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Determination of yellow iron oxide

2013-09-13 by seoer8

Method: Determination of iron oxide yellow iron oxide --- --- redox titration
Application: This method uses titration of iron oxide yellow iron oxide content .
This method is suitable for yellow iron oxide.
Principle of the method : the test sample and acid 2.5mL, water bath heated to dissolve, add hydrogen peroxide solution 1mL, heated to boiling a few minutes , add water, 25mL let cool, add 1.5g of potassium iodide and hydrochloric acid 2.5mL, Mesa, shake even in the dark for 15 minutes, with sodium thiosulfate solution (0.1 mol / L) titration , near the end, add the starch indicator solution 2.5mL, continue titration until the disappearance of the blue , yellow iron oxide content calculated .
Reagents : 1. Hydrochloric acid
(2) Hydrogen peroxide solution
3 KI
4 sodium thiosulfate solution (0.1 mol / L)
5 Starch indicator solution
Equipment:
Sample Preparation: 1 . Sodium thiosulfate solution (0.1 mol / L)
Preparation: 26g anhydrous sodium thiosulfate 0.20g, add boiling over cold water to dissolve into 1000mL, shake, place one month after filtration .
Calibration: 120 ℃ drying to constant weight at baseline potassium dichromate about 0.15g, accurately weighed, set the iodine flask, add water to dissolve 50mL , add potassium iodide 2.0g, gently shake to dissolve , add dilute sulfuric acid 40mL, shake, Mesa ; placed in the dark for 10 minutes, diluted with 250mL of water , using the droplet to near the end , add the starch indicator solution 3mL, continue titration until the blue disappears and visible light green , and the titration of the blank test correction. Each 1mL sodium thiosulfate (0.1mol / L) is equivalent to 4.903g of potassium dichromate . According to the liquid consumption and take the amount of potassium dichromate , calculate the concentration of the solution , that is, too .
Temperature above 25 ℃ , the reaction solution should be diluted with water cooling to about 20 ℃.
(2) Starch indicator solution
Take soluble starch 0.5g, add water, 5mL, stir , slowly poured into 100mL boiling water , with the added with stirring and continue to boil for 2 minutes , let cool, pour out the supernatant , ie. The liquid should be Pro with the new .
Procedure : To about 0.15g, accurately weighed, set stoppered Erlenmeyer flask, add hydrochloric acid 2.5mL, water bath heated to dissolve, add hydrogen peroxide solution 1mL, heated to boiling a few minutes , add water, 25mL let cool, add 1.5g of potassium iodide and hydrochloric acid 2.5mL, Mesa, shake , placed in the dark for 15 minutes, with sodium thiosulfate solution (0.1 mol / L) titration , near the end, add the starch indicator solution 2.5mL and continue titration until the blue disappears , and the titration of the blank test correction .


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