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-
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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. TABLE I-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.”
T H E J O U R N A L O F I N D U S T R I A L A N D EIVGINEERING C H E M I S T R Y
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is a reliable agent; its run in t h e factory has confirmed its good qualities. A is a slow-acting e a r t h ; t o obtain a n y tangible results large amounts are needed, a fact which prohibits its extended application. Another feature of t h e curves is toshow approximately how much of t h e different earths would be necessary t o obtain t h e same results. For instance t o bleach t h e oil of our experiment t o a “White Oil,” there must be used of Brands A , B , C or D , 5.8, 3.0, 2.4 or 1.0 per cent of earth, respectively. T o determine the loss of oil d u e t o absorption, 300 g. of oil were agitated with I O g. of each of t h e fuller’s earth samples for a given time a t a given temperature. T h e n t h e oil was filtered b y means of a Buchner funnel.’ When t h e earth seemed t o be dry, vacuum was kept u p for 15 min.; t h e earth was t h e n removed from t h e funnel a n d weighed. Now when there is known t h e loss due t o absorption when working with one of t h e earths, i t is possible t o figure out t h e loss t o be expected using another earth, provided t h e working conditions remain t h e same. For instance, t h e earth C was known t o cause a loss of 8 per cent; t h e presumptive losses of t h e other earths based on this figure are shown in t h e following table : FULLER’SEARTH Oil Absorbed Presumptive Loss Per cent Per cent 17.7 8.3 87.3 40.8 17.1 8.0 40.5 19.0
TABLE11-ABSORPTION OF OIL Earth plus Oil Grams A. 11.77 B . . . . . . . . . . . . . . . 18.73 11.71 D...... . . . . . . . . . 14.05
Brand . ~-
.............. c ................
T H E VALUATION
v=
d I 0 O P IO0
+-A?)
+ xAI1oo
cents,
when x is t h e percentage of earth needed, A t h e presumptive loss, P a n d 0 t h e price i n dollars for I O O lbs. of earth a n d oil, respectively; or, X A I I O Oin t h e denominator being negligible as compared with 100, t h e raw costs are simply: IO0
TABLE I11 Price(a) Presumptive Per cent of of Earth LOSS BRAND Earth for 100 lbs. Per cent $0.70 8.3 A 5.8 B $0.68 40.8 3.0 $0.79 8.0 cD . . . . . . . 2 . 4 83.15 19.0 1.0 ( a ) All prices are figured f. 0. b. Portsmouth, Va.
....... ....... ........
CONCLUSIOS
I n spite of t h e highly developed bleaching power of E a r t h D its application is not t o be recommended on account of its excessive price. A n extended use would be desirable only with t h e dropping of its price t o about $1.90 per I O O Ibs. or with a n oil price of around $4.50; in both cases t h e bleaching cost would then be about 4 cents. Brand C is t h e most economical of all; t h e higher amount of earth used is compensated by t h e low absorption. Brand B is not vie11 recommended because of its high absorption value. Finally, Brand A is not suitable for practical work on account of t h e large amount needed, which calls for large sized filter presses. I n conclusion, i t should be noted t h a t t h e work in t h e actual run is usually less costly t h a n t h e preceding figures show; t h e intense contact of earth a n d oil under pressure increases t h e effect. T o state t h a t t h e actual raw bleaching costs fluctuates between jo and 7 5 p e r cent of t h e above figures would be a fair estimate. P. 0. B o x 27, PORTSMOUTH. VIRGINIA
AN APPARATUS FOR THE PURIFICATION OF MERCURY B y HARRISON E. PATTEN AND GERALDH. MAINS Received February 2, 1917
BY
The value of fuller’s earth a n d consequently t h e economy of its use is dependent on price, bleaching power, absorption value a n d t h e utilization of t h e residue. The latter, being for all earths practically constant, may be omitted. On account of t h e impossibility of determining absolute figures for bleaching power and absorption value, t h e earth’s worth can be so ascertained t h a t i t is assumed t o bleach a n oil t o a certain lightness. The raw bleaching cost for I O O lbs. of oil is then:
Raw Bleaching Cost for 100 lbs. Cents 9.36 15.50 4.01 5.24
For t h e assumed case t h a t a “White Oil” has t o be made from o u r oil, t h e figures are collated in Table 111, t h e price of oil being taken as $11.00per I O O lbs. 1 See “Fuller’s Earth,” by Charles I ,. Parsons, Washington, D. C., Bull. 71, Bureau of Mines.
Vol. 9, No. 6
I n this laboratory we have need of mercury in a very pure state not only for standard cells, a n d calomel halfcells, b u t also in rather large quantities for t h e filling of thermoregulators used in controlling constant temperature baths. The presence of even a slight trace of foreign metal, such as lead or zinc, after t h e mercury stands a short time in contact with air, gives rise t o t h e formation of a n oxide film on t h e surface which dirties t h e capillary tubes a n d interferes greatly with t h e delicacy of t h e thermoregulator. We have tried out t h e various methods which have been proposed for t h e purification of mercury, and have used a number of t h e types of apparatus described in t h e literature. The well-known method of Lothar Meyer,’ in which mercury is passed in a fine stream through a long column of dilute nitric acid, is slow, tedious, a n d cumbersome. The speed of operation is greatly increased b y t h e modification of J. H. Hildebrand,* where t h e mercury is broken u p into numerous extremely fine streams b y passing i t through muslin into t h e acid column. L. J. Desha devised a modification3 b y which t h e mercury, after running through t h e nitric acid column, was automatically raised t o t h e t o p a n d t h u s kept in continuous circulation. Loomis and Acree4 incorporated with t h e Desha apparatus t h e means of electrolytic purification, i. e . , making t h e mercury t h e anode in a nitric acid solution.6 Even after t h e above modifications, t h e purification demanded considerable watching a n d personal attention. Also there was no means provided for renewing t h e nitric acid without cleaning a n d refilling t h e entire apparatus. We have endeavored t o construct a Z . anal. Chent., 2 (1863), 241. J . A m . Chem. Soc., 31 (1909), 933. s A m . Chem. J . , 41 (1909), 152. 4 N. E. Loomis and S . F. Acree, A m . Chem. J . , 46 (19111, 594. 5 Wolff and Waters, Bureau of Standards, Bull. 3, 623; 4 (1907), 1 . 1
2
