Auguct, 1925
ISDCSTRI9IJ A S D EXGI-YEERISG CHEJNSTRY
above. The extent of frosting varied but did not change much in appearance under the microscope. Conclusion I-The frosting or devitrification appearing on used quartzware results frequently from the deposition of slag particles in the surface of the ware.
537
2-The devitrification is a surface effect. 3-Continued usage of devitrified quartzware results in early destruction by breakage, the ware becoming brittle. &-Devitrified quartzware can be cleaned by hydrofluoric acid to eliminate the surface frosting. &Elimination of the surface frost with hydrofluoric acid greatly increases the life and serviceability of quartzware.
Clarification of Wool Scourers' Effluent and Recovery of Wool Fats' By Jean de Raeve DARLINGHURST, S Y D N E Y , AL'SIRALIA
M
UCH has been written about the effluents of wool washers. All kinds of ingenious processes have been formulated, but they always fall back on the acid treatment. The acid treatment is capricious; one day the fat floats, the next it precipitates, and another day sand has to be strewn on the surface of the waters to drag down the fats. It is a dirty job to dig out and pack the magma in burlap sacks for the press, etc. Chlorine, the base of this process, is the surest element for oxidizing the proteins without deteriorating the fats, and the agency that imprisons the fat with those waters is riot the alkali but the protective colloids formed by the proteins. The alkali produced by titration is really in combiriation with those proteins and not with the fat. The acid proces. alters the alkali albumins to acid albumins or in other words changes the negative electrolytic charge of the albumin into a positive charge; but that does not sterilize the peculiar cohesive force of these albumins, called protective colloids. The process described herein has been run on a commercial scale, with consistent results and is essentially a flotation of the fats and can be conducted by any one of ordinary intelligence. Two conditions are imperative for successful treatment; the first is to purify the effluent from deleterious matter; the second, to chlorinate a t the coldest possible temperature. This process of recovering the wool fat and clarifying the wool washers' effluent a t the same time commences a t the point where all other wool-scour clarifying processes end. Kobody seems to have observed the waste of chemical reagents on substances that did not in the slightest degree contribute to the desired results. The whole is first filtered to eliminate all the dirt, sand, etc., and render the clarified solution more amenable to chemical reaction. It must be understood that wool washers' effluent is a colloidal emulsion, and its stabilization is in proportion to the foreign substances suspended in that medium. It contains a gelatinous, nitrogenous colloid, which is one of most tenacious protective colloids and renders the decomposition of wool washers' effluent difficult. The cost of treatment will depend on the class of wool to be treated; clean wool or good fleece will show profits, but dirty wool such as pieces will not. The reasons are obvious. -1clean fleece, after scouring, gives a return from 40 to 65 per cent of clean wool, reckoned to produce 10 to 15 per cent of marketable fat. Pieces or low-grade wool will return 13 to 20 per cent of clean wool. 1
Received December 22, 1924.
The wool washers can treat in 8 hours twice the quantity of clean fleece as dirty wool. Conversely, the clean wool gives more than four times the quantity of fat and also produces a cleaner effluent, whereas the dirty wool, during the same period, gives a heavy effluent with dirt and only a quarter as much fat. Therefore the treatment of the effluent from dirty wool cannot compensate the manufacturer's exchequer. The precipitation of the dirt by sedimentation is not satisfactory, because the minerals in suspension hinder the decomposition of those wool scours in order to recover the fats. By sedimentation a troublesome sludge is left, which is filtered a t the end of any process, giving a fat disrolored by some pigment formed by an unknown mineral. Therefore, a filtration of the whole from the start is the only way to prepare an emulsion either for decomposition or crystallization. The cost of filtration is undoubtedly more than offset by the benefit gained in the reduction of chemicals wed. First Stage
The wool scour, or washing effluent, is released into a vat and kept gently agitated with a steam blower, whirh helps to maintain the temperature a t 70" to 80" C. and keep the dirt evenly distributed in the waters, as soon as possible after all the wool scour has reached the vat or pit. One pound of fresh lime slaked in one gallon of water is added for every 100 gallons of wool scour. The mixing is done by the motion of the steam blower after the filtration is started, a vacuum continuous filter being more appropriate. The filtrated waters are then allowed to remain quiescent until they reach 29" C., anything below that temperature is an advantage. The paramount function of the lime is to avoid fermentation while cooling; it changes the acid carbonates into hydroxides, neutralizes the volatile acids, and expels the ammonia. Also, chlorine combines or substitutes a hydroxyl better than a carbonate. The proteins, or the albumins, are then metaproteins as alkali albumins, which are more favorable to the chlorine. Second Stage
The waters are drawn off by a floating arm pipe inside the vat connected outside to the suction pipe of a rotary pump, which delivers the waters in the chlorinating vat. This pump had a 1.5-inch suction and delivery pipe and a KO.4 Penberby ejector fitted in the delivery pipe near the pump. The back pressure of the solution in the pump was from 75 to 95 pounds to the square inch. The quantity of delivery
I,VDlJSTRIAL A S D E-YGI,VEERI,VG CHEMISTRY
838
Vol. 17,
KO.8
7a
8 p
Pipe
? :
ter
(0
= =--- - -
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.
