Galvanized sheets are non-toxic, but the cyanide in the hot-dip galvanizing solution is toxic.
Galvanized steel plate refers to a thick steel plate coated with layers of zinc on the surface. Hot-dip galvanizing is an economical and effective anti-rust treatment method that is often used. About half of the world's zinc production is used in this process.
Hot-dip galvanizing aqueous solutions include cyanide plating solutions and cyanide-free plating solutions. Cyanide plating solutions are divided into micro cyanide, low cyanide, medium cyanide and high cyanide. Cyanide-free plating solutions include alkaline zincate plating solutions, ammonium salt plating solutions, sulfate plating solutions and ammonia-free fluoride plating solutions.
Cyanide hot-dip galvanizing solution has good casting ability and the obtained coating is smooth and fine, so it has been used for a long time in manufacturing. However, because cyanide is toxic and causes serious air pollution, in recent years there has been a tendency to use low-cyanide, micro-cyanide, and cyanide-free hot-dip galvanizing solutions.