I,VDlJSTRIAL A S D E-YGI,VEERI,VG CHEMISTRY
838
Vol. 17,
KO.8
7a
8 p
Pipe
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T a n k for Chlorinated Water wherein the F a t s Rise to t h e Surface
per hour is reliable if speed is kept up to what the makers guarantee. The chlorine cylinder stands on a pair of accurate scales and a 0.25-inch flexible steam pipe is coiled round it to prevent the chlorine from freezing during release. The quantity of delivery of solution by the pump per hour being known, the release of chlorine is calculated to suit the equivalent quantity needed, and is drawn up by the vacuum of the ejector and combines under pressure in the delivery part of the ejector. The quantity of chlorine is calculated by taking the titration of alkali in the waters 2NaOH C12 = NaOCl NaCl HzO
+
+
+
Chlorine is diatomic, sodium monatomic; if the 10,000 liters contain 25 kg. alkali, the calculation will be one half of the alkali-viz., 12.50 X 70.96/80 = 11.75 kg. of chlorine will be needed. During chlorination a thick, white foam containing considerable grease rises to the surface. The quantity varies, good fleece giving a larger quantity than others. When all the solution is drawn off, the pump is stopped and the white foam is taken off before the next step is undertaken. At no time was there any evolution of chlorine, so no corrosion of the general plant need be feared. Fifty cubic centimeters of the chlorinated waters are titrated with "*SO4 to estimate the quantity needed to change the hypochlorites into hypochlorous acid. The required quantity of sulfuric acid is mixed with two or three times the quantity of water, and is added to the chlorinated solution and agitated for 2 or 3 minutes with compressed air to get an even distribution. All the fats, which constitute the finest lanolin, and are the most refractory to dissociate from water, will rise to the surface, leaving the residual water clear and yellow and containing from 0.25 to 1 gram of acid per liter. This percentage of acid is very irregular, as is also the color. Where hydrochloric acid or carbon dioxide is easily obtainable, the reaction with it will be the same. The action of the acid on the hypochlorite of soda and chlorites of albumin yields hypochlorous acid, which directly changes into hydrochloric acid and nascent oxygen 2HC10 = 2HC1
+ 20
This nascent oxygen is retained outside or in the pores of the elements and causes the fats and other elements to rise to the surface; also the fat picks up all the fine dirt. Those fats are skimmed off and added to the greasy foam collected from the same waters a t first. The chlorinating vat is a square, longitudinal tank, the fat is easily pushed over the narrow side by a skimmer the width of the tank (see accompanying figure). The small quantity of sludge found in the cooling tank is added to the incoming effluent to be filtered with the remainder. Third Stage The fatty foam is collected and thrown into an iron or n-ooden tank or vat, in which is a dry steam coil. This vat is placed near the chlorinating vat, and should be large enough for 2 or 3 days' storage. The fat cannot deteriorate, as it contains the strongest antiseptic known. This fat is mixed with acidulated water and contains a lot of dirt and a fibrous substance like tow, which is the gelatinous element oxidized by hypochlorous acid. Whensufficient stock is collected it isheatedandsent through a hot filter press. The grease will be pale yellow from good fleece and a shade darker from the pieces. The odor of chlorine can be eliminated by a hot water wash to which is added sodium bisulfite (Antichlor) or sulfurous acid. All the residual waters are released into a tank, neutralized with lime, and allowed to stand until clear in order to conform to the requirements of the Pollution of Rivers Act. Or the waters may be added to the general residual waters of the mill, which will help to clear them, since they contain different organic sulfates and chloride.
Electrodeposition of Rubber-Correction In the article by S. E. Sheppard and I,. W. Eberlin, THIS JOURSAL, 17, 711 (1925), the following corrections should be noted: Page 713, first column, 9 lines from bottom, the current density range is from 1.54 to 15.4 amp. per sq. dm.; 4 lines from bottom, from 3.85 to 5.13 amp. per sq. dm. Page 713, second column, Table 11, the figures for current density, amp. per sq. dm., should have the decimal point moved one place to the right, reading 0.85, 0.85, 0.85, 2.39, 2.51, 2.51; 4 lines from bottom should read 0.03 to 15.4 amp. per sq. dm. Page 714, first column, line 7, should be 15.4 amp. per sq. dm.
