GB/T 5121.29-2015Methods for chemical analysis of copper and copper alloys - Part 29: Determination of aluminium oxide content (English PDF)

2.1 Method Summary

The base copper and other metals in the sample were selectively dissolved in a water bath of less than 25 ° C with dilute nitric acid and filtered. Quantitative separation of trioxidation

Aluminum is melted and leached with potassium pyrosulfate. Determination of aluminum oxide content by disodium EDTA - zinc acetate titration with ethylenediamine tetraacetic acid.

2.2 Reagents and Materials

Unless otherwise stated, only the reagents identified as analytical reagents and distilled or deionized water or comparable purity were used in the analysis.

2.2.1

potassium pyrophosphate.

2.2.2

glacial acetic acid (rho1.05g/mL).

2.2.3

ammonia (rho0.90g/mL).

2.2.4

hydrochloric acid (1 1).

2.2.5

nitric acid (1 1).

2.2.6

nitric acid (1 10).

2.2.7

nitric acid (1 49).

2.2.8

Sodium hydroxide solution (300 g/L).

2.2.9

Potassium fluoride solution (150 g/L).

2.2.10

copper solution (1.0g/L). Weigh 0.100g pure copper (aluminum mass fraction < 0.0005%), add 5mL nitric acid (2.2.5) heating

Dissolve it, boil to remove nitrogen oxides, and cool it. Into the 100mL volumetric flask, diluted with water to the mark, mix.

2.2.11

ethylenediamine tetraacetic acid disodium (C10H14N2O8Na2 · 2H2O) solution (0.1mol/L). Weigh 37.2g disodium ethylenediaminetetraacetate (C10H14N2O8Na2.2H2O) was dissolved in about 400 mL of hot water, cooled, transferred into a 1000 mL volumetric flask, diluted to a scale with water,

Mix well.

2.2.12

hexamethylenetetramine solution (300 g/L).

2.2.14 aluminum standard solution

Weigh 1.0000g pure aluminum (aluminum mass fraction >= 99.95%) placed in 150mL polytetrafluoroethylene beaker, add

Into 20mL sodium hydroxide solution (2.2.8), slow heating dissolved completely, cooling. With hydrochloric acid (2.2.4) transferred to the precipitation disappeared, the solution clear, this

When the solution is acidic, cooling, into the 1000mL volumetric flask, diluted with water to the mark, mix. 1 mL of this solution contains 1 mg of aluminum.

2.2.15

zinc acetate standard titration solution c [Zn (CH3COO) 2 · 2H2O] ~ 0.0093mol/L.

2.2.15.1 Preparation

Weigh 2.050 g of zinc acetate [Zn (CH3COO) 2 · 2H2O] in a 250 mL beaker, add 1.0 mL of ice

Acid (2.2.2), 100 mL of water, and stirred to dissolve it. Into the 1000mL volumetric flask, diluted with water to the mark, mix.