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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
entries (the organic names excepted) with the abstracts before them and all are being gone over again for such revisions as can be made, only after all the entries have been assembled under the various subject headings I t takes many weeks just to handle the cards. We have indexed subjects, not merely words, and abstracts, not merely titles: the difference is very great. The second volume of authors, which has been in course of printing since last September, will appear soon. As an example of a source of delay in the case of this part of the index, attention is called to the fact that many times it has been necessary to write letters to authors or to abstractors to whom the original papers are available in order to straighten out discrepancies in the spelling of authors names. COLUMBUS, OHIO E. J. CRANE January 31, 1918
THE UTILIZATION OF NITER CAKE Under ordinary conditions the disposal of niter cake is a troublesome problem. The best practice has been to add small amounts to the charge of salt and sulfuric acid for making muriatic acid. Sometimes this addition is in solid form and sometimes the niter cake is stored in a cast-iron tank as it is discharged from the nitric acid retorts and is run into the muriatic pots as wanted. Before 1914, so far as I can learn, niter cake alone was very seldom used for muriatic acid manufacture. Since that time it has often been impossible to secure a sufficient supply of sulfuric acid and considerable amounts have been and are being made in this way. On the whole, notwithstanding the fact that heat economy is secured by the use of the material direct from the retorts, I am inclined to think the use of cold niter cake the best practice. I have made several thousand tons from this material in this way without serious difficulty. A patent owned by the General Chemical Company provides for grinding and mixing the materials, but this is quite unnecessary, expensive and, in damp weather, troublesome. Muriatic acid made from niter cake always contains more sulfuric acid and unless carefully watched, this may run up to I or even z per cent. If the workmen about nitric acid plants were careful, the cake need not contain more than 27 per cent free acid, but they are not, and large experience has shown that about 32 per cent is better practice. For the same reason, cake should be free from nitric acid and iodine, but practically all muriatic acid made from cake contains both. While most niter cake is free from all but a trace of these undesirables, every little while a clock watcher will dump his fire before iodineshows in the condensing tubes and the resulting cake will be bad. For these reasons I am convinced that where practicable it is desirable to keep the muriatic made from niter cake entirely separate from that made from salt and sulfuric. This method of working up niter cake is insufficient to take care of the product even in time of peace. I n war time what to do with niter cake becomes a serious problem. Near the coast it is dumped in the rivers without any unnecessary display. I believe that not less than j0,OoO tons monthly are now thus disposed of near New York. I n inland locations the fish wardens are apt to get wise and raise a row. The du Ponts have succeeded in finding a large number of new uses for niter cake and have organized an agency for disposing of it which has been very successful, notwithstanding which they could probably find a supply for new customers. It is thus evident that the time is ripe for a process for organizing the disposal of this material in a separate department of the plant where it may be resolved into salt cake or Glauber’s salt and free acid and utilized. I t may be objected that salt cake is not a readily marketable product and to some extent this may be true, but the market for this product has greatly enlarged during the last decade and is steadily improving.
Vol.
IO,
No. 3
My proposal (Application No. 170,607 for U. S. Patent, granted but not yet issued) is to dissolve the cake in water to a solution having a specific gravity of 1.35 and to blow cold air through the solution in proper receptacles well insulated to prevent inflow of heat. The sodium sulfate separates as Glauber’s salt in small crystals which are dumped into a centrifugal and washed with a Glauber’s salt solution. A very pure salt cake containing less than one-fourth of one per cent free acid may be readily obtained, and a mother liquor containing only a small amount of sodium bisulfate with much free sulfuric acid. This is evaporated, either in a glass apparatus, which I have recently invented, or in Duriron pans, and the resulting mixture used in place of a part of the sulfuric acid in nitric acid making. For this work ordinary ice apparatus will be found unsuitable. Too much time is required to withdraw the heat, and the crystals are large and enclose mother liquor. I find that although the use of cold air is theoretically less efficient, it is better suited to this purpose. The agitating action is also essential in securing a rapid separation since this solution, like water and all watery solutions, is a poor conductor of heat. This method of separating crystals is in principle somewhat like the granulation of sugar, and in the massecuite produced the size of crystal may be regulated as in sugar-making. It is clear that this method may often be applied with advantage to other salts. There seems to be no reason why the majority of these salts may not just as well be prepared of regulated crystal size and with great improvement in purity. LABAYETTE COLLEGE
EDWARD HART
EASTON, P A .
January 9 , 1918
READJUSTMENTS AT THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY TO MEET WAR CONDITIONS Within two months after the declaration of war by the United States, the Massachusetts Institute of Technology had arranged to allow its advanced classes to anticipate the work of the following year by taking special courses during the summer. A considerable number of juniors availed themselves of this opportunity and in consequence will be graduated early. The chemists, of whom there is a great need in war work, will be graduated in April. Seniors in other courses who were in good standing when they left to enter the service have been given their degrees. The present junior class, through a readjustment of its program of studies, will drop out practically a term of senior work, will study throughout the summer, and, if they enter the service, will receive their degrees in October. Thus they will be ready for service eight months earlier than they would be normally. Then, too, the Institute is to admit on February 4th, a t the beginning of the second term, a special class of freshmen who will be admitted without entrance examinations, the certificate of the master of the preparatory school that they are mature enough for the work of the Institute being considered sufficient. The response which is being mdde t o this offer of the Institute fully justifies this setting aside of tradition as to time and conditions of entrance. It is expected that this new class will be composed of unusually fine s t d e n t s eager to begin their higher education without delay, in order to be ready as soon as possible to do their part in meeting the growing demand for technically trained men. DIRECTIONS FOR ASSISTANT EDITORS AND ABSTRACTORS The Editor of Chemical Abstracts has recently published a revised edition of the pamphlet entitled “Directions for Assistant Editors and Abstractors,” which gives in a concise form rules on the preparation of abstracts, forms, spellings, nomenclature, etc., which have been adopted in the publications of the AMERICAN CHEMICAL SOCIETY, and have come to be
