SODIUM DICHROMATE (Na₂Cr₂O₇)

SYNONYMS
Sodium bichromate.
GENERAL PRECAUTIONS
Use a fume hood.
Avoid skin and eye contact.
Avoid inhalation or ingestion of the powder.
Keep away from oxidising materials.
Keep away from moisture.
Keep away from combustible substances.
Keep away from reducing agents.
Keep the container tightly sealed.
Wash hands thoroughly after handling.
CHARACTERISTICS
Orange red hygroscopic crystals which, when dissolved in water, attack many materials especially in the presence of acids. Strong oxidant ­ reacts violently with combustible and reducing materials causing fire and explosion hazard.
HEALTH HAZARD DATA
May be absorbed by ingestion or inhalation, corrosive to skin, eyes and respiratory tract. May cause lung oedema; serious cases may be fatal. Inhalation may cause sore throat, coughing, shortness of breath, laboured breathing. Skin contact causes redness, pain, skin burns and may cause dermatitis. Eye contact causes redness, pain and blurred vision. Ingestion causes sore throat, abdominal pain and vomiting. Potential carcinogen.
TREATMENTS
Skin ­ immediately wash the affected area with soap or mild detergent and large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If hypersensitivity develops seek medical attention.
Eyes ­ wash the affected eye with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation or pain persist seek immediate medical attention.
Inhalation ­ remove from the area of exposure to fresh air. Keep warm and allow to rest. If irritation persists or signs of toxicity develop seek medical attention.
Ingestion ­ wash out the mouth thoroughly with water and give water to drink. Do not induce vomiting. Never give anything by mouth to an unconscious person. Seek immediate medical advice.
INCOMPATIBILITY
Keep separate from combustible substances and reducing agents. Keep dry.
STORAGE
Store in a cool, dry atmosphere away from heat or ignition sources.
HANDLING
Use a fume hood to minimise exposure to this substance. Wear protective clothing to avoid skin or eye contact, inhalation or ingestion. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard.
DISPOSAL
WEAR:
Rubber gloves, face shield and laboratory coat. A body shield should be available for the more active agents. Replace the face shield with self contained breathing apparatus for such agents as chlorine and bromine.
SPILLS:
Gas leak: if the valve is leaking because it cannot be closed, the gas can be bubbled through a reducer (sodium sulphite) and excess sodium bicarbonate solution. Be sure to include a trap in the line to prevent the solution being sucked back into the cylinder. If this cannot be done the cylinder should be placed in or adjacent to a fume hood and left to bleed off. If the leak is in the valve assembly, a plastic bag can be fastened over the head of the cylinder which can then be taken outside or to a fume hood.
Liquid or solid: cover with a reducer (sodium thiosulphate, a bisulphite or a ferrous salt not carbon, sulphur or strong reducing agent). Mix well and spray with water. A sulphite or a ferrous salt will require addition of 3mol/l sulphuric acid to promote a rapid reduction. Scoop the slurry into a container of water and neutralise with soda ash. Discharge to sewer with a large excess of water. Wash the site thoroughly with a soap solution containing some reducer.
PACKAGE LOTS:
Add to a large volume of concentrated solution of reducer (sodium thiosulphate, a bisulphite or a ferrous salt and acidify with 3mol/l sulphuric acid). When the reduction is completed add soda ash or dilute hydrochloric acid to neutralise the solution. Discharge to sewer with a large excess of water.
ENVIRONMENT:

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