DECEMBER 20,1939
NEWS EDITION
799
Recovering Soaps and Greases f r o m Wool-Scouring l i q u o r s C. H. S. Tupholme, 65 Kinnerton St., London, S. W. I, England NEW process, illustrated in the acA companying flowsheet, has been devised for recovering soaps and greases
from waste wool-scouring liquors. The spent liquor is mixed with finely divided chalk or milk of lime in sufficient quantity to ensure precipitation of the soaps. The liquor is then precipitated further bv passing to a tank where it is treated with carbon dioxide, or carbon dioxide-containing gases. Precipitation can be increased by the addition of fuller's earth, California bentonite, an increased pressure of carbon dioxide, or by the addition of carefully regulated quantities of soluble salts, such as aluminum sulfate, calcium and magnesium chlorides and sulfates, or ferrous sulfate. These salts form insoluble soaps or, at least, facilitate the formation of insoluble soaps. The quantity of salts added should be sufficient to precipitate the soaps, but an excess will decrease the alkaline carbonate or bicarbonate content. If the liquor is not to be reused the quantity of salt added is immaterial. The resultant precipitate is filtered out, the filter aid being a precipitate recovered from subsequent treatment with organic solvents. The filtrate is freed from calcium bicarbonate by boiling, either at atmospheric or reduced pressure, or by blowing air through the liquor which is held at about 160° F. Another method is the addition of a caustic alkali, such as milk of lime or caustic soda, in an amount just sufficient to precipitate the maximum possible quantity of calcium. The liquor or filtrate is again settled or filtered, and, as it contains alkaline carbonates and small amounts of soap, it may be reused in the scouring machine, either with or without the addition of other scouring agents, or the alkalinity may be reduced with fatty acids. As the liquor, because of repeated circulation, becomes too concentrated, part of it may be employed for the recovery of potash. The remainder may be diluted with water before reuse. The moist precipitate from the first filtration is passed to the first extraction plant. The precipitate is dried or partially dried and is then boiled in an extraction vessel with a liquid solvent which is preferably almost insoluble in water and which, while dissolving lanolin and metallic soaps, forms a minimum boiling mixture with water. The solvent, on the other hand, may be boiled in the extraction vessel below the precipitate, allowing the vapor to permeate the precipitate. Solvents used are benzene or toluene or mixtures of these, as well as some aliphatic alcohols. The solvent most favored is benzene, as its lower boiling point permits easier recovery from the extracted grease. The benzene-water vapor mixture is condensed in a reflux, or other type of condenser, and led to a separator where the water is withdrawn. The benzene is returned to the extractor. The mixture containing the grease is run off, or filtered, and distilled. In some plants the pipe from the bottom of the extractor, leading to the vessel in which the solvent is distilled from the crude grease, is equipped with a separator in which part of the water is removed from the mixture.
The crude crease is recovered by wellknown methods, such as distillation of the solvent, followed by the use of vacuum or live steam to expel the remainder of the solvent. It can also be expelled by a current of air and adsorbed by activated carbon. The exhausted precipitate can be used as a fertilizer or as a filter aid in the various filtration operations. The grease recovered in the first extraction is separated into its two main constituents by a second process. The grease is treated with a mixture of acetone and ethyl acetate, or methyl acetate, in such ratio that only the wool grease is dissolved. The remaining undissolved residue is a mixture of impure metallic soaps. Prior to purification the mixture of wool grease and metallic soaps may be neutralized with oxides or hydroxides of the alkaline earths. It may also be given a prior treatment with an aqueous mixture of a soluble calcium salt, with or without an alkaline earth hydroxide, at raised temperatures. From this the grease may be separated or extracted with benzene and the benzene recovered as already described. The crude grease is mixed, for example, with 10 times its volume of the mixed solvents (acetone and ethyl or methyl acetate) and then warmed above 40° C. for a few minutes. Fuller's earth or a similar coagulant may be used as a clarifier if the grease solution is cloudy. The mixWOOL SCOURING MACHINE EFFLUENT LIME AND/OR CHALK
MIXING
PRECIPITATION TANK
COjOR FLUE GAS
BENTONITE AND/OR ALUMINUM SULFATE
FILTRATION MOIST PREqPlTATE
SOLVENT ADDiTION EXTRACTION SOLVENT RECOVERY
SETTLING OECANTATIOM ACETONE. ACETATE ADDITION METALLIC SOAPS SULFURIC ACID ,1
SECOND EXTRACTION
T
SOLVENT RECOVERY
MJXJN6 \
\ A L K A U N E EARTH SULFATE
FATTY ACIDS SAPONIFICATION
PURIFIEO GREASE
ture is decanted or filtered after clarification. The residue of metallic soaps, unreacted alkaline earth oxides or hydroxides, and* fuller's earth, is washed with further quantities of solvent. The solvent is recovered by distilling the solution containing the wool grease and also by volatilizing the solvent by subjecting the recovered grease and metallic soaps to a current of warm air. The use of acetone alone is not very satisfactory, as pure wool grease is not completely soluble in it. A smaller proportion of ethyl acetate or methyl acetate (which, by themselves, dissolve too much of the metallic soaps) allows all of the pure wool grease to be dissolved at temperatures above 40° C. The ash content of the recovered lanolin is about 0.07 per cent. The precipitate remaining after the acetone and acetate extraction is mostly metallic soap. It is processed further by treating with sulfuric acid, the products recovered being an alkaline earth sulfate and fatty acid. The fatty acid is saponified and returned as soap to the scouring machines. The particular alkaline sulfate recovered in the sulfuric acid treatment depends on the salt used in the first precipitation. Manganese Output in September OMESTIC production of manganese ore D containing 35 per cent or more manganese (natural) during September was
3000 long tons, shipments were 2500, and stocks at the end of the month were 1300, according to U. S. Bureau of Mines figures predicated on reports from producers who accounted for 92 per cent of the 1938 total. The monthly average in 1938 was 2110 tons. September imports of 35 per cent ore for consumption were 87,581 long tons containing 42,734 tons of manganese bought from the Gold Coast, British India, and Russia. Total imports for consumption through September, 1939, were 358,984 long tons with 179,416 tons of manganese. In addition, 18,424 tons with 5343 tons of manganese (29 per cent) were entered from the Union of South Africa. Stocks of manganese ore in bonded warehouses as of September 30 amounted to 953,028 long tons containing 472,763 tons of manganese compared with 842,048 tons with 418,721 of manganese a t the beginning of 1939. Arkansas, Montana, and Tennessee supplied about 89 per cent of the total manganese ore snipped in September. Production was reported from Georgia, New Mexico, Virginia, and West Virginia. Safety Record of Merrimac Division of M o n s a n t o HE Camden, N. J., plant of the MerriT mac Division of the Monsanto Chemical Co. on November 16 achieved three years of three-shift seven-day a week operation without a single lost-time accident. The plant, managed by John J. Heck for the past eleven years, manufactures lampblack, bone ash, and phosphate salts and functions as an eastern general warehouse for the other twelve Monsanto plants. The last accident occurred November 15, 1936, when an employee suffered a foot injury. _««__ A contract for the 33,000,000 laboratory building for the Bell Telephone Laboratories at Murray Hill, N. J., has been awarded to John Lowry, Inc.
790
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Estimating Costs of Factory Construction EW firms of architects and engineers have had as much experience in the F construction of industrial buildings as the
well-known Detroit firm of Albert Kahn, Inc. In a communication to the Editor, Mr. Kahn's firm points out the dangers of estimating costs of proposed industrial construction on the easy and so frequently employed "cost-per-square-foot" basis. The dangers of this method of approximating costs are due to items wnich vary over wide ranges and which cannot show up in a cost-per-square-foot estimate, since they do not bear a direct relation to area but result from special requirements of particular projects. Among the items which affect total costs but have no direct relation to areas, Mr. Kahn's firm cites such considerations as the particular plant requirements; city, state, federal, and trade codes; personnel service requirements; types of building construction, finish, facing, etc.; extent and variety of mechanical equipment; varying wage, material, and insurance scales. Over the country, great variation is found in site conditions, grading, excavation, filling, proximity of railway sidings for ease and economy in delivery of materials, etc. The size and shape of the site will determine whether future expansion can be made horizontally with a light frame, or must be provided for vertically by means of a much heavier frame. The type of the building may be such that the simplest of foundations will be adequate, whereas some types of buildings require substructures as costly as the buildings themselves. The cost of industrial construction is very materially affected by such details as the spacing of structural supports, an item governed by the equipment which it is intended to place upon the floors. The type of the industry will determine the kind and amount of ventilation required, the character of floor and wall finish—items which vary between extremely wide limits and cannot be reduced to any basis directly related to area. In some factories, all of the help may be of one sex, resulting in simple provisions for comfort and sanitation: in others, both sexes may work together, with the resultant doubling up of rest and toilet facilities. Special provisions for covered parking of employees' cars may be required; it may be necessary to provide space and equipment for cafeteria or other types of dining rooms, with their kitchens and other services; it is possible that spaces will have to be provided and equipped for use as infirmaries, recreation rooms, conference rooms, etc. Each of these possibilities, if present in the scheme, affects total cost without bearing m y direct relation to area cost. Certain types of industrial buildings need only the simplest kind of electric lighting, while others will require highintensity fluorescent lighting tor equivalent areas. Some factory buildings will be well serviced by the most simple plumbing and drainage provisions: others will demand most complicated plumbing systems. A chemical factory will require special piping and. perhaps, special traps and fittings throughout, or at least in part. The distance from sewer, water, gas, and lighting mains will directly affect the cost of making such utilities available in the building but has no relation to the building's area. Other considerations that increase costs very materially are imposed by agencies. such as insurance companies, which may
require fire and property protection calling for high-pressure water lines with many hydrants; fences surrounding the plant; night flood lighting; etc. The advertising value of the plant's appearance may be great, in which case the grounds surrounding the building will have to be landscaped, perhaps to a considerable and costly degree. Advertising signs of large size and correspondingly high cost may be required. The foregoing are but a few of the items which affect the costs of industrial buildings and which are inadequately dealt with, by the cost-per-square-foot method of approximating costs. They can only be provided for properly, in an estimate of cost, through a detailed study of the particular problem of the building under consideration. There is no sadder moment in a building committee's existence than that in which the bids are opened and found to be "out of line" with what had been thought to be an ample appropriation based upon a cost-per-square-foot estimate! A Useful Expansion
T*>
100° F., what will be the total expansion in inches? Simply connect the 100° temperature difference, Column A, with the 100-foot length, Column C. The intersection with Column B gives the answer as 0.8 inch. That is all there is to i t The chart can also be used for determining the allowable temperature difference where a definite amount of space is available for expansion and contraction. Thus, if the length of the pipe is 100 feet and the allowable expansion is 0.8 inch, the same line would snow that a temperature difference of 100° P. would be the limiting amount. Also, if the factors in Columns A and B are known, the unknown in Column C is immediately found. In other words, if any two of the factors are known, the third is quickly found, and without any computation whatever. The range of the chart is wide enough to care for almost any expansion or contraction problem. The temperature difference, Column A, varies all the way from 20° to 1000°. Seldom, if ever, do we have as high a temperature as 1000°. The length of pipe line, also, is great, varying all the way from 10 to 3000 feet And the total expansion between these limits varies from 0.02 to 300 inches.
Chart
W. F. Schaphorst, 45 Academy St., Newark, N . J. HIS chart is useful for determining the expansion in piping, rods, tubes, etc., for any ordinary temperature difference. It makes longhand figuring unnecessary. Simply lay a straightedge across the chart once or stretch a fine black thread across, as indicated by the dotted line, and the problem is solved. Thus, if a certain pipe line 100 feet long is subjected to a temperature variation of
T
VOL. 17, NO. 24
How t o Organize a Science Club HE Science and Engineering Clubs of T the American Institute, 60 East 42nd St., New York. N. Y., have issued the re-
vised edition of a 36-page booklet, entitled "How to Organize a Science Club", which is available from the institute at 25 cents a copy. In addition to suggested programs and activities for science clubs for boys and girls from 12 to 18 years old, the booklet contains lists of books and magazines.
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