Universal method of determining bromides in raw materials and products formed in magnesium production

This article presents a method of determining bromides in substances that also contain significant quantities of chlorine ions. This problem has become particularly important in analyzing magnesium electrolytes (carnallites, bischofite, etc.) in which the quantity of chlorine salts is significantly greater than the content of bromide ions. A method is developed to determine bromine in electrolytes used in magnesium production when the chloride background in the electrolyte is 10 and 100 times greater than the bromine content. An optimum oxidizing mixture has been found, this mixture being unique in that it selectively oxidizes bromides to elemental bromine without affecting the chlorides that are also present. The occurrence of three successive reactions – oxidation of bromides to elemental bromine, replacement of the bromine by an equivalent amount of iodine, and reaction of the iodine with starch – makes it possible to determine bromides within a wide range of concentrations: from 0.001 to 100%. The proposed method is universal – it is not tied to any specific type of analytical specimen.