May,
1912
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y .
The defendants claimed t h a t the nuisance was caused b y unskilful management of the farm and t h a t tannery effluents were as capable of bacterial treatment as sewage. A decision was rendered in favor of the defendants, on the ground t h a t the sewage farm was ineffective. A biological treatment of tannery effluents has also been proposed (Eitner, Gerber, 32, 199,213,2 2 7 ) . , Alsop [Chem. Eng., 15, 115 (I~IZ)] has recently reported t h a t the solids of tannery waste may be separated from the liquids by means of precipitating tanks, settling basins or centrifugal separators. He considers t h a t the best plan is t o use continuous centrifugal separators, which give control of the odors, and by means of which the solid; can be placed in receptacles for incineration, for chemical treatment to recover ammonia, greases, etc., or for drying for use as fertilizers. The liquid waste, after the removal of the solids, is, according t o Alsop’s plan, r u n through ozone atomizers in a spray tower, falling on coke filters through which currents of ozonized air are continuously passing. It is said t h a t the effluent resulting from this treatment is entirely unobjectionable from a sanitary standpoint, and t h a t the cost of the treatment will in no case exceed, with all expenses of every kind, IO cents per one thousand gallons of effluent.
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as sand is eliminated from well-washed clays, its addition has a tendency t o weaken a body, and a high temperature of firing which would tend t o strengthen would be disadvantageous from the point of view of the formation of glazed cracks, as the density developed promotes their formation. It is found t h a t the larger the fire-shrinkage is, the smaller the coefficient of expansion, and the greater the sintering the larger the expansion. Additions of lime and feldspar increase t h e strength of the biscuit: t h e effect of the feldspar is attributable t o its fusion, b u t a t that temperature deformation results, although this is not observed when lime is added in amounts u p t o 20 per cent.; lime alone softens a body, and the burning temperature is slightly increased.
THE DECOLORIZATION OF SUGAR JUICE WITH “ EPONITE.” I n 1910,a substitute for animal charcoal in sugar-refining was placed on the market by a Stockerau firm; this decolorizing substance, called “Eponite,” is now being manufactured by two European companies, and is said t o have received favorable consideration by some sugar refiners. Eponite, as marketed, is a fine mealy powder, possessing a dull black color; i t contains about 82 per cent. of carbon and 1.7 per cent. of ash, and secms to be of vegetable origin. Strohmer SCIENTIFIC METHODS IN EARTHENWARE MANUFACTURE. (0esterr.-Ungar. Z. Zukerznd., 39, 687) conducted experiments which showed t h a t i t effected decolorization best o n being heated It has been said that the technology of the lower grades of pottery (common earthenware, Rockingham ware, majolica, with the sugar liquor for ten minutes at 80’ C. with agitation, faience, and stoneware) is comparatively simple; this is un- and that i t had IO times the decolorizingpower of new char of doubtedly correct, viewing the earthenware industry as it exists , fine grain and good quality. H e found that whereas a n ordinary to-day, but it is also true t h a t less advantage has been taken refinery charcoal had no decolorizing action whatever on a 0.25 of scientific methods and research in earthenware manufacture per cent. solution of saccharane, a definite chemical constituent than in other industries. Harkort has recently discussed of caramel (Ehrlich, Bull. Assn. Chim. Sucr. et Dtst., 27, 140), (2. angm. Chem., 24, 2348) the composition of earthenware eponite, under the same conditions, decreased the dark color bodies and its relation t o scientific results; i t is from this con- of the solution by about 40 per cent. Further experiments by Strohmer demonstrated that its decdorizing power was not tribution t h a t the following material is taken. The strength of earthenware is dependent, not as in porcelain affected b y the reaction of the solution; that i t did not absorb o n the fusion of the feldspar, b u t principally upon the close sugar from concentrated solutions when heated for I O minutes packing of the clay particles; i t follows, therefore, t h a t a de- at 80’ C.; and that i t had a deodorizing action on impure sugar termination of strength merely by the “ring” of the articles solutions, a property of some importance when working with leaves out of account such factors as thickness, shape, etc. beet liquors. He also pointed out t h a t the very high decolorThe value of earthenware depends, to a large extent, upon the izing power of eponite would permit of smaller plant than is flawless adhesion of the glaze, and as a defect may not become at present required for passing sugar liquors over charcoal, apparent for a considerable period, a rapid method of testing and t h a t treatment in small tanks with the separation of the is important. Harkort heats the test-pieces in a n electric oven, spent material by small filter-presses would appear feasible. in which t h e temperature is gradually increased, and quenches The experiments made by Prinsen-Geerligs ( Archzef Suzkerznd. them in water from different temperatures. His observations, Neder1.-Ind., 19, 1085), published more recently, indicate t h a t extending €or a year, have demonstrated that test-picces which eponite is hardly suitable for the decolorization of sugar juice will stand higher temperatures withstand ordinary variations in practice. From experiments on the large scale in the refinery, of temperatures longer; and t h a t if no cracks are developed at i t was found by Prinsen-Geerligs t h a t taking the total cost of a certain quenching temperature, a satisfactory deportment decolorizing with animal charcoal as 1.0, t h a t with eponite is towards changes of temperature can be predicted. Seger Apart from 1.7, and with another material, “Blankit,” 2.0. attributed the formation of cracks and the splitting off of a the disadvantage of its comparatively high cost, he concluded glaze t o a difference between the coefficients of expansion of t h a t eponite is unsuitable for use because i t passes t o a greater the body and the glaze. Damaur made measurements on earth- or less extent through all filtering materials, owing to i t s enware bodies and confirmed Seger’s assumption ; he showed very finely divided state. As a result, there appears in the t h a t the coefficient of expansion increased with a n increase in juice or sirup a black turbidity which exerts a detrimental the silica content, but was affected by the temperature of firing, influence on the color of the finished product. if this is raised t o the point of fusion. Harkort finds t h a t silica lowers the expansion in glazes, b u t in sintered bodies the opposite THE PREVENTION OF IRON AND STEEL COROSION. effect is observed, since i t retards the drawing together of the The Bradley process of rust-proofing iron and steel, as described particles of clay substance; and t h a t when the silica is finegrained, the bodies are less liable t o have glaze cracks. By by Brown (see Eng. .lfi%. J., 93, KO.1 1 , 5 3 8 ) , consists in promeans of his quenching process, definite limits have been found ducing a n unoxidizable coating on the surface of the metal. This is effected by heating the iron or steel objects i n a muffle for the ratio of clay substance t o silica in earthenware bodies. furnace heated with coal or coke. After introducing the objects A certain amount of clay substance must be present t o yield an easily workable body, b u t the silica content must be such into the furnace, the doors are sealed with brick t o e x c h d e air, and a j e t of hydrogen is passed into the muffle t o mingle t h a t the coefficient of expansion represents a n applicable value. It is pointed out t h a t while finely ground silica must be added with a stream of kerosene which is forced into the muffle under
