GB/T 6730.37-2017Iron ores—Determination of cobalt content—4-[(5-chloro-2-pyridyl)azo]-1,3-diamino-benzene spectrophotometric method (English PDF)

1 Scope

GB/T 6730 provisions of this section 4 - [(5-chloro-2-pyridyl) azo] -1,3-diaminobenzene spectrophotometric determination of cobalt content.

This section applies to the determination of cobalt content in iron ore, iron ore concentrate, sinter and pellet. Measurement range (mass fraction).

0.0050% ~ 0.10%.

2 Normative references

The following documents for the application of this document is essential. For dated references, only the dated version applies to this article

Pieces. For undated references, the latest edition (including all amendments) applies to this document.

GB/T 6682 analytical laboratory water specifications and test methods

Preparation of pre-dried samples for analysis of iron ores GB/T 6730.1

GB/T 8170 rounded repair rules and limit values of the representation and judgment

GB/T 10322.1 Iron ore sampling and sample preparation methods

GB/T 12806 laboratory glassware single standard line capacity bottle

GB/T 12807 Laboratory glassware graduated pipette

GB/T 12808 laboratory glassware single standard pipette

3 principle

In pH 5 acetate media, cobalt and 5-Cl-PADAB form a red complex with a composition of 1. 2, which is converted to

Stable wine red complex. The absorbance is measured at a wavelength of 570 nm, whereby cobalt is measured.

Copper, nickel and iron also form colored complexes with 5-Cl-PADAB, the colored complex of copper and nickel is destroyed when heated in a boiling water bath,

The cobalt complex is not destroyed. A large number of iron interference, plus the solution before the developer, adding phosphoric acid and heated in a boiling water bath,

Can eliminate its influence.

4 Reagents and materials

Unless otherwise indicated in the analysis, the use of only approved analytical reagent and in line with GB/T 6682 more than two distilled water or purity

Quite water.