POTASSIUM DICHROMATE (K₂Cr₂O₇)

SYNONYMS
Potassium bichromate.
GENERAL PRECAUTIONS
Use a fume hood.
Avoid skin and eye contact.
Avoid inhalation or ingestion of the powder.
Wash hands thoroughly after handling.
CHARACTERISTICS
Orange red crystals or crystalline powder.
HEALTH HAZARD DATA
This substance is a known carcinogen and must be handled with extreme care. It may cause fire when in contact with combustible material. It is a corrosive and will cause permanent damage to eyes and skin. Frequent exposure of skin to the dust can cause ulceration. Inhalation and ingestion can cause permanent liver and kidney damage especially if contact is prolonged.
TREATMENTS
Skin ­ remove contaminated clothing and immediately wash the affected area with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation or discomfort persist seek immediate medical attention. Wash contaminated clothing before re­use.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If burning 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 or pain persist seek medical attention.
Ingestion ­ wash out the mouth thoroughly with water and give plenty of water to drink. Seek immediate medical attention.
INCOMPATIBILITY
Potassium dichromate is incompatible with anhydrous hydroxylamine, it explodes violently on contact.
STORAGE
Store in a cool, dry atmosphere.
HANDLING
Use a fume hood that will keep the level of exposure below the recommended threshold limit, ie. 0.05 mg/m³. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard. Handle with extreme care.
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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