Deflocculated graphite

Deflocculated graphite

:Nov., r g o z . ] Deflocculated Graphite. 375 Mining and Metallurgical Section. (Slated Meeting held Thursday, October 3, I9°7.) Deflocculated Gr...

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:Nov., r g o z . ]

Deflocculated Graphite.

375

Mining and Metallurgical Section. (Slated Meeting held Thursday, October 3, I9°7.)

Deflocculated Graphite. BY E, G. ACHESON, Member of the Institute.

In the year I9O'~ I was engaged in a series of experiments having as their object the production of crucibles from artificial graphite. In this work I was led into a study of clays. What I learned may be briefly stated as follows: I s t . - - T h e American manufacturers of graphite crucibles impor[ed from Germany the clay used by them as a binder of the graphite entering into the crucibles. 2nd.---The German clays are much more plastic and have a greater tensile strength than American clays of very similar chemical composition. 3rd.--Residual clays--those found at or near the point at which the parent feldspathic rock was decomposed--are not in any sense as plastic or strong as the same clays are when found as sedimentary clays at a distance from their place of origin. 4th.--Chemical analysis failed to account for those decided differences. I reasoned that the greater plasticity and tensile strength were developed during the period of transportation from the place of their formation to their final bed, and I thought it might be due to the presence of extracts from vegetation, the washings from the ~orests being in the waters which carried them. Imade several experiments on claywith extracts of plants, tannin being one of them, and I found a moderately plastic, weak clay, when treated with a dilute solution ef gallotannic acid or extract of straw, was increased in plasticity, made stronger,--in some cases las much as three hundred per cent.,--required but sixty per

376

Acheson:

[J. F. I.,

cent. as much water to produce a given degree of fluidity, was caused to remain suspended in water and made so fine that it would pass through a filter paper. Being acquainted with the record of how the Egyptians had the Children of Israel use straw in the making of bricks, and how they substituted stubble for straw, and believing it was not used for any benefits derivable from the fibres but for the extract, I called the clay so treated "Egyptianized Clay." Having in 19o6 discovered a process of producing a fine, pure, unctuous graphite, I undertook to work out the details of its application as a lubricant. In the dry form, or mixed with grease, it was easy to handle, but I wished it to enter the entire field of lubrication as occupied by oil. In my first efforts to suspend it in oil, I met the same troubles encountered by nay predecessors in this lhle of work,---it would quickly settig out of the oil. It obey¢d the same laws covering the natural product. So things stored until the latter part of I9o6 when the thought occmred to me that tannin might have the same effect on graphite that it (lid on clay. I tried it with satisfactory results, the effect being obtainable with the natural graphites as found i n the Ticonderoga and Ceylon varieties, and with the artifieiaI product as found in Acheson-Graphite. It was more easily and cheaply produced when the soft, unctuous variety of my graphite was used, this Idnd being composed of pseudomorphs of carbide crystals, which had been decomposed in the electric furnacei the resultant graphite being very loose, porous and r e a d i l y disintegrated and deflocculated. The effect was produced by treating the graphite in the disintegrated form with a water solution ot tannin, the amount of talmin heing from three to six per cent. by weight of the graphite treated. The results are much more pronounced when the mass of graphite, water, and tannin has been pugged or masticated for a considerable time, I having to advantage carried on this process continuously, without interruption, for a period of one month. I have also found that while the effect may be produced in a very satisfactory way with distilled water, the waters as found in rivers, deep wells, etc., are improved by the addition of a trace of ammonia. The presence of carbon dioxide in the water will prevent deflocculation. The accompanying Figures I and 2 show the effect of tannin in suspending graphite. Figure, 1 is that of two test tubes, one

De[locculated Gr~phitc.

Nov., ~ 9 o 7 . ]

377

containing water, a drop of ammonia and disintegrate
Fig'. l

F[ ~t. 2

nearlv all of it had settled, only sufficielat remaining in llle water to give it its blackness. To cause a complete suspension ,)f all the graphite necessitates prolonged mastication in the fl~rm ~f a paste with the water and tannin, and I find that after this mastication has been carried out that the effect is very much improved by diluting the mass with considerable water, and allowing it to remain some weeks with occasional stirring. After the prolonged masticating and additional time of exposure of the graphite to the water and tann:n, an intensely black liquid is obtained consisting of water, a small amount of tannin and graphite; the latter may be present in varying amounts. In this condition I call the graphite "deftocculated," a state of subVoI,. CLXIV.

No. 983

25

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Acheson:

[J. F. I.,

division much finer than possible o{ attaimnent by mechanical means, one that may perhaps be correctly spoken of as molecular. It is in that condition called "colloidal." This term, however, does not appeal to me, being only the name of a condition or state. The term "deflocculated" is much more readily understood, and, to an extent, it carries with it its own definition. I have founct this liquid would pass throught the finest of filter papers, and the contained graphite would remain in suspension for weeks and months,--apparently for all time. One per cent. of graphite content makes the liquid so thick that it runs through the filter paper slowly; reduced to o.2 of one per cent., it goes through quickly.

F i g . ;~

Fig

4

Figures 3 and :! illustrate an experiment with water containing o.2 of one per cent. graphite. Figure 3 shows a glass funnel containing a fine filter paper resting in a test tube. In the tube below the funnel is a black liquid, which has passed through the filter paper. This black liquid is water containing o.2 of one per! cent. deflocculated Acheson-Graphite. The fact of its havingi passed through the filter paper leaves no doubt in our minds o}I the impossibility of separating the water and graphite while i~ this condition b~ ordinary filtration. I have found that the addi4.

Nov., 1 9 o 7 . ]

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tion of a very minute alnount of hdyrochlorie acid causes the contained graphite to flocculate, i. e. group its molecules into masses so that it will no longer pass through the paper. Figure 4 shows, as in the former case, the funnel, filter paper and test tube; but now in the lower part of the tube, below the filter, we find a clear liquid, this being the water in which the deflocculated graphite was formerly suspended, the graphite now being caught entirely in the filter paper above. It will be noticed that the filter paper in Figure 3 is black on the outside, this having been produced by the deflocculated graphite passing through the paper, whereas the filter paper, as shown in Figure 4, remains white on the outside, the graphite not having passed through its b o d y . This effect is obtainable with non-nmtallic amorphous bodies generally, having been secured with silica, almnina, lamp-black, clay, graphite and siloxicon. _An interesting line of thought may be entered into as to the part this effect plays in nature's economy. It is by this means Nature prepares the Potter's clay. This graphite, even after flocculation, is so fine in its particles that when dried en masse it forms a hard article. It is self-bonding, like a sun-drie~ clod of clay. [ have successfully used defiocculated graphite in water instead of oil in sight-drop feed oilers and with chain feed oilers. I have a shaft in my laboratory measuring 2 5-16" in diameter, revolving at 3000 revolutions per minute in a bearing IO inches long that had no oil on it for a month, deflocculated graphite and water being the only lubricants used, the feed being by chain, and it ran perfectly. On the same shaft is a similar bearing lubricated with oil, and this ran much the warmer of the two. A few days after this test was started a pessimistic friend remarked that just plain sinlple water would give the same results, that the presence of .graphite was unnecessary. We are influenced by the opinions of others even when we know or think they are wrong. I emptied the oil out of the second bearing on the shaft and substituted plain water. The results during the first twelve hours seemed to support the contention of the friend. The next day after the machine had stood motionless over night, things did not look so well for the water; it was a lame "second" on account of rust, and was hurriedly removed. I think I shall not recommend clear water as a permanent lubricant. Deflocculated graphite in water possesses the remarkable power of preventing rust or corrosion of iron or steel. This character-

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Achcson:

[J. F. I.,

istic will unquestionably make it of great value f~r scm~e uses, and while, as yet, little has been done to explore the fi~Id, some work has already been accomplished in using it as a cutting compound in screw cutting, and I have been advised by on? large manufacturer that the results obtained showed it to be equal or Superior to lard oil when the water was carrying as little as onehalf of one per cent. of its weight i~ graphite. It will readily be underst()od that while preventing rt,sting; the high specific heat of the water renders it of great importance, permitting of a high speed of the machinery, and consequently increased output. Another probable application of deflocculated graphite in water will be as a lubricant for condensing engine cylinders. While, as I have stated, deflocculated graphite in water is an excellent lubricant for light work, it has the disadvantage of losing its water by evaporation, and I realized that to utilize the possible advantages of deflocculated graphite, it would be necessary to replace the water with oil; therefore, I set before me the task of accomplishing that result. \ ¥ h e n it is remenibered that a removal of the water by evaporation previous to its replacement by oi! would cause the contained graphite to assume the condition of a hard, flocculated, self-bonded mass, it will be seen tha', the problem was not simply one of the evaporation of the water a n d suspending the resultallt dry graphite in oil. A very great deal of difficulty and many discouraging conditions were met with in my attempt to cross this apparently bottomless chasm. and I am pleased to say that l eventually s,.:cceeded, and I have been successful in suspending the defl~)cculated graphite in oil in a dehydrated condition. The graphite will remain suspended i,a the manner that it formerly did in the water, and we now have in this article a truly new lubricating bed),. A new material having been created, as this would evidently seem to be, a new name is necessary, and I have added the initial letters of Deflocculated Acheson-Graphite, D-A-G, to "Oil'; or "Aqua," when the deflocculated grapiaite is carried in oil or water as the case might be, and have "Oildag" and "Aquadag" respectively. Prof. C. H. Benjamin, formerly of the Case School of Applied Science, Cleveland, 0., and now Dean of the Engineering School of Purdue University, is engaged in making extensive tests to determine the value of deflocculated graphite as a lubricant, and,

N c v . . ~9c7.]

DeflocculatcdGraphite.

3 8I

while these tcs:s are not as vet completed, he has proved that o.5~)'~ by weight of this ~'raphite in oil greatly reduces the coefficient of fricti~)n and materially extends the life of the oil in which it is suspended as a lubricant. Figure 5 shows some of the results ()btained il; his tests with spindle oil, and by a study of them we find that~ comparing the initial co-efficient of friction of plain oil a:~
Co.. N i a g a r a Fall% N. Y., U . S . A .

I n i t i a l F r i c t i o n Oil a n d o 5 p e r c e n t . G r a p h i t e . A f t e r 12o Ill. F r i c t i o n .... " F r i c t i o n o f Oil i n c r e a s e d . . . . . . F r i c t i o n of Oll a n d G r a p h i t e i n c r e a s e d . . . . . . A f t e r l u b . w a s s h u t o f f f r i c t i o n of oil i n c r e a s e d . . . . A f t e r l u b . w a s s h u t o f f f r i c t i o n o f oil a n d g r a p h i t e S p i n d l e oil wa~ u s e d in all

. • 65 p e r c e n t , o f o i l a l o n e • 55 . . . . . 54 p e r c e n t . . 3° " 125 p e r c e n t . in 30 r a i n . . . ~4 .... 80 " test~

but sixty-five per cent. of the plain oil, while after one hundred and twenty minutes, it was but fifty-five per cent., the friction of the oil having increased fiftv-f()ur per cent., while with the contained graphite it increased but thirty per cent. After shutting off the supply of the hlbrical~t (~11 the bearing, the co-efficient of

3~4

;\Totes and Comments. QUARTZ (FLINT) AND FELDSPAR

PRODUCTION

[J. F 1., I N 19o6.

Quartz, the ,most a b u n d a n t of all the minerals, occurs in so g r e a t variety of i o r m and is utilized commercially in so mar~y different ways t h a t the statistics of its annual p r o d u c t i o n p r e p a r e d by the U n i t e d S t a t e s - G e o logical Survey are c o m p r i s e d u n d e r several heads. Certain t r a n s p a r e n t , colored varieties of the mineral, such as rose and s m o k y quartz and amet h y s t i n e quartz, have a gem value and are discussed in c o n n e c t i o n with precious stones; sand used for building, molding, and in pottery m a n u f a c t u r e is separately treated, as are also s a n d s t o n e and quartzite used for building purposes, a l t h o u g h all of these materials consist of nearly pure quartz. T h e massive crystalline quartz, often called vein quartz, with flint and with quartzite, used for o t h e r t h a n building purposes, and the associated and widely distributed feldspar deposits are g r o u p e d t o g e t h e r and are discussed in an adwmce chapter from the r e p o r t on " M i n e r a l R e s o u r c e s of the U n i t e d States, Calendar Y e a r 19o6." This chapter, p r e p a r e d by E d s o n S. Bastin, is n o w ready for distribution. T h e varieties of quartz dea]t with in Mr. B a s t i a n ' s r e p o r t have a wide r a n g e of uses. Massive crystalline (vein) quartz is p r o d u c e d in Connecticut, New York, Maryland, and Virginia. T h a t from the l a s t - n a m e d State is used in the manufacture of metallic silicon and ferro-silicon by electrolyric processes, these ,materials b e i n g largely employed in steel m a n u f a c t u r e to increase the t o u g h n e s s of the product. A large p r o p o r t i o n of the quartz from N e w York, Comlecticut and M a r y l a n d is g r o u n d and utilized in the m a n u f a c t m e of a wood filler. _Massive quartz in blocks is used in the chemical industry as a filler for acid t o w e r s and to some e x t e n t as a flux for s m e l t i n g copper; ground, it is used extensively in the m a n u f a c t u r e of sandpaper, sand belts, s c o u r i n g soaps, and polishes as a s c o u r i n g a g e n t in sand-%last apparatus, and in filters, and some of the finest grades are used by the dentists as cleaners. So far as k n o w n very little domestic flint has ever heen commercially utilized, a l t h o u g h its quality apgears to he equal to that of the imported flint, which is b r o u g h t in cheaply as ballast from France, Greenland. Norway, and E n g l a n d , and much of which is b u r n e d in kilns and g r o u n d for use in the p o t t e r y trade. Vein quartz is also used by p o t t e r y manufacturers. A c c o r d i n g to Mr. Bastian, the p r o d u c t i o n of quartz in the U n i t e d States in t9o6 a m o u n t e d to 4E,3I 4 s h o r t tons of the crude material, valued at $37,632, and 25,383 s h o r t tons of g r o u n d quartz, valued at $2o5,38o; a total of 66,697 s h o r t tons, valued at $243,oi2. T h e s e figures do not r e p r e s e n t the entire a m o u u t of quartz and flint c o n s u m e d for the year, for flint is i m p o r t e d to the value of $272,6o7. T h e commercial fieldspar p r o d u c e d in the U n i t e d States occur nsually as c o n s t i t u e n t s of pegmatites, and to m e e t the needs of the p o t t e r y manufacturers, by w h o m they are chiefly used, they n m s t contain from I5 to 20 p e r cent. of free quartz. T h e material is used principally as a c o n s t i t u e n t of b o t h body and glaze in true porcelain, white ware, and vitrified sanitary ware, and as a c o n s t i t u e n t of the slip (underglaze) and glaze in the so-called "porcelain" sanitary wares and enameled brick. A t p r e s e n t it is quarried in Maine, New Y~)rk, Connecticut, Pennsylvania, Maryland, Texas, and

Nov.. ~9o7.]

Yoole Xotices.

385

Minnesota. and the total producti~m in 19o6 a m o u n t e d to 39,976 shorL tons of crude feldspar, valued at .$~32,643, and 32,68o s h o r t tons of g r o u n d feldspar valued at $268,888; a totai p r o d u c t i o n of 72,656 s h o r t tons, valued at $4oi,53I. T h e use of the mineral is increasing and the domestic supply is supplemented by large importati~ns from1 Ontario, Canada.

Book Notices. ]~leme~tts of General Chemistry with experiments, by J o h n H. Long.

4th edition, revised :rod enlarged. 443 pages illustrations, i2-mo, Philadelphia, B. Blakiston's Son & Co., z9o6. Price, cloth, ~LSo. This work first appeared in the year I898. T h e p r e s e n t edition is b r o u g h t up to date and includes a c h a p t e r c)n the theorie~ o[ solution and the conditions of chemical equilibrium. 'Lhere are one h u n d r e d and seventy-five e x p e r i m e n t s in all fields of chemistry, interspersed with much i n f o r m a t i o n of value to beginners in the study of the science. R.

A Tc.rt-Book of Elementary Analytical Chemistry, qualitative and volumetric, by J o h n K. L o n g . T h i r d edition, revised and enlarged. 299 pages, illustrations, z2-mo. Philadelphia, P. Blakiston's Son & Co., I9o6. Price, cloth, $I.25. The present volume is intellded for studcnts who have gone t h r o v g h the work on general c h e m i s t r y by Prof. Long. T h e a u t h o r has a r r a n g e d his course, to meet the special needs of the students in the chemical laboratories of the N o r t h w e s t e r n U n i v e r s i t y M~edical Scho~fl, at Chicago. The book is t~niform i1~ al)i)caranec and slz~- with the one previously noted. t,'.

}lTclbvmr's Photographic E.rposure Nccord and Diary. U n i t e d States Edition. ~9o7, 26o pages, illustrations, plates, 24-mo. New York, Burroughs, \Vellcome 8: C,h. Price. 5o cel~ts. This annual contains considerable i n f o r m a t i o n which will be useful to the a m a t e u r p h o t o g r a p h e r . It deals with developers and development, restrainers, fixing and harde~ling, and (~thcr m a t t e r s of importance in the p h o t o g r a p h i c laboratory. The leading feature of the b o o k is the exposure calculator which is attached t~ the back cover. It is a movable disc, by means of which the a p p r o x i m a t e cx~:~sure can be ascertain.ed for any subject or plate. A dozen pages are dev()ted to light values of the different months, and a table giv.cs the speed ()f a b o u t two h u n d r e d makes of plates and fihns. In addition to the blank pages for the' diary there arc also a n u m b e r of pages carefully ruled for the p u r p o s e of recording negative exposures and positive exposures. The work is issued in p o c k e t - b o o k form and is a d o r n e d with several half-tone reprod*1etions of p h o t o g r a p h s . R.

Elementary Practical Chemistry. P a r t II.

Analytical Chcmistry. Qualitative and Quantitative. By F r a n k Clowes and J. B e r n a r d Coleman. Fifth edition. 237 pages, iJlustrati(~ns. I 2 - m o L~mdon, J. & A. Churchill,