The substance named potassium ferrous chloride does not exist. There is an inorganic compound potassium ferricyanide, also known as potassium hexacyanoferrate, which appears as a yellow crystalline powder: 1. Industrial field. It is mainly used as carburizing agent in iron and steel industry to improve the surface hardness of iron and steel parts. It is used as oxidizing agent in printing and dyeing industry to maintain the quality of cotton dyeing. It is used as coagulant in pharmaceutical industry to remove impurities and improve the quality of medicines. Used as iron remover in chemical industry. 2. Clarifying agent. Used in conjunction with zinc acetate for the extraction and clarification of dairy products, soy products and soluble sugar. 3. Salt anti-caking agent. Added to table salt, it can prevent table salt from clumping due to high moisture content and keep table salt loose.