GB/T 4698.9-2017Methods for chemical analysis of titanium sponge,titanium and titanium alloys - Part 9: Determination of tin content - Potassium iodate titration and inductively coupled plasma atomic emission spectrometry (English PDF)

2.1 Method summary

The sample was dissolved in sulfuric acid - fluoroboric acid, tin (II) was reduced to tin (II) by iron powder or aluminum foil in hydrochloric acid medium, starch was used as indicator,

Potassium iodate standard titration solution titration until the solution showed a blue end.

Titration solution containing more than 5.0mg of copper, 15.0mg of vanadium interference, other elements do not affect the determination.

2.2 Reagents

Unless otherwise specified, only reagents that are identified as analytically pure and laboratory-grade water are used in the analysis.

2.2.1

Reducing agent Iron powder or aluminum foil (wSn < 0.001%).

2.2.2

Hydrochloric acid (p = 1.19 g/mL).

2.2.3

Hydrogen peroxide (p = 1.10 g/mL).

2.2.4

fluoroboric acid (wHBF4 >= 40%).

2.2.5

sodium bicarbonate saturated solution.

2.2.6

Hydrochloric acid (1 1).

2.2.7

sulfuric acid (1 1).

2.2.8

potassium iodide solution (200g/L).

2.2.9

tin standard storage solution Weigh 1.0000g metal tin (wSn >= 99.95%) placed in 250mL beaker, add 100mL hydrochloric acid (2.2.6), dissolved in low temperature heating, cooling, into 1000mL volumetric flask, diluted with water to the mark, mix well. This solution contains 1mL

1.0 mg tin.

2.2.10

Potassium iodate standard titration solution [c (1/6KIO3) = 0.02mol/L].

2.2.10.1

Preparation Weigh 1g sodium hydroxide, 10g potassium iodide dissolved in.200mL of water, weighed 0.7134g potassium iodate was dissolved in the solution , Into 1000mL volumetric flask, diluted with water to the mark, mix well.

2.2.10.2 Calibration

Pipette 20.00mL tin standard stock solution (2.2.9) 3 were placed in three 500mL Erlenmeyer flask, add

20mL sulfuric acid (2.2.7), 5mL borofluoric acid (2.2.4), the following 2.4.4.2 ~ 2.4.4.4 carried out. Parallel calibration of the potassium iodate consumed standard

Quasi-titration solution (2.2.10) The volume of the difference should not exceed 0.10mL, whichever is the average.

With the calibration to do a blank test.

According to equation (1) Calculate standard titration solution of potassium iodate (2.2.10) titration coefficient of tin.