Liquid Caustic Soda A Discussion of Advantages of Handling This Essential Chemical in Liquid Form By ROBERT J. QUINN URING the past half-dozen years a change of economic importance has been taking place in the method of distributing caustic soda to large industrial consumers. Many thousands of tons formerly shipped in solid form in drums are now being delivered to the users in tank cars in the form of a solution containing about equal parts of water and caustic soda. Although the tonnage shipped in this liquid form is increasing rapidly every year, it still represents only a part of the total consumption of those users of caustic soda who can be served economically in this manner. The purpose of this article is two-fold .'--first, to present to those interested in a possible change f r o m solid to liquid caustic, facts which will enable them to judge the benefits of such a change in their own plants; and second, to place in the hands of those now using liquid caustic, some useful data on approved methods for its transfer, handling and storage, together with some notes on the dilution, testing and properties of caustic liquors. This material has been selected for its practical value to the plant executive and operating staff and is based upon the wide experience of chemists and engineers and upon information from authoritative reference sources.

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W h y Liquid Caustic Soda? A brief review of the operations in the manufacture and handling ,of caustic soda, both in solid and

Robert J. Quinn

in liquid form, will make it clear that the increasing use of liquid caustic is a sound economic development. In the manufacturing process caustic soda is first obtained in the form of a water solution containing from 10% to 25% of sodium hydroxide. To produce solid caustic, it is necessary to drive off a/l the water in this solution by evaporation processes which consume a large amount of fuel. Drums must then be provided for the fused caustic and labor expended in filling, handling and' loading these containers for shipment. At the consumer's plant these operations are reversed, the solid caustic being made once more into a water solution with the attendant cost Of

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differential b e t w e e n the two rates at different points. Third, in t r a n s p o r t i n g every 100 pounds of caustic soda in the f o r m of 50% liquor, 100 pounds of w a t e r are also carried. I n other words, f o r every 100 pounds of caustic soda received in the f o r m of 50% solution, t h e c o n s u m e r pays f r e i g h t charges on 200 pounds of m a t e r i a l . Some examples of delivered costs, will serve to make this clear: CASE A - - R a t e on solid caustic 19c; on liquid 19c Solid Liquid Price per 100 lbs. f.o.b. works . . . . . . . . . . . . . $3.00 $2.65 Freight per 100 Ibs. caustic soda . . . . . . . . . . 19 .19 Freight per 100 lbs. water . . . . . . . . . . . . . . . 00 .19

unloading, handling and cutting open m a n y drums, dissolving the caustic a n d disposing of the w o r t h less e m p t y drums. I n the case of liquid caustic soda the e v a p o r a t i o n process is c a r r i e d only to the p o i n t w h e r e the original dilute solution has been "boiled down" to a c o n c e n t r a t i o n of app r o x i m a t e l y 50% by w e i g h t of caustic soda. I n this f o r m it is shipped to the c o n s u m e r i n t a n k cars a n d h a n d l e d m e c h a n i c a l l y by m e a n s of s u i t a b l e p i p i n g connected to the car. I n the c o n s u m e r ' s p l a n t the 50% caustic liquor is r e a d i l y diluted to the desired c o n c e n t r a t i o n . t n f u r n i s h i n g liquid caustic t h e m a n u f a c t u r e r ' s processing a n d h a n dling costs are reduced to a m i n i m u m , p e r m i t t i n g h i m to offer caustic in t h i s f o r m a t a lower price. The user t h u s has the adv a n t a g e of a s u b s t a n t i a l r e d u c t i o n in price over caustic soda in solid form, as well as the economy a n d convenience of h a n d l i n g his caustic e n t i r e l y by m e c h a n i c a l means. W h o C a n Use L i q u i d C a u s t i c ? W h e t h e r or not a p l a n t m a y profi t a b l y use liquid caustic soda is det e r m i n e d by the following f a c t o r s : - - ( 1 ) delivered cost on solid a n d on liquid, (2) y e a r l y c o n s u m p t i o n , a n d (3) cost of h a n d l i n g sol~d caustic. I n d i s c u s s i n g delivered costs, t h e r e are several facts to be kept i n m i n d r e g a r d i n g solid a n d liquid caustic soda. F i r s t , as to works prices, there is u s u a l l y a price diff e r e n t i a l of 35 c e n t s per 100 pounds i n f a v o r of caustic soda in liquid form. Second, the f r e i g h t r a t e bet w e e n two g i v e n p o i n t s on solid caustic does not always apply on liquid caustic as well; i n some terr i t o r i e s both r a t e s are the same a n d in others a lower r a t e applies on liquid caustic, w i t h a v a r y i n g

Delivered cost per 100 lbs . . . . . . . . . . . . . . . . . $3.19 $3.03 Differential in f a v o r of liquid canst i c - - 1 6 c per 100 lbs. CASE B - - R a t e on solid caustic 381/2c; on liquid 25c Solid Liquid Price per 100 lbs. f.o.b. works . . . . . . . . . . . . . $3.00 $2.65 Freight per 100 lbs. caustic soda . . . . . . . . . .~85 .25 Freight per 100 lbs. water . . . . . . . . . . . . . . . 00 .25 Delivered cost per 100 lbs . . . . . . . . . . . . . . . . . . . $3.385 $3.15 Differential in f a v o r of liquid caust i c - - 2 3 8 9 per 100 lbs. CASE C - - R a t e on soIid caustic 451/2c; on liquid 451/2c Solid Liquid Price per 100 lbs. f.o.b. works . . . . . . . . . . . . . $3.00 $2.65 F r e i g h t per 100 lbs. caustic soda . . . . . . . . . . 455 .455 Freight per 100 lbs. water . . . . . . . . . . . . . . . 00 .455 Delivered cost per 100 lbs . . . . . . . . . . . . . . . . . . $3.455 $3.560 Differential against liquid caustic - - 1 0 8 9 per 100 lbs.

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I t will be noted f r o m t h e s e exa m p l e s t h a t t h e f r e i g h t r a t e s on b o t h solid a n d liquid c a u s t i c m u s t be k n o w n in o r d e r to w o r k out a c o m p a r i s o n of t h e delivered costs in t h e s e two f o r m s . A n i t e m in the d e l i v e r e d cost of t h e solid m a t e r i a l , n o t included in t h e p r e c e d i n g examples, is t h a t of f r e i g h t on the t a r e w e i g h t of solid caustic drums. T h i s a m o u n t is small, b u t should n o t be overlooked. I t will v a r y a c c o r d i n g to t h e solid freight fate from a little more than h a l f a cent p e r 100 pounds in Case A to one and o n e - t h i r d cents p e r 100 p o u n d s in Case C. In general, provided the delivered cost is f a v o r a b l e , a c o n s u m e r p u r c h a s i n g solid caustic, in c a r l o a d lots, m a y p r o f i t a b l y t a k e d e l i v e r i e s o f 50% caustic liquor, in t a n k cars. A n 8,000-gallon t a n k c a r of 50% c a u s t i c liquor c o n t a i n s a p p r o x i m a t e l y 25 tons of caustic soda in solution, or t h e e q u i v a l e n t of a m i n i m u m c a r l o a d o f solid c a u s t i c in s t a n d a r d 700-lb. d r u m s . On t h i s b a s i s a b u y e r of several c a r l o a d s of solid c a u s t i c p e r y e a r m a y be cons i d e r e d a p o t e n t i a l u s e r of 50% liquid caustic. I t will be obvious t h a t t h e cons u m e r of liquid c a u s t i c soda m u s t have access t o r a i l r o a d s i d i n g f a c i l i t i e s f o r t h e u n l o a d i n g of t a n k cars. A s i d i n g a t some d i s t a n c e f r o m the p l a n t m a y be c o n v e n i e n t l y used, however, since t h e l i q u o r is t r a n s f e r r e d f r o m t h e c a r into s t o r a g e b y m e a n s of p i p i n g . T h e cost of i n s t a l l i n g t r a n s f e r e q u i p m e n t m a y be offset in a s h o r t t i m e b y the economy of m e c h a n i c a l h a n d l i n g in place of t r u c k i n g a n d m a n ual h a n d l i n g of solid caustic. H a n d l i n g solid c a u s t i c soda, inc l u d i n g u n l o a d i n g and b r e a k i n g open t h e c o n t a i n e r s , d i s s o l v i n g t h e caustic a n d d i s p o s i n g o f t h e w o r t h less e m p t y d r u m s , costs a p p r o x i 291

m a t e l y 12 cents p e r 100 pounds in t h e a v e r a g e plant. T h i s figure is based on c o n s e r v a t i v e e s t i m a t e s and will v a r y only in accordance w i t h h a n d l i n g m e t h o d s and local w a g e - s c a l e s on labor. H a n d l i n g is a v e r y small i t e m w i t h c a u s t i c l i q u o r ; t h e c h a n g e f r o m solid caustic will t h e r e f o r e effect a s a v i n g in h a n d l i n g cost of a r o u n d 10 cents p e r 100 pounds. T h i s is in a d d i tion to a n y s a v i n g t h a t m a y be obt a i n e d in d e l i v e r e d cost. E v e n w h e r e no m o n e y s a v i n g can be shown f o r liquid c a u s t i c t h r o u g h a c o n s i d e r a t i o n of delivered costs and h a n d l i n g costs, t h e g r e a t e r convenience of u s i n g caustic soda in liquid f o r m m a k e s it a t t r a c t i v e to l a r g e consumers. The g r e a t i n c r e a s e in s h i p m e n t s of liquid caustic soda w i t h i n t h e p a s t few years indicates that growing n u m b e r s of p r o g r e s s i v e consumers a r e r e c o g n i z i n g t h e economy and eonvenienee of t h i s commodity. C o n s u m e r s served in t h i s m a n n e r r e p r e s e n t all t h e p r i n c i p a l industries using caustic soda--soap makers, petroleum and vegetable oil refiners, p a p e r mills, m a n u f a c t u r e s of chemicals, r a y o n a n d liquid bleach, t e x t i l e bleachers a n d mereerizers. P u r i t y of L i q u i d Caustic I n a d d i t i o n to t h e a d v a n t a g e s it f r e q u e n t l y offers f r o m a cost s t a n d point, caustic soda in liquid f o r m is ordinarily a purer product than the solid m a t e r i a l in d r u m s . A t N i a g a r a F a l l s one l a r g e elect r o l y t i c p l a n t p r o d u c e s an e x t r e m e ly p u r e l i q u i d c a u s t i c w h i c h is known as "cell l i q u o r " because obt a i n e d d i r e c t l y f r o m t h e electrolytic cells w i t h o u t e v a p o r a t i o n or p r o c e s s i n g of a n y kind. T h i s socalled cell liquor is d i s c h a r g e d f r o m the cells a t a c o n c e n t r a t i o n of f r o m 25% to 30% by w e i g h t o f c a u s t i c

soda. A l t h o u g h t h i s solution has a l i m i t e d r a d i u s of d i s t r i b u t i o n due to t h e g r e a t e r a m o u n t of w a t e r t h a t m u s t be t r a n s p o r t e d , it offers a h i g h l y d e s i r a b l e f o r m in w h i c h to h a n d l e the c o m m o d i t y on account of t h e v e r y h i g h p u r i t y of t h e caustic it c o n t a i n s and because of t h e low f r e e z i n g - p o i n t of t h e liquor. I t is an i n t e r e s t i n g f a c t also t h a t t h i s p r o d u c t is t h e only c a u s t i c liqu o r t h a t can be s h i p p e d as originally p r o d u c e d w i t h o u t s u b s e q u e n t processing. L i q u o r s f r o m some t y p e s o f e l e c t r o l y t i c cells a r e so

Percentage Content of: Sodium Hydroxide . . . . . . . . . . . . . Sodium Carbonate . . . . . . . . . . . . Sodium Chloride . . . . . . . . . . . . . . . Sodium Sulphate . . . . . . . . . . . . . . Sodium Sulphide . . . . . . . . . . . . . . Silica . . . . . . . . . . . . . . . . . . . . . . . . Iron Oxide & Alumina . . . . . . . . . Calcium Oxide . . . . . . . . . . . . . . . . Magnesium Oxide . . . . . . . . . . . . .

low in c o n c e n t r a t i o n of caustic a n d u s u a l l y c o n t a i n such l a r g e a m o u n t s of salt in solution t h a t t h e y cannot be s h i p p e d as o r i g i n a l l y p r o duced. The o r i g i n a l l i q u o r o b t a i n e d f r o m the a m m o n i a - s o d a p r o c e s s is also too low in c o n c e n t r a t i o n o f c a u s t i c to p e r m i t its economical distribution. The following a r e t y p i c a l a n a l y ses of t h e s e v e r a l c o n c e n t r a t i o n s o f liquid caustic s o d a as s h i p p e d f r o m t h e t w o d i f f e r e n t p l a n t s of one p r o ducing company, one of t h e count r y ' s l a r g e s t s h i p p e r s of caustic.

Electrolytic Cell Liquor 27.5 0.10 0.05 0.008 (None) 0.005 0.002 0.003 0.001

The figures in t h e first column r e p r e s e n t an a v e r a g e a n a l y s i s of cell liquor. I n t h e second column is shown an a n a l y s i s of t h e 50% c a u s t i c solution o b t a i n e d t h r o u g h p a r t i a l e v a p o r a t i o n of t h i s cell liquor. I t is of i n t e r e s t to n o t e the low salt c o n t e n t of these liquors. I n both t h e cell l i q u o r a n d t h e conc e n t r a t e d solution, t h e s o d i u m hyd r o x i d e content of t h e c a u s t i c soda is in excess of 9 9 % . T h e figure~ in t h e t h i r d column r e p r e s e n t a n a v e r a g e a n a l y s i s of t h e liquid caustic p r o d u c e d by t h e a m m o n i a - s o d a process. Tank Car Equipment L i q u i d Caustic Soda is s h i p p e d in t a n k c a r s of 8,000 gallons capacity ( e q u i v a l e n t to a p p r o x i m a t e l y 100,000 p o u n d s of 50% caustic l i q u o r ) . T h i s e q u i p m e n t is of

Caustic Liquor Concentrated 49.8 0.25 0.10 0.016 (None) 0.007 0.008 0.005 0.002

Soda Process Caustic Liquor 50.07 0.35 0.29 0.21 (None) 0.14 0.034 0.005 0.007

the l a t e s t type, c o n f o r m i n g to A.R.A. Specifications f o r Class I I I T a n k C a r and to I.C.C. Specification No. 103. All t a n k c a r s f o r c a u s t i c l i q u o r should be equipped w i t h s t e a m h e a t i n g coils, f o r use d u r i n g t h e w i n t e r months, a n d w i t h an a u x i l i a r y b o t t o m o u t l e t valve. S t e a m h e a t i n g coils should be of 2-in. e x t r a - h e a v y steel pipe, w i t h 2-in. connections, a n d all j o i n t s welded throughout to p r e v e n t l e a k a g e sometimes experienced with threaded j o i n t s . The a u x i l i a r y b o t t o m outlet valve m e n t i o n e d above w a s a d o p t e d several y e a r s ago by a l a r g e s h i p p e r a s a protective measure for users of c a u s t i c liquor. I t h a d been f o u n d n e x t to impossible to m a i n t a i n t h e regulation Tank Car Bottom Outlet Valves t i g h t a g a i n s t l e a k a g e be-

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Approved Methods for Unloading Liqmd Caustic Soda --

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Typical Layout for Unloading Liquid Caustic by Purep and by Air Pressure NOXE Addmr

E ~ p ~ e m lbl Uoloadmg by Air Plessure lndlcaled b~ Ootled L s ~ . Marked " p " ~ d " X "

Instructions for Unloading

By Pump. 1-Attach two,inch pipe at valve (D) by means of flanged connections. 2-Remove plug (A) for release of internal pressure. 3-Remove dome cover (B). 4~Open valve (C) (Inside dome). 5g3pen valve (D) and start transfer pump,

By Compressed.Air. 1-Attach two-inch pipe at valve (D) by means of flanged connections. 2-Remove plug (A) and connect compressed air line (P) at this point. 3-Remove dome cover (13). 4-Open Valve (C) (Inside dome). 5-Replace dome cover (B) (Tight gasket). 6-Apply air pressure (not to exceed 30 lbs. per sq. inch). NotE: Lead disc (E) irr vent (F) ruptures at 30 lbe. per .sq, inch air pressure. This is sufficient to lift 50% caustic liquor 35 ft. above R R . track level.

7-Open valve (D) and other valves in line to storage. Nor~: When unloading by mea~s r compressed ;at. by-pass commotion (X) with valve must be provided.

LongitudinalSectionThroughDomeand Bottomof Car

cause of t h e i r location and t h e req u i r e m e n t s i m p o s e d b y I.C.C. specifications. Such l e a k a g e r e s u l t e d in t h e d i s c h a r g e nipple b e c o m i n g filled w i t h c a u s t i c liquor, w h i c h v e r y o f t e n spilled over t h e w o r k m e n w h e n the cap w a s removed. To p r e v e n t this, a c h a n g e in t h e I.C.C. specifications was o b t a i n e d p e r m i t t i n g the i n s t a l l a t i o n of t h e

a u x i l i a r y b o t t o m d i s c h a r g e valves on t a n k c a r s f o r caustic l i q u o r service. All c a u s t i c liquor c a r s a r e i n s p e c t e d on t h e completion of each t r i p , w a s h e d out, tested, a n d t h e valves g r o u n d w h e n n e c e s s a r y . D u r i n g t h e cooler m o n t h s t h e s t e a m h e a t i n g coils a r e t e s t e d on t h e r e t u r n f r o m each t r i p . T h i s c a r e f u l m a i n t e n a n c e of t a n k

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c a r equipment insures the customer a g a i n s t t r a n s p o r t a t i o n delays and a g a i n s t contamination or loss of material. Transfer Equipment Liquid caustic is t r a n s f e r r e d to s t o r a g e tanks by means of a pipe line connected to the car at a point on the consumer's railroad siding. The two approved methods for unloading into storage are by means of pump and compressed air. These methods are shown in connection with the sectional drawings on the previous page. In r a r e cases where s t o r a g e tanks are located below the siding track level, caustic liquor m a y be t r a n s f e r r e d by g r a v i t y , with the same procedure as f o r unloading by pump. It is also possible to unload by suction, t h r o u g h the manhole opening, but this practice is not recommended. Lubricated plug cocks or valves, t r a n s f e r pumps and pipe lines should be of all-iron construction. Storage E q u i p m e n t Specifications CAPACITY :

To conform with consumer's requirements; minimum capacity approximately 16,000 gallons. PLATES :

Of flange steel having ultimate s t r e n g t h of 55,000 lbs. per sq. in. :RIVETS :

Of boiler rivet steel driven hot. JOINTS :

To be double riveted and calked inside and outside. W i n t e r H a n d l i n g and Storage Concentrated solutions of caustic soda (25% to 50% NaOH content) will deposit crystals of the solid h y d r a t e s of sodium hydroxide under normal w i n t e r w e a t h e r conditions. At abnormally low temperatures, around 0 ~ F., and depending upon the concentration of the solu-

tions, complete solidification may take place. This consideration necessitates t h e use of steam coils in t a n k cars and in storage tanks exposed to w i n t e r weather. Outside pumps, t r a n s f e r lines, etc., must be effectively protected from the cold. D u r i n g the w i n t e r months the physical condition of liquid caustic should be noted before t r a n s f e r from car or storage is attempted. An examination can r e a d i l y be made by probing the liquid with an iron rod for indications of solid h y d r a t e s or to determine the extent to which solidification has progressed. If a top crust has formed, it must be broken before steam is applied in the h e a t i n g coils in order to provide for expansion of the heated liquid. The steam p r e s s u r e applied should not exceed 10 lbs. Where storage is provided w i t h i n heated buildings steam coils inside the tanks are not required. Caustic liquor of 50% concentration is more conveniently handled in this type of storage. When 50% liquor is stored in outside tanks, it is necessary to m a i n t a i n heat in the coils almost continuously d u r i n g the w i n t e r months. Less difficulty is experienced with outside storage in the case of more dilute solutions of 25% concentration or less. Shipments usually consist of 50% liquor which requires a dilution with 1.4 ,volumes of w a t e r to reduce the concentration to 25% sodium hydroxide. A t a n k of 20,000 gallons capacity would be r e q u i r e d for storing the contents of one t a n k car (8,000 gallons) of 50% liquor a f t e r such a dilution. H e a t of D i l u t i o n When water is added to liquid caustic soda, heat is evolved and a rise in the t e m p e r a t u r e of the solution takes place. This is due to

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the heat of reaction in the f o r m a tion of the various h y d r a t e s of sodium hydroxide, and is generally t e r m e d h e a t of dilution. This heat effect is considerable and allowance should be made for it in diluting caustic liquor, p a r t i c u l a r l y if the diluted solution is to be used in the p r e p a r a t i o n of bleach liquor. In general, a sharp rise of t e m p e r a t u r e will be noted until a volume of w a t e r has been added about equal to the original volume of the liquor. F r o m this point on, f u r t h e r dilution results only in a decrease in t e m p e r a t u r e . The extent of these t e m p e r a t u r e changes is indicated by the results of thefollowing dilutions in a Dewar flask. One volume of a solution cont a i n i n g 50% NaOH by weight was diluted with successive portions of distilled w a t e r each equal to onehalf the original volume of 50% solution. The initial t e m p e r a t u r e of both solution and w a t e r was 14.5~ (58.1~ and the temp e r a t u r e of the solution was observed following each dilution. A f t e r dilution (1) the t e m p e r a t u r e was 38.5~ (101.3~ ; (2) 45.5~ (113.9~ ; (3) 46.5~ (115.7~ (4) 44.8~ (112.6~ ; (5) 42.5~ (108.5~ (6) 40.0~ (104.0~ D a t a based upon l a b o r a t o r y experiments is only of value, h)wever, in e s t i m a t i n g the t e m p e r a t u r e increase t h a t may be expected upon diluting caustic liquor in the plant. The size and shape of dilution tanks, their heat capacities and their heat radiations, all exert such an i m p o r t a n t influence t h a t theoretical figures cannot be applied in actual practice. It is advisable for the operating man to determine this factor by observation under plant conditions. 295

S a m p l i n g of Caustic L i q u o r Careful sampling is absolutely essential to the accurate analysis of tank car shipments of liquid caustic. Particularly in cold weather, it is i m p o r t a n t t h a t heating be continued until all crystals have gone into solution and the entire contents of the car has been converted into a liquid condition. Samples containing crystals of hydrates of sodium hydroxide will obviously not be representative of the liquor in the t a n k car. Since some of these h y d r a t e s may f o r m in concentrated liquors even under mild weather conditions, it is desirable t h a t 50% liquid caustic be warmed until a surface t e m p e r a ture of approximately 75 ~ F. has been reached. Samples should be taken at t h r e e different depths in cars of cell liquor (27.5% caustic soda) and at five different depths in more concentrated liquors. The best method of sampling is by means of an iron or wooden rod, fitted at one end with a basket in which is fastened a small-necked 16 oz. bottle. This is provided with a cork attached to a wire, so t h a t it can be removed when the bottle has been submerged to the proper level. Separate samples are thus taken at various depths in the car. Analysis of Caustic L i q u o r TOTAL A L K A L I :

If no determination for carbonate is to be made, weigh out directly in a closed weighing bottle about 1.5 grams from the sample of 50% liquor, or a correspondingly l a r g e r amount for liquors of less concentration. The weighed sample is t r a n s f e r red to a beaker and t i t r a t e d with N/2HC1 in the presence of methyl orange. This t i t r a t i o n (A) is

(A--B)

m e a s u r e of the t o t a l alkali p r e s e n t a n d m a y be e x p r e s s e d in t e r m s of Na..O and N a O H .

Wt, of sample in aliquot X 2 % Na:CO~

AX3.1 Wt. of sample X 2 % Total Alkali as Na~O AN4.0 Wt. of sample X 2 % Total A l k a l i as N a O H SODIUM HYDROXIDE AND SODIUM C.a.RBONkTE : When a determination for carb o n a t e is to be made, a l a r g e r s a m ple of f r o m 14 to 16 g r a m s of t h e 50% liquor is used. The w e i g h e d s a m p l e f o r a n a l y s i s is diluted to t h e m a r k in a 500 cc. v o l u m e t r i c flask w i t h w a t e r f r e e f r o m CO 2. A i r should be excluded as much as possible during this operation. T r a n s f e r a 50 ec. aliquot of t h e s a m p l e and a d d 10 ca. of a 10% s o l u t i o n of BaC12. U s i n g one d r o p o f p h e n o l p h t h a l e i n f o r an indicator, t i t r a t e w i t h N/2HC1 to a l m o s t an end point. A f t e r w a s h i n g down flask w i t h d i s t i l l e d w a t e r ( f r e e of COs), an a d d i t i o n a l drop of t h e ind i c a t o r solution is a d d e d a n d t h e t i t r a t i o n then c o n t i n u e d to t h e end point. F o r e x t r e m e accuracy, a i r f r e e of COs should be i n t r o d u c e d into t h e flask d u r i n g t i t r a t i o n . T h i s t i t r a t i o n (B) is a m e a s u r e of t h e a l k a l i n i t y due to s o d i u m h y d r o x i d e . B•

Wt. of sample in aliquot X 2 % Actual NaOH The difference b e t w e e n t h e two t i t r a t i o n s ( A ) a n d ( B ) is a m e a s u r e of t h e NafCO ~ p r e s e n t .

X 4.3

The figure f o r t o t a l alkali as Na20, calculated f r o m t h e p r e c e d i n g m e t h o d o f a n a l y s i s is t h e t r u e or a c t u a l s o d i u m oxide ( N a f O ) content. To o b t a i n t h e p e r c e n t a g e of t o t a l alkali as NafO a c c o r d i n g to the N e w Y o r k and Liverpool t e s t , m u l t i p l y the figure f o r t o t a l alkali as NafO, as d e t e r m i n e d f r o m a n a l y s i s , b y t h e f a c t o r 1.0323. Selling Basis on Liquid Caustic D u r i n g t h e first f e w y e a r s a f t e r caustic soda in liquid f o r m w a s placed on t h e m a r k e t , t h e r e w e r e m a n y d i f f e r e n t p r a c t i c e s in use as r e g a r d s specifications a n d prices. Much confusion e x i s t e d in t h e m i n d s of consumers, who f o u n d i t difficult to c o m p a r e t h e p r o d u c t a n d price offered b y one p r o d u c e r w i t h t h a t offered b y a n o t h e r . T h e s i t u a tion was f u r t h e r c o m p l i c a t e d b y the f a c t t h a t liquid caustic w a s dem a n d e d by c o n s u m e r s in a v a r i e t y of c o n c e n t r a t i o n s r a n g i n g f r o m 25% to 50%, none of w h i c h w a s a s t a n d a r d a r t i c l e of commerce. T h r o u g h t h e c o - o p e r a t i o n of p r o g r e s s i v e m a n u f a c t u r e r s a n d cons u m e r s , liquor of 50% c o n c e n t r a tion h a s now been e s t a b l i s h e d as the standard for the commodity liquid caustic soda. I t was also d e s i r a b l e t h a t some s t a n d a r d p r a c t i c e be a d o p t e d in marketing and invoicing liquid caustic, and t h a t t h i s p r a c t i c e be based a s f a r a s possible on t e r m s f a m i l i a r to the b u y e r . Most c a u s t i c l i q u o r is now sold on t h e b a s i s o f its c a u s t i c soda c o n t e n t e x p r e s s e d in t e r m s of solid c a u s t i c soda of s t a n d a r d test, t h a t is, 76% act u a l NafO. C o n t r a c t s u s u a l l y spec i f y a given t o n n a g e of "solid c a u s 296

tic soda (76% actual Na20) to be shipped in the form of 50% solution." Buyers can now c o m p a r e on a common basis t h e i r quotations from various producers, or check t h e i r price on caustic in liquid f o r m a g a i n s t past m a r k e t levels on solid caustic. The following rule may be used f o r computing the value of a c a r of liquid caustic : Wt. of liquor • % Total Alkali as NaOH X % Purity of Caustic Price z Value of Car F o r example: A shipment cons i s t i n g of 100,000 lbs. of liquor is

found by analysis to contain 49.00% NaOH. The m a r k e t price on solid caustic (76% actual Na20) is $3.00 per 100 lbs.; liquid caustic is 35 cents lower in price, or $2.65 per 100 lbs. 49.00 X $0.0265 = $1,325.00 100,000 X - 98.00 The average 76% solid caustic soda contains approximately 98% NaOH and 2% of solids other than NaOH. In the above rule, the term "% P u r i t y of Caustic" r e f e r s to this average figure 98%. In special cases where the p u r i t y of the caustic f u r n i s h e d averages above or below this figure, the actual percentage p u r i t y of such caustic should be inserted.

President Trevithick Names Additional Committees N e u t r a l Oil and Detergent Bodies to be H e a d e d by McLean and Howells R e s p e c t i v e l y RESIDENT TREVITHICK L . T . Howells, Vice-chairman of the American Oil ChemH. C. Bennett ists' Society, in a communC . P . Long ication to the Edi'.or of OIL • FAT W . T . Reese INDUSTRIES, announces the personJ . S . Boulden nel of the following committees of E . T . Marceau the Society for the year 1927-1928: A . S . Richardson Refining Sub-committee A V . K . Cassady ( N e u t r a l Oil Ccmmittee) E . R . Millard Claude E. McLean, Chairman, F . H . Rhodes c / o Choctaw Cotton Oil Co. A . K . Church Ada, Oklahoma. H . S . Mitchell George S. Jamieson F . W . Smither M. G. Boulware T . G . Vail E. C. Ainslie L . F . Hoyt A. S. Richardson W . C . Preston F. R. Robertson Due to the fact t h a t Mr. Hoyt will be exceptionally busy this year, Detergents Committee he found it necessary to decline F. H. Guernsey, Chairman, re-appointment as chairman of the c / o Cowles Detergent Co. Lockport, N. Y. Detergents Committee.

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