YS/T 252.4-2007 English PDF (YST252.4-2007)

This standard specifies the method for determination of copper content in high nickel matte. This standard is applicable to the determination of copper content in high nickel matte. Measuring range: 6% ~ 55%. 2 Method summary The sample is decomposed with hydrochloric acid and nitric acid-potassium chlorate saturated solution. The ammonium bifluoride is used to mask the iron and the solution is controlled at pH3.5 ~ pH4. Potassium iodide is added, to cause the copper to precipitate copper iodide and precipitate an equal amount of iodine. Use the starch solution as an indicator; use sodium thiosulfate standard titration solution to indirectly determine the amount of copper. 3 Reagents 3.1 Ammonium bifluoride. 3.2 Potassium iodide. 3.3 Ammonia water (¦Ñ0.90 g/mL). 3.4 Hydrochloric acid (¦Ñ1.19 g/mL). 3.5 Nitric acid (¦Ñ1.42 g/mL). 3.6 Nitric acid (1 + 1). 3.7 Sulfuric acid (1 + 1). 3.8 Urea saturated solution. 3.9 Potassium sulfate solution (100 g/L). YS/T 252.4-2007 www.ChineseStandard.net ? Buy True-PDF ? Auto-delivery. Page 6 of 9 3.10 Nitric acid-potassium chlorate saturated solution: Dissolve potassium chlorate in nitric acid (3.5) until saturated. 3.11 Starch solution (5 g/L). 3.12 Copper standard solution: Accurately weigh 1.0000 g of metallic copper (mass fraction of copper ¡Ý 99.95%). Place it in a 400 mL beaker. Add 20 mL of nitric acid (3.6). Dissolve at low temperature and evaporate to a viscous state. Cool it. Add 5 mL of sulfuric acid (3.7). Heat until a lot of white smoke comes out. Cool it slightly. Add water to boil to dissolve the salts. Cool to room temperature. Pipette it into a 1000 mL volumetric flask. Use water to make the volume reach to the mark. 1 mL of this solution contains 1.0 mg of co