YS/T 273.8-2020 English PDF (YST273.8-2020)

This Part specifies the method for determination of sulfate content in cryolite. This Part applies to the determination of sulfate content in cryolite. Determination range: 0.10%~1.50%. 2 Method Summary The test material is melted by a mixed flux of sodium carbonate and boric acid; and the melt is dissolved by perchloric acid. In the acidic medium, barium chloride is used to precipitate sulfate ions. The precipitated barium sulfate is burned at 850¡ãC and weighed. Calculate sulfate content. 3 Reagent Unless otherwise stated, only reagents and deionized water determined to be of analytically pure were used in the analysis. 3.1 Anhydrous sodium carbonate. 3.2 Boric acid. 3.3 Perchloric acid (¦Ñ¡Ö1.67 g/mL). 3.4 Sulfuric acid (¦Ñ=1.84 g/mL). 3.5 Hydrochloric acid (1+1). 3.6 Barium chloride solution: Weigh 61g of barium chloride dihydrate, dissolve it in water and dilute it to 1L. 3.7 Silver nitrate-nitric acid solution: Weigh 0.5 g of silver nitrate and dissolve it in a small amount of water; add 10 mL of nitric acid (¦Ñ = 1. 40 g/mL), dilute with water to 100 mL, and mix well. YS/T 273.8-2020 www.ChineseStandard.net ? Buy True-PDF ? Auto-delivery. Page 6 of 9 4 Apparatus 4.1 Platinum dish: flat bottom, diameter 75 mm, height 30 mm, with platinum cover. 4.2 Platinum crucible: diameter 30 mm, height 30 mm. 4.3 Oven: The temperature can be controlled at 110¡ãC¡À5¡ãC. 4.4 High temperature furnace: The temperature can be c