s o l - ., I 9 I 3
T H E J O C R S A L 0 F I .V D CS T RI .-I L A ATD E SGI,V E E R I S G C H E M I S T R Y
T h e authors realize t h a t no sweeping conclusions can be drawn from a n y one series of tests, a n d while t h e y feel t h a t more care 1 cs been t a k e n t o eliminete all variables except t h e pigments t h a n has been t a k e n in a n y previously published service tests. t h e y think t h a t results which are not in accordance with previous tests a n d experience should be t a k e n with caution. T h e excellent showing. however. of Paints 14 a n d I j are wholly in accordance with investigations b y others a n d with t h e experience of users of paint for steel. Red lead a n d linseed oil a n d American vermilion (scarlet lead chromate) a n d linseed oil are undoubtedly among t h e very best for t h e protection of iron. T h e suggestion is therefore offered t h a t future tests be macle by adopting such a formula as Paint 11 as a s t a n d a r d a n d painting half of each plate tested with t h e s t a n d a r d a n d t h e other half with t h e paint t o be tested. If t h e plates are cleaned b y sand blasting instead of pickling it can safely be assumed t h a t t h e only variable is t h e paint a n d much better conclusions m a y be drawn t h a n when possible variations in t h e metal must also be considered. BUREAU OF CHEMISTRY A N D BUREAUO F WASHINGTON
STANDARDS
THE CORROsION OF METALS BY WATER
nificant t h a t the results obtained are the same for all samples of water except sample "G." Although these figures are practically identical, there are extreme a n d important differences in t h e character of t h e water. T h u s , i t was found t h a t raw LOSSES I S I v E I G I i T
''
4. 5. 6. 7.
From From From From
Ottawa, Ottawa, Ottawa. Ottawa,
O n t . , "mechanically filtered," Sample "D." O n t . , "raw," Sample "E." O n t , "chlorinated" (only), Sample "F." O n t . . M g O used as precipitant, S2ample"G."
Experiment 1-4 showed t h a t waters "A," " B , " a n d "C" were equally corrosive. I t is evident from these figures t h a t no appreciable differences exist in t h e action on iron of raw or treated waters (mechanical filtration) in so far as t h e y m a p be revealed b y losses in weight of t h e metals. I t is sig-
O F l ' A R I O L 5 AfETALS
DI.E T O CORROSIONBY
----
"h"
"F" \Vater
"B"
a -
A t 2 2 3 c. At 600 C.
0 0274 0.031i
0 0267 0.0394
Exp. 2-
"E"
IVater At 270 C . At 50' C .
0.0280 0.0324
,-._i___
0 0284 0 0316
0 0282 0 0300
Iron IVire "A'' .'line "D"
0 027; 0 . 0540
0 0271 0.0258
"G"
0.0261
0.0203 0.0185
0.0529
Bxp. 3-Metals
in Contact f I r , ) n \\-ire "B")
Water "E"
\rater "D"
-h__
Iron a n d copper At 220 C . At 500 c.
Iron
Copper
Iron
Copper
0.0369 0,0743
0 . 0000
0 0375 0 0592
0 0000
Iron a n d aluminum At 220 c. At 50' C. Iron alone At 22' C . At 50' C.
Iron 0,0248 0.0315 Iron
0,0000 Aluminum
0.0000 0.0023
0.0016 0.0023 Lead 0.0012 0.0011
0.0000
hluminum
0 0225 0.0260
0.0000 0 0028
0.0328
...
.... Lead
Iron
Iron
0.0317
Lead P; aluminum
w
1. F r o m Watertown, hT.Y . ,"mechanically filtered," Sample "A." 2. F r o m Watertown, N . Y . , "mechanically filtered," Sample "B." 3. From Watertown, S . Y . , "raw," Sample "C."
(GR-ws)
WATER Exp. I-Iron \\-ire "A" .ilone
At 22' C. By A. T. S T C A R T A t 50' C . Lead alone Received June 17. 1913 A t 22' C. P A R TI-RELATIVE CORROSIVITY O F " ~ \ I E C H A X I C A LAt LY 5 O 0 C. F IL T E R E D " A s D R A " W A T E R
Conditions in each of t h e following series of experiments were quite uniform so t h a t comparisons within t h a t set are possible. T h e metals used were employed in t h e form of wires, cut in equal lengths. These were coiled a n d suspended in bottles containing 4 0 0 CC. of t h e mater t o be examined. T h e measure of corrosion was obtained by wiping t h e wires with a cloth a n d finding t h e loss in weight. In order t o ascertain t h e effect on corrosion of unlike metals in contact. t w o common metals of greatest difference in potential were chosen. T h e wires were wound around each other, t h e n coiled a n d suspended as before. These tests were not allowed t o last longer t h a n seven days. for it was felt t h a t in t h a t time actual conditions i n a n y cix-ic supply were already exaggerated, contact surfaces considered. At t h e end of t h a t time considerably larger amounts of iron were capable of being transported b y t h e water t h a n could ever be tolerated in practice. T h e following waters were tested:
90 5
4luminum
n
0003 0 0003
Lead
Aluminum
0 . 0 0 6 i ( ? i 0,0000 0.0013 0.0014
Lead 0 000i 0 0014
(XVater "F" used in All Cases. At 2 2 0 c .
Iron Wire "B") At 500
c.
Iron alone Iron. . . . , . . . .
0,0289
0.0292
0.0589
0.05T8
Iron & aluminum Iron . . . . . , , . Aluminum. . . . .
0 0220 o 0000
0 0211 o.0000
0,0125 0 0034
0 0168 0.0076
0 0,318
0.0314 0 0000
0.0623 0.0000
0.0601
0000
0.0016
0.0020
0.0045
0 0034
0 0032 0 0010
0 003' 0 0004
0 1203
0 1192
0.0000
0 oono
Iron & copper Iron . . . , . , , . Coppcr. . . . . . Lead alone Lead. . . , , .
.
o ,
Lead P; aluminum Lead. . . . . . . . . .4luminum . . . I.ead S: copper Lead. . . . . . . . Copper. . . . . .
0.0336 0.0000
0.0436 0.0000
0
oono
Copper S; a l u a i n u m Copper . . . . . Aluminum
v-aters. although corroding iron t o t h e same extent, do not coat the iron with as much flocculent material nor do t h e y a1loLv it t o settle out. as is the case with treated waters. b u t retain a large proportion in solution. which m a y perhaps be of a colloidal nature. Treated waters. a t ordinary temperatures, became very murky a n d opaque and. .shen h o t , large amounts of broivnish red rust appeared. This is popularly k n o w n as the "red water trouble." Hon-erer. it must be noted t h a t our figures indicate t h a t the actual amounts of iron corroded were the same for treated or raw waters. P A R T11-EFFECT O F WATERo s M E T A L SIS C O ~ T A C T Apparently t h e state assumed b y the iron corroded from t h e metal is a much more important question from t h e standpoint of a city supply t h a n t h e actual amounts. The conclusion in this connection is t h a t
a
906
~
T H E J 0 U R AVA L 0 F I LVD U S T RI il L A X D EAVGISEERILVGC H E M I S T R Y
t h e so-called mechanical t r e a t m e n t of waters of these t y p e s is very liable t o bring about this troublesome discoloration. It m a y be noted here t h a t both these waters examined were of low mineral content and highly colored b y p e a t y m a t t e r . It would be of interest t o follow t h i s m a t t e r f u r t h e r with various other types. These figures are i n excellent accord with t h e electrolytic theory of corrosion a n d illustrate a n easy means for investigating t h i s subject. A graphic representation could be presented with t h e aid of further figures which would be very interesting. CHEMICAL LABORATORY, DEPARTMENT OF h R I C U L T U R E EXPERIMENTAL F A R M ,OTTAWA.ONT.
SOME EXPERIMENTS ON THE CONVERSION OF LONGLEAF PINE TO PAPER PULP BY THE SODA AND SULFATE PROCESSES' E y SIDNEY D WELLS
I S T R OD U C T I 0 li
During 1912 t h e Forest Service in cooperation with t h e University of Wisconsin undertook a series of experiments on longleaf pine, P i n u s p a l u s h i s , with t h e following objects : I . T o s t u d y nThat influence t h e variable cooking conditions have i n t h e sulfate process of pulp-making. 2 . T o determine t h e suitability of longleaf pine for paper pulp. 3 . T o compare t h e sulfate process with t h e soda process. This work has been only partially completed b u t since there is urgent demand for information on t h e adaptability of longleaf pine, or southern pine as i t is more commonly called, for t h e manufacture of paper pulp, it has been t h o u g h t advisable t o give what indications our work has so far made manifest. Longleaf pine was chosen on account of t h e large quantities of this wood t h a t are being wasted in t h e lumber operations of t h e southern states a n d also because m a n y logs are a t present being sawed into lumber a t little or n o profit on account of their small diameter which would be of admirable size for pulpwood. Furthermore, t h e large a m o u n t of resinous matter in this wood made i t desirable as a n extreme test of a cooking process a n d t h e long, thick-walled fibers of t h e wood assured a strong pulp if i t could be produced without a too drastic t r e a t m e n t . E X P E R I M E X C. A L P R O C E D U R E
1'01. 5 , No.
11
T h e wood used was procured i n Louisiana a n d l l i s sissippi, a n d was fairly average i n r a t e of growth, size, a n d content of resinous m a t t e r . It was freed from bark a n d reduced t o chips five-eighths of a n inch long with t h e grain. These chips were allowed t o become air-dry a n d were thoroughly mixed a n d sifted t o remove a n y dirt a n d small pieces. The cooking liquors were made u p b y dissolving t h e required amounts of commercial caustic soda, sodium sulfide, Glauber's salt, a n d soda ash t o produce solutions of t h e desired concentration of each of these chemicals. I n studying t h e influence of t h e variable factors entering into t h e cooking operation t h e small autoclave was used. T h e effect t h a t a n y one variable condition exerted was determined b y a series of cooks made varying t h e condition under observation, a n d maintaining t h e other conditions as nearly identical as possible i n each cook. T h e effects were ascertained b y determining t h e yield of pulp a n d carefully treating t h e pulp in a hollander beating engine t o develop a stuff capable of producing as strong a sheet as possible when made i n t o paper. T h e quality a n d color of t h e pulps were judged b y inspection, feel, a m o u n t of beater t r e a t m e n t necessary, a n d t h e strength a n d wearing qualities of t h e paper produced. T H E E F F E C T S O F VARYING T H E A X O U N T S O F CHEMICALS
T h e effect of varying t h e caustic soda or sodium sulfide was a decrease i n yield a n d a lighter colored pulp with a n increase i n either one or both of t h e chemicals. Caustic soda was found t o be a b o u t twice as drastic in i t s action as sodium sulfide a n d with t h e same yield t h e pulp produced b y t h e former was lighter t h a n t h a t produced b y t h e l a t t e r . T h e yields, however, do not decrease directly i n proportion t o t h e amounts of chemical used, a n d between 30 a n d jo pounds of caustic per IOO pounds of chips t h e decrease in yield is much less for equal steps t h a n below or above these amounts. T h e disagreeable odor caused b y t h e production of mercaptans increased with t h e increase of t h e sodium sulfide, a n d was much more noticeable where t h e larger proportions of t h i s chemical were used. T h e sodium carbonate a n d sulfate present in t h e cooking liquor produced no very apparent effect except where t h e former was present in relatively large amounts when a retardation i n t h e action of t h e other chemicals present was noticeable. Enough cooks were not made, however, t o definitely establish t h i s indication.
T h e cooking operations i n this work were conducted i n t w o forms of digesters. T h e first form consisted of a small rotary autoclave of about a-gallon capacity which was heated with Bunsen burners. T h e other T H E E F F E C T O P V A R Y I X G T H E P R E S S U R E , D U R A T I O N O F form was a vertical digester of 60-gallon capacity, C 0 0 K I iX G A N D C 0 h-C E N T R A T 1O S S heated b y direct steam. T h e greater portion of t h e T h e effect of increasing a n y one of these variables work was accomplished in t h e former a n d in all 115 was t o increase t h e severity of t h e cooking action a t cooks made. T h e d a t a obtained i n these cooks &-ere tainable with t h e same q u a n t i t y of cooking chemicals. used i n determining t h e conditions for t h e larger diWith a n y combination of t h e above conditions there gester in which 19 cooks were made t o obtain conditions more nearly comparable with those used in com- is a definite a m o u n t of chemical necessary t o produce a pulp of t h e best quality a n d it is possible t o use a mercial practice. wide range of conditions t o produce approximately 1 Paper presented a t the 48th Meeting of the A. C. S I Rochester, t h e same result. September 8-14. 1913.
