1 N U U Y T I< I A L A N U
l3Jb
18) Merkien. "Die Iiernaeiien," Gerniaii lrUmdh:.iw
E N G I N E E I< 1 N G C H E M 1 S T K Y
by Gobi-
schmidt, Hallc. 1907. (9) Odtwald and &bring. KoUoirdBeihe/tc, 31, 291 (1930). (10) Kiciiert, "Das Ausaiscu von Seiic," Dissertation, Kariaiuhu, 1911. 1 i 1 ) Thhrl. "IJsr Aussulsen veri &de," Diaaertation. Karbmho. 1918. (12) Ubbelohde. Ilandbuch der bie uncl Potto. Vol. 111, Part 2. D. 173, Hired, Leipzk, 1930.
Vol. 24,No. 12
(13) Ubbelohde, IM.. Vol. 111, Psrt 2. p. 177. See d s o Kursmann, Kolloid-Beihe/fie,5,427 (1014): McBain, Lsisrus. snd Pitter. Z. phusik. Chew&:. 147, 81-11? (1930). (14) W O ~ R , z. deut. oi-~.'elcid.,41, 289-90 (1941);
see
Kawnkami, Y..J . SOC.Chem. Ind. (Japan), 35, Suppi. binding, 44 (1932). I ~ C B I V SAueust D 1, 1932.
Stabilization of' Aqueous Dispersiom of Asphalt A. W. IiixsoIv
AND
1
J. M. FAIN,D e p a r t m e n t of
m H E applicatioit of asphalt in emulsified foim passesses many advantages. Its preparation has d e v e l o p e d to an i m p o r t a n t i n d u s t r y . D i s n e r s i o n of a s p h a l t . however; presents several problems. I n t h e s o l u t i o n of s o m e of "lese
was
Chemical Engineering, Columbia University, N e w York, N. Y.
The addition of ferrous sulfale to a soaoemuk$ed asph[tc&lai,iingp,&ssium tannate alone or potassium caseinate alone results in a on screenins. Potassium lannate and potassiwn caseinale are both present, practically no deposit is obtained. An explarialion based on the stabilizatiorL asp/lalt urilh u f n e l y divided solid ernuls@r is advanced to e w l a i n this action.
silica, which B ~ g g aalso recommends, a n d a l u m i n a , which Lewis (12) found successful for
direct
as well as
iron t a n n a t e (used in writing inks),were tried. The arsenious sulfide hydrosol was p r e p a r e d by boiling about 0.5gramof finelypowdered arsellious oxide with 300 cc,
of building an emulsion with a of distilled water for about 15 hydropirilic mlloid as emulsifying agent and replacing it with a m i n u t e s . Into this arsenious finely divided solid emulsifier. The hydropkiilic colloid used acid solutiun were poured 300 cc. of saturated hydrogen sulfor the purpose was soap. Ease of emulsification, due to fide solution. The arsenious sulfide hydrosol was purified by marked lowering of the interfacial tension between water and dialysis against distilled uvatcr. Various quantities of the asphalt, was thus obtained. The form in which soap can hydrosol were added to portions of an asphalt emulsion prebest be manipulated in the laboratory when a mechanical pared by dispersing 200 grams of Mexican asphalt in 100 cc. st,irrer is used is by incorporating a fatty acid in the asphalt of an 0.078 N potassium hydroxide solution. The emulsion and emulsifying the product in an aqueous solution of alkali. remained unbroken, but in the subsequent operation of adding When asphalt is emulsified by agitation in a soap solution calcium chloride solution to precipitate the soap, coalescence directly, considerable foaming rcsults, and the emulsion con- of the asphalt resulted. tains ail excess of air. On standing, the air escapes, but a Simitarly the antimony sulfide hydrosol was prepared by number of coarse-grained asphalt particles reinsin behind in dissolving 2.5 grams of tartar emetic in 500 00. of distilled the dispersion. Mexican asphalt naturally contains free water and saturating with hydrogen sulfide. The sol was acids, thus obviating the necessity of adding fatty acids tu purified by dialysis. Additions of this sol were made to por:isphhalta obtained by the refining of crude mineral oils froin tiom of an asphalt emulsion preparcd as described above. many other sources. Mexican asphalt was therefore used Coalescence of the asphalt resulted 011 precipitation of the i n this research in the investigation of the problem. soap with calcium chloride solution. Various hydrophobic hydrosols and frclslilv imciriituted Precirritation of silie:t in situ was attempted by emulsification of Mexian a s p h l t in s o l i d s w e r e t e s t e d in an effort to obtain a protective a solution of sodium silicate. Preliminary experic n v c l o p o for t h e asphalt irientation i n d i c a t e d the pnrticles which would stabiconcentration of s o d i iini lize the disliersion when the silicate that gave good dissoap was destroyed. Kot much aid could be obtained p e r s i o n . h one per cent s o l u t i o n was found to Lie froni a study of the consatisfactory. Theemulsion tact angles of various fine powders and mirierals. Tlie broke, liovever, on the addition of calcium chloride soludata are not abundant and tion. the values for the contact Similar a t t e n i p t s were angles :we greatly affected by the c o n d i t i o n of thc itintie to precipitate alumina i n situ by emulsification of solid. A r s e n i o u s sulfide, Mexican asphalt in a solusuggested by Briggs ( 1 ) for the proniotion of emulsions tion of potassium aluminate. The potassium a l u m i n a t e of benzene and kcrosanc in s o l u t i o n was prepared by water, and antimony trisulslowly adding potassium hyfide with much the same droxide solution to a soluproperties were used for exUSE OF A s m t a ~EMULS~ON MASTE FOX MAINTENANCE ow tion of AICla.6€II0 until the STREETCARROADWAY perimentation. L i k e wise
1338
I L I) 1;
s 'I' II IA
I. .k N D
E N G I N E F; II I N G
reeogiiized that t h e wuul~ifyitigpower of a soap is reflected in the fineness of diq~crsionof the oil ghhules in the resrilting emulsion. IIc therefore made a quantitative investigation of the disperrity of emulsion. Tlis rrretliods 'sere I x s e d on Stokes' law of settliiig. In Iiis first inethod the rate of cliange of concentration wit,li tirnc at a fixed height is detcr-
c 51 E ~LI I s 'r IS Y
Vol. 24, Nu. 12
field, and
