June, 1916
T H E J O U R N A L OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
years warns u s of t h e importance of a prior elimination of unnecessary dependence on potash as well as otherJforeign supplies, so t h a t in t h e event of a n y unexpected cessation of supply we can coniine ourselves t o t h e problems arising from t h e crippling of indutb-ies or operations unavoidably hampered b y such curtailment. We should plan t o be annoyed as little as possible by these minor troubles in a national emergency. This is preparedness in which all chemists can t a k e p a r t . We chemists can be of national help in this matter b y eliminating as soon as possible all unnecessary use of potash a n d permitting our soda industries t o grow gradually t o t h e higher demands instead of expecting t h e m t o do so in time of stress. Recent high prices might be expected t o solve this problem for us, b u t t h e y will not do so without our concerted efforts. Even chemists do not readily forsake wasteful habits a n d if t h e y did, not every one who uses potash has t h e advantage of chemical advice. M a n y chemists already have information on potash elimination which their judgment or economic situation has caused t h e m t o work up. We perhaps cannot always make this information public when it is t h e property of a manufacturer b u t in all other cases, a n d these too if we can secure permission, let us make this contribution t o t h e public welfare. I can well remember, when we h a d our first intimation, nearly fifteen years ago, of t h e importance coal t a r derivatives were t o have in future warfare, a n d began in this country our investigations on synthetic phenol, t h a t we labored under t h e delusion t h a t potassium
487
hydroxide was a necessity for t h e proper fusion of t h e sodium benzene-sulfonate. Now we manufacture thousands of pounds per d a y without a pound of potassium hydroxide. It takes little imagination t o see other cases where a similar revolution should be possible. For instance, one Ohio machinery manufacturing concern has saved $8,000 per year b y replacing with sodium compounds t h e potassium compounds formerly used in incidental operations, such as cleaning. This was a result of t h e efficiency of their chemists a n d was accomplished sometime before t h e war. Since t h e war others have been forced t o do t h e same t o avoid complete elimination, a n d m a n y have been surprised t o find sodium salts not only more economical but a t times apparently better. Let us resolve to-day, therefore, t o do away with all unnecessary use of potassium compounds. Let us do away with such use of potassium compounds in our schools a n d universities, a n d in our technical laboratories a n d a t t a c k i t vigorously at every opportunity in its strongholds of manufacturing a n d every-day use. Let every teacher of laboratory chemistry, therefore, a n d every director of a n y kind of chemical work look u p his potash consumption and have sodium tried where t h e y have been using potassium if sodium is available. Let students be taught t h e results a n d give t h e m publicity for t h e benefit of other chemists, teachers a n d t h e general public. J A M E S R. WITHROW INDUSTRIAL CHEMISTRY LABORATORY
THEOHIOSTATEUNIVERSITY,COLUMBCS
ORIGINAL PAPERS FURTHER EXPERIMENTS ON THE VOLATILIZATION OF PLATINUM By G. K. BURGESSAND R. G . WALTENBERG
Received April 17, 1916
T h e experiments here described are a n extension of those of Burgess a n d Sale,' undertaken at t h e SUggestion of Dr. Hillebrand, Chairman of t h e Committee on "Quality of Platinum Utensils" of t h e American Chemical Society. I n t h e earlier papers are described a convenient thermoelectric method of testing platinum purity a n d observations on loss of weight of crucibles subjected t o heating a t 1200' C. and subsequent acid treatment, together with certain magnetic a n d photomicrographic observations. The present investigation consists of a series of observations on change in weight of several platinum crucibles of various degrees of purity when subjected t o heating at 7 0 0 ° , IOOO', a n d 1200' C. Determination of t h e loss of iron content after successive heatings a n d of other materials soluble in hydrochloric acid have also been made as well as a few observations b y t r e a t m e n t with hydrofluoric acid t o detect t h e presence of silica, which may largely if not entirely from t h e m a r q u a r d t porcelain portions of t h e furin previous papers, to which papers naCe
w.
ITHISJOURNAL, 6 (1914). 452; 7 (1915), 561, Bureau of Standards, Sccenf$$c Pa+er, 264 (1915)
reference should also be made for t h e details of apparatus a n d methods. The choice of heating temperatures of 7 0 0 ° , 1000' a n d 1200' C. proved a fortunate one in t h a t it not only covers t h e temperature range t o which platinum crucibles are ordinarily subjected in practice, b u t besides i t so happens t h a t there also occurs within this t e m perature interval a reversal f r o m a loss t o a gain in weight of all grades of platinum ware observed in this investigation. The observations a n d t h e numerical inferences from
them are recorded in Tables I and II for the Seven crucibles of this investigation, ranging from t h e purest thermoelement a n d "tiegel platin" ware of Heraeus
to crucibles containing up to 2 , 7 per cent iridium and 8 per cent rhodium a n d with divers amounts of iron a n d other unknown soluble materials (including probably Pt itself, which in presence of Fe is slightly soluble in HC1) also as impurity. Five of these crucibles-all except I and which are practically newh a d been used in t h e previous investigation a t I 2 0 0 O C.
The
which had been previously heated were heated at Iooo0 c. and then at 700' C.; t h e others were heated i n t h e reverse order: 7 0 0 0 , Iooo0 and I 2 O o 0 c' When have been prepared for use b y strong ignition a n d treatment at
I2Oo0
c.
T H E JOURNAL OF I N D C S T R I A L A N D ENGINEERING CHEMISTRY
488
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