Introduction and Background

DEUUAUUDUUELO Grr.“ TAPELSE Es RACTICAL MANUAL Sor Moanit UfactUurers, Ghemists, Ges a $, y) Cornell Aniversity Pibvary BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Henry W. Sage 1891 je AAREIIQ on W508, : 9963, Comeii University Lit arV19178 my Ney ii ifiiaiin 3 1924 031 273 50: Advertisements. PHILIP HARRIS & Co., Ltd., BIRMINGHAM, Manufacturers and Importers of every description of Chemical Apparatus and Chemicals for Analysis. secccceccccccccs ALLEN’S, BUNTES’, ORSAT’S, HEMPEL’S, &c., APPARATUS FOR GAS ANALYSIS. STANDARD PENTANE LAMP. HARCOURT'S COLOUR TEST APPARATUS. SULPHUR TESTING APPARATUS. PRESSURE GAUGES, METERS, &c. PYROMETERS AND THERMOMETERS OF EVERY FORM. Agents for Oertling’s, Becker’s, &c., Balances. Schleicher and Schull’s Rhenish, and Mincktell’s Swedish Filter Papers. Our Illustrated Catalogue of Chemical and Physioal Apparatus and Chemicals, with upwards of 1200 Illustrations, sent post free on application. AMMONIA AMMONIUM COMPOUNDS Comprising their Manufacture from Gas-liquor, and from Spent- oxide (with the recovery from the latter of the bye-products, Sulphur, Sulphocyanides, Prussian-blue, etc.); special attention being given to the analysis, properties, and treat- ment of the raw materials and final products A PRACTICAL MANUAL FOR MANUFACTURERS; ; CHEMISTS, GAS-ENGINEERS, AND i DRYSALTERS ' FROM PERSONAL EXPERIENCE, AND INCLUDING THE MOST RECENT DISCOVERIES AND IMPROVEMENTS BY Dr. R. ARNOLD ‘TRANSLATED FROM THE GERMAN BY HAROLD G. COLMAN, Pu.D., M.Sc. ILLUSTRATED BY NUMEROUS WOODCUTS SECOND EDITION LONDON SAMPSON LOW, MARSTON, SEARLE, & RIVINGTON Limited ‘St. Dunstan's Bouse Ferrer Lane, Firer Street, E.C. 1890 [AU rights reserved] LONDON : PRINTAD BY GILBERT AND RIVINGTON, LIMITED, ST, Joun's HOUSE, CLERKENWELL ROAD. PREFACE. NOTWITHSTANDING the existence of the Handbooks of Lunge and Fehrmann, I have ventured, at the request of the publishers, to treat of the present position of the Ammonia industry in this little work. I have also found it necessary to include a description of the treatment of the “spent-oxide” from the coal-gas purification—an industry which is inti- mately related to the foregoing, and of which no connected description has as yet been published. The book may therefore be regarded as an attempt to collect descriptions of all the processes necessary for the utilization of the nitrogen present in coal. I have omitted mentioning obsolete views, even when still held by certain chemists and others, the object of the work being to portray briefly the present position of the two above-named industries, both of which are so closely connected with the coal- gas manufacture. To remedy a want in the present literature on this subject, I have given special attention to the analysis of the final products, and also of the raw material and other substances required in the various processes. Should these methods, which are based upon practical experience, prove acceptable, a step will have been taken in the direction of unity in analytical methods, which result is greatly to be desired in this as in other industries. iv Preface. In the description of the treatment of the spent- oxide many gaps will doubtless be found, owing to thedifficulties which surround the task, thepublications on the subject being neither numerous nor exhaustive. Moreover, the various processes employed are kept strictly secret, so that, except for the scanty literature at my disposal, I have been thrown back on my own experience. THE AUTHOR. October, 1888. CONTENTS. I. CHemistry oF AMMONIA :— x. Ammonia . a, Composition ‘and Properties 6, Occurrence and Formation 2. Ammonium Compounds a. Ammonia and Water 6. Ammonium Sulphate ” Chloride (Sal- ammoniac) fn Carbonate . a d. € ” Sulphide . ye 5 Nitrate. & ” Phosphate . 4 ca ee ” Oxalate. ke a Metavanadate ZL » Molybdate . mM. a5 Chromate . n a a Cyanide 3- Detection and Estimation of Ammonia . a. Qualitative Detection of Ammonia. 6, Estimation by Distillation ys the Azotometric Method | . cl # Thiocyanate (Sulphoeyaniae) 99 Thiosulphate (Hyposuipnite) d. Preparation of Standard Solutions and Reagents . . II. ManuracturE oF AMMONIUM CoMPOUNDS 1. Raw Material. a a. Gas-Liquor - . vi Contents. MANUFACTURE OF AmMoNtUM ComPounns (continued). 4. Sulphuric Acid . . « Lime . . da. Hydrochloric Acid 2 e. Nitric Acid . . . 2. Ammonium Sulphate . Z ‘ a. Old Methods of Manufacture . 6, Continuous Working Apparatus. . ¢. Subsidiary Apparatus. . . . d. Regulation of the Process. F; S e. Analysis of Ammonium Sulphate . fF Applications A - < « &. Double Salts . * - 4 a . 3. Caustic Ammonia (Liquor Ammoniz) . é a. Manufacture . . . 6, Analysis and Application 4. Concentrated Gas-Liqur . . . 5. Ammonium-Chloride or Sal-Ammoniac . . a. Manufacture of Crystallized Sal-Ammoniac 4, Other Methods of Preparation . - ¢. Sublimation of Sal-Ammoniac . . d, Application and Valuation. 6. Ammonium Carbonate . . ‘ . 7 ve # Nitrate fi . 5 a8 cw 8 3 Thiocyanate (Sulphocyanide) 9% 3 Phosphate. . Pa a. Manufacture . . . . 6, Ammonium Superphosphate : . to. Ammonium Chromate. . . . 1. # Oxalate . g . % 12. » Sulphide. 2... 13. » Vanadate. 5 S * 14. 93 Bye-Products and Waste Pro- ducts from the Gas-Liquor . PAGE Contents. vii MANUFACTURE OF AMMONIUM CoMPOUNDS (continued). PAGE a. Waste-Gases . . . . > » 82 6.LimeMud . «we 8G ¢. Waste-Liquor ‘a ° 4 “ . 84 III. Uriuization or THE “SpentT-OxipE” . * *86 1. Chemical Changes in the Purification of Coal- Gas by Ferric Oxide . . . 86 a. Separation of Sulphur . * 86 4. Separation of Nitrogen Compounds ; Composition of certain Spent-Oxides . 89 c. Revivification of the Spent-Oxide . + 92 2.-Treatment of the Spent-Oxide * a +» 93 a, The Raw Material . . 93 b. Recovery of the ‘Thiocyanates (Sulpho- cyanides) . . ‘ » 98 ¢. Recovery of Ferrocyanides E é + 10K d. Extraction of the Sulphur. : + 105 APPENDIX . . . . . . % cee’ 1. Tables . . . : * fapees 2. Recent Literature . g ‘ a + 120 3+ 9, Patents . * . ¥ © + 124 INDEX . . : . . . . + 127 L CHEMISTRY OF AMMONIA. 1. AMMONIA. “(a.) Composition and Properties——Ammonia is a compound of one volume of nitrogen with three volumes of hydrogen, and is therefore represented by the chemical formula NH,. It contains dy weight 82°35 per cent. of nitrogen, and 17°65 per cent. of hydrogen. Its molecular weight is 17. Ammonia gas was discovered by Priestley in 1774, and described by him under the name of “alkaline-air.” Ten years later, Berthollet showed that it consisted of nitrogen and hydrogen, but its exact quantitative composition was first ascertained at the commencement of the present century, Al- though, however, ammonia is a comparatively recent discovery, its compound with hydrochloric acid (sal- ammoniac), was known as early as the eighth century to the Arabian alchemist Geber, and was a valuable article of commerce in the fifteenth century. Ammonia is a colourless gas, possessing a very cha- racteristic pungent smell, It is much lighter than air, having a specific gravity (air = 1) of 0°586, one litre of the gas weighing at the normal temperature and pressure 0°76193 grams. When strongly cooled or B 2 Chemistry of Ammonia. subjected to great pressure, it condenses to a liquid, which boils under the ordinary pressure at — 33°7. If it be further cooled below — 75° it solidifies, form- ing a colourless crystalline mass, which possesses only a faint odour. If the liquid ammonia be allowed to evaporate quickly, it absorbs heat rapidly from its sur- roundings, a property which has been largely made use of for the preparation of artificial ice. It isextremely soluble in water, one volume of water absorbing at the ordinary temperature more than 700 volumes of the gas. The solution possesses the characteristic odour of the gas, colours red litmus paper blue, and turmeric paper brown, and possesses all the character- istic properties of an alkali. When ammonia is passed through a red-hot tube, or is subjected to the action of the electric spark, it is resolved into its constituents ; from two volumes of ammonia, three volumes of ‘hydrogen, and one of nitrogen are obtained. Under ordinary conditions it is incombustible, but if mixed with oxygen, it burns with a pale yellow flame. Ammonia is especially distinguished by its property of uniting with acids. Its solution in water acts in every respect like an alkali; it hasan alkaline taste, is strongly caustic, and saponifies fats. By the addition of various acids to the solution and evaporation to dry- ness, ammonia salts of the acids are obtained, which are very similar to the corresponding potassium and sodium salts. Further, like caustic potash and soda, it precipitates the heavy metals from their solutions as hydroxides. If a galvanic current be passed through mercury Ammonia. 3 and caustic soda solution in such a manner that the mercury forms the negative pole, whilst the positive pole is placed in the caustic-soda solution, sodium separates at the negative pole, and unites at once with the mercury, forming an amalgam. If a solution of ammonia be substituted for caustic soda, an amalgam is likewise obtained; it forms a light, buttery mass, which becomes crystalline at low tem- peratures, but rapidly decomposes into ammonia, hydrogen, and mercury. Up to the present, the constituent of the amalgam corresponding to the sodium has not been isolated, but it has been found that it differs from ammonia by containing an additional atom of hydrogen, and is therefore represented by the formula NH, To this hypothetical compound the name Ammonium has been given. From this, and further theoretical considerations, we are justified in regarding the compounds of am- monia with acids, as salts of the hypothetical ammo- nium; this assumption, moreover, shows in the clearest possible manner, the analogy between these substances and the corresponding potassium and sodium salts, as will be plainly seen from an examina- tion of the following formula :— Potassium chloride. Sodium chloride. Ammonium chloride. KCL Hy) Cl Potassium sulphate. Scdings sulphate: Ammoniatn sulphate 5 Na,SO, (NH,): $0, Potassium nitrate. Sodium nitrate. | Ammonium nitrate. Os NaNO, (NH,) NO, (.) Occurrence and Formation—Ammonia plays a very important part in the economy of nature. It is B2 4 Chemistry of Ammonia. invariably formed by the putrefaction of the nitro- genous constituents of plants and animals, being either given off into the atmosphere, or dissolved in running water, The atmospheric ammonia is absorbed by falling rain, and again brought to the earth’s surface, and there taken up by the soil, to serve as one of the chief sources of nitrogen for the vegetable world. Although the atmosphere contains about 80 per cent. of nitrogen, the plants have not the power of absorbing it directly, and are therefore dependent on the more active nitrogen compounds, ammonia and nitric acid, for their supply of this element, which is required especially for the formation of the seeds and fruit. It seems probable, however, that the plants can only assimilate the nitrogen from nitric acid, and that the ammonia is first oxidized to that compound by some as yet unknown process which takes place in the soil. It will be seen, therefore, that ammonium compounds form, either directly or indirectly, a powerful manure, and in fact, their cheapest repre- sentative, ammonium sulphate, is employed almost solely for this purpose. Moreover the value of stable manure depends largely on the amount of ammonia which has been found in it by putrefaction. Ammonium compounds do not occur in large quantity in nature. A thin layer of ammonium carbonate is found in the guano deposits on the West Coast of South America. Ammonium sulphate and chloride are also contained in the Tuscan “ Suffioni.” Sal ammoniac is further found as a sublimate in the craters of active volcanoes. None of these occur- rences have, however, any technical importance. In Ammonia. 5 former times ammonium compounds were obtained almost entirely from decayed nitrogenous matter, camel’s excrement being, a few centuries ago, the chief source of sal-ammoniac.’ Later on it was also prepared from human urine, and even at the present time ammonium salts are here and there recovered from sewage. When nitrogenous substances of either animal or vegetable origin are subjected to the process of dry distillation, they are decomposed. Charcoal remains behind, and combustible gases, tarry matter, and ammoniacal water are evolved. For a long time substances rich in nitrogen, such as bones, horn, leather, &c., were thus distilled for the sake of the ammonium salts they yielded ; at present, although these processes are still carried out, the ammonium compounds have become a merely secondary con- sideration, the chief object being the preparation of animal charcoal, or of potassium ferrocyanide (prussiate of potash). The quantity of ammonia obtained from these bodies forms but a very small fraction of the present production. At the present day the dry distillation of coal, the valuable residue of a past vegetable world, forms the richest and almost inexhaustible source of ammonia. When coal is heated in closed vessels to a tem- perature of 1100°—1200° C. (2000°—2200° F.) it de- composes, coal-gas, coal-tar, and ammoniacal liquor are evolved, and a more or less pure form of carbon, termed coke, remains behind, Coal contains on the average about I per cent. of nitrogen, but the 6 Chemistry of Ammonia. amount varies considerably in the different varieties, as the following table shows :— Localits Percentage of Nitrogen a “treet. Northumberland... 221 Upper Silesia 2°00 Lancashire 1°93 S. Staffordshire v7 Westphalia 165 Ohio 1°50 ‘Wales 118 Scotland rod Saarbriick we 0°60 Zwickau . 050 In the process of dry distillation only a com- paratively small quantity of the nitrogen is evolved as ammonia, amounting as a general rule to 15—20 per cent.; about 30 per cent. is given off in the form of cyanides and sulphocyanides, nitrogenous compounds in the tar, and other gaseous bodies, whilst 50 per cent. remains inthe coke. According to a recent statement, if steam be passed into the retorts at the close of the distillation, the yield of ammonia can be raised to 70 per cent. of the total nitrogen. The chief purpose of the distillation of coal on the’ large scale is either the preparation of coal gas for lighting purposes, or the manufacture of coke. In the former case it is absolutely necessary to collect all the liquid products, whereas in the coke manu- facture the condensation is frequently neglected. The relative proportions of the products formed from 2 cwt. of coal in coal-gas manufacture and coking are given in the following table :— Ammonia in Gas-liquor. 7 [Gas liquor con ae fees ae oe | ‘far! | Coke. | Per cent. | Cubic feet. |Per cent.|Per cent. Gas manufacture.| 5—I0 700—g00 — 60—70 [Coking ... ro—15 _| 700—1100 |_2—3 6 The gas-liquor obtained from these processes has a yellow or brown colour, is mostly turbid, and smells strongly ofammonium sulphide and tarry matter. Its composition is variable, but it contains as a rule I'§—3'0 per cent. of ammonia. This exists partly as volatile compounds (including ammonium sulphide and carbonate), and partly as non-volatile compounds, such as sulphate, chloride, thiosulphate (hyposulphite) and thiocyanate (sulphocyanide). In the coal-gas manufacture a second ammoniacal bye-product, the so-called “spent-oxide,” is obtained. After the ammonia gas has been freed from ammonia in the washers and scrubbers, it is passed over hydrated oxide of iron to absorb the sulphuretted hydrogea, When the mass ceases to absorb sulphur, it is;exposed to the action of the air and frequently damped and stirred to promote oxidation. By