«Foreword This handbook outlines recommended methods for handling, storing, preparing and using caustic soda. It also includes information on the ...»
C AUSTIC S ODA
Occidental Chemical Corporation (OxyChem) is a leading North American
manufacturer of polyvinyl chloride (PVC) resins, chlorine and caustic soda,
key building blocks for a variety of indispensable products such as plastics,
pharmaceuticals and water treatment chemicals. Other OxyChem products
include caustic potash, chlorinated organics, sodium silicates, chlorinated isocyanurates and calcium chloride. For every product it makes, OxyChem’s market position is No. 1 or No. 2 in the U.S. Based in Dallas, Texas, the company has manufacturing facilities in the United States, Canada and Chile.
OxyChem has been an active participant in the American Chemistry Council's Responsible Care® initiative since its inception in 1988.
Demonstrating their commitment to attaining the highest levels of safety and environmental achievement, Responsible Care companies implement world-class management systems, measure performance based on industry wide metrics, and are subject to review by independent auditors.
Foreword This handbook outlines recommended methods for handling, storing, preparing and using caustic soda.
It also includes information on the manufacture, physical properties, safety considerations and analyti- cal methods for testing caustic soda. Additional information and contacts can be found on the internet at www.oxychem.com
"IMPORTANT: THE INFORMATION PRESENTED HEREIN, WHILE NOT GUARANTEED, WAS PRE-
PARED BY TECHNICAL PERSONNEL AND IS TRUE AND ACCURATE TO THE BEST OF OUR
KNOWLEDGE AS OF APRIL 2013. NO WARRANTY OF MERCHANTABILITY OR OF FITNESS
FOR A PARTICULAR PURPOSE, OR WARRANTY OR GUARANTY OF ANY OTHER KIND, EX-
PRESS OR IMPLIED, IS MADE REGARDING PURITY, PERFORMANCE, SAFETY, SUITABILITY,
STABILITY OR OTHERWISE. THIS INFORMATION IS NOT INTENDED TO BE ALL-INCLUSIVE AS
TO THE MANNER AND CONDITIONS OF CAUSTIC SODA USE, HANDLING, STORAGE, DIS-
POSAL AND OTHER FACTORS THAT MAY INVOLVE OTHER OR ADDITIONAL LEGAL, ENVIRON-
MENTAL, SAFETY OR PERFORMANCE CONSIDERATIONS, AND OXYCHEM ASSUMES NO LI-
ABILITY WHATSOEVER FOR THE USE OF OR RELIANCE UPON THIS INFORMATION. OXY-
CHEM DISCLAIMS ANY OBLIGATION TO UPDATE OR CORRECT THE INFORMATION SET
FORTH HEREIN. WHILE OUR TECHNICAL PERSONNEL WILL BE HAPPY TO RESPOND TO
QUESTIONS, SAFE HANDLING AND USE OF THE PRODUCT REMAINS THE RESPONSIBILITY
OF THE CAUSTIC SODA USER. NO SUGGESTIONS FOR USE ARE INTENDED AS, AND NOTH-
ING HEREIN SHALL BE CONSTRUED AS, A RECOMMENDATION TO INFRINGE ANY EXISTING
PATENTS OR TO VIOLATE ANY FEDERAL, STATE, LOCAL OR FOREIGN LAWS."Page 2 of 64
INTRODUCTIONCaustic soda (sodium hydroxide or NaOH) is most commonly manufactured by the electrolysis of a sodium chloride (NaCl) solution. OxyChem manufactures caustic soda using either membrane or diaphragm electrolytic cells. OxyChem does not use mercury based electrolytic cells to produce caustic soda. The coproducts formed from the electrolytic production of caustic soda are chlorine and hydrogen.
The largest users of caustic soda are the pulp and paper, detergent and chemical industries. Caustic soda is also used in the alumina, oil and gas and textile industries, mostly for its alkalinity value.
OxyChem has played a leading role in providing caustic soda to meet the increasing demands of industry.
OxyChem plants are strategically located to conveniently and economically serve industry.
Terminals are used to maintain stocks of our caustic soda in many principal cities. Distributor stocks are also available in these and many other cities and form a network of supply for the end user‟s convenience.
Liquid caustic soda is available as a 50% solution in two main grades. The names of these grades correspond to the electrolytic cells used to produce the caustic soda; membrane grade and diaphragm grade. Specification sheets for each grade can be found on our website at www.oxychem.com To be technically correct, only molten caustic soda should be called liquid, but since the term liquid caustic soda has historically been used to describe solutions of caustic soda, it is used in this document interchangeably with the term solution.
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PRINCIPAL USES AND CONSUMPTION OF CAUSTIC SODA
Caustic soda is one of the very few chemicals utilized in a very broad range of applications. Some principal products or processes in which caustic soda is used are:
Caustic soda is produced by OxyChem by an electrolytic process as shown in the following diagrams. Brine, prepared from sodium chloride (NaCl), is electrolyzed in either a membrane cell or a diaphragm cell. The production of caustic soda (NaOH) also results in the coproducts of chlorine and hydrogen.
In the membrane process, a solution of approximately 32% in strength is formed. The solution is then sent to evaporators, which concentrate it to a strength of 50% by removing the appropriate amount of water.
The diaphragm process is similar to the membrane process except that a solution of only 10- 12% is formed in the cell. Again, additional evaporation is required to reach the saleable concentration of 50%.
The caustic soda solution is inventoried in storage tanks prior to shipment. The product is shipped via pipelines, tank trucks, railcars, barges and ships.
The major difference in the two grades is the amount of starting material (sodium chloride) remaining in the final product. Membrane grade caustic soda will have less than 100 ppm of the sodium chloride remaining in the product. Diaphragm grade material will have less than 1.2% sodium chloride. Several other differences can be seen in the products when the specification sheets are compared.
OxyChem‟s caustic soda (sodium hydroxide) meets the test requirements specified in the Food Chemicals Codex (FCC), Eighth Edition, 2012. However, the caustic soda is not produced under all cGMP (current Good Manufacturing Practices) requirements as defined by the FDA (Food & Drug Administration).
OxyChem does not represent or warrant general compliance of this product for food use.
Each prospective use of a product in a food or food related application must be carefully assessed against appropriate regulations by the user and it cannot be assumed that products meeting FCC test requirements are satisfactory for all uses without such assessment.
Liquid caustic soda is available from OxyChem‟s many plants and terminals in tank truck, rail tank car, barge and ship quantities. Each form of transportation has its own advantages. The type of service selected will depend upon such factors as size and location of storage, rate of consumption, plant location, freight rates, etc.
Caustic soda, liquid, is regulated by the U.S. Department of Transportation (DOT) and is classified as a corrosive material. The DOT identification number is UN I824 for liquid caustic soda.
Caustic soda in any concentration must be respected by everyone who handles and uses it. Before starting to work with it, the user should be aware of its properties, know what safety precautions to follow, and know how to react in case of contact. Accidental exposure to caustic soda may occur under several conditions. Potentially hazardous situations include handling and packaging operations, equipment cleaning and repair, decontamination following spills and equipment failures. Employees who may be subject to such exposure must be provided with proper personal protective equipment and trained in its use. Some general guidelines follow.
Read and understand the latest Safety Data Sheet.
Provide eyewash fountains and safety showers in all areas where caustic soda is used or handled. Any caustic soda burn may be serious. DO NOT use any kind of neutralizing solution, particularly in the eyes, without direction by a physician.
Move the patient to a hospital emergency room immediately after first aid measures are applied.
FIRST AID MEASURESFor Eyes: Immediately flush eyes with a directed stream of water for at least 15 minutes, forcibly holding eyelids apart to ensure complete irrigation of all eye and lid tissues. Washing eyes within several seconds is essential to achieve maximum effectiveness. GET MEDICAL ATTENTION IMMEDIATELY.
For skin: If caustic soda comes in contact with skin or clothing, immediately flush with plenty of clean water for at least 15 minutes. Remove contaminated clothing and footwear. Thoroughly wash affected clothing and rubber/vinyl footwear. Discard contaminated leather footwear. GET
MEDICAL ATTENTION IMMEDIATELY.
For inhalation: If a worker is overcome due to the inhalation of caustic soda dust, mist or spray, remove them from the contaminated area to fresh air. If breathing is difficult, have a trained person administer oxygen. If breathing has stopped, have a trained person administer artificial respiration. GET MEDICAL ATTENTION IMMEDIATELY.
For ingestion: NEVER give anything by mouth to an unconscious or convulsive person. If swallowed DO NOT induce vomiting. Give large quantities of water. If vomiting occurs spontaneously, keep airway clear. Give more water when vomiting stops. GET MEDICAL ATTENTION IMMEDIATELY.
PROTECTIVE EQUIPMENTOSHA requires employers to supply suitable protective equipment for employees. When
handling caustic soda, the following protective equipment is recommended:
Wear suitable chemical splash goggles for eye protection during the handling of caustic soda in any concentration. The goggles should be close fitting and provide adequate ventilation to prevent fogging, without allowing entry of liquids. The use of a face shield may be appropriate when splashing can occur, including loading and unloading operations.
Wear rubber gloves or gloves coated with rubber, synthetic elastomers, PVC, or other plastics to protect the hands while handling caustic soda. Gloves should be long enough to come well above the wrist. Sleeves should be positioned over the glove.
Caustic soda causes leather to disintegrate quite rapidly. For this reason, wear rubber boots.
Wear the bottoms of trouser legs outside the boots. DO NOT tuck trouser legs into boots.
Wear chemical resistant clothing for protection of the body. Impregnated vinyl or rubber suits are recommended.
Wear hard hats for some protection of the head, face and neck.
If exposures are expected to exceed accepted regulatory limits or if respiratory discomfort is experienced use a NIOSH approved air purifying respirator with high efficiency dust and mist filters.
PROTECTIVE PRACTICESKeep equipment clean by immediately washing off any spill or accumulation of caustic soda.
Weld pipelines where practical. Use flanged joints with gaskets made of caustic soda resistant material such as rubber, PTFE, or EPDM rubber. If a screwed fitting is used, apply Teflon® tape to the threads.
When disconnecting equipment for repairs, first verify that there is no internal pressure on the equipment and that the equipment has been drained and washed.
Provide storage tanks with suitable overflow pipes. Overflow pipes should be directed to a protected overflow area away from operations Shield the seal area of pumps to prevent spraying of caustic solutions in the event of a leak.
When releasing air pressure from a pressurized system, take every precaution to avoid spurts or sprays of caustic solution.
In case of a spill or leak, stop the leak as soon as possible. After containment, collect the spilled material and transfer to a chemical waste area. Remove large liquid spills by vacuum truck. Neutralize residue with dilute acid. Flush spill area with water and follow with a liberal covering of sodium bicarbonate or other acceptable drying agent.
HANDLING LIQUID CAUSTIC SODA
In handling caustic soda solutions, care must be taken to avoid solidification which will plug pipelines and equipment. Graph 1 shows the freezing points for solutions of caustic soda at various concentrations.
Should a caustic soda solution become frozen in process equipment or piping, care must be taken when thawing the material. The use of atmospheric pressure steam is suggested. Accelerated corrosion can occur in areas where equipment is subjected to extremely high temperatures.
GENERAL INFORMATIONLiquid Caustic soda has a markedly corrosive action on all body tissue. Even dilute solutions may have a destructive effect on tissue after prolonged contact. Inhalation of mists can cause damage to the upper respiratory tract, while ingestion of liquid caustic soda can cause severe damage to the mucous membranes or other tissues where contact is made.
It is important that those who handle caustic soda are aware of its corrosive properties and know what precautions to take. In case of accidental exposure, immediately flush the exposed area with large amounts of water and seek medical attention. For more specific information refer to the Safety in Handling Caustic Soda section of this handbook and in the OxyChem SDS for Caustic Soda liquid.
PLACEMENT OF THE RAILCAR FOR UNLOADING
1. After the car is at the loading spot, DOT regulations require that the hand brake be set and the wheels blocked (chocks).