GB/T 38389-2019Methods for chemical analysis of indium-tin oxide target (English PDF)

2.1 Method summary

The sample was decomposed by hydrochloric acid, the pH of the solution was controlled to be 3.0 ~ 4.0, the tin was masked with sodium fluoride, xylenol orange was used as an indicator, and ethylenediamine was used.

The titration solution of disodium tetraacetate standard titration until the solution changes from red to bright yellow is the end point, according to the standard of disodium ethylenediamine tetraacetate consumed

Calculate the indium content of the solution volume.

2.2 Reagents

Unless otherwise stated, only reagents and distilled or deionized or fairly pure water identified as analytically pure were used in the analysis.

2.2.1

Sodium fluoride.

2.2.2

Hydrochloric acid (rho = 1.19g/mL).

2.2.3

Hydrochloric acid (1 1).

2.2.4

Sodium hydroxide solution (200g/L).

2.2.5

Ammonia solution (1 1).

2.2.6

Hexamethyltetramine buffer solution (pH~5.5). Weigh.200g of hexamethylenetetramine into a 1000mL beaker and add 600mL

Water, add 25mL hydrochloric acid (2.2.2), transfer to a 1000mL volumetric flask, dilute with water to the mark, and mix.

2.2.7 Indium standard solution

Weigh 1.1g (accurate to 0.0001g) metal indium (wIn>=99.99%) in a 250mL triangle beaker, slowly

Add 30mL hydrochloric acid (2.2.2), heat and dissolve at low temperature, transfer to a.200mL volumetric flask, cool, dilute with water to the mark, and mix.

2.2.8

Disodium ethylenediamine tetraacetate (Na2EDTA) standard titration solution [c (EDTA) ~0.02mol/L]. among them.

a) Preparation. Weigh 7.5g disodium ethylenediaminetetraacetate, dissolve slightly with water, cool to room temperature, transfer to a 1000mL volumetric flask, and use water

Dilute to the mark and mix. After 3 days of calibration.

b) Calibration. Transfer 10.00mL indium standard solution (2.2.7) into a 250mL triangle beaker and adjust with sodium hydroxide solution (2.2.4)

When precipitation occurs, add hydrochloric acid (2.2.3) dropwise until the precipitation disappears, add 20 mL of hexamethylenetetramine buffer solution (2.2.6),

A white precipitate is generated, and then adjust the hydrochloric acid (2.2.3) until the precipitate just disappears, continue to add 0.5mL hydrochloric acid (2.2.3) to control the pH […]