GB/T 5687.4-2016Nitrogen-bearing ferrochromium and nitride ferrochrome with high nitrogen content - Determination of nitrogen content - The distillation-neutralization titration method (English PDF)

1 Scope

This part of GB/T 5687 specifies the nitrogen content of ferricyanide and high nitrogen ferrochrome by distillation-neutralization titration.

This part is applicable to the determination of nitrogen content in ferric chloride and high nitrogen ferrochrome. Chromium ferric nitride measurement range (mass fraction). 2.00% ~

7.00%; high nitrogen ferrochrome determination range (mass fraction). > 7.00% ~ 12.00%.

2 normative reference documents

The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this article

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

GB/T 4010 Ferroalloy chemical analysis of the sample to take and preparation

GB/T 6682 Analytical laboratory water specifications and test methods

3 principle

The soluble sample is decomposed with hydrochloric acid, and the insoluble sample is decomposed with hydrochloric acid, sulfuric acid and phosphoric acid, wherein the nitrogen is converted into an ammonia salt, and under the action of an excess of alkali,

Steam distillation separation of ammonia, boric acid solution to absorb distillate, methyl red - methyl methyl blue as an indicator, with sodium sulfamate standard titration solution

Titration.

4 reagent

In the analysis, unless otherwise stated, only the confirmed analytical reagent and three or more distilled water in accordance with GB/T 6682 specifications

Purity of pure water.