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THE JOURrVAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY. July, 1909
ples but it has apparently given good results on all samples which have come under the author's notice. The two precipitations of barium sulphate are made in large bulk without reference to dissolved silica being present. All my results have checked closely with those obtained by fusion with sodium carbonate and removing silica by dehydrating and filtering, previous to precipitation. Treating the barium sulphate with sulphuric acid and hydrofluoric acid, evaporation and ignition have failed to show the presence of any silica. If lead be determined, it should be calculated to the sulphide and the proper amount of sulphur deducted from that remaining after calculating barium sulphate, before calculating the remainder to calcium sulphate. Should the mineral exhibit evidence of the presence of iron pyrite it would be difficult to properly place all the sulphur, and a direct fluorine determination would be necessary unless one be willing to consider all the calcium, insoluble in acetic acid, as the fluoride, no sulphate being present. The whole scheme is offered merely as a means of quickly classifying a material which heretofore has required a long time for its proper analysis. LABORATORYOFTHELUXENSIRONANDSTEELCO., COATESVILLE, PA.
ADDRESSES. SOME INTERESTING POINTS I N THE MANUFACTURE OF C. P. CHEMICALS.' By J. T. BAKER.
The source from which the manufacturing chemist obtains his supply of raw material and the methods employed for making the various chemical products are subjects of considerable interest and inquiry t o those who have never paid much attention to the manufacturing side of chemistry. T h e analytical chemist who is interested only in the purity of his reagents is not particularly concerned a s to their origin or method of preparation, nor is the student particularly interested, a s his attention is taken up solely i n experimenting with such chemicals as are placed before him. The manufacturer, however, is interested from a n economical point of view and is looking for the cheapest source and the most economical methods. It is sometimes imagined b y those who are totally ignorant of the nature of chemicals t h a t there is something mysterious and uncanny about chemical manipulations and chemical preparations are imagined by them to be derived from roots and herbs or some other mysterious sources on the earth. To a certain extent this is true, for we shall not go very far in our search for a source of supply before reaching Mother Earth. The chemical manufacturer, however, especially the manufac1 Paper
read before the Philadelphia Section, February IS,1909.
turer of C. P. chemicals, seldom resorts the raw material a s if i t comes from the earth, for the greater part of his raw material is the product of other industries in which the material as found in nature is converted into a commercial product better suited to his requirements, as for instance the various metals, copper, zinc, cadmium, etc., brimstone, nitrate of soda, salt, alkalis and many other crude salts. I n a great many instances i t is more economical t o use raw material in a partly purified form rather than t o attempt to follow out every step of the preparation from the natural material to the finished product. This is especially true in the case of the manufacturer of C. P. chemicals, for his products cover a large field and include a great variety of chemicals, the demand for many of which is comparatively small, so t h a t he is dependent to a great extent upon other industries for a large part of his supply. The chemist of old was very independent in this respect, for previous to the time that chemistry became a distinct science, the chemist sought his own raw material and prepared his limited stock of reagents himself, but a s the field of chemistry enlarged and his wants increased he began to realize his limitations and became either a n analyst or a manufacturer. This resulted in a division of labor and a specialization which is the condition which we find to-day. The manufacturer also, instead of attempting t o cover the whole field of chemical products, takes up special lines, as commercial chemicals, C. P. chemicals, pharmaceutical preparations, etc. The division of labor and devotion t o specialties seems to be inevitable, not only because the field of labor is so large and man's capabilities are limited, b u t because concentration of energy is necessary to gain perfection. Even in large industries where a great variety of products are manufactured, the greatest efficiency is gained by dividing the work into departments devoted to special lines. The manufacture of C. P. chemicals is a specialty and requires a knowledge and experience peculiar to itself. While the preparation of chemical compounds is to be found described more or less in books, these descriptions are intended mainly for laboratory experiments and are seldom of practical value when working on a commercial scale. Two requisites confront the manufacturer in his efforts to keep down the cost of production, first a cheap source of supply, and second economical methods of manufacture. Vbe' are principally concerned at this time with the source of supply. C. P. acetic acid is prepared by distilling glacial acetic acid of commerce which is the product of the d r y distillation of certain kinds of wood. The commercial acid can be obtained in a number of grades of strength and purity, but the glacial is the most suitable for making C. P. acid. C. P. arsenious and arsenic acids are prepared from the arsenious acid of commerce, obtained a s a sublimed product from roasting various kinds of arsenical ores. C. P. boric acid is prepared by recrystallizing boric acid of commerce. The latter is derived indirectly from the borax deposits in the earth, mainly from the great borax beds found in Southern California. C. P. chromic acid is made from bichromate of potash, a n article of commerce made on a large scale from chrome iron ore. C. P. citric acid is prepared by recrystallizing citric acid
ADDRESSES. of commerce. Citric acid is the acid of the lemon and production of the commercial acid forms a n extensive industry in countries where this fruit grows abundantly. C. P. hydrochloric acid is prepared by redistilling commercial muriatic acid. Rock salt, and to some extent crystal salt, forms the basis for the manufacture of this acid, which is one of the largest products of the chemical industry. The C. P. acid is made from so-called pan acid, this being the acid made in the first part of the operation, where iron pans are used and is stronger and contains less impurities than the acid found in the latter part of the run where roasters are used. This acid cannot be made economically on a small scale, owing to the large percentage of weak and very impure acid formed, as well as the residue of sodium sulfate, for which a market must be found. Another source from which C. P. acid is sometimes made, is muriatic acid made by synthesis of chlorine and hydrogen gases obtained in the electrolytic decompositions of sodium and potassium chloride. This makes a very pure acid absolutely free from arsenic but always contaminated more or less with free chlorine. C. P. nitric acid is prepared by redistilling nitric acid made from nitrate of soda and sulfuric acid. This acid can be made cheaply on a comparatively small scale for the reason t h a t i t does not require a very complicated apparatus, and all of the acid produced is suitable for redistilling to make C. P. acid. The nitrate of soda used is the refined product of the niter deposits in South America. C. P. sulfuric acid is prepared by redistilling and concentrating commercial sulfuric acid. Sulfuric acid forms the largest product of the chemical industry and is produced in enormous quantities. The source from which it is made is either native sulfur, the acid from which known in commerce as brimstone acid, or from sulfur ores forming what is known as pyrites acid. For C. P. manufacture the brimstone acid is preferred, as i t contains less arsenic than pyrites acid. C. P. hydrofluoric acid is prepared by redistilling commercial hydrofluoric acid which is made from native fluorspar and sulfuric acid. C. P. oxalic acid is prepared by recrystallizing oxalic acid of commerce. The latter is made generally from sawdust and caustic potash or soda. C. P. phosphoric acid is made from phosphate rock or from the bones of animals. The best grades of commercial acid now being made are of a C. P. grade. C. P. tartaric acid is prepared by recrystallizing commercial tartaric acid. The latter is made from the acid found in the grape. The original source of the aluminum salts is principally bauxite, native oxide of alumina, although cryolite, the double fluoride of sodium and aluminum, furnishes some of the aluminum oxide of commerce a s a by-product in the manufacture of bicarbonate of soda. From bauxite are made the sufate and potash alum from which are prepared the C. P. salts by recrystallization. Aluminum metal is also made from bauxite by the electric current and is the source from which are made the chloride and nitrate. All ammonium salts originate from ammonia gas obtained a s a by-product i n the manufacture of coke and illuminating gas from bituminous coal. The hydrate, chloride, carbonate and sulfate are commercial products made directly from the ammonia thus obtained and from them
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the C. P. products are prepared by recrystallization on redistillation. All the other ammonium salts are prepared directly from C. P. ammonia by combination with acids. All barium salts originate from witherite, the native carbonate of barium, From this the chloride and nitrate are made and purified by recrystallization. From these the other salts are made by decomposition. Bismuth salts: Chloride, nitrate and sulfate are made direct from the metal, which is soluble in acids, and then purified. The carbonate and oxide are made from the chloride or nitrate. Cadmium salts: Chloride, nitrate and sulfate are also made direct from the metal and then purified and from the chloride are made the carbonate and oxide. The metals, copper, tin, iron, mercury and zinc also form the basis from which most of the salts of these metals are made. All C. P. calcium salts are made from marble. All C. P. chromium salts are made indirectly from bichromate of potash. All C. P. cobalt salts are made from the oxide, an article of commerce obtained in smelting cobalt ores. C. P. copper sulfate is prepared by recrystallizing the commercial sulfate, blue vitriol. This is the only salt of copper not made directly from the metal by the C. P. cheniical manufacturer. C. P. ferrous sulfate is prepared by recrystallizing the commercial sulfate known as copperas, the other salts being made from the metal as noted above. Lead compounds are made from lead oxide of commerce, except C. P. acetate of lead which is prepared by recrystallizing the commercial acetate of lead. C. P. magnesium compounds are made from magnesite, the native carbonate, with the exception of the sulfate which is prepared by recrystallizing Epsom salt. Molybdic acid, MOO,, is made direct from the mineral molybdenite, the native sulfide of molybdenum. The oxide is soluble in ammonia and forms the basis from which are made all the other compounds of molybdenum. This is one of the few instances where the chemical manufacturer uses the native raw material. The principal source of all potassium compounds is the Stassfurt Mines in Germany, which yield the chloride and sulfate of commerce, from which are made the following commercial products: Nitrate of potash by double decomposition of the sulfate with sodium nitrate; chlorate of potash by oxidation of the chloride with chlorine gas, obtained by the electrolytic decomposition of the chloride in the manufacture of caustic potash; carbonate of potash from the chloride (to a limited extent), and also indirectly the bichromate, permanganate and cyanide of potash. The carbonate is also made from wood ashes and beet sugar pulp. The commercial grades of the above are the basis from which the C. P. grades are prepared by recrystallization, while all the other C. P. salts of potassium, such as the acetate, arsenate, chromate, citrate, fluoride, nitrite, sulfite and sulfide, are made by combining the C. P. carbonate or hydrate with the proper acid. The principal source of all sodium compounds is common salt. From this source the carbonate is made either by the LeBlanc process or the ammonia soda process and the sulfate as a by-product in the manufacture of hydrochloric
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and nitric acids. Cryolite, the double fluoride of sodium and aluminum, is also a source from which is made the bicarbonate of soda, and the nitrate of soda is the refined nitrate deposit of South America. From these commercial products the C. P. grades are prepared by recrystallization. C. P. sodium acetate is prepared by recrystallization of commercial acetate of soda. C. P. carbonate of soda is prepared from the bicarbonate. C. P. caustic soda is made from the chloride of electrolysis. C. P. sodium phosphate is prepared by recrystallizing commercial phosphate which is derived from phosphate rock. All other C. P. sodium salts are prepared from the carbonate or hydrate by combination with the different acids. All C. P. strontium salts are made from commercial carbonate of strontium. As noted above, all the salts of tin and zinc are made direct from the metal and purified by recrystallization.
THE UTILIZATION OF ATMOSPHERIC NITROGEN, PARTICULARLY FOR THE MANUFACTURE OF AIR-SALTPETRE.‘ BY HOPRATPROF.DR. A. BERNTHSEN
Ludwigshafen a/Rh., Director of the Badlsche Anilin- u Soda-Fabrik.
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Of the two chief constituents of the atmosphere, n e have hitherto been accustomed to look upon oxygen as the fundamentally important element. \&’e are compelled to breathe i t in order to support life; i t is indispensable to almost every process of heating and combustion, and in the form of oxides, salts and the like, i t constitutes nearly one-half of the earth’s crust. Nitrogen, on the other hand, we regard as a gas which will not support combustion. IVe breathe i t in and out without i t benefitting us in any way, in fact, unless mixed with oxygen, we are unable to exist in it, and i t is generally characterized by a great disinclination to enter into chemical reaction, In spite of this, however, compounds of nitrogen play such a n important part in the nutrition of all living organisms, that the task of finding out and opening up new sources of nitrogen compounds, has become one of the most interesting and pressing problems of the day. Schulz-Lupitz, one of the first of Liebig’s pupils in the domain of agricultural chemistry, has written: “Nitrogen is, after water, the greatest factor in the creation, growth, and working of nature; to bind i t and be its master, that is the problem, to make use of it, therein lies real agriculture, t o bring its sources, which are inexhaustible, into service, that i t is which creates wealth.” I propose, therefore, to occupy your attention for a short time, with the problem of the utilization of atmospheric nitrogen, a problem on which, a few decades ago, scarcely any one would seriously have thought of lecturing. The supply of nitrogen conipounds has become of particular importance t o the department of agriculture, and this is a branch of national economy on which the prosperity of nations to a great extent depends, for even if a country, owing t o special circumstances, develops into a n industrial state, i t is nevertheless dependent on progress in agriculture, if not within its own shores, then in other countries. This progress is, however, by no means such a matter of course, as was often assumed in former times. 1 An address delivered at the Seventh International Congress of Applied Chemistry, London 1909.
I t used to be generally believed that the carbonic acid contained in the air, and continually supplied thereto from processes of combustion and putrefaction, and also from the breathing of men and animals, formed sufficient food for the plant, and for the production of starch, sugar, fats and cell walls, but Liebig investigated the ashes of plants and showed that mineral substances, in particular, potassium and phosphoric acid, also play a n important part in the builiding up of plant organisms. H e taught us further, that plants also derived nitrogen from the earth, in order to be able to build up the nitrogenous part of their organisms, in particular, for the synthesis of albumen, which in its turn is used a s nourishment for the human and animal organism, just as much as are the carbohydrates and fats. Consequently, the necessity arises, not only of returning to the earth in the shape of manure all the products of decomposition and other changes of living matter (this had been carried out empirically for a long time, and in China was even enforced by law), but also of adding a n extra supply of potassium and phosphoric acid salts, and of nitrogen compounds to the ground. I t is true that the soil can yield crops for many years in succession, even when no such additions be made. This is especially the case if the cultivation be not forced too much, and if a suitable rotation of crops be followed, but if greater demands are made on the earth, sooner or later the fertility diminishes, and the soil finally becomes exhausted. Liebig, who is the founder of modern agricultural chemistry, ascribes the decline of civilized nations from the height of their prosperity, to the robbery of the soil, and to the ignorant and unscrupulous using up of its treasures, without any regard to the possibility of exhausting them. He says: “Both the rise and decline of nations are governed by the same law of nature. The deprivation of the soil of its conditions of fruitfulness brings about their decline, while the maintenance of such conditions leads to their permanence, prosperity and power.” H e goes on to say: “The nation is not fed by peace, nor destroyed by war, these conditions only exercise a temporary influence on it. I t is the soil on which man builds his home, which is instrumental in holding human society together, or dispersing it, and in causing nations and empires to disappear, or to become powerful The absolute fruitfulness of the ground is independent of mankind, but he possesses the power of diminishing or prolonging such fruitfulness.” I n Liebig’s treatise on the relation of organic chemistry to agriculture and physiology, which appeared about seventy years ago, he protested most strongly against the way in . which the English wasted manure through their method of sewage canalization. This treatise, however, although i t created a tremendous sensation throughout the whole civilized world, was not a t all well received by the landowners of that period. We, who long ago absorbed Liebig’s precepts into our very flesh and blood, find it difficult t o understand how great the opposition was, which was then raised against them. I n his excellent biography of Liebig, which has recently been published, Volhard describes, in a very interesting manner, the battle waged, and the reason of its failure at the commencement. H e mentions, as a symptom of the feeling then prevalent, that a n English agricultural paper even refused to print a correction sent them by J,iebig himself. Since the end of the fifties, however, Liebig’s teach-
