Potassium Dichromate

Potassium Dichromate is an inorganic chemical reagent with a chemical formula of K2Cr2O7. It is also commonly referred to as Di-potassium Salt, Chromic Acid, Di-potassium Dichromate, Bichromate of Potash and Potassium Bichromate. Potassium Dichromate appears as bright reddish-orange crystals. Potassium Dichromate appears naturally as a rare mineral known as Lopezite which is found in parts of Chile and South Africa.

There are a number of uses of Potassium Dichromate. The building industry uses Potassium Dichromate as an ingredient in cement to improve its density and texture. However, Potassium Dichromate should always be handled with care as contact with skin can result in severe dermatitis, known as Chromium Dermatitis. Gloves should always be worn when handling Potassium Dichromate.

Potassium Dichromate is used to prepare Chromic Acid to clean and etch glassware. It can also be used to tan leather to be used in the manufacture of footwear. Potassium Dichromate is important in the photographic industry and, together with a strong mineral acid it is used in screen printing as an oxidizing agent.

Potassium Dichromate is used to finish certain types of wood as it brings out the colour and grain, giving a deep, rich appearance. It is particularly effective when used on mahogany and has been used in this way in the manufacture of mahogany furniture for many years.

When Potassium Dichromate is dissolved in a solution of 35% Nitric Acid, it is used to test for the presence of metals, particularly to determine the purity of Silver. Pure Silver will turn the solution bright red, whilst Sterling Silver will turn the solution dark red. Lower grade Coin Silver will turn the solution brown. This is because of the presence of Copper in Coin Silver.

In addition to its Corrosive nature, Potassium Dichromate is a carcinogen which means that exposure can lead to cancer. Appropriate Personal Protective Equipment should always be worn when working with or handling Potassium Dichromate. This should include protective clothing, approved eye protection, safety footwear and compatible safety gloves. Use in a well-ventilated area of wear suitable respiratory equipment.

Potassium Dichromate is very hazardous in case of contact with the skin, of eye contact and ingestion. Skin contact causes desensitisation and prolonged exposure may result in skin burns and ulcerations. Over-exposure by inhalation may cause respiratory irritation and severe over-exposure can result in death. Inflammation of the eyes is characterised by watering, itching and redness whilst inflammation of the skin is characterised by scaling, redness, itching and blistering.

Containers of Potassium Dichromate should be kept tightly sealed and away from heat and sources of ignition. Keep Potassium Dichromate away from incompatible and organic materials.