T H E J O l - K S AL OF InI‘DCSTRIAL A N D E N G I N E E R I S G C H E M I S T R Y
June, 191;
intricate design present a true platinum appearance. All are very malleable a n d ductile. and can be rolled, spun, or otherwise worked into a n y desired form. Figures for some physical properties are given in Table ITr. TABLEI\--I”YSICALPROPERTIES OF RHOTANIUM ALLOYS ’
Melting point O
ALLOY 5
A A5 B C D Au Pd Pt
C. 1150 1220 1280 1350 1410 1450 1063 1550 1775
F.
(Calc.) 2100 2228 2335 2462 2570 2642 1945 2822 3191
Sclero- Tensile Electrical scope Strength ConducHard- K g . per tivity ness sa. mm. X 10-4 26 ... 13.5 35 40 10 ~. 9.8 45 7.85 13 5.5 50 16 3.8 51 l; 21 45.5 9.45 11 30 9 24 9.94
4
Temperature Coefficient 0.00097 0.00065 0.00060 0.00050 0.00032 0.00326 0.00328 0.00348
-4s may be judged from t h e above described properties these alloys are well suited t o replace platinum in many of its applications in all fields, and have been so used for a long period with entire satisfaction. By taking advantage of t h e ease with which chemical a n d physical properties may be modified through adjustment in composition, various alloys of this series have operated fully as satisfactorily as platinum in chemistry, dentistry, jewelry. a n d i n many electrical appliances. Various grades of this material have undergone extended field trials, t h e results of which may be summarized as follows for t h e various fields of application. CHEMICAL
Rhotanium cannot substitute platinum when exposed t o t h e action of hot concentrated nitric acid, or when used as anodes in electrolytic work, b u t for all other purposes i t is entirely satisfactory ij the p r o p e r composition is chosen, a n d if f i r o p e d y manufactured. It is equal t o platinum in t h e case of hot concentrated hydrochloric or hydrofluoric; hot dilute nitric; fused potassium bisulfate; hot concentrated sodium hydroxide solution; fused sodium carbonate; hot concentrated sodium sulfide solution; and in its resistance t o oxidation a t high temperatures. It is superior t o platinum in its resistance t o t h e action of hot concentrated sulfuric acid or fused sodium hydroxide. It is satisfactory as material for cathodes in t h e electrolytic determination of metals. Losses b y volatilization a t temperatures below 1300’ C. are less t h a n for commercial platinum. Rhotanium may be rolled into sheets of a n y size, a n d may be formed either cold or white hot into any desired shape. I t welds as readily as wrought iron a t a white heat without t h e use of flux or other reagent. Due t o greater strength a n d lower specific gravity, articles of rhotanium weigh only half, or less t h a n half as much as similar articles of platinum. The specific gravity of alloys in this series varies from 18. j t o about 16.0, depending upon t h e composition: t h a t of platinum is 2 1 . j . ELECTRICAL
Rhotanium is satisfactory within its temperature limitations as t h e material of resistor elements in electric heating units. I t is not oxidized a n d is less volatile below 1300’ C. t h a n platinum. I t s high resistance and low temperature coefficient are valuable in this connection.
597
It is satisfactory as material for contact terminals in many forms of automatic-electric devices a n d may be used in this capacity on certain types of telephones, switchboards, signal devices, lighting a n d ignition systems, and in most other cases except where i t has been found necessary t o use a high percentage of iridium alloyed with t h e platinum. I t s behavior when tested on certain magnetos was satisfactory, b u t other experiments performed on a high-duty aeroplane engine magneto ga7-e negative results. DEKTAL
Certain of these alloys have been in t h e hands of operating dentists for some time a n d have proved t o be equally as good as platinum for many purposes. They have been used for pins and baked into porcelain teeth and as thin foil a n d heavy sheet for other types of construction, all with t h e most satisfactory results. 1E LVELRY
Rhotanium is superior t o pure platinum for use in jewelry. It is harder a n d stronger, a n d takes a better finish. It is absolutely not tarnishable or corrodible, and its color is practically platinum-white. It can be as readily worked as platinum, a n d scrap may be remelted for further use. It may be forged either cold or white-hot a n d may be “sweated” or otherwise treated as platinum without oxidizing or darkening in color. Finished articles of rhotanium jewelry of t h e more intricate designs can b y no ordinary means be distinguished from platinum. This material passes t h e common jeweler’s and platinum buyers’ tests a n d there will no doubt be some confusion resulting from t h e passing of this material for platinum. Exhaustive tests have shown t h a t most of t h e uses for which platinum has heretofore been considered indispensable can be filled b y one of these alloys, t h u s freeing platinum for those remaining applications where no other material can be employed. T h e extent t o which platinum may be replaced in this manner is limited b y t h e amount of palladium available, and when i t is considered t h a t these alloys contain from 90 t o 60 per cent of gold i t is evident t h a t t h e effective supply of platinum may thus be increased by many thousand ounces. 1706 GLENMOSTROAD CLEVELAND, OHIO
A PRACTICAL METHOD FOR DETERMINING THE VISCOSITY OF STARCH FOR MILL PURPOSES By G. M. MACNIDER Received March 16, 1917
Several years ago t h e author described in THIS a method for determining t h e viscosity of starch solutions for determining t h e value of different starches for cotton mill purposes. Since t h e publication of this article t h e author has had t h e opportunity of applying this method t o practical mill work a n d has worked out a modification of t h e method which is described in this paper. T h e original method is briefly as follows: 1 2 grams * THISJ O D R N A L 4 (1912), 417. JOURNAL’
598
T H E JOL'KiY.IL OF I N D U S Z ' K I 4 L A N D E N G I N E E R I N G C H E M I S T R Y
o f the starch a r e weighed i n t o a 600 C C . Beaker, 3 0 0 cc. distilled water added (thus making a 4 per cent solution), heated over a Bunsen burner with constant stirring to the boiling poini, and boiled 10 min.; zoo cc. of this solution are then poured into t h e cup of a Scott viscosimeter, t h e tenipcrature being allowed t o beconic constant, and j o cc. run o u t into a graduate, the time hcing acciirat,ely nieasured with a stop-watch. onds reijiiired to deliver j o cc. The numlxx of n t thc soliit.ion divided l i y the number of seconds required to deliver i o c r . of Imiling vatel- gives t h c viscosity. A P P ~i n :\'I t
s
The m e t h o d makes :i vei-y satisiacttii-y laboratory method for determining t h e comparative ralue oi dicerent starches, but in mill work i t is frequently of importance t o know the viscosity of the starch solai . i m after i t has been boiicd x i t h steam for an hour o r more as is doric in the iise o? the starch in preparing
Vol. 9 , No. 6
thick builing starches o . j lb. of starch per gal. of water is used; for medium thin boiling corn starch, I Ib. per gal. of water; for very thin corn starch and oilier chemically treated starches t h e amount is increased t o 2 or 2 . j ibs. per gal. of water. I'ROCEUUKE
One galloii of water is measured into the kettle, llie agilators started and the starch, accmately weighed, put into the kettle. T h e agitators are now run I O t o I.; minutes before turning on the steam in order t o produce a perfectly smooth cream t o avoid the formation of lumps. T h e steam is theii turned on a n d t h e solution boilcd for one hour after it comes t o a boil. When t h e boiling is complcled, some of t h e solution is drawn out into ii beaker, quickly poured into t h e cup of a Scott viscosimeter a n d t h e viscosity determined as described i n t h e original inethod. T h e figures in Table I illustrate t h e application of this method in comparing several grades of thick boiling corn starches, using o . 5 lb. starch per gal. of water a n d boiling for one hour. T i i l i s I-VXSCOSI~(Y NO.
I
2 3 4 S
MBASWRBIBNTSOB VIX~OUY C X A U I ;01 ~ STARCN
vlscDsiIY
ST*KCEi
neEuiar reartcornsearch.. . . . . . . . . . . . . . . .3. i o
Powdeied Starch ............. 4.30 PuiiGedStarch ............................ 4.30 Chemically Treated Starch.. ...............2.89 Ilighly Purified SLamh ..................... 4.58
Some of the gluten a n d impurities of S o . 2 were removed by t h e powdering process so t h a t this starch shows a higher viscosity t h a n KO.I . KO. 3 was another ?arm of starch which had been subjected t o t h e same amount of purification as No. 2 . While t h e viscosity of starch No. 4 was lower t h a n t h a t of starch No. I , due t o t h e chemical treatment, t h e actual value of starch No. 4 was greater. T h e actual mill practice substantiated these figures; i. e . , if under certain conditions a size mixing of starch No. I made on t h e basis of 0.j lb. starch per gal. of water gave t h e desired results, if No. z or No. 3 were substituted, under t h e same conditions, i t would be necessary t o use less starch in order t o obtain t h e same thickness of solution and consequently t h e same results; whereas, if No. 4 were substituted i t would be necessary t o use more starch. it for warp sizing, etc.. i n the mill. T o accomplish tliis, a miniature size kettle was constructed. similar in every respect to the large kettles used in cooking starch in the mill. 'This kettle1 (see Fig. I) has a capacity of about gallons and is equipped with double agitators of the propcller type, revolving in opposite directions. T h e steam Tor cooking enters through a perforated coil tin t h e bottom of t h e kettle. I n order t o overcome variations in the amount of steam condensed the steam is passed through a t r a p just before entering t h e kettle. T h e time of boiling is one hour, t h e time being takcn a t t h e time t h e starch hegins to boil. T h e aniount of starch taken for a determination varies with t h e grade of starch. For thick boiling corn starch, potato starch, and similar $ This hefile w r e coiiiiructed hy Mr. 3. S. Drake of the Exposition Cottao Mills, Atlnniil, GI.. arid the author is indebted f~ Mr,Drake for
valuable assistance hnd suggrstions in working out the method.
T h s i . ~II-VISEUSXITY MBASUXL~YBNTS ox SEVItrnL G x I ~ l i s0%-MDUlXLaD OP TIIIN.UOZLIN(i
ST*BCHHS
Les. STABCH PIE GAL.WATPR I ................... 1 Lb.
KO.
VISEOFIT.
... 1 Lb. 3 . . . . . . . . . . . . . . . . . .1 Lb. 4....... . . . . . . . . . . . . 2Lbs. 5 (same grade as 4).., 4 Lbn. 6 (same wade as 5 ) . .. 4 Lhs. ( 2 oz. KOH added te kettle) ? (rum* grade as 1)
2.43 2.16 1.94 1.27 3.54 2.63
Sos. I and 2 were t h e same grade of boiling starch; i n using No, 2 in t h e mill i t was found necessary t o use slightly more than was used of No. I ; t h e figures show t h e difference. No. 2 was a higher fluidity or thinner starch t h a n No. I . Nos. 4 and 5 were t h e same grade of a very t h i n starch, t h e figures showing t h e difference in viscosity when t h e amount of starch used per gallon is doubled. No. 6 was t h e same as No. j, b u t with t h e addition of 0 . 2 oz. KOH t o t h e kettle. T h e viscosity figure shows t h e very marked thinning effect of this amount of caustic potash on
June, 1917
T H E J O C R N A L O F I N D U S T R I A L A N D E N GIN E ElU N G C H E iVf I S T R Y
t h e starch solution. I t frequently becomes necessary t o a d d t o a starch mixing some reagent such as caustic alkali, chlorides of calcium, magnesium, zinc, etc., a n d i t is very important t o know just what effect t h e reagent will have on t h e thickness of t h e starch solution. The advantages of this method over t h e laboratory method for mill work are as follows: t h e viscosity is determined when t h e starch has been boiled for t h e same length of time as i t is boiled in preparing it for use in t h e mill and under t h e same conditions. The amount of starch used can be in t h e same proportion t o t h e amount of water as in a regular size mixing; this makes t h e figures obtained by practical value as they show t h e viscosity of a size mixing. Also, in comparing two or more starches on such a basis. this fact t h a t t h e viscosity figures represent t h e actual thickness of a size mixing makes it possible in case of a variation in viscosity t o determine in t h e small kettle t h e amount necessary t o use, thus saving t h e time a n d expense of experimenting on a large scale. GREENVILLE, SOUTHCAROLINA
FULLER’S EARTH AND ITS VALUATION FOR THE OIL INDUSTRY By THEODORE G. RICHERT Received December 1 1 , 1916
An important part of a modern oil refinery is the filtering department, where by means of fuller’s earth t h e refined oils are bleached t o t h e desired lightness in color. As many varieties of such bleaching agents are offered, i t might be of interest t o describe a cheap a n d quick method of determining. in t h e laboratory, t h e efficiency a n d economy of fuller’s earth. T h e earths for bleaching edible oils are clays which are used in t h e natural s t a t e as they occur or which sometimes are especially prepared in order t o increase their bleaching power. T h e y include hydrous silicates of aluminum, magnesium and calcium, containing small amounts of other substances, such as iron. sodium, potassium, etc. Fuller’s earth, owing t o its colloidal character, when brought in contact with refined oil, forms, with t h e colloids soap a n d coloring matter, colloidal aggregates a n d settles out as such; after separating t h e oil a n d t h e fuller’s earth, t h e oil has a n earthy taste a n d a p a r t of it remains with t h e fuller’s earth. Essential points in t h e use of fuller’s earth in t h e oil industry are: I-Precipitating of minutely suspended particles of soap left in t h e oil from t h e refining. 2-Removing of coloring matter, which, owing t o t h e refining, is contained in t h e oil in a n unstable state. 3-The earthy taste imparted t o t h e oil should be removable by means of deodorization. 4-The loss of oil due t o absorption should be as low as possible. For trials like ours, Points I a n d 3 may be neglected; all fuller’s earths have t h e ability of settling out t h e soap in sufficient degree a n d t h e earthy taste can always be removed by means of a well conducted deodoriza-
599
tion process. As t o t h e other points, a valuation of fuller’s earth concerning its bleaching power a n d its absorption of oil can be accomplished in t h e laboratory. Owing to t h e varying behaviors of t h e refined oils, as well as t o working conditions in t h e plants, it is impossible t o determine a n d fix absolute values for these properties. The only alternative is t o compare t h e results obtained from viorking a new unknown earth with t h e results of one already tested. The principal condition is t h a t for all tests and all earths t h e same oil a n d methods be used. T o determine t h e bleaching powers of different earths a number of bleaching tests1 were made with a well refined cottonseed oil, using from I t o 8 per cent of t h e earths (a greater per cent t h a n 8 was not tested, since a higher amount is commercially prohibitory). I n Table I , the earth B is a domestic, C a n imported English, D a n imported German earth; t h e origin of A could not be ascertained. TABLEI-COLORS (LOVIBOND TINTOJIETER) OB OILS BLEACHED WITH DIFFERENT PERCENTAGES O F FULLER’S EARTH Bleached with Fuller’s BRANDA BRAA-DB BRAA-DC BRANDD Earth Yellow Red Yellow Red Yellow Red Yellow Red 3.2 35 4.0 20 5.4 35 2.4 1 ....... 35 2.6 35 3.0 18 20 1.8 2 ....... 35 4.5 2.6 20 2.0 14 20 1.4 3 ....... 35 4.0 2.4 18 1.8 14 20 1.4 4 ....... 35 3.4 16 1.6 16 20 2.4 1.6 5 20 2.6 2.4 18 1.8 14 2.8 20 1.4 6 20 2.4 16 1.6 14 2.2 20 1.4 i 20 2.4 16 1.6 16 2.0 20 8 ....... 20 1.6
....... ....... .......
The results indicate t h e exhaustion and efficiency of t h e earth. The maximum effect is reached for Brands A , B , C and D with 8, 4, j and 3 per cent of earth, respectively. T o show even more distinctly t h e differences of t h e several tests, t h e results are plotted below, with t h e amount of fuller’s earth used and t h e red color obtained as ordinates. The dotted line indicates t h e color for “White Oil”--20 yellow, 2 . j red.
A EARTH O F UNKNOWN OR/G/N 5
4 3 2 /
j
1
PER CENT o f FULLERS EARTH u&. 2
3
4
5
6
7
~
8
T h e faster a curve arrives at t h e lowest point of its course, and t h e nearer i t approaches t h e horizontal axis, t h e greater is t h e bleaching power of its earth. I n our case, Brand D is t h e most effective; as shown by t h e curve, small amounts of B are highly advantageous, therefore, this earth seems t o be well fitted for use in combination with other earths. Brand C 1
See Official Method of the “Society of Cotton Products Analysts.”
