mechanical disintegration and elutriation a separation or a t least a concentration of the potash-bearing parts could be effected, advantage to be taken of the differences in mass and density of the disintegration products. The results, showing only a moderate segregation in the coarse (harder) fractions, indicate a fairly uniform distribution of the potash throughout the aggregate. The elutriation of roasted material showed even less segregation.

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already been shown by various experimentalists that greensand could be completely extracted with this acid, it remained to be determined, first, whether it could be made to yield the silica in the form of an active adsorbent, and second, whether the potash, aluminium and iron sulfates could be fabricated into useful products. The results obtained were affirmative. It was found that under properly controlled conditions the residue remaining after the extraction of the basic oxides consisted of noncrystalline silica in the form of granules representing the siliceous skeletons of the original greensand grains. After washing, drying, and screening, when applied as a purifying and decolorizing agent it showed the anticipated adsorptive properties even in the crude state. I n activity it proved quite equal to other well-known siliceous adsorbents and thus established for itself a fairly definite value. The sulfates, yielded in highly concentrated solution, were easily separable one from another in a fair state of purity by fractional crystallization methods, the potassium and aluminium sulfates combining to separate first as alum, thus introducing no complication in the subsequent precipitation Action of Mineral Acids on Greensand of the iron sulfates. The optimum concentrations of sulfuric acid to be used in It having been accepted as a fundamental principle that extracting greensand were found to lie between 40 and 60 to obtain potash profitably from present-known American raw materials it is necessary that by-products be obtained per cent, provided external heating be applied. At lower simultaneously capable of bearing the main costs of producing concentrations the extraction is either incomplete or the time the potash, the investigations in this bureau of greensand of digestion is too prolonged. At higher concentrations there as a source of potash were planned with a riem to the develop- is a reprecipitation of the sulfates formed, often resulting in the formation of solids of greater volume than that of the ment of by-products. original greensand. Under extreme conditions of concentraThe efficacy of the siliceous adsorbents, such as fuller's tion the reacting mass sets to a solid. I n the absence of earth, infusorial earth, and clays, among the natural products, and the silica gels and the so-called colloidal clays, among the external heating the optimum concentrations are delimited fabricated products, in the purification of oils in general and by the amount of heat liberated by the reactions involved. of petroleum products in particular led to the thought that This must be such as to accelerate the speed of reaction suffiit should be possible to produce useful siliceous adsorbents ciently to complete the extraction in a reasonable length of from potash silicates as a by-product of potash manufacture, time. The separation of the three sulfates was studied with a view thus swelling the number of by-products to share with the to the utilization of their respective and relative heat coeffipotash the costs of manufacture. The investigation of greensand was, accordingly, directed cients of solubility. The potassium and aluminium sulfates toward the development of a process for the large-scale pro- readily crystallize as alum and as such are separable from duction not only of potash and alumina but especially of a the iron sulfates. High concentrations are easily attainable siliceous product that could be used in the arts and industries as the direct result of extraction, so that little evaporation is However, high concentrations are involved as a decolorizing and purifying agent as a substitute for other required. throughout the operation so that a careful control of temperasiliceous adsorbents. The peculiar, naturally colloidal nature of greensand made it appear readily adaptable to such a pur- tures and volumes is required, adding to the difficulties inpose. Furthermore, former processes had been directed volved. This investigation had to have as its basis a careful toward the conservation and utilization of the smaller con- analytical survey of the products obtainable and the equistituents of greensand and ignored the silica, itself constitut- libria involved. The acid requirements for greensand are based on the foling 50 per cent of that raw material. The elaboration of the lowing composite analysis: silica into a useful product would make possible the utilizaPer cent tion of all the constituents of that raw material and thus 6.51 KzO materially enhance the economies obtainable. 18.64 F~~OP 5.81 AlnOa The potash of greensand, it has long been known, is readily a All iron calculated as ferric. soluble in the stronger inorganic acids. At the same time in Silica with small amounts of calcium, magnesium, etc., makes up the most acids the other constituents, iron and aluminium oxides, balance. are also soluble, to form compounds which in the past have On the basis of 100 pounds of raw material of this analysis, not been sought, thus requiring the use of a large excess of the acid-soluble ingredients contained are shown in Table 11. the reagent over that needed to react with the potash and of Greensand (per 100 Pounds) carrying into solution with the potash other salts subsequently Table 11-Sulfuric Acid Requirements and Yield in Sulfates to be separated through purification methods more or less Weight Equivalent sulfate Acid required CONSTITVEST I.bs. Lbs. Lbs. elaborate. Practical considerations impose the conditions 6.5 12.0 6.8 Kz0 that the acid chosen be a cheap one, that it be usable in a 34.3 18.6 46.6 FezOs 16.7 0.8 19.5 A1203 highly efficient manner, and that the salts produced concurTotal .. 78.1 57.8 rently yield values great enough to sustain a considerable part of the cost of processing-a severe set of requirements. It is seen that the theoretical yield in anhydrous sulfates is Sulfuric acid, from a tested list including nitric, hydro- 78 pounds, requiring 57 pounds of anhydrous or 60 pounds of chloric, phosphoric, and carbonic acids, was chosen as the 95 per cent sulfuric acid. There is a slight further exhaustion reagent best meeting these requirements. Although it had of acid in the neutralization of calcium and magnesium.

I N D U S T R I A L A N D ENGINEERING CHEMISTRY

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The iron, although calculated to the ferric state, is present in the law material in both the oxidized and reduced state. Since the ratio of aluminium sulfate to potassium sulfate in the greensand is 1 to 1.62 and in alum is 1 to 1.96, it is obvious that the crystallization of alum will not remove all of both of these constituents from solution and that there will be a residuum of potash to be recovered as the simple sulfate. The theoretical yield of alum accordingly is 54 pounds per 100 pounds of greensand, which leaves 2 pounds of potassium sulfate to be recovered as such. UTILIZATION OF SULFATES-The choice is offered of marketing the alum produced in whole or in part, of breaking it down into its constituent sulfates, or of roasting it for the production of alumina and potassium sulfate, with the recovery of the sulfuric acid evolved. Likewise, the most advantageous treatment of the iron sulfate is its roasting to produce the oxide for use as ochers or in other ways. The sulfates of iron, aluminium, and potassium may be separated by crystallization methods as indicated and processed separately, or they may be precipitated together and the entire mass subjected to calcination. I n the latter case the temperature is chosen at which the iron sulfate is broken down into the oxide and sulfuric gases and the mass is then leached for the separation of the potassium and aluminium sulfates. From the resulting concentrated lixiviate the alum is readily recoverable. Large-Scale Experiments

In order that the results here obtained might be made to serve most effectively in promoting the development of a potash industry based on greensand, it was essential that the processes yielding them be made to conform as closely as possible with lines of work being carried on by industrial concerns with a like objective, laboring in the same field of endeavor. Most opportunely announcement was made of the important results obtained by A. J. Moxham, president of the Electro Company a t Odessa, Del., in an experimental and demonstrational plant designed for the development of a process for the extraction of potash, alumina, and iron oxide from this same raw material, greensand, and with the same reagent, sulfuric acid.lo The lines of attack in the two researches were so nearly parallel that little modification in procedure was required to render the results obtained in the Bureau of Soils investigations entirely applicable in the Moxham process. MOXHAMPROCESS-The process now employed by the Electro Company prescribes the digestion of greensand with chamber sulfuric acid and the manipulation of the resulting products after the following manner: Greensand as obtained from the pits, without preliminary treatment, is treated with hot, dilute sulfuric acid of a specific gravity of 1.30 to 1.40. The reaction starts at a temperature of 85' to 90' C., attained, not by external heating, but by the dilution of the acid with water and the heat of reaction of the acid on the greensand. With an excess of acid of about 50 per cent and with a moderate agitation of the reacting mass, the extraction is complete at the end of 5 to 6 hours. The efficiency of the extraction is high, as shown by Table

111. Table 111-Efficiency of Acid Leach Ore charged 2200 pounds. Average temperature 99' C. Specific gravity . of solution obtained 1.44 Charged Recovered Efficiency INORBDIBNT Lbs. Lbs. Per cent Iron 242 222.6 93 . Alumina 133 130.2 98 Potash 107 107.0 100

The insoluble residue of granular siliceous material settles readily and is easily separated by gravity methods or by 18

Iron A g e ,

l i s , 1637 (1924).

Vol. 17, No. 11

filtration. Any suspension remaining in the solution is separated by adsorbents, yielding a clear solution of the sulfates of potassium, aluminium, and iron. The choice is offered of several methods of precipitating and separating the sulfates, but a procedure which commends itself is the simultaneous, one-operation precipitation of the bulk of the sulfates by the addition of sulfuric acid or by evaporation, the high concentration of the solution making this easily possible. The mother liquor containing the residual acid and sulfates is returned to the system. The mixture of sulfates, made up principally of alum and iron sulfates, is roasted at about 500' C. for the thermal decomposition of the latter into ferric oxide and the regeneration of sulfuric acid. Upon lixiviating the roasted mass there is yielded high-grade iron oxide and a concentrated solution of potassium and aluminium sulfates, from which alum is readily crystallized. This salt in turn is roasted a t about 900" C., for its decomposition into potassium sulfate and alumina and the regeneration of a further quantity of sulfuric acid. On leaching the resulting calcined mixture potassium sulfate is dissolved, leaving the alumina. By a simple preliminary expedient the alum is rendered iron-free, so that the final product, alumina, is obtained in a high state of purity. The insoluble residue from the original extraction of the greensand, consisting of the siliceous skeletons of the greensand grains and of quartz particles, an impurity present in the greensand, is washed, first, to recover the retained solution of sulfates, the wash water being returned to the system. This is followed by further washing, drying, screening, or elutriating to remove the quartz, grinding, and any further treatment required for its purification and the further development of its adsorptive and other properties. The trade name "Glaucosil" has been assigned this product. PRODUCTS-The products yielded by the combined Moxham and Bureau of Soils processes, accordingly, are iron oxide, ochers, alum, aluminium sulfate, alumina, potassium sulfate, Glaucosil, and fuming or other sulfuric acid-representing as finished products practically all of the constituents of the raw material from which manufactured, and the regeneration of a large percentage of the single chemical reagent employed, sulfuric acid. EFFICIENCY OF PRocEss-On the pilot-plant scale of operations the detailed costs and efficiencies of this process are being determined. While the cost data obtained are not available for publication, from the results so far obtained it appears to be an entirely satisfactory solution of the problem of the profitable recovery of potash from this the greatest present-known American potash resource. It embraces a remarkable combination of favorable aspects, represented by the facts that the extractive reagent employed is cheap; the procedure is simple, requiring little supervision and susceptible of largely automatic mechanical operation; the utilization of the raw material is practically complete; the various products yielded concurrently represent a well-balanced output; all of them enter markets capable of absorbing a heavy tonnage, thus making possible large-scale operations; and the potash produced is amply supported economically by several other products, placing it in a remarkably strategic position for meeting the competition of the foreign commodity. As an added advantage, the potash is yielded as the sulfate, the form which now receives a preferential price in the American market. General Considerations

A survey of the many processes for the extraction of potash from greensand proposed and attempted, in seeking a reason why none of them to date has been successfully employed, reveals the fact that nowhere has a process been put into oper-

INDUSTRIAL A N D ENGINEERING CHEMISTRY

November, 1925

ation which developed a by-product capable of carrying any considerable portion of the manufacturing costs involved. Most of them required high-temperature treatments followed by leaching and the evaporation of the resulting solutions for the crystallization of the potash. Although affording a high-grade product, they failed to provide for the recovery of other values. The Eastern Potash Corporation, as has been seen. based its wartime plans on the proposed utilization of the extracted residue for the manufacture of brick. This by-product of potash manufacture was of excellent character. The process provided for the production of the potash in the form of caustic, itself yielding a high price as a chemical and easily convertible into forms more acceptable for fertilizer use with the simultaneous production of another valuable byproduct, caustic soda. Their plans seemed to offer promise of success. Their process has much to commend it and it is hoped it will yet be piit into operation.

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The slight unit value of most of the materials to be yielded from greensand as by-products makes it necessary to produce them on the large scale. The Moxham process has been designed particularly from that point of view, and owes its great potential value largely to that consideration. The ultimate goal has been the simultaneous production of raw materials for three major industries-pure iron oxide for the steel, pure alumina for the aluminium, and potassium sulfate for the fertilizer industries. Difficulties encountered to date in the exploitation of our greensand deposits, while serving to defeat past efforts t o develop an acceptable commercial process, should not be permitted to prevent the thorough exploration of this field of industrial research, since the successful solution of the potashfrom-greensand problem will mean the addition to our potash supplies of very large and important contributions of that essential material, and to a very considerable degree the solution of our potash problem.

Total and Per Capita Wealth, Income, and Expenditure for Public Education b y States [COMPILED BY THE N A T I O N AEDUCATIONAL ~ ASSOCIATION] Wealth

STATES (1) United States

Alabama Arizona Arkansas California Colorado Connecticut Delaware District of Columbia Florida Georgia

Idaho Illinois Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New Hampshire New Jersey New Mexico New York North Carolina North Dakota Ohio Oklahoma Oregon Pennsylvania Rhode Island South Carolina South Dakota

Wealth 1922 Census (2) $314,718,830,000 3,002,043,000 1,314,291,000 2,599,617,000 15,031,734,000 3,229,412,000 5,286,445,000 625,766,000 1,697,270,000 2,440,491,000 3,896,759,000 1,533,941,000 22232796000 8:829:726:000 10,511,682,000 6,264,058,000 3,582,391,000 3 416 860 000 2:006:531 :OOO 3 990 730 000 12:980:839:000 11 404 861 000 8:547:918:000 2,177,690,000 9 981409 000 2:223:189:000 .5,320,075,000 54 1,716,000 1,374,135,000 11,794 189 000 851:836:000 37,035,262,000 4,543,110,000 2,467,772,000 18,489,552,000 3,993,524,000 3,419,459,000 28,833,745,000 1,924,326,000 2,404,845,000 2,926,968,000 4,228,251,000 9,850,888,000 1,535,477,000 842,040,000 4,891,570,000

capita (3) $2977 127s 3933 1484 4386 3437 3829 2806 3879 2520 1346 3552 3428 3013 4373 3541 1482 1900 2553 2661 3370 3109 3581 1216 2932 4050 4104 6998 3101 3737 2364 3566 1775 3815 3210 1969 4365 3345 3184 1428 4597 1809 2112 3417 2389 211s

Annual income 1919 (4) $66,252,601,000 810 226 000 221:788:000 663,742,000 2,808,992,000 600,483,000 990,388,000 176 591 000 386:929:000 406,477,000 1,141,953,000 260,665,000 4,962,384,000 1,702,776,000 1,697,401,000 1,065,339,000 946,610,000 771,414,000 448,106,000 999,529,000 3,034,020,000 2,58 1,907,000 1,386,514,000 629,071,000 1,822,428,000 281,130,000 909,558,000 65,791,000 264,530,000 2,392,104,000 147,107,000 9,074,859,000 980,596,000 352,916,000 3,967,713,000 1,083,S51,000 556,622,000 5,958,018,000 434,988,000 735,398,000 436,254,000 553,867,000 2,c511,050,000 232,324,000 186,479,000 990,107,000 1,066,073,000 855,723,000 1,466,513,000 153,297,000

Income Pe? capita (5) $627 345 664 379 820 639 717 792 884 420 394 604 765

Expenditures for education per capita (7) $14.95

706 602 392 429 583 689 788 704 58 1 351 535 512

Expenditures for education in 1922 (6) $1,680,671,296 12 827 S45 7:065:1?9 8,828,859 93,534,315 19,366,016 21,34 1,789 2,465,708 5,722,520 9,768,506 13,505,702 9,556,267 103,201,265 63,368,907 49,514,571 34,319,377 14,149,189 16 452 576 8:266:289 14,719,273 67,332.711 72,739,880 52,210,972 9,390,413a 40,986,065 13,976,623

702 850 597 758 408 874 383 515 689 534

30 687 770 1:673:249 4,883,243 63 966 428 5:162:6744 183,421,841 22,079,183 15,420,977 116,568,994 30,479,357

19.83 21.87 5.24 12.04 25.46 23,67 21.62 11.02 20.27 14.33 17.66 8.63 23.84 20.24 15.03

711 683 720 437 685 365 538 517 529 429

13,629,983 109,468,075 7,135,714 9,567,519 15,552,102 15,155,845 52,452,075 9,9.59.777 4,129,368 21,212,606 29,633,324 18,616,312 40,146,691 5,067,272

17.40 12.55 11.81 5.68 24.43 6.48 11.25 22.16 11.72 9.19 21.84 12.72 15.25 26.07

581

RANK,IN ,

Wealth (8)

..

5.46 21.14 5.04 27.29 20.61 15.46 11.06 13.08 10.09 4.66 22.13 15.91 21.62 20.60 19.40 5.85 9.15 10.76 10.15 14.88

48 9 44 4 19 11 32 10 35 47 17 20 29 5

27 15 49 31 8 7 1 28 14 37 16 43 12 24 40 23 26 46 3 42 39 21 36 38 13 25 30 2

18

45 41 34 33 22

6

PRR CAPITA

Expenditures for [ncome education (9) (10)

..

*.

49 21 46 4 22 12 5 1 41 43 23 9 28 14 24 44 39 26 18 7 15 27 48 31 36 16 3 25 10 42 2 45 35 17 32 13 20 11 38 19 47 30 34 33

46 13 48 1

14 23 35 28 36 49 8 22 11 15

19

44 41

37 38 26 18

9

47 31 3

6 12 35

16

27 20 42 5

17 28 21 30 32 45 4

43 Tennessee 34 Texas 7 Utah 35 Vermont 40 40 Virginia 8 1o 5,122,405,000 3776 786 Washington 37 29 3196 448 4,677,910,000 West Virginia 29 24 2989 557 7,866,081,000 Wisconsin 6 2 5022 789 Wyoming 976,239,000 Statistics for 1923. The figures in this table were taken from the following sources: Column 2: Estimated Value of Nalional Wealth, 1922. I. S. Department of Commerce Bureau of Census Release. "The estimate covers the materia wealth or value of tangible property located within the limits of continental United States." (These estimates do not include the value of vessels of t h e United States Navy and Merchant Marine.) Harcourt, Brae & Co.. pp. 25 and 26. Natiqpa i Columns 4 and 5: Distribuiion of InLome by Slates. National Bureau of Economic Research, N. Y., income is defined by them as follows: National income is taken to consist of the commodities and services produced by the people of the country. Column 6 : The figures in this column are those of the Bureau of Education and include all expenditures for public elementary and secondary schools. I n calculating per capita wealth and expenditures for education the population figures of the 1920 census were used.