INDUSTRIAL A N D ENGINEERING CHEMISTRY
December, 1931
required to obtain a reliable value for the agglutinating This at least to the use Of the sand dilllent* Literature Cited ( 1 ) D u m , J., J . SOC.Chem. Ind., 32, 397-8 (1913). (2) Kreulen, D. W. J., Chem. Weefiblad, 23, 449-54 (1926).
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(3) Marshall, S. M., and Bird, M. M . , Am. Inst. Min. Met. Eng., Tech. Pub. ai6 (1929). O D ., (4) Mott, R. A,. and Wheeler, R. V..“Coke for Blast Furnaces.” 267 _ The Colliery Guardian Co., Ltd., 1930. (5) Sinnatt, F. S.. and Grounds, A. J., J . SOC. Chem. I n d . , 39, 83-6 (1920).
Color in Fertilizers’ John 0. Hardesty and John T. Scanlan BUREAU OF CHEMISTRY A N D SOILS, DEPARTXRNT OF AGRICULTURE, WASHINGTON, D C
Colors in fertilider materials are discussed. A study ERTILIZER materials steps in the various processes was made of three methods of coloring synthetic ferc a n b e conveniently of manufacture offer opportilizer materials: by adding a concentrated dye soluclassified into three tunities for the addition of a tion to a melt of the material to be colored, by adding groups according as they are coloring agent, and in many the dye solution to a strong solution of the material derived frommineral deposits, cases the addition of the dye and evaporating to dryness with stirring, and by thorindustrial wastes, or atmosis the only extra step necesoughly mixing a small amount of concentrated dye pheric nitrogen. The matesary to obtain a colored prodsolution with the dry material. Each material was u c t . I n t h i s investigation rials of the third group differ satisfactorily colored violet, blue, green, yellow, and from those of the other two in a study was made of three red. The cost of dye required varies from 7 to 58 cents that they are white or nearly methods of coloring: by per ton of material colored. The triphenylmethane w h i t e , while those of the adding a concentrated dye dyes proved the most satisfactory of the several classes other two groups vary greatly solution to a melt of the matried. in color. terial to be colored, by addMaterials o b t a i n e d from ing a dye solution to a strong mineral deposits owe their color t o the presence of pigmented solution of the materials and evaporating to dryness with stirimpurities or to their association with salts that have the ring, and by thoroughly mixing a small amount of a co2cencharacteristic property of selectively absorbing or reflecting trated dye solution with the dry material. different light rays. Most of the organic wastes used as The principal considerations influencing the selection of fertilizers are even more highly colored than the mineral ferti- dyes for this work were high tinctorial power, solubility in lizers, owing to the presence of a pigment, such as carbon, water, stability under the conditions involved, low cost, and or to such dyes as chlorophyll, xanthophyll, and carotin. The availability. The quantities of dyes given in Table I are color associated with most of the fertilizer materials of the expressed in terms of strengths most commonly encountered, f i s t two groups is usually sufficiently characteristic t>oserve as and the costs are calculated on that basis. The dye names used a means of distinguishing between them. The materials of are those of the pre-war prototypes, and each dye name is the third group, on the other hand, are usually lacking in accompanied by its Colour Index number (2),2which serves to characteristic features, particularly when granulated. Arti- distinguish and identify it a t all times. ficial coloring has therefore been proposed as a convenient For convenience in measuring the quantity of dye emmeans of readily differentiating between such materials as ployed and because of differences in dye content and tincare without marked distinguishing characteristics. torial power of the various dyes employed, the strengths of the According to a French patent issued to I. G. Farbenindus- aqueous dye solutions varied between approximately 0.01 trie ( I ) , a colored fertilizer has been obtained by adding 1 to 3 and 0.1 per cent. I n large-scale work such dilute solutions parts of a substantive dye or the leuco form of a vat dye to would not be necessary. The materials to be colored included 10,000 parts of a melted fertilizer composed of ammonium neutral, acid, and alkaline compounds. They contained such nitrate and calcium carbonate. Among other examples bases as lime, potash, and ammonia, and such acid radicals as given in this patent is one in which a concentrated dye solu- phosphate, sulfate, and nitrate. All the colored final prodtion is added to a 45 per cent solution of sodium nitrate, and ucts were screened to the same particle size in order to the mixture evaporated to dryness. facilitate color comparison. The coloration of fertilizers offers a convenient means of Coloring Melts studying segregation in fertilizer mixtures, and the primary purpose of the work outlined in this paper was to facilitate The method of coloring melts is limited to materials, such as the study of methods for preventing this undesirable feature of urea, Calurea, and calcium nitrate, which melt a t temperatures mixed fertilizers. Methods are described for giving a range of below that a t which the dye used in the process would decolors, including red, yellow, blue, green, and violet, to some of compose. the more common synthetic fertilizer materials. Data are In the coloring of these compounds, the desired quantity of also included on the amount and cost of the dyes used in giving standard dye solution was added, and the material was heated characteristic colors to fertilizer salts. KOtests were made on just to the melting point and then allowed to recrystallize with the use of pigments for coloration of fertilizers, oF-ing to the continuous stirring. relatively large quantity required to give a characteristic color,
F
Experimental Data
Suitable methods of imparting color to fertilizer salts vary with the chemical and physical properties of the material. I n the commercial production of fertilizer materials, certain 1
Received August 21, 1931.
Coloring from Solution
Potassium nitrate, potassium chloride, and monoammonium phosphate were selected as materials having suitable solubiliFurther information concerning American dye manufacturers and the brand names of their products is available in the current Year Book of the American Association of Textile Chemists and Colorists.
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ties for coloring from saturated solution. For a p p l y i n g the t r e a t m e n t to these salts, a measured quantity of the desired standard dye solution was thoroughly mixed with a hot saturated solution containing 100 grams of the salt, and the colored solution was evaporated to dryness on the steam bath with intermittent stirring during the last stages of evaporation. Particle Surface Coloring A measured quantity of the desired standard alcoholic dye solution was slowly added and rapidly mixed with 100 grams of potassium sulfate until the color was thoroughly distributed over the surface of the particles. The same procedure was used in treating potassium nitrate and diammonium phosphate with standard dye solutions. The absorbent properties and the solubilities of the material to be colored by this lastn a m e d method cause a variation in the amount of solution n e c e s s a r y to acquire even distribution of the dye.' The use of aqueous dye s o 1u t i o n s gave equally good results by this method but required drying a t 105" C. Approximately 10 cc. of aqueous dye solution were required t o distribute the color over the particle surface of the potassium nitrate, while 2 cc. were sufficient to evenly color the same quantity (100 grams) of the lesssoluble potassium sulfate or of diammonium phosphate. These salts are all practically insoluble in alcohol; therefore, in most cases only 2 to 4 cc. of alcoholic dye solution were necessary to color 100 grams of the salt, or from 5 to 10 gallons of alcohol per ton of material colored, depending upon its absorbent tendencies. This method of coloring is applicable to all fertilizer materials, and it is the only one of the three that is adapted to the coloration of infusible and insoluble materials. I n Table I, the columns headed "Method 1, 2, and 3" describe the quality of color obtained with each material colored by the c o r r e s p o n d i n g m e t h o d . Results under these columns in italics show, for each of the materials, a t least one dye for each color of the range which was most Satisfactory. A blank in these columns indicates that the dye was not tried with that material, but does not necessarily mean that it would be unsuitable. Dyes which were used with less satisfactory results and not listed in the table are Sulfon Cyanine 5 R. Ex. (Colour Index No. 289), Acid Violet 4 B. N. (Colour Index No. 695), Chloraaol Dark Green (Colour Index No. 583),Acid Alizarin Green B (Colour Index No. 1049), Chinoline Yellow (Colour Index No. 801), Orange G (Colour Index No, 27), Alizarin Yellow 2 G (Colour Index No. 36), and Congo Red (Colour Index No. 370). I Naphthol Yellow S (Colour Index No. 10) is not sufiaently soluble in alcohol to give an adequate
concentration of dye; therefore, only an aqueous solution of this dye wua employed.
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December, 1931
INDUSTRIAL A N D EiVGINEERING CHEMISTRY Discussion
Coloring from melts gave far greater intensities of color in the final products, especially with calcium nitrate, than was the case with materials which were colored by other methods. This was caused by greater occlusion of the dye per unit volume of material during rapid crystallization, and the especially good results with calcium nitrate may be attributed to its water of crystallization. The final products by this method did not require drying. Coloring of very soluble materials by evaporating to dryness the colored saturated solution produces well-colored crystals, owing to the occlusion of the dye. The coloring of a dry fertilizer material by thoroughly mixing with it enough concentrated dye solution to color the surfaces of the particles has the advantage that the moisture content of the original material is increased only very little. When coloring potassium chloride in solution, most satisfactory results were obtained with very soluble dyes. Less soluble dyes were either salted out or reacted to form a precipitate. Poor distribution of color resulted with monoammonium phosphate when basic dyes were employed, owing to the formation of a flocculent precipitate when the dye was added to the solution. Acid dyes, because of their greater solubility and lower sensitivity to the action of acid or alkali, were not affected to any great extent.
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The triphenylmethane dyes as a class were found to give the best results because of their high tinctorial power. Greater concentrations of the yellow dyes were required in most cases because of their low covering power. Monoammonium phosphate proved to be the most difficult to color. The estimated cost of the dye required to impart a satisfactory color to a ton of any of the materials varied from 7 to 58 cents. Acknowledgment Grateful acknowledgment is made to W. H. ROSS, of this bureau, for his advice and suggestions during the course of this investigation. The authors also wish to acknowledge with thanks the assistance of the following dye manufacturers, who furnished dye samples and information upon which cost estimates were based: National Aniline and Chemical Co., 40 Rector St., New York; E. I. du Pont de Nemaurs and Co., Wilmington, Del.; and Newport Chemical Works, Inc., Phssaic, N.J. Literature Cited (1) 1. G. Parbenindustne Akt.-Ges., French Patent 674,217 (Oct. 15. 1929); Canadian Patent 308,130 (May 27, 1929). (2) Society of Dyers and Colourists, “Colour Index,”
Bradford, Yorkshire,
1924.
Net and Gross Heating Values’ Their Definition and Proper Use Horace C. Porter 1833 CHESTNUT ST.,PBILADELPHIA, Pa.
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EATING values of solid, liquid, and gaseous fuels are generally, in this country, quoted as the gross values obtained by the laboratory calorimeter. These values include the heat derived from condensation of water formed by combustion (as well as of the original moisture in the fuel), this water ranging in amount from 40 to 50 per cent in the case of solid fuels, to 100 or 110 per cent for liquid, and 200 per cent for gaseous. Therefore the amount of heat, derived from this source, but almost never realized in any degree of practice, is very appreciable, ranging from 500 to 550 B. t. u. per pound for solid fuels, to 1000 to 1200 for liquid, and 2100 for gaseous. Accordingly, some authorities believe that it is more reasonable, in considering relative efficiencies in the use of fuels, not to charge the gross heating value, which is really not a true measure of inherent fuel value, against the fuel but only the net value which expresses properly the fuel value without inclusion of latent heat of condensation. I n 1928 the World Power Conference a t its meeting in London took up this matter and by resolution called representatives of the different countries into conference on the question a t the Berlin meeting in 1930. This resulted in a further resolution requesting the properly constituted standardizing bodies in each of the various countries to assist in creating international standard definitions for the terms “gross” and “net” calorific value. A subcommittee of the American Society for Testing MateriaIs has therefore been appointed under the chairmanship of the author to undertake the fixing of a standard definition for the terms. There are likely to be misunderstandings of what meaning is 1 Received August 11, 1931. Presented before the Division of Gan and Fuel Chemistry at the Sand Meeting of the American Chemical Society, Buffalo, N. Y.,August 31 to September 4, 1931.
conveyed by the term “net heating value.” In this country the term has been commonly understood to mean a value lower than the total or gross value by an amount resulting from one single correction factor-namely, that depending on the water formed in combustion. The standard A. S. T. M. method for determining calorific value of coal and coke (1) now prescribes for deriving net calorific value a deduction of 1040 B. t. u. for each pound of water formed. This is an arbitrary and approximate correction, and may or may not give the excess heat obtained in the bomb method a t constant volume over that obtainable at constant pressure without condensation of water. Similarly there is a correction applied for the higher oxidation of sulfur that occurs in the bomb a8 compared to what takes place in ordinary combustion in air, but this has been considered as necessary even in deriving the gross value. There is a tendency sometimes, however, to interpret net heating value as effective heating value realizable under ideal conditions of practice. This is illustrated by the recommendations of the German national committee of the World Power Conference made June 20, 1930, reading as follows: “The application of two different standards of measurement is recommended*** Btandard of measurement A and standard of measurement B, respectively, and which of the two should be applied depend8 on whether the whole potential quantity of heat or fuel is to be measured, or whether that quantity of heat that is available according to the proces~of application is to be measured.” This clearly implies that the lower or net heating value is to express the quantity of heat made effective under the conditions of practical application of the fuel. Such an interpretation of net heating value would be difficult of standardization. There would arise the necessity
