.

ANTIFREEZE RECYCLING USING THE GLYCLEAN SYSTEM

ROBERTC. MILLER, JR. VICE PRESIDENT, RESEARCH AND DEVELOPMENT

FPPF CHEMICALCO., INC

The following report was presented at the Hazardous Materials Management Conference & Exhibition of Canada, in September

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t I FPPF CHEMICAL CO., INC.

ANTIFREEZE RECYCLING USING THE GLYCLEAN SYSTEM FUEL ADDITIVES TREATMENTS CONDITIONERS

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BY

ROBEX" C, MILLER, JR. VICE PRESIDENT, RESEARCH AND DEVELOPMENT

FPPF CBEMICAL CO. INC 117 WEST TUPPER STREET BUFFALO, NY 14201

WHY USE A COOLANT IN ENGINES

Antifreeze or antiboil or simply a coolant is used today in almost all types of internal combustion engines. Whether the fuel is gasoline, diesel, propane, natural gas or the heavier fuels such as #4, #6 or Bunker C, most all engines need to employ the use of some liquid medium to remove heat from the combustion area. In water cooled engines, water passes through a jacket surrounding the combustion chamber, absorbes the heat, and transmitts it to a radiator where it can be dissipated to the air.

Since the 1950's the most common choice of coolant has been a 1:l mixture of ethylene glycol and water, with the ethylene glycol containing selected inhibitors. Whether it is called antifreeze in the colder parts of the world or antiboil in the warmer zones the coolant's function is to depress the freeze point fo r winter operation or raise the boiling point for warmer weather operation.

Pure 100% ethylene glycol freezes at +9OF ( - 1 4 O ) . water freezes at +32OF ( O°C ) but a 1:1 mixture freezes at -34OF. Most engine manufacturers recommend and provide a factory fill of a 1:l mixture or 50% ethylene glycol with 50% water. In continuous extreme cold weather operation up to 70% ethylene glycol and 30% water is in use.

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Although ethylene glycol does not meet all the requirements of a coolant, it provides a fairly good overall balance. It has a specific heat of about 60 percent that of water, but a 5 0 : 5 0 mixture of ethylene glycol and water raises this to about 80 percent. In addition, a 50 percent solution has a 15OF (7OC) higher boiling point than water alone and this provides a definite advantage.2

The function of the coolant is, very simply, to remove some of the heat from the engine, be it automotive, truck, bus, locomotive, etc. In actuality the hotter an engine runs, up to a point, the more efficient a machine it becomes. However, cooling is necessary to prevent lubricating oils from breaking down and thus protecting against serious expensive metal wear of critical moving parts.

Engine cooling is more critical in diesel engines because diesel engines run hotter due to the longer vertical distance (higher compression ratio) the piston moves within the cylinder. Most diesel engines utilize what is called a "wet sleeve" or "cylinder liner" around the outside of the piston. This cylinder liner is designed to allow for the flow of coolant to remove the heat from the walls of the cylinder so the film of oil formed between the piston rings and cylinder walls is not thermally degraded. If this heat was not removed, the oil would start to varnish, piston rigs would wear, cylinder liners would scorch and loss of power would result. Combustion gases would blow past the piston rings and introduce corrosive sulfur and other gases in the lubricating oil which would cause corrosion of metals in contact with the oil.

Cooling system deposits, corrosion, cavitation and pitting of surfaces, all have a negative effect on heat transfer, so clean surfaces are important. Detroit Diesel has proven that as little as 1/16 inch of hard water scale on a cylinder liner has the heat insulating properties equal to 4 1/4 inches of cast iron in heat tran~ferability.~

It has been estimated by the major diesel engine manufacturers (Cummins, Detroit Diesel, Caterpillar, Perkins, etc.) that from 40% to 60% of diesel engine problems or failures were directly or indirectly caused by improper coolant treatment, neglected coolant or chemically depleted coolant.

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In automobiles coolant maintenance is less critical due to what had previously been the extensive use of large flow cast iron cylinder blocks and valve heads. However, the increasing use of aluminum engines is presenting problems of a different nature. The need for a coolant for engines and the wide acceptance to the use of ethylene glycol produces ultimately a large consuming public.

With ethylene glycol production in the United States of around 500,000,000 gallons per year and approximately 250,000,000 gallons produced as antifreeze for various vehicles, the changing and disposal of antifreeze has become an environmental problem.

TYPES OF COOLANTS

Ethylene glycol is by far the most widely used coolant in use today. Some engine manufacturers are, and have, experiment- ed with propylene glycol, but the cost, physical properties and higher operating temperatures (poor heat release) have kept propylene glycol from widespread use.

Chemically, about l/2 cup of pure ethylene glycol if ingested could be fatal to an average size man. Propylene glycol is far less toxic and is even produced in a food grade as a heat transfer medium in food production.* Pure 100% ethylene glycol or propylene glycol if discharged to the environment breaks down very quickly from ultra violet rays into harmless components and water.

Some types of coolants are being promoted as "non-toxic" or "easily discharged - non polluting" as alternatives to ethylene glycol. It does not matter what the coolant fluid is, what matters are the levels of toxic heavy metals it contains after having been in an engine.

Drained, used coolant typically will contain, in either dissolved or suspended form, significant quantities of iron, copper, lead, tin, zinc and smaller quantities of silver, cadmium and aluminum. It is these metals that most sewage treatment authorities are unable to remove or remain in the ground if dumped.

There are applications where coolant can be ordinary water and the use of ethylene glycol is not needed for freeze or boil protection, such as stationary indoor or shipboard engines. Inhibitors such as chromate, nitrite, molybdates are used to protect the metal surfaces.

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Since inhibited ethylene glycol is by far the most widely used and accepted coolant product and the topic of disposal, the rest of this discussion shall only include the ethylene glycol coolant solution.

INHIBITED COOLANTS

Pure uninhibited ethylene glycol has a pH of slightly below 7 . 0 so it is, in most situations, slightly acid. Depending on the source of the water used for dilution, the final solution can produce a coolant pH anywhere from 5.0 to as high as 9.5. The most typical final solution pH is usually around 7.5 - 8.5.

Our extensive testing has shown us a coolant pH below 8.3 is not acceptable for use in engines due to its corrosive nature. Typical of gasoline and diesel engines is the use of cast iron, mild steel, aluminum, copper, lead, tin, zinc to name the most common. The corrosion potential between dissimilar metals due to galvanic coupling is very high. The diluent water contains oxygen and since all engines cool, ambient air is introduced which contains about 20% oxygen, thus providing a continuing release of oxygen bubbles which cause pittings of metal surfaces.

To protect engines from corrosion and pitting of metal surfaces antifreeze manufacturers employ inhibitors and other additives in their product such as nitrites, silicates, borates, MBT (mercaptobenzothiazole), antifoam, molybdates, silicones, dye, phosphates, surfactants and alkalinity builder.

The specific functions of these inhibitor additives is generally recognized as follows:

TABLE I

ANTIFREEZE ADDITIVES AND INHIBITORS FUNCTION

Additives Function

Nitrites (NOz)

Silicates (Si02)

Corrosion Inhibitor for Ferrous Surf aces

Corrosion Inhibitor for Aluminum Surfaces and helps to Buffer Coolant Solution

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TABLE 1

ANTIFREEZE ADDITIVES AND INHIBITORS FUNCTION (CONTINUED)

Additives

Borates (B04)

MBT

Function

Buffering Agent some Inhibition of Aluminum Surfaces

Corrosion Inhibitor for Copper and Copper Alloys

Ant i foam Prevents Foaming of Coolant

Molybdates (Mo04)

Si 1 icones

Phosphates (PO4)

Surfactants

Alkalinity Builder

Polymers/Dispersants

Sequesterants

Corrosion Inhibitor for Ferrous and Aluminum Surfaces

Anti f oam and slows Silicate Reaction with Magnesium

Green or Blue-green for Coolant Identification

Multi-metal Corrosion Inhibitor and helps to Prevent Cavitation Pitting

Acts as Bubble Breaker and Reduces Coolant Surface Tension

Raises pH of Coolant, Inhibits Ferrous Surfaces

Prevents deposits from forming, disperses existing deposits

Chemically "ties up" metals to prevent metal salt deposits

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How long will a properly inhibited cooling system last (50% bited antifreeze and 50% water)? Antifreeze manufacturers in r fall advertising T.V. campaigns suggest "it is time to

replace your old, depleted antifreeze now" and show a interior close-up of a corroded interior of a radiator. It is generally accepted to be ideal to change once yearly - most people do not.

Most automobile manufacturers recommend checking the antifreeze concentration (via hydrometer) to maintain the 5 0 / 5 0 blend and changing if the antifreeze is rusty or dirty looking. The average automobile owner changes antifreeze once in the life of the vehicle.

Diesel engine manufacturers vary greatly in their changing recommendations; Volvo recommends changing at each 40,000 mile interval, Cumins recommends changing out at 200,000 miles.

A s the inhibitors in new ethylene glycol deplete, the pH of the coolant solution decreases and (based on our research and field analysis) at a pH of 8.2 - 8.4 metal corrosion starts to take place. Typical depletion reactions or changes that take place are inhibitors such as nitrites are converted to nitrates, silicates can combine with magnesium thus losing their aluminum inhibition properties, MBT is easily oxidized and is insoluble so as the pH drops thus copper protection is lost, phosphates in their original poly (soluble) form reverts to the ortho form, which can combine with calcium to form an insoluble ~ludge.~

As the inhibitors are depleting the ethylene glycol is also changing. Ethylene glycol does, contrary to popular belief, chemically breakdown. The breakdown products are all acids, acetic, glycolic, formic and others, all of which decrease the coolant pH and significantly increase the corrosion within the engine.

The net result is the consumption of 2 5 0 , 0 0 0 , 0 0 0 gallons of antifreeze consumed in the United States per year which when diluted to "use" strength represents 500,000,000 gallons for new cars, trucks and car replacement, make-up f o r loses from broken hoses, water pumps, etc. No one is sure how many gallons are discharged on the ground, into lakes and rivers and into sanitary sewers.

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LAWS AFFECTING COOLANT DUMPING

An important distinction needs to be made regarding the toxicity of new antifreeze and used antifreeze. New 100% pure inhibited or uninhibited antifreeze while toxic if ingested, is not toxic if discharged to the environment because it decomposes and degrades so quickly. As has been previously mentioned, the type of coolant that goes into an engine is totally different from what comes out.

It is my understanding a new Canadian law, #309, from the Ministry of Environment of Ontario prohibits the dumping or discharge of any used coolant into the environment. Large consumers of antifreeze such as truck, bus and automotive fleets are faced with paying from $2.00 - $12.00 per gallon to have it removed by a government approved toxic waste hauler. In the United States the Federal Environmental Protection Agency ( E P A ) has not clearly regulated the proper handling or disposal of used antifreeze. Consequently each state, and in many cases each municipality, has enacted laws regarding the disposal of antifreeze. Some businesses generating less than 1 drum (55 gal1ons)are classified as small waste generators, those generating more than 1 drum are classified as large waste generators - some states make no distinction. In the transportation market all types of fleets are affected as are radiator repair shops, large garages and vehicle salvage yards.

Most states have adopted a Federal ECRA law which is the Environmental Conservation Recovery Act. This Act prohibits any industrial or commercial property from being sold until the premises and ground soil have been laboratory approved as being free of toxic materials (including toxic heavy metals). When a piece of real estate is determined to be contaminated, the soil must be removed down to a depth of 6 feet, hauled away as a toxic substance and replaced with fresh soil.

There is no doubt in the mind of anyone purchasing, using or attempting to dispose of used antifreeze that existing and pending laws will have a serious impact on their actions, and make the concept of recycling very attractive.

SHORTAGE AND COST OF ANTIFREEZE

There was a time the consuming public could purchase, at retail, a gallon of a name brand antifreeze for $2.00 with a coupon for a $0.50 rebate from the manufacturer.

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In the middle of 1988 the price of that same antifreeze, in drums, varied from $8.00 to $11.00 per gallon.

What happened?

True, Texaco and Shell both had refinery fires that disrupted their antifreeze production, but that had only a short term effect on costs and prices. The longer term effect on prices is related to capacity.

We have reached our chemical processing capacity of ethylene in the United States and the processors have a choice as to what finished product to produce. Plastics such as polyethylene are much more profitable so most of the ethylene raw material goes to plastics - less towards ethylene glycol. The demand is met but the refiners may only produce if the profit levels are comparable to plastics.

It is not expected this situation will change before the mid 199O's, and since the cost to increase ethylene capacity is in the hundreds of millions of dollars it may be closer to the year 2000 before the investment is made.

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THE CONCEPT OF RECYCLING

Recycling used antifreeze is new!

We would like nothing better than to be able to reference this section with numerous footnotes from prestigious authors of well known ethylene glycol producers about their work on recycling antifreeze.

We can't!

We cannot site any previous attempts at recycling antifreeze that we know or have been able, after extensive literature searches, to find.

It appears used antifreeze, since its first use after World War I1 until about 1985, did not merit consideration for recycling due to its inexpensive nature and previous to 1985 w a s not considered to be a discharge problem.

What was required on our part was to review hundreds of engine cooling water laboratory analysis we performed over the past 8 years to determine the contaminants present.

Basically the contaminants can be divided into insoluble (suspended) matter and soluble (dissolved) matter. Our review showed the following products in antifreeze coolant:

SUSPENDED MATTER

IRON OXIDE COPPER OXIDE CALCIUM CARBONATE MAGNESIUM CARBONATE MAGNESIUM PHOSPHATE TIN OXIDE

MAGNESIUM SILICATE CALCIUM PHOSPHATE DIRT - SILT LEAD OXIDE ZINC OXIDE

DISSOLVED MATTER

IRON COPPER LEAD ANTIFOAMS TIN LEAD CHLORIDES MOLYBDATES

NITRITES NITRATES PHOSPHATES BORATES SULFATES MBT POLYMERS

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While there are many ways of purifying antifreeze such as distillation, reverse osmosis, ion-exchange, selective membrane separation and electrodialysis, these methods are expensive in terms of capital required and require extensive operator training.

We felt simple filtration would most probably remove most of the suspended matter but how to remove the dissolved metals presented a challenge.

From our experience in industrial water treatment we know one of the methods used in the pretreatment of well water used for potable purposes is aeration. Deep well water is often aerated to kill anaerobic bacteria and to remove dissolved iron. The aeration of iron-bearing waters is common practice, for the oxidation of the ferrous iron to ferric hydroxide converts the soluble iron to an insoluble material which can then be removed by settling and filtration. The pH of the water has a marked effect on the speed of this reaction, at a pH of 7.0 or above the reaction is fast enough for oxidation to be completed.6 Precipitation of the iron occurs as ferric hydroxide,illustrated by the following eq~ation:~

4Fe (HC03)2 + 02 + 2H20 ----- 4 Fe (OH)3 + 8 CO2

Aeration of used antifreeze in our laboratory using ambient air (which is approximately 20% oxygen) showed iron removal in the range of 96%-98%. Our analysis of the used antifreeze solution before and after aeration showed the levels of other dissolved metals (copper, tin, lead, zinc) decreased from 20%- 70%.

It seemed that if we could treat the dissolved metals in the used antifreeze to produce a metal oxide, where possible, the resultant metal oxide could then be removed by filtration.

The following contaminants can be reacted via aeration:8

Silica (Si02) - silica can be removed by absorption on ferric hydroxide. (which we have already formed via the oxidation of iron)

Borate (B04) - can be removed by absorption (on ferric hydroxide - although this is not very efficient.)

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Phosphate (P04) - Phosphate can be reduced to very low levels with a formation of insoluble aluminum phosphate and iron phosphate (aluminum and iron are both usually found in used antifreeze)

Tin (Sn) - converted to the hydrous oxide colloid at neutral pH or in HCOa/C03 environment.

Nitrite (NO2) - can be oxidized to nitrate (Nos) MBT - mercaptobenzothiazole is easily oxidized

As has been previously mentioned, used antifreeze has a lower pH than a new ready to use (50 :50) mixture, the ethylene glycol breakdown products are organic acids and their formation reduces the pH below the ideal range of 9.0 - 10.0.

Since recycling of used antifreeze must include raising the pH, why not raise the pH with inorganic alkaline hydroxides such as sodium or potassium hydroxides?

Knowing that the following metals are insoluble as the hydroxide, magnesium, zinc, iron, aluminum, silver and copper while calcium, and lead are very slightly soluble, hydroxide addition could raise pH and precipitate metals. ( refer to solubility chart on page 11 B .

The specific solubilities of the metal hydroxides:

I RON 8.0 X 10-16

ZINC 1.2 X 10-17

CADMIUM 2.5 X 10-14

NICKEL 2.0 X 10-15

COPPER 2.7 X 10-20

LEAD 1.2 X 10-15

MERCURY 3.0 X 10-26

SILVER 2.0 X 10-8

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The first prototype unit was built by a Mr. Mark McNally of Philadelphia Electric Company to address a problem of disposing of used antifreeze. The unit was built with the chemistry input from FPPF Chemical in 1985 and although there has been refinements the basic concept has remained.

We have recently added an ion-exchange module as an (optional) means of "polishing" the used antifreeze to remove any traces of dissolved metals. The ion exchange resin is a strong acid cation type of polystyrene cross linked divinylbenzene. The module containing the resin can, depending on the dissolved metal content of the antifreeze. last from 6,000 to 8 , 0 0 0 gallons of liquid flow before it needs to be replaced.

GLYCLEAN FLOW CHART (refer to chart #2)

The unit is filled with used antifreeze and pumped through the filters (1) the discharge is then aerated ( 2 ) to form oxides of dissolved metals which is then continuously refiltered ( 4 ) and aerated (5).

A pH is taken and using a chart, tells how much GLYCLEAN additive is necessary to raise the pH to 9.5 with the additive introduced (6) the hydroxide portion forms suspended matter (7) which is continuously filtered (8) and aerated (9).

A sample is then taken to check for freeze point via refractometer. Again a chart is used to tell the operator how much 100% pure antifreeze must be added to achieve a 50:50 mixture to provide -34OF freeze protection.

The circulating pump is then used to transfer the recycled antifreeze to clean drums for future use.

SOME OBSERVATIONS

The GLYCLEAN additive besides containing the alkali hydroxides to raise pH and precipitate dissolved metals also contains a very unique inhibitor package.

The inhibitor package contains our FPPF-4000 product which is molybdate, low level nitrite, tolytriazole, high temperature antifoam, surfactant, anionic polymers, organic phosphate, dispersant and sequestering agent. We feel this inhibitor package is far superior to the package used in new antifreeze.

SOLUBILITY TABLE

Na$ Sodium K+ Potassium NHq+ A"on i urn ii+ Hydrogen Ca+2 Calcium ~ g + 2 btagnes i um Ba+2 Barium Sr+2 Strontium ~ n + 2 Zinc Fe+2 I r o n Fe+3 I ron Al+3 Aluminum ~ g + l Silver Pb+2 Lead ~ g + l blercury ~ g + * Elercury cu+2 Copper

S S S S S S S S I S vss s vss s vss s S S ss S ss S S S I I vss s I I ss S ss S

S S S S S S S S S S S S I ss I S

S

S S S S S S

S co2 S ss S S S vss S vss S vss S ss S I S X I I vss I I I I I vss I

S S S S S S H20 S vss S I S S S ss S I S vs s S I S I S I S vss S I S ? S ? S

S S S

co 2 I vs s vss I I vss I X vss I S I I

S S S S vss S

I vss S S S S S I vss vs s S

S S S

H20 X X X X I I X X I I I I I

S S

S S

S S

S S

S I S I

I I vss I vss 1

X I X I

X I

I I

I I

vss I ss I I 1

s - ss - vss - I - x -

Soluble, over 5000 mg/l Slightly Soluble, 2000-5000 mg/l Very Slightly Soluble, 20-2000 mg/l Insoluble, less than 20 mg/l Not a Compound

I ) .

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GLYCLEAN does not rely on high (800 - 1200 ppm) levels of nitrites which cause solder bloom deactivate MBT and cause radiator leaks.

Silicates are not used due to their ability to combine with magnesium from the dilutant water and form "green goo", also called silicate gel.

The anionic polymers provide negative charges on any suspended matter to prevent and remove existing engine deposits.

The sodium and potassium salts of glycolic, formic, acetic and oxalic acids formed from the degradation of ethylene glycol actually slow further ethylene glycol degradation.

The use of aluminum in engines seems to act as a catalyst to speed the degradation of ethylene glycol.

The level of chlorides in the used antifreeze is a function of the chloride level in the original make-up water. Sufficiently high levels of molybdate in the glyclean additive allow for chloride levels up to 500 ppm before any impact is seen on corrosion rates.

GLYCLEAN recycled antifreeze has shown the ability to reduce diesel and gasoline engine water pump seal failures.

Coolant pH control in aluminum engines is very important. Aluminum is amphoteric, it will go into solution at pH's near neutral and at around 10.5, so coolant pH control is very important.

Phosphates as an inhibitor can and do form sludge of (tri) calcium phosphate, iron phosphate and magnesium phosphate. Volkswagen, Mercedes and Audi prohibit the use of phosphate in additives or antifreeze, to use them voids their new engine warranty.

High levels of dissolved solids (up to 12,000 ppm) has not had any negative effect on coolant performance.

_- - I USED ANTIFREEZE I Suspended Matter

Iron Oxide Copper Oxide Calcium Carbonate btagnesium Carbonate Nagnes ium Silicate Ca lc i um Phosphate Dir t/Silt Lead Oxide Zinc Oxide

Dissolved Matter

I ron Copper Zinc Tin Lead Nitrites Phosphates Borates Sulfates Chlorides PIBT

FLOW SHEET OF THE GLYCLEAN ANTIFREEZE RECYCLING PROCESS

Jc -.

1 I 4 1 2 1 5

9 Converts

Metals to Oxides as Suspended Matter

Dissolved

I Removes

Matter

SUSPENDED DISSOLVED MATTER

Iron Oxide Copper Oxide Tin Oxide Lead Oxide Zinc Oxide

Nitrite Nitrate Sulfate Chloride MBT Phosphates

6 ! I

1 G LYC LEAN ADD IT I VE /

Raises pH Adds Hydroxides, Antifoam and Inhibitors

1

7 t I SUSPENDED

MATTER I Iron Hydroxide Copper Hydroxide Zinc Hydroxide Lead Hydroxide Tin Hydroxide Magnesium

Calcium Hydroxide Hydroxide

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GLYCLEAN TODAY

At present there are over 300 GLYCLEAN units in service in the United States and Canada. We estimate there are over 85,000 vehicles, all types, trucks, cars, boats, etc., running on GLYCLEAN antifreeze and we have not had one sincrle rePort of any engine failure related to the cooling system.

The major truck and bus fleets, being the largest consumers of antifreeze, are our majority of customers and have determined the significant economic advantage of recycling.

The cost for recycling antifreeze is between $1.40 - $1.70 per gallon. Based on GLYCLEAN and antifreeze costs. The cost of the unit is around $4,000 and these fleets have determined the pay back is less than 1 year (depending on how much antifreeze is recycled).

These same fleets are reporting an 80% decrease in the quantity of antifreeze they now purchase.

As the price of antifreeze will go down in years to come the concept of distillation, reverse osmosis and other capital intensive equipment will look less attractive. The proven filtration, aeration, oxidation and precipitation approach of glyclean will continue to be economically attractive.

REFERENCES

Rowe. L.C., Automotive Engine Coolants: A Review of their Requirements and Methods of Evaluation, Engine Coolant Testing: State of the Art, ASTM STP 705.

Bevon. E., Cooper, N., and Hanniqan, H., Soap and Chemical specialties, Vol. 47, No. 2, 1971, p.44

Detroit Diesel Corporation, Publication 753298/8810, 13400 Outer Drive, West, Detroit, Michigan 48239-4001.

W A C FOCUS, Winter 1988, Dow Chemical, U.S.A., 48674

J.H. Conlev and R.G. Jamison, Research and Development Efforts in Military Antifreeze Formulations, Engine Coolant Testing: State of the Art, ASTM STP 705, W.H. Ailor, Ed. American NORDELL, ESKEL., Water Treatment for Industrial and other uses., Second Edition, Reinhold Publishing Corporation, New York, 1961, P. 303.

Betz Handbook of Industrial Water Conditioning., Sixth Edition. Betz Laboratories,Inc., Trevose, PA 19047. P. - 61. The Nalco Water Handbook., Frank W. Kemmer, Editor-in-

Chief., McGraw - Hill Book Company, New York, 1970, P6-1, 6-23. (9) Water and Waste Treatment Data Book., The Permutit Company,

East 49 Midland Avenue, Paramus, NJ 07652, 1961, P. 137