Patent ID: 7601198

Claim:
A method for producing ammonium hexachlororuthenate, (NH 4 ) 3 RuCl 6 , comprising the steps of: adding ammonium chloride to a hydrochloric acid solution containing ruthenium to thereby precipitate ammonium hexachlororuthenate crystals, wherein the hydrochloric acid solution containing ruthenium is held at a temperature of 80 to 95° C. for three hours or longer prior to adding the ammonium chloride, the ammonium chloride is then added to the hydrochloric acid solution containing ruthenium which is stirred by a stirring mill at the rotation of 200 revolutions per minute or more, the hydrochloric acid solution is held at a temperature of from 85 to 95° C. for 1 hour while being stirred at 200 rpm (revolution per minute) or more after adding the ammonium chloride, and filtering precipitated ammonium hexachlororuthenate crystals, thereby obtaining crystals of precipitated ammonium hexachlororuthenate having 10 mass % or less of moisture content.