GB/T 4333.6-2019Ferrosilicon - Determination of chromium content - Diphenylcarbazide spectrophotometric method (English PDF)

1 Scope

This part of GB/T 4333 specifies the determination of chromium in ferrosilicon by diphenylcarbazide spectrophotometry.

This section applies to the determination of chromium content in ferrosilicon. Measuring range (mass fraction). 0.010%~0.600%.

2 Normative references

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

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

Preparation and preparation of GB/T 4010 ferroalloy chemical analysis sample

GB/T 6379.1 Accuracy of measurement methods and results (accuracy and precision) Part 1. General and definition

GB/T 6379.2 Accuracy of measurement methods and results (accuracy and precision) Part 2. Determination of standard method of measurement

Basic method of sex and reproducibility

GB/T 6682 Analytical laboratory water specifications and test methods

GB/T 7729 Metallurgical products - Chemical analysis - General rules for spectrophotometry

GB/T 8170 Numerical Rounding Rules and Representation and Determination of Limit Values

GB/T 12806 laboratory glass instrument single standard line volumetric flask

GB/T 12807 laboratory glass instrument indexing pipette

GB/T 12808 laboratory glass instrument single standard line pipette

3 Principle

The sample is dissolved with nitric acid and hydrofluoric acid, and the perchloric acid is smoked to remove silicon. In the silver nitrate solution, ammonium persulfate is used to oxidize chromium to a positive hexavalent amount.

The amount of sodium carbonate solution is such that iron, manganese and other elements are precipitated and separated from chromium. Divide part of the filtrate to make hexavalent chromium and diphenylcarbonyl in sulfuric acid medium

The diterpene reaction produces a purplish red compound, and its absorbance is measured at a wavelength of 550 nm of the spectrophotometer to calculate the mass fraction of chromium.

4 reagents

In the analysis, unless otherwise stated, only the reagents confirmed as analytically pure are used, and the test water is the third and third grades specified in GB/T 6682.

Distilled water or water of comparable purity.