Prosqïc gas has gone ori growing in good years and bad· N e w uses keep turning up, too, as producers work hard to solve their seasonal demand problems

Jackson D. Leonord is a chemical engineering con­sultant who has specialized in chemical process work; he has had his own consulting practice since 1950. H e lias a B.S. from Pennsylvania State University, and lias had 15 years of industrial experience with General Chemical, Du Pont, and Merck. He is a licensed professional engineer in Delaware, N e w Jersey, New York, and Michigan. Since becoming a consultant, Leonard has served clients in the U . S., the Έατ East, and Europe. Although his organiza­tion -works chiefly on process design and know-how, it must provide preliminary market, economic, and en­gineering studies for many clients. This article is based on one such preliminary study.

114^ C & E N O C T . 6, 1 9 5 8

CO2

JCKOUUCTIOX of carbon d ioxide h a s grown steadily in the U . S. Even in years when genera! business activity, i n ­cluding chemicals, was level or deci in-hig, carbon dioxide sales continued t o increase. Sales dollars wen t u p even more, a s several pr ice increases were i m ­posed dur ing this period.

At t he present time, the tota l com­bined capacity of carbon dioxide plants in the U. S. is abou t 3 .0 million tons a year. Almost 1.5 million tons can l>e produced a s solid **dry ice,** while t h e ba lance represents l iqu id a n d g a s p ro ­duc ing capacity. All p lan t s first sep­arate carbon dioxide from a gas stream containing a mixture of gases. Then they purify and liquefy it before con­ver t ing part of the l iquid to solid.

The big difference be tween total c a ­pacity and actual product ion is due to the high d e m a n d for dry ice during t h e summer for refrigeration; carbonated beverages and food processing also reach peak demand during the summer months . Major producers h a v e spent substantial amounts of money to d e ­velop both all-year-round uses for car­bon dioxide, and uses which might reach a peak during the winter months, i n order to use more of their existing plant capacity. These efforts have re ­sul ted in t h e many new and interesting uses for al l three forms of carbon dioxide.

A detai led cost s tudy performed in 1952 shows the following elements in the cost of producing and distributing carbon dioxide:

Ful l mill cost Transfer loss Warehouse and freight

loss Pa ten t s and royalties F re igh t and delivery Sell ing expense Cylinder main tenance

and expense To ta l :

Since 1952, labor i

Cost per Ton Solid

$15.00 3.00

11.00 2.00 7.00 3.00

— $41.00

increases,

Liquid $ 9.00

—

— 2.00 8.00 3.00

7.O0 $29.00

higher freight rates, a n d higher materials ' costs have raised the production cost of solid COo to about $45 to $46 a ton, the l iquid to $33 to $34 a ton. Prices for solid C 0 2 have been q u o t e d at $60 to $70 a ton plus delivery in 1950, a n d S70 to $85 a ton plus delivery a t pres­ent. Liquid prices are quoted at $50 t o $60 a ton, in low tempera tu re tank car units, t o $140 to $160 a ton in 50 p o u n d cylinders. O p e n market prices, however, a re only an indicat ion of the over-all average price, since most C 0 2

sales a r e handled on a contract basis where quanti ty and t ime of delivery both enter into the price structure.

The cost tabulation shows obvious advantages for the producer w h o is located close to the consumer—the basic cost of producing C 0 2 about doubles due to the loss incurred be­tween the d r y ice product ion plant and delivery of the p roduct t o the con­sumer. Liquid C 0 2 does not have this disadvantage. But it cannot be used in many of the ways that have been developed for the solid material. Also, the liquid costs the small and medium consumers considerably more, since it is available to them only in 5 0 pound cylinders. Cylinder loading and handl ing costs a d d an additional $60 a ton to the cost of l iquid C 0 2 . Large scale liquid users gain t h e ad­vantage of the cheaper production cost for liquid COL» by using insulated low temperature, low pressure tank cars and trucks to receive bulk shipments. Many small users of l iquid C 0 2 also purchase it in the solid form and then convert it into liquid in standard liqué­fier units available from the major pro­ducers and various equipment makers.

M a n y Sources

Carbon dioxide today is recovered from many different sources: fermen­tation off gases, limestone kiln gases,

. - _ - « „ . 1 . * i _ . .

luuuicti v»v^2 wc-iia, euruLnxatiuii ^aacra from coke breeze, natural gas, and various oils, as well as gas streams from chemical and petrochemical operations. Carbon dioxide is purified a n d liquefied by at least seven different processes, but regardless of the source or process, the mill cost of production usually runs less than $15 a ton for solid material , and less than $10 a ton for liquid a n d gas.

In the past few years, many chemi­cal manufacturers having C 0 2 waste streams located close to large cities have considered produc ing d ry ice. But the seasonal nature of the demand plus the high losses incurred in storing and transporting solid C 0 2 have de­terred most entrants. Likewise, am­monia producers have scrutinized this field due to the large C 0 2 off-gas streams. I n most cases they have been reluctant to risk tying a COo plant to an operation like ammonia , which is also subject to considerable variation in demand. Also, the mechanical and operating difficulties of t h e ammonia plant reflect in the C 0 2 p lan t operation.

Investment for a fully modern CO.>

plant equipped t o produce gas, liquid, and solid will run about $20,000 per daily ton of capacity. Since a 50 ton-a-day plant would be the minimum eco­nomic size for most locations» a $1 mil­lion investment must be justified for the plant alone. On the other hand, one of the largest plants in the world (Olin Mathieson*s plant at Saltville» Va. ) recovers C O s from lime kilns and successfully distributes product all over the East Coast. As with many other chemical projects, it is difficult to make generalizations that cover all cases.

Aside from refrigeration, little change has occurred in the distribution pattern since 1950. Tonnages of COo con­sumed in each mafor area have in­creased substantially, even in refrigera­tion, where the percentage of the total has dropped bu t the total number of tons has increased. This use pattern was developed from industry sources, literature sources, and consumer sur­veys. Therefore, it should be regarded as an approximation. Due to the di­versity of uses and users it is exceed­ingly difficult to get exact totals used in any one end use area, and the end use of much of the COo consumed still remains unclassified. This problem has been aggravated greatly in recent years because of the many new uses being developed for CO.» and the many small distributors who handle this material.

Food Big User

The most important use of "dry ice" by far is in food preservation and dis­tribution. Containers have been de­veloped for bulk and semi-bulk ship­ments of meat, fish, fresh fowl, vege­tables, fruit, flowers, and ice cream in which the dry ice used to keep safe temperatures is a small part of the total weight transported. Also, as the dry ice evaporates, the vapor acts as an anti-oxidant, and there is no water to soften the package or dispose of. For small producers, dry ice is especially valuable since i t eliminates expensive capital investments in mechanical re­frigerating equipment. The containers developed range from small "take-home" packages for ice cream, through boxes, barrels, and drum size containers, up to full size bunkers designed to occupy large trailer trucks or railroad cars. Actually, dry ice has played a key role, in the fact that practically any fresh food can be bought anywhere in the U. S. Few other countries in the world of comparable size have this

(Continued on page 118)

O C T . 6. 1958 C & E N 1 1 5

H e r e ' s W h e r e C O i G o e s

T o n s / Y e o t

3 7 1 , 0 0 0

1 4 1 , 0 0 0

5 1 , 0 0 0

4 5 , 0 0 0

1 3 , 0 0 0

1 9 , 0 0 0

6 4 0 , 0 0 0

REFRIGERATION: F O O D S ,

PERISHABLES, A N D

INDUSTRIAL C O O l l N G .

C A R B O N A T I O N : BEVERAGE^

PLASTICS. RUBBER

I N C I T I N G : RRE EXT INGUISHER^

INERT ATMOSPHERES

CHEMICAL· C H E M I C A L

SALTS & REACTIONS

MISCELLANEOUS: FERTILIZER,

RESPIRATORY STIMULANT,

RODENT C O N T R O L ETC,

P O W E R : PRESSURIZING A N D TRANSFER USES; P A C K A G I N G & M F G .

T o n s / Y e a r

4 0 4 , 0 0 0

Refrigeration

Solid CO- (dry ice) is widely used for a variety of products and applications; some liquid is used as the refrigerant in me­chanical refrigerating systems; some liquid is expanded to pro­vide rapid and controlled cool­ing for special applications. The bulk, however, is solid C 0 2 .

M f g . Processes:

Adhesive mfg. Aluminum rivets Aluminum parts Aluminum anodizing Aromatic oil extraction Bakeries: bun & cake topping Chilling: rubber, plastics, & flexible

materials to permit machining, etc. Chill gr inding—heat sensitive m a ­

terials Chemical etching Coolant for masonry drills Deflashing of rubber & plastic parts

by tumbling Dye & pigment blending & grind­

ing Distillation of solvents by low temp,

fractionation Freeze drying o f blood plasma,

serums, solvents, etc. Freezing of p l iable materials to per­

mit threading, stamping Grinding & machining of metals as

coolant to prevent surf ace d a m a g e a o ! f balls

Grinding of vegetab le matter, glands, etc.

Hardening of fancy ice cream and cakes prior to storing

Investment casting using w a x or mercury

Low temp, processing of animal semen, synthetic rubber» fract. crystallization, etc.

Machine tool coolant for aenecal grinding & machining

Mixing; & blending of many sticky, gummy, or moist materials

Nuclear reactions—chilling cores Pie & pastry mixes Sewaçje'disposal Silicon refining Steel hardening Sub-zero treatment of alloys Shrink fitting Temperature control in critical proc­

esses Vacuum traps We ld ing stainless steel We ld ing heavy steel plate

Storage Uses:

Animal semen Apples, eggs. Bowers, fruits, furs, nuts,

paints, etc. Emergency refrigeration to supple­

ment mechanical systems Storage of aluminum parts Storage of frozen foods

Transportation:

Adhesives & sealing empds. Aluminum parts * Booster for mechanical refrigeration

on trucks, cars, planes Catering services—airlines, rai lroads,

etc. Dining cars Frozen food transportation Fresh iood transport Flower distribution

Ice cream &Ί frozen desserts Mail order foods & perishables Meat transportation, Medical specialties Piggy back refr igerator trailers Polymerization cataslysts distribution Vendors* carts

Laboratory:

Experm. freezing Freezing tissues Genera l utility Low temperature reactions

2 5 1 , 0 0 0

76,000

8 4 , 0 0 0

1 7 , 0 0 0 8 y 0O0

8 4 0 , 0 0 0

CO-, and dry ice converters. Carbonation of rubber and plas­tics are newer developments in this classification.

Beer Carbonated beverages

soda fountain, pre-mix Milk

-bott led,

Inspection-Testing:

Calibration o f instruments Dew point tests Environmental tests

Miscel laneous Refrïg.:

Cooling denta l drills Freezing cofferdams Freezing oil samples Freezing asphalt t i l e Preservation o f corpses Point-of-sale displa-ys Refrigerant in mechanical refr igerat­

ing systems Transplanting of shrubs Theatrical effects

iCarbonatiori ^

butter & ice-cream Foam plastic—elastomer process Foam rubber-—pH control & foaming

action Polyurethane plastics Sparkling waters Sparkling wines

Carbonated beverages have grown in popularity and ac­count for a substantial volume of liquid C 0 2 in 20 and 50 pound cylinders, bulk liquid

Inerting

This classification includes fire extinguisher use» inert atmos­pheres in storages and canned food products to prevent oxida­tion, handling, and transfer of dangerously flammable mate­rials, and many manufacturing processes.

Fire Protection:

Barge tanks Ship compartments Cotton ginning Engine tests Coal fires & others uncontrollable

with water

1 1 6 C & E N O C T . 6, 1 9 5 8

CO* Plants in the U. S. at Mid-Year

Cardox Corp. {seven plants) Columbia-Sou them ( 2 plants ) Commercial Solvents ( 2 plants) Liquid Carbonic, division of

General Dynamics ( 2 9 plants) Pure Carbonic, division of

Air Reduction ( 9 plants ) U. S. Industrial Chemicals ( 2 plants ) Allied Chemical» Hopewell, V a . Collier Carbon & Chemical, Brea, Calif. Parker-Browne Co . , Fort Worth, Tex. Carbon Dioxide & Chemical,

Price, Utah Carbonic Products Co., Tulsa, Okla. California Carbonic Co. ,

Los Angeles, Calif. Carbonic Chemical, Mosquero,, Ν. Μ. Cal-Dri Co., Hopland, Calif. Carbon Dioxice & Chemical,

Wellington, Utah Note: Does not include brewers who recover carbon dioxide from their own-fermentation gases and re-use it in transferring and carbonating beer. * Not now in production.

Capacity (TonsiDmy)

Liquid Solid 360 90 70*

1450

600 40*

110 70 50

10 10

45

30

60

265 90 65

1350

500 40*

110 70 40

5 10

40 45 30

60

Capacitif ( Tons J Day )

Liquid S&lid

75 30

4 60 25

60 30

50 25

45

20

45

20

Food Machinery & dieniicalj, Lawrence, Kan.

Gas Ice Co. , Klickitat» Wash. Henry Bower Chemical,

Philadelphia, Pa. Hiram Walker, Peoria, 111. Ideal Dry Ice Co. , Ada, Okla. Lion Oil, division of Monsanto

Chemical, Luling, La. New England Alcohol Co. ,

Everett, Mass. Oklahoma Portland Clement Co.,

Ada, Okla. Olin Mathieson, Saltville» Va. Publicker, Philadelphia, l?a. Spencer Chemical, Military, Kan. Union Oil, Santa Maria, Calif. Wyandotte Chemicals, Wvandotte,

Mich. Others

** Carbonic Chemical uses natural carbon dioxide wells with such high pressure that most of the CO* conies out as liquid.

10 300 200

70 70

250 375

10 280 175

60 60

240 315

Fuel tanks H igh temp, testing Maintaining dissolved solids in sol­

vents O z o n e m f g . Purging hydrogen - ,* fems Purging c · -r U twel systems Purging process equipment & sys­

tems Purging conrdrnVcri f>7fo» to 's^cïding Recharging o f fire extinguishers &

systems Storage of flammable materials Storage of oxygen sensitive materials

Flushing Agent & Vehicle:

Dehydration—stripping moisture or solvents from liquids with dry CO» gas

Microanalysis Refining of silicon, platinum, zir­

conium, etc. S p a r g i n g of paint, varnish, plastic,

ink, &. other reactors; agitat ion & anti-oxidation

M f g . Processes:

Aging o f cheese Annealing ovens Electronic tube mfg. Inerting Ni &. Cu catalysts in alcohol

manuf. M f g . o f catalysts Mix ing, blending, &. homogenizing of

oxygen sensitive materials Shielded arc welding Spray dry ing—coffee , tea, etc.

Packaging & Storage:

Bulk shipping—fruits, vegetables , flowers

Canned cheese, eggs, milk, meat , cocoa, coconut, coffee, nuts, ex ­tracts, potato chips, etc.

Fumigation of grains Fur storage Tobacco packaging Paints & varr.ish cans Pharmaceutical'-—in capsulatfcig vita-

. u ^ , ~us. e tc Phenol—to reduce v a p o r losses Gr a in & vegetab le storages

Miscel laneous:

Animal immobilization Laboratory blanketing

Iron pelletizing Ladle linings Leather tanning Methyl salicylate Neutral ize alkalies in textile process­

ing O i l detergents Perborates Phthalîc anhydride distillation Potassium carbonate Refractory manufacture Revivification of foamite fire

systems Soda ash Sugar refining—calcium removal Testing tin plate Text i les—vat dying, pH control Urea W a t e r treatment Whi te lead

The chemical properties of CO» are used to produce a host of carbonates, for p H centrol in acid reactions, cement curing, and other applications where the CO- enters into a chemical reaction with other materials.

Asbestos cement shingles mfg-Acid—used for ρ Η control as α w e a k

acid Ammonium carbonate Aspirin Carbonate salts Cement curing Catalyst Foundry cores & molds Glycerides Ingot mold tops

- > Pressurizing

>r Power Uses

Liquid CO» has a pressure of 800 to 900 p.s.i. at ordinaxy temperatures, and this pres­sure can be used to operate equipment where ordinary power is not available o r suit­able, for pressure spraying and packaging, and many other applications.

Aerosol packaging Blast ing—Ccrdox process Cal ibrat ion &. testing Cleaning of pipes & tubes

Dispensing beer Dispensing beverages Ether starting o f Diesels Fire extinguishers—propellanr for

powder type Inflation of rafts, life belts, air b a g s ,

mattresses, balls Mot ive power for torpédos O p e r a t i o n of bell buoys, tools, power

cylinders, e t c Portable power cylinder Rubber—cellular Revivification o f w a t e r & oil wells Spraying paint Spraying of chemicals, asphal t , &

hazardous liquids Transferring o f hazardous & flam­

mable liquids W h i p p e d cream—diluent f o r N 2 0 &

anti-oxidant

Miscellaneous

This includes all applications which do not fit in the more specific classifications.

Carbonated baths Drying of tubing & piping Escharotic Humane killing of animals Inflating of airships Insecticide, storage silos Plant fert i l izei—roses, orchids Rain making Respiratory stimulant Rodent control, warehouses Therapy for psychoneurosis

O C T . 6, 1958 C & E N 1 1 7

announcing new improved

performance in

HYDROGENATION G-49, a new reduced, stabilized nickel catalyst in finely divided form" has been developed 03* Girdîer Research and is now available in commercial quantities. Tests show it will provide better performance in certain applications than previously available types. There are no organic components and, being non-pyrophoric, i t is safer t o handle. Write for full details and sample of new G-49.

. . . a n o t h e r n e w d e v e l o p m e n t in

GIRDLER 3FHE

Standard and custom-designed to

meet your needs

manufactured by C H E M I C A L P R O D U C T S

D I V I S I O N CHEMETRON CORPORATION

Louisville 1# Kentucky Telephone: Spring 8-4421

M«cilita t*&stiï<à ie*<;of cheraîcaI ir ea çtiobsga s - « Λ *

C H E M I C A L PRODUCTS D IV IS ION P . O . Box 3 3 7 Louisvi l le I , Kentucky

Send free copy of Data Book G245A,

Company Name

Company Address

Gty -Zone. _Stat«_

Your N a m e .

Dual Shield aissc wdding~ process, developed b y Nat ional Cylinder Gas, uses speciad flimx-corscd electro-des a n d carbon dioxide gas . Used on mild steel, it's ssaicl feo he· up t o I S times faster t h a n manua l stick electrode welding

asset. Tlikâs is apart o f the^ reason why America today is one of the fcest fed narioras in the workL

Ac*ually% the «<leve!opnie=nt of suitable containers for «sing d ry icre is a s much responsible for the g r o w t h of dry ice use on thus fieLd as any other factor. Likewise, new and bettser insulating materials a r e inuiking possible t h e con­struction «of insulated tm»cks a n d rail­road -cars fthat permit m o r « efficient use of d r y ice. Portable containers are also beings lightened, and improved. Credit for su3ch dl«evelo^)iiieiit mus t go t o many contaminer manutfactuxers sas well as to the COo p»rodu«c?ers.

Qumite irecentfly, "no-te^ar" c h o p p e d onioims ha w e be«en offered in the frozen food sections o ^ the natiosn's supermar­kets, and Arre^rican housewives have respcwndedl \vitfh r o u s i n g purchases. Processors; discovered not long ago that onioims conoid b^ cooled, Hflien chopped with dry ice iwito fine pieces without losing the essential oils armd aroma that characterize fr^sh cmionss—but which cause· tear—s \vh«en an onio»n is c h o p p e d up. Thes-e n e w frozen cruopped onions have all tuhe tat-ste a n d ar-onia of fresh onioras, anted are^ all ready to o se . But they don't causse "tears."

F e w people realize that potential for C 0 2 in food preservation has been barely scratched. It bas been well sçs-tablished tha t gaseous C 0 2 , in high enough concentration, will inhibit bac­teria formation, kill insects and rodents, p reven t oxidation, and retard mold and fungus growth. The flavor of some fruits is affected by C 0 2 , bu t others are affected very little, while many vegetables and grains can be stored for long periods without adverse affect. T h e present government program of storing excess food products in storage silos could be greatly benefited by using C 0 2 as a preservative, bu t re­design of the silos would first b e neces­sary. However, since the U. S. is one of the few nat ions in the world tha t has such a food storage problem—and maximum efforts are being directed toward eliminating this surplus—per­haps this p roblem will eventually dis­appear . But future needs for long term food storage may stimulate further development in this field.

A recent plastics s tudy reveals that salvaging and re-using scrap plastics h a s assumed the proportions of a $200 million per year business. Much of this increase is due to the fact tha t

1 1 8 C & E N O C T . 6, 1 9 5 8

INDUSTRIAL •PHEMICALS

COPPER COPPER SULFATE

Industrial Crystals « d all tommoD grades.

MQHOHYDRATED COPPER SULFATE

3$%, Copper as metallic packaged in steel dnaas at no extra cosf.

COPPER CARBONATE CUPRIC CHLORIDE CUPRIC OXIDE *mr

We mine Copper, Sulfur, Iron and Zinc and are basic producers of their chemical derivatives. Our technical know-how and basic position in these minerals is your assurance of exact­ing quality control, strict uniform consistency and a plenti ful supply.

m l |SULFURIC"*CIDi

ι ;-,')%> *' * *f* * 'ΛΑ1!: * - « -: : , t Various strengths and

; f | grades 60° through the Oleums. Available In task

^ c a r s or tonnages. t , , ; > < '

., LIQUID SULFUR : : DIOXIDE

Highest commercial quality, available in tank cars, tank wagons, ton cylinders and 150-lb. cylinders.

55% Copper as metallic light and dense grades.

SULFUR CHLOR0SULF0NIC ACID

Iron less than 1.0 ppm as loaded. Water white. De­livered in glass-lined tank wagons, also in stainless steel drums.

37% Copper as metallic. Available In polyethylene-lined drams or bags.

Minimum 76% Copper as metallic. Technical grade . . . HOT A BT-ITOO0CT.5

SODIUM HYDROSULFITE

Κ HYDRO is a dry, white, free flowing, crystalline powder of uniform particle size and structure. I t is dust free, assuring highest stability and uniformity.

PARA TOLUENE SULFONIC ACID, ANHYDROUS

Other organic Sulfonic Acids. \ w * ?

IRON ZINC FERRIC IRON SULFATE

Partially hydra ted, free flowing granular form. Available in bags or bulk.

MONOHYORATED ZINC SULFATE

36% Zinc as metallic. White, free flowing powder.

ZINC OXIDE

Secondary Zinc Oxide.

MANGANESE MANGANESE SULFATE MONOHYORATED

MANGANESE SULFATE MANGANOUS OXIDE

Designed specifically for in­clusion in mixed fertilizer.

Samples, specifications and detailed information upon request.

?3% Mn, SO,, H=0. Highest purity, technical gracie ; Γ. HOT A BY-PRODUCT.

Minimum 48% Manganese as metallic. Feeds, ferti­lizers, spray or dust grades.

TENNESSEE CORPORATION TENNESSEE CORPORATION'

O C T . 6, 1958 C & E N 1 1 9

BUGS BEWARE!! MARASPERSES MAKE BUG KILLERS MOR£ EFFECTIVE

Stable dispersions of wettable powders are easily obtained with the addition

of one to two percer* of Marasperse. And spray tank contents axe

maintained at a uniform concentration for maximum effectiveness throughout

the spraying period. The Marasperses are not hygroscopic,

won't cake, nor will they affect the potency of the toxicant.

Wri te f o r suggested formulat ions of sev­eral types of wet -table powders.

M A R A T A N For: Leather tann ing

MARACELL Ε For: Water- t reat ing compounds

M A R A C A R B Ν For: Pesticides

M A R A C O N For: Concrete admixtures

MARASPERSE C For: Gypsum, Pesticides, Ceramics,

industr ia l cleaners

MARASPERSE CB For: Carbon black, Dyestuffs, Pesticides»

Ceramics

MARASPERSE CE For: O i l we l l d r i l l i ng muds

MARASPERSE Ν For: Industr ia l cleaners, Dyestuffs, Pesticides

Also ava i lab le : MORLIG

A calcium l ignosulfonate — 25 to 6 0 % solids solut ion — spray-dr ied powder.

MARATHON, a division of AMERICAN CAN CO. CHEMICAL SALES DEPT. · ROTHSCHILD, W I S . Please send in format ion about

Marasperse • Other • Samples, too Q

fo r use in

NAME -

COMPANY

ADDRESS _ .

E-108

I I I ι ι

J

Put more SOLIDS

info suspengion

IN CHEMICAL AND APPLICATION RESEARCH

You can greatly increase the solids content of sus­

pensions without increasing viscosity with

Marasperse low cost, more effective dispersants.

The addition of only .0596 to 3-0% of Marasperse

disperses insoluble particles in

water suspension and prevents agglomeration-

Viscous pasty masses become thin free-flowing fluids

. . . Settling of suspended solids is prevented or

greatly retarded . . . Slurries are kept fluid

even with greatly increased concentration of solids.

Marasperse dispersants are non-hygroscopic,

free-flowing powders.

For more information, see our unit in CMC — page 322.

MARATHON A D i v i s i o n of A m e r i c a n C a n C o m p a n y

CHEMICAL SALES DEPARTMENT ROTHSCHILD, WISCONSIN

1 2 0 C & E N O C T . 6. 1 9 5 8

very finely ground scsrap plastic can be incorporated into virgin plasstic with little harxnful effect for mos« applica­tions. Tlus permits using substantially higher percentages of scrap* in such mixtunes* The problem w a s how to "fine-grime!" scrap plastic^ since most grinding machines produced enough heat t ô melt the material so» that the fine particles simply fused together. Dry i ce mixed with the scrap plastic kept the grinder and the plastic cool, thus permitting the production of very Snely ground material. This discovery was a staot-in-the-arm for uW plastics materials; industry, and it accounts for the magnitude of salvaging operations today.

The rmetal industries have adso bene­fited greatly from the searcla for new C 0 2 u s e s . Some examples:

•Shielded arc welding, wEhere C 0 2

gas replaces more costly raelium or argon.

• Precision casting, where? mercury or wax i s poured into intricate or com­plex patterns, then frozen fiard with dry ice to produce perfec* positive molds.

• Semi-precision foundry molding, where a silicate binder i s nmixed with the molding sand and tampead into the master onold. A shot o f 0 0 2 gas is used t o react with t h e silicate, forming r* *tiff S— v v hiçh harsdcns thç îând SltO a usable mold. This eliminates a costly and t i m e consuming bakintg of the mold.

• S tee l hardening, using alcohol and dry i ce baths to obtain very low tem­peratures.

• Madiining-grinding amplications, where C 0 2 replaces ordinary coolants and savers on grinding and ^finishing the work, as well as making at possible to do t h e work faster.

These and other uses have saved millions of dollars, at the same time making i t possible to turn o u t better products^

A. ]M- Kidder & Co., finaoicial ana­lysts, points out that carbonasted bever­age consumption in the U. S. has in­creased 130 % since 1946. Swich stories of increased use or novel or industrial uses o f C 0 2 appear so frequently that they arosuse little comment. But each new use- makes the total consumption of carbon dioxide assume ev-en greater proportions and makes the outlook for producers brighter and brighter. •

COORS U.S.A.

MORTARS A N D

No. 525

Coors Mortals and Pestles axe

available in s ix styles and forty-

nine sizes.

Porcelain, Mullite and Alumi­

num Oxide mortars and pestles

provide t h e r ight materia l for

economical and efficient grinding.

All Coors Mortars and Pestles

are completely vitrified and non-

absorbent. Sizes up to 9 liters in

capacity. AVAILABLE FROM YOUR LABORATORY S U W . Y DEALER m COORS PORCELAIN COMPANY

GOLDEN. COLORADO

PHENYLMERCAPTOACETIC ACID

OCT. 6, 1958 C&EN 121

EVANS Chemetics Inc.