Description: Potassium dichromate is a bright orange crystalline subststance that is used to treat magnesium powder. The treatment makes magnesium more resistant to spontaneous reactions that could result in lower reliability of the mixture or spontaneous ignition.
Hazards: Potassium dichromate is toxic, corrosive and a carcinogen. It should be handled with extreme care and proper protective clothing.
Sources: Potassium dichromate is available from chemical suppliers and dedicated pyro suppliers. Although, it can be sythesized by melting together various chemicals. More details on this in the source below. A heat source able to melt most of the ingrediants, a clay crucible and safety gear is required. Not to be attempted by the inexperienced. Hazard Symbols: T+, N, O, Carc.
Safe working procedure:
In fact there is no totally safe working procedure.
It can not be stressed too strongly, that this substance is very toxic, especially when inhaled. It's LC50 value in air for rat (minimum concentration, where half of test subjects have died) is 94mg/m3/4h. As a comparison, respective value for potassium cyanide is 160mg/m3/1h.
It is not advisable to mill this chemical alone, but together with the oxidizer. This will lead "in situ" to a smaller dichromate concentration. Use a milling jar dedicated to dichromate operations only. A respirator and a protective apron must be used at all times, when handling the ready composition, priming stars, or loading primed stars into shell cases.
What goes up, must come down. The dust will stay airborne for a quite long time, and will eventually land on the surfaces - avoid it getting airborne. Work in an area where you can thoroughly clean the working table and floor afterwards with a wet cloth few days afterwards. Never vacuum clean your working area! It is probably good idea to use a glove-box, like that is used for sandblowing.
Symptoms of poisoning include a sore throat, coughing, burning sensation on the upper respiratory tracts, shortness of breath and laboured breathing. If you develop any of these symtoms, you should seek medical advice. You might have received a lethal dose.