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Southern IonicsI N C O R P O R A T E D


C R E A T I V E S O L U T I O N S T O D A Y

Sulfur Products Handbook

SI I

Southern Ionics Incorporated (SII) was founded in 1980. The corporateheadquarters and research facilities are located in West Point, Mississippi. Thecompany has eleven facilities located in Port Allen, Louisiana; Baton Rouge,Louisiana; Calhoun, Tennessee; Chickasaw, Alabama; Columbus, Mississippi;Lake Charles, Louisiana; Midlothian, Texas; Pasadena, Texas; Terrell, Texas;Tuscaloosa, Alabama; and West Point, Mississippi.

C U S T O M E R F O C U S

Southern Ionics is committed to building a team of motivated individuals whocan advance the technology of our business, manufacture quality products, andprovide our customers with the service and know-how to maximize the valueof our products. We provide comprehensive technical service and applicationassistance for our products through our engineering, technical, sales, and R&Dpersonnel. Southern Ionics’ quality management system is certified to meetISO 9001:2000 Standards. Potable water treatment products are NSF certifiedfor use. Many of our products meet the Food Chemical Codex specificationsand are classified by the FDA as GRAS (Generally Recognized As Safe).

C U S T O M E R S E R V I C E

Our number one priority is meeting our customers’ expectations. SII has acentrally located Customer Service Department with toll free telephone andfacsimile numbers for the customers’ convenience in ordering during businesshours, and there is a toll free number for after hours and emergencies. Theafter-hours operator is equipped with pertinent information to handle anycustomer request. This allows for 24 hour, 7 days a week, 365 days a yearservice to handle customers’ needs.

Inventory management is also available. SII personnel simply contact thecustomer via an electronic dial-up remote tank level monitor system. SII thenschedules delivery based on the customer’s inventory targets and usage rates.Customer contacts for inventory management are also made by scheduledphone or internet queries.

P R O D U C T I N F O R M A T I O N

Southern Ionics manufactures sodium bisulfite solutions and sodium sulfitesolutions at Pasadena, Texas and Tuscaloosa, Alabama. Sodium Thiosulfatesolutions are produced at Baton Rouge, Louisiana and Pasadena, Texas. Allthree products are aqueous solutions. Standard products are a 40% sodiumbisulfite solution, 15% sodium sulfite solution, and 30% sodium thiosulfatesolution. Other concentrations of these products are available; however, thesolubility of the materials and individual customer requirements dictate thepractical concentrations that can be produced, shipped and stored (seeTemperature Solubility Curves on pages 18 & 19.)

The chemistry of the three products is similar in that they are sulfur basedreducing agents and will react with many of the same oxidizing agents. Theyare also similar in that they can be used in reactions that add functionality tothe compounds produced.

C R E A T I V E S O L U T I O N S T O D A Y

ALUMINUM CHLORIDE

POLYALUMINUM CHLORIDE

ALUMINUM CHLOROHYDRATE

ALUMINUM SULFATE SOLUTION

AQUA-CAT™ AQUA AMMONIA

CEMENT MANUFACTURING ADDITIVES

SI-SOLV™ FOR DEINKING RECYCLED PULP

SODIUM ALUMINATE

SODIUM BISULFITE

SODIUM SULFITE

SODIUM THIOSULFATE

MAGNESIUM SULFATE

VARIOUS ZIRCONIUM COMPOUNDS

CUSTOM COMPOUNDS & FORMULATIONS

SII manufactures and markets the following products:

1

The solutions range from mildly acidic, as in the case of bisulfite, to slightly basic, in the case ofsodium sulfite and sodium thiosulfate. The pH of these sulfite solutions dictates the existence ofsodium bisulfite and/or sodium sulfite (see Speciation of Sulfurous Acid-Bisulfite-Sulfite vs. pH onpage 21). Sodium thiosulfate on the other hand is more stable and usable at pH levels above 8.

There is a long list of applications where these products are used.The most significant uses are:

• In chemical reactions as a raw material

• As a reducing agent to destroy active halogen compounds

• As an oxygen scavenger (sulfite and bisulfite)

• As a sulfonating agent for organics

• Acrylic polymerization catalyst component (bisulfite)

• Metals reduction

• Photographic developer compounding

• Pulp and paper production

• Food preservation (bisulfite)

M A N U F A C T U R I N G P R O C E S S

While there are a number of potential processes that yield bisulfite, sulfite, and thiosulfate, allcommercial processes react sulfur or sulfur dioxide with alkali in an aqueous solution. SouthernIonics produces sodium bisulfite by burning elemental sulfur in air to form a gas containing sulfurdioxide. The combustion gas is cooled and absorbed into an alkaline solution, either caustic sodaor soda ash, to form sodium bisulfite.

Sodium bisulfite is further reacted with caustic soda or soda ash to produce sodium sulfite. Byadding additional sulfur and heat, the sodium sulfite can be converted to sodium thiosulfate solution.

REACTOR

FILTERSODIUM

THIOSULFATESTORAGE

Sodium SulfiteSolution

Sulfur

Heat

Loading

SODIUM THIOSULFATE PROCESS

2

S A F E T Y

Sodium bisulfite solution is classified as a Hazardous Chemical Class A by DOT standards.Sodium sulfite solutions and sodium thiosulfate solutions are not regulated by DOT; however, allthree products deserve respect as reactive chemicals in regard to personal safety during handlingand use. Contact with eyes, skin, or mucous membranes can cause severe irritation and evenburns. To avoid irritation, these products should be handled in well-ventilated areas and allpersonal protective equipment should be utilized.

Appropriate personal protective equipment, including safety glasses, chemical goggles, rubberboots, chemical resistant gloves, rubber apron, and face shield should be worn. In the case ofsodium bisulfite, respirators should be worn unless ventilation is adequate to keep concentrationsof sulfur dioxide below exposure standards. Some individuals are highly sensitive to sulfur dioxideand sulfites. These individuals should not be placed in a situation where they could becomeexposed to these products or the vapors from the products. THE MSDS SHOULD BE READ,UNDERSTOOD, AND FOLLOWED BEFORE HANDLING THESE OR ANY OTHERCHEMICALS.

F I R S T A I D

Eyes: Immediately flush eyes with a large amount of water for at least 15 minutes. Get promptmedical attention.

Skin: If exposed to skin: Wash skin thoroughly with soap and water. Remove contaminatedclothing while continuing to apply water. Get prompt medical attention if irritation persists.

Inhalation: Move victim to fresh air. If breathing is difficult, give oxygen. If breathing hasstopped, start artificial respiration. Get prompt medical attention.

Ingestion: Induce vomiting by giving 2 glasses of water to drink and touching back of subject’sthroat with finger. IMMEDIATELY see a physician. Never give anything by mouth to anunconscious person. Contact local Poison Control Center. In case of ingestion of sodiumthiosulfate, induce vomiting if gross amounts are swallowed. See MSDS for more information.

F I R E P R O T E C T I O N

FLAMMABLE LIMITS EXTINGUISHING MEDIA SPECIAL FIREFIGHTING PROCEDURES

Sodium Bisulfite Non Flammable

Sodium Sulfite Non Flammable

Sodium Thiosulfate Non Flammable For fires involving this material wear SCBA.

Move containers promptly out of fire zone. Ifremoval is impossible, cool containers with waterspray. Remain upwind. Avoid breathing noxiousfumes (sulfur dioxide) from fire-exposed material.

Use extinguishing mediaappropriate for surrounding fire.


Wear complete fire service protective equipment,including full-face piece MSHA/NIOSH approvedself-contained breathing apparatus. Use water tocool fire-exposed container/structure/protectpersonnel. Water or foam may cause frothing, ifproduct is heated above 93ºC/200ºF.

S A F E T Y


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R E A C T I V I T Y

S Y M P T O M S & E F F E C T S O F O V E R E X P O S U R E

T R A N S P O R T A T I O N R E Q U I R E M E N T S

Stability Conditions To Avoid Incompatibility Hazardous Decomposition Products Hazardous Polymerization

Sodium Bisulfite Stable Will not occur.

Sodium Sulfite Stable Will not occur.

Sodium Thiosulfate Stable Will not occur.

Avoid exposure toexcessive heat. Sulfurdioxide may be releasedif allowed to contactstrong acids or if driedmaterial is overheated.

Avoid contactwith acids andoxidizing agents.

Liberates sulfurdioxide in thepresence ofstrong acids.

Strong Acids

Thermal decomposition may yield thefollowing: sulfur dioxide – toxicfumes.

Oxides of sulfur fumes emitted whenheated to decomposition

If dried material is overheated, sulfurdioxide is given off.

DOT DOT UN/ID Packing OtherShipping Name Classification Number Group Labels

Sodium Bisulfite 8 UN2693 III Corrosive

Sodium Sulfite Sodium Sulfite Solution N/A N/A N/A N/A

Sodium Thiosulfate Sodium Thiosulfate N/A N/A N/A N/ASolution

Sodium Bisulfite Sodium Sulfite Sodium Thiosulfate

Eyes Severe Irritation; Mild irritation Slight irritationcorneal burning possible

Skin Irritation – dermatitis Mild irritation Moderate to low irritant.Inhalation N/A

Ingestion Up to 12 grams can be taken daily by mouth with no ill effects except catharsis.

Toxicity LD50 in rats 2000 mg/kg orally Large doses internally have a cathartic action.

Irritation of nose, throat, and lungs– coughing – shortness of breath

Harmful if swallowed.Gastrointestinal irritation; allergicreaction; In large doses may cause:abdominal pain, control nervoussystem depression, diarrhea,depression and death.

Sulfite-sensitive individuals,upon inhalation of this productmay experience a severe allergicreaction.

Oral exposure or swallowingmay produce gastrointestinalupset. Sulfite sensitiveindividuals may experience asevere allergic reaction.

LD50 in rats is 5.66 g/kg. Dermal toxicity in LD50 rabbitis >16.0 g/kg

Bisulfites, inorganics,aqueous solutions, n.o.s.

(Sodium Bisulfite)



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B U L K S T O R A G E

Bulk storage of sodium bisulfite solution is straightforward; there are four importantconsiderations addressed here that can have major impact on the successful planning of a storagesystem.

V O L U M E O F S O L U T I O N S T O R E D

Standard bulk deliveries of sodium bisulfite solution are 4,200 gallons by tank truck and 17,000gallons by tank car. It is normal practice to install tanks that have at least 1.5 times the capacityof the expected deliveries. Other factors will also influence the decision on the tank volume. Therate at which the solution will be used could require a larger tank. Installing a smaller tank couldincrease the cost of deliveries for the life of the system. It is important to remember that sodiumbisulfite solution is quite stable, and bulk economics are favored even if deliveries are requiredonly a few times a year.

T A N K C O N S T R U C T I O N

Sodium Bisulfite Solution is corrosive to mild steel, brass, and copper alloys. Premium resin FRP,316 SS, rubber-lined carbon steel, or polyethylene are all suitable material for sodium bisulfitestorage tanks. Tanks can be of single wall or double wall construction. Local regulations oncontainment will determine what is required in a specific situation, but materials such as sodiumbisulfite normally require either double wall construction or some form of containment.

Tank insulation is generally recommended for single walled tanks and even for some doublewalled tank installations. Most installations in the south do not require tank heaters. If a heatingsystem is considered necessary because of the specific product or location, the equipment selectedshould avoid prolonged product contact with surfaces heated above 150 degrees F. Some typeof recirculation is generally adequate in preventing such situations.

A schematic of a typical sodium bisulfite storage tank is shown on the next page. Southern Ionicspersonnel are available for consultation and to answer specific questions.

S T O R A G E T A N K V A P O R S

The vapor above a solution of sodium bisulfite contains water vapor and sulfur dioxide. Thevapor pressure of the solution is low (32.5 mm Hg) and not a significant concern except duringunloading into the tank. During a normal unloading into the tank, vapor from the tank isdisplaced through the tank vent. The vapor displaced by unloading a 4,200 gallon tank truck willcontain about 0.2 pounds of sulfur dioxide at 25 degrees C. This vapor can be discharged to theatmosphere at many locations, but may require special handling in some situations. Small ventscrubbers, as shown in the tank schematic, or piping to return the vapor to the tank trailers canhandle this issue.

S T O R A G E T E M P E R A T U R E

Sodium Bisulfite Solution is sensitive to storage temperatures. The product is shipped at about90 degrees F. The recommended storage temperature is 60 to 95 degrees F. Forty-percent (40%)sodium bisulfite will begin to crystallize at approximately 43 degrees F. Care must be taken toprevent the 40% product from falling to this level or below. Tank insulation is generally sufficientto do this, but if material is stored for long periods during cold weather, heating of the product couldbe required. In any event, if heating is required, isolated temperatures above 150 degrees and bulktemperatures above 100 degrees F should be avoided.

S O D I U M B I S U L F I T E S O L U T I O N

9

Southern Ionics has experience with customers with tanks in many different locations and canmake recommendations consistent with your particular area. Please contact your Southern Ionicstechnical/sales representative if you have questions or need additional information.

P I P I N G A N D P U M P S

Stainless steel, PVC, rubber-lined steel, CPVC, and Teflon lined steel piping are recommendedfor sodium bisulfite service. Pumps with wetted parts of these materials are suitable as well. Anypiping exposed to the outdoors should be insulated, and if the system runs intermittently, or iftemperatures get to freezing or below, heat tracing the piping is recommended.

Piping assembly should be via welded or flanged connection. Threaded connections arediscouraged due to the difficulty in maintaining a positive seal with aqueous solutions of this type.

D E L I V E R I E S A N D U N L O A D I N G

Tank truck deliveries are the most common bulk deliveries. Tank car deliveries are possible butwill not be addressed here.

Southern Ionics has its own tank trucks and makes many of the deliveries with this equipment;however, common carrier tank trucks are also used on occasion to supplement our equipmentand assure timely delivery.

Five thousand (5,000) to seven thousand (7,000) gallon stainless steel tank trailers are used todeliver sodium bisulfite solution. These trailers are equipped with 40 feet of 2” chemical hosewith cam and groove fittings. The trucks are capable of unloading with their own air supply;however, it is faster to unload using a customer supplied unloading pump or plant air regulatedat 25 psi. In special situations, a truck mounted transfer pump can be provided; however, thereis an extra cost assessed for each such delivery. A product transfer pump is required (either a truckmounted pump or a pump provided by the customer) if vapor recovery to the trailer is required.

The tank trailers are 40 feet long, and with the tractor, the entire rig may be as long as 70 feet.This information should be kept in mind to provide adequate access for the tank truck fordeliveries.

The unloading area, and particularly the location where the trailer is placed for unloading, shouldbe arranged to contain any spill. The customer is also asked to provide for the disposal of theproduct remaining in the hoses when delivery is completed. The driver will attempt to minimizethe volume of this material, but, typically, several gallons of product are drained from the hosesat the end of the unloading.

On arrival at the delivery location, the tank truck driver will report to designated customerpersonnel with appropriate paperwork and will verify the specific tank and connections forunloading. The driver will be equipped with all required personal protective gear and will adhereto the customer’s safety practices and policies. The driver will hook up the unloading hoses andoperate valves, pump, and any other necessary equipment to enable the unloading. The driverwill also close all valves as required, unhook all hoses, and dispose of any product from the hosesas directed by customer personnel. Any special requirements during deliveries should bediscussed with Southern Ionics personnel prior to delivery, no later than at the time the purchaseorder is placed.

S T O R A G E A N D H A N D L I N G

11

Bulk storage of sodium sulfite and sodium thiosulfate solutions is simple and straightforward.The following considerations can have a major impact on the successful planning of a storagesystem.

V O L U M E O F S O L U T I O N S T O R E D

Standard bulk deliveries of sodium sulfite solution are 4,600 gallons by tank truck and 19,500gallons by tank car. For sodium thiosulfate, the respective volumes are 4,300 gallons and 18,200gallons. It is normal practice to install tanks that have at least 1.5 times the capacity of the expecteddeliveries. Other factors will also influence the decision on the tank volume. The rate at whichthe solution will be used could require a larger tank. Installing a smaller tank may increase thecost of deliveries for the life of the system. It is important to remember that these solutions are quitestable, and bulk economics are favored even if deliveries are required only a few times a year.

T A N K C O N S T R U C T I O N

Neither sodium sulfite solution nor sodium thiosulfate is corrosive to mild steel. However, werecommend polyethylene, premium resin FRP, 316 SS to minimize the pickup of iron that wouldhappen to some degree with mild steel. Aluminum, copper, brass, or zinc fittings will be attackedby the alkalinity in sulfite and thiosulfate solutions, and their use should be avoided. Tanks can beof single wall or double wall construction. Local regulations on containment will determine whatis required in a specific situation. Since these materials are not considered hazardous, regulationsare generally less strict than with sodium bisulfite, but local regulations and/or companystandards should be consulted.

Tank insulation is generally recommended for single walled tanks and even for some doublewalled tank installations for sodium sulfite solutions. Sodium thiosulfate tanks may or may notrequire insulation since the crystallization temperature is lower for this product. Mostinstallations in the South do not require tank heaters for either product. If a heating system isconsidered necessary because of the specific product or location, the equipment selected shouldavoid prolonged product contact with surfaces heated above 180 degrees F. Some type of re-circulation is generally adequate in preventing such situations.

A schematic of a typical tank installation for sodium sulfite and sodium thiosulfate storage tank isshown on the next page. The schematics are similar to sodium bisulfite, but no vent scrubber isrequired. Neither of these products have sulfur dioxide in the vapor above the solutions.Southern Ionics personnel are available for consultation and to answer specific questions.

S T O R A G E T E M P E R A T U R E

Sodium sulfite solution and, to a lesser degree, sodium thiosulfate solutions are sensitive tostorage temperatures. The products are shipped at between 90 and 140 degrees F. Therecommended storage temperature range for these products is 60 to 80 degrees F, buttemperatures as high as 150 degrees are not a problem for the product.

Fifteen percent (15%) sodium sulfite will crystallize at approximately 40 degrees F. Care must betaken to prevent the fifteen percent (15%) product from falling to this level or below. Thirtypercent (30%) sodium thiosulfate will crystallize at about 14 degrees F. Tank insulation isgenerally sufficient to deal with ambient temperatures in the South, but, if material is stored forlong periods during cold weather, heating of the product could be required. In any event, ifheating is required, isolated temperatures above 180 degrees and bulk temperatures above 150degrees F should be avoided.

S O D I U M S U L F I T E & S O D I U M T H I O S U L F A T E

12

Southern Ionics has experience with customers with tanks in many different locations and canmake recommendations consistent with your particular area. Please contact your Southern Ionicstechnical/sales representative if you have questions or need additional information.

P I P I N G A N D P U M P S

Stainless steel, CPVC piping, and plastic-lined steel piping are recommended for sodium sulfiteand or sodium thiosulfate service. Pumps with wetted parts of these same materials are suitableas well. Any piping exposed to the outdoors should be insulated, and if the system runsintermittently, or if temperatures get to freezing or below, heat tracing the piping isrecommended.

Piping assembly should be via welded or flanged connection. Threaded connections arediscouraged due to the difficulty in maintaining a positive seal with aqueous solutions of this type.

D E L I V E R I E S A N D U N L O A D I N G

Tank truck deliveries are the most common bulk deliveries. Tank car deliveries are possible butwill not be addressed here.

Southern Ionics has its own tank trucks and makes many of the deliveries with this equipment;however, common carrier tank trucks are also used on occasion to supplement our equipmentand assure timely delivery.

Five thousand (5,000) to seven thousand (7,000) gallon stainless steel tank trailers are used todeliver sodium bisulfite solution. These trailers are equipped with 40 feet of 2” chemical hosewith cam and groove fittings. The trucks are capable of unloading with their own air supply;however, it is faster to unload using a customer supplied unloading pump or plant air regulatedat 25 psi. In special situations, a truck mounted transfer pump can be provided; however, thereis an extra cost assessed for each such delivery.

The tank trailers are 40 feet long, and with the tractor, the entire rig may be as long as 70 feet.This information should be kept in mind to provide adequate assess for the tank truck fordeliveries.

The unloading area, and particularly the location where the trailer is placed for unloading, shouldbe arranged to contain any spill. The customer is also asked to provide for the disposal of theproduct remaining in the hoses when delivery is completed. The driver will attempt to minimizethe volume of this material, but, typically, several gallons of product are drained from the hosesat the end of the unloading.

On arrival at the delivery location, the tank truck driver will report to designated customerpersonnel with appropriate paperwork and will verify the specific tank and connections forunloading. The driver will be equipped with all required personal protective gear and will adhereto the customer’s safety practices and policies as advised. The driver will hook up the unloadinghoses and operate valves, pump, and any other necessary equipment to enable the unloading.The driver will also close all valves as required, unhook all hoses, and dispose of any product fromthe hoses as directed by customer personnel. Any special requirements during deliveries shouldbe discussed with Southern Ionics personnel prior to delivery, no later than at the time thepurchase order is placed.

S T O R A G E A N D D E L I V E R Y

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PUMPSGoulds Pumps240 Fall StreetSeneca Falls, NY 13148315-568-2811www.gouldspumps.com

Flowserve CorporationRotating Equipment Div.P.O. Box 1145Dayton, OH 45401937-226-4000www.flowserve.com

STORAGE TANK CONSERVATIONVENT/BREATHER The Protectoseal Company225 West Forester AvenueBensenville, IL 60106630-595-0800www.protectoseal.com

Groth CorporationP.O. Box 15293Houston, TX 77020800-552-2960www.grothcorp.com

L&J Technologies (Shand & Jurs)5911 Butterfield RoadHillside, IL 60162708-236-6000www.ljtechnologies.com

MAGNETIC TANK LEVEL GAUGESISE – Magtech907 Bay Star BlvdWebster, TX 77598800-221-3653www.isemagtech.com

K-Tek18321 Swamp RoadPrairieville, LA 70769800-735-5835www.ktekcorp.com

Jogler9715 DerringtonHouston, TX 77064800-223-8469www.jogler.com

Ernst Flow IndP.O. Box 925Farmingdale, NJ 07727800-992-2843www.ernstflow.com

VAPOR SCRUBBERSBionomic Industries Inc.777 Corporate DriveMahwah, NJ 07430800-311-6767www.bionomicind.com

Branch EnvironmentalCorp.P.O. Box 5265Somerville, NJ 08876908-526-1114www.branchenv.com

EST CorporationP.O. Box 890Quakertown, PA 18951215-538-7000

Indusco Inc.P.O. Box 43447Birmingham, AL 35243205-967-7721

STORAGE TANKS DESIGNSTANDARDS American PetroleumInstitute1220 L. Street, NorthwestWashington, D.C. 20005202-682-8000www.api.org

API 650 – Welded SteelTanks for Oil StorageAPI 653API 2000 – VentingAtmospheric and Low-Pressure Storage Tanks

American Society ofMechanical Engineers3 Park AvenueNew York, NY 10016800-843-2763

COMPRESSOR FITTINGSFOR TUBING Swagelok29500 Solon RoadSolon, OH 44139www.swagelok.com

Tube Fittings Division3885 Gateway Blvd.Columbus, OH 43228914-279-7070www.parker.com

STORAGE TANKS– METAL TANKSReco USAP.O. Box 4147West Columbia, SC 29171803-794-3360www.recousatanks.com

Paul Mueller CompanyP.O. Box 828Springfield, MO 65801800-683-5537www.muel.com

Alloy Fabricators, Inc.P.O. Box 650Trenton, GA 36752800-275-7565www.alloyfab.com

Southwest Tank & TreatorManufacturingP.O. Box 340Henderson, TX 75653903-657-3556Email: [email protected]

Dal-Worth Fabrication2750 E. Main StreetGrand Prairie, TX 75050800-325-8265www.dalworthfabrication.com

Southern Tank & RepairP.O. Drawer 697Grand Bay, AL 36541251-865-6153

STORAGE TANKS– FRP TANKSRed Ewald, Inc.P.O. Box 519Karnes City, TX800-242-3524www.redewald.com

Augusta FiberglassRt. 2 Box 138Highway 3 SouthBlackville, SC 29817803-284-2246

Tankinetics, Inc.P.O. Box 1195Harrison, AR 72601870-741-3626

Viatec Process/StorageSystemsP.O. Box 99Belding, MI 48809800-942-4702

Troy Mfg, Inc.200 Preston RoadHenderson, TX 75653903-657-9404

AC Plastiques1395 Montee ChenierLes Cedres, Quebec JOP 1L0450-455-3311

Diamond FiberglassFabricators, Inc.P.O. Box 106Victoria, TX 77902361-572-4040www.diamondfiberglass.com

Belco ManufacturingP.O. Box 210Belts, TX 76513800-251-8265www.belco-mfg.com

RESIN MANUFACTURERSAND RESIN NAMES

Dow – DerekaneAshland – HetronReichold – Dion

E Q U I P M E N T S U P P L I E R S

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T Y P I C A L P R O D U C T I N F O R M A T I O N

16

The solubility information providedis intended to assist in making deci-sions about the use and storage ofthe specific sulfur chemical. In prac-tice, these solutions become super-saturated as they approach the indi-cated temperature, and the com-pound may stay in solution severaldegrees below the indicated tem-perature. Disturbing a supersaturat-ed solution or adding anything thatwill encourage crystallization is verylikely to cause a significant numberof crystals to form very rapidly.

In addition, information on thewater freezing point for dilute solu-tions of these sulfur chemicals isgiven to help manage storage solu-tions. As indicated, solutions ofsodium bisulfites, sulfites and thio-sulfates can be diluted to lower thefreezing point to minimize coldweather storage problems.

The specific gravity of these reducing agents is not a dependable indication of concentration. Impurities such as sodium sulfate can vary and cause variationsin the specific gravity of solutions. The specific gravity information given here is typical of that expected based on concentration but is provided as a meansof roughly determining the relationship between volume and weight of the solutions. It can also be used to make rough dilutions of concentrated solutions.

18

Sodium bisulfite solutions (SBS) will react with oxygen during storage, resulting in a reductionin the sodium bisulfite assay, an increase in the level of sulfates, and a decrease in pH. The graphbelow shows the change in bisulfite assay (%NaHSO3) as a function of time for a drum of 40%sodium bisulfite solution stored under ambient conditions. The drum was substantially full andvented to the atmosphere. The particular situation described here represents less than idealstorage conditions but does provide some useful information about the decomposition of SBS.

As can be seen, after 138 days storage, the %NaHSO3 decreased from 39.1% to 37.6%. The%Na2SO4 increased from 0.65% to 1.99%, and the pH decreased from 4.6 to 3.3.

Our experiences suggest that SBS in storage containers closed (or significantly closed) to theatmosphere and at recommended storage temperatures can be stored for six (6) months with littleor no decomposition. If not sure of how closed to the atmosphere a particular SBS storagecontainer is, it is recommended that assay, pH, and sulfate levels be checked every 4 to 6 weeksto determine suitability for a particular use. For proper storage conditions, consult the storage andhandling section of this handbook.

S T A B I L I T Y O F S O D I U M B I S U L F I T E S O L U T I O N S

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©2004 SOUTHERN IONICS INCORPORATEDREPRODUCTION, IN WHOLE OR IN PART, PROHIBITED WITHOUT PERMISSION OF COPYRIGHT OWNER. PRINTED IN USA

CORPORATE HEADQUARTERS:

201 Commerce Street

P.O. Drawer 1217

West Point, Mississippi 39773

Telephone: 662/494-3055

Fax: 662/494-2828

E-Mail: [email protected]

Website: www.southernionics.com* ISO 9001:2000 Certified** NSF International Certified

SOUTHERN IONICS IS AN EQUAL OPPORTUNITY EMPLOYER N/F/H/V

Research facilities exploreproducts and applications forSII customers.

SII’s large trucking fleet assureson-time delivery.

Sophisticated technology at SouthernIonics ensures product consistency.

Production capacity is supportedby extensive storage capabilities.


H O W T O O R D E R :To place an order, obtain samples, prices, and/or technical information from any location inthe continental United States, call Customer Service toll free: 800/953-3585 or use CustomerService Fax: 800/953-3588.

OPERATIONS:

Baton Rouge LA * **Port Allen, LA *Calhoun, TN * **Chickasaw (Mobile), AL * **Columbus, MS (Barge Terminal)Westlake, LA * **Midlothian, TX (Transloading)Pasadena, TX * **Terrell, TX **Tuscaloosa, AL *West Point, MS * **

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