GB/T 4333.2-2023Ferrosilicon—Determination of phosphorus content—Bismuth phosphomolybdate blue spectrophotometric method (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document is Part 2 of GB/T 4333.GB/T 4333 has released the following 9 parts.

---Determination of ferrosilicon content by perchloric acid dehydration gravimetric method and potassium fluorosilicate volumetric method;

---Determination of silicon, iron and phosphorus content by bismuth phosphorus molybdenum blue spectrophotometry;

---Chemical analysis method of ferrosilicon and determination of manganese content by potassium periodate photometry;

---Determination of ferrosilicon and aluminum content by chromium azure S spectrophotometry, EDTA titration and flame atomic absorption spectrometry;

---Determination of ferrosilicon silicon, manganese, aluminum, calcium, chromium and iron content by wavelength dispersive X-ray fluorescence spectrometry (fused glass plate method);

---Determination of ferrosilicon and chromium content by diphenylcarbazide spectrophotometry;

---Determination of ferrosilicon and sulfur content by infrared absorption method and chromatography barium sulfate gravimetric method;

---Determination of calcium ferrosilicon content by flame atomic absorption spectrometry;

---Determination of silicon, iron and carbon content by infrared absorption method.

This document replaces GB/T 4333.2-1988 "Methods for chemical analysis of ferrosilicon - Determination of phosphorus content by bismuth phosphorus molybdenum blue photometric method". This document is consistent with Compared with GB/T 4333.2-1988, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) The method summary is changed to principles (see Chapter 4, Chapter 2 of the 1988 edition);

b) Added the stepwise dilution method of phosphorus standard solution [see 5.9a)];

c) Added instruments and equipment (see Chapter 6);

d) The name of the chapter "Samples" is changed to "Sample Preparation", and the sampling and preparation according to the provisions of GB/T 4010 is added (see Chapter 7, 1988 version of Chapter 4);

e) The number of measurements has been increased (see 8.1);

f) Changed the process of perchloric acid secondary smoke removal of silicon (see 8.4.1.1, 5.3.1~5.3.3 of the 1988 edition);

g) Added a method for preparing a solution for fuming sulfuric acid to remove silicon (see 8.4.1.2);

h) Changed the expression of calculation results (see 8.5, Chapter 6 of the 1988 edition);

i) Changed the expression of precision, replacing "allowable difference" with statistically obtained repeatability limit (r) and reproducibility limit (R) (see 8.6, 1988 Chapter 7 of the annual edition);

j) Added test report (see Chapter 9);

k) Added appendix A flow chart of sample analysis result acceptance procedure (see appendix A).

Introduction

Since there are many detection elements involved in the ferrosilicon detection process, the applicable scope and applicable methods of the elements are different. To ensure silicon The iron detection standards are convenient and accurate. For the analysis methods of different elements of ferrosilicon, a national standard system has been established to support the detection of ferrosilicon.

GB/T 4333 Ferrosilicon series analysis methods are the basic standards for ferrosilicon testing in my country and consist of 9 parts.

---Determination of ferrosilicon content by perchloric acid dehydration gravimetric method and potassium fluorosilicate volumetric method. The purpose is to measure the silicon content in ferrosilicon For the quantity, the perchloric acid dehydration gravimetric method and the potassium fluorosilicate volumetric method were used.

---Determination of ferrosilicon and phosphorus content by bismuth phosphorus molybdenum blue spectrophotometry. The purpose is to measure the phosphorus content in ferrosilicon, using bismuth phosphorus molybdenum blue Photometry.

---Chemical analysis method of ferrosilicon. Determination of manganese content by potassium periodate photometry. The purpose is to measure the manganese content in ferrosilicon, using periodic acid Potassium photometry.

---Determination of ferrosilicon and aluminum content by chromium azure S spectrophotometry, EDTA titration and flame atomic absorption spectrometry. The purpose is To measure the aluminum content in ferrosilicon, Azure S spectrophotometry, EDTA titration and flame atomic absorption spectrometry were used.

--- Determination of ferrosilicon silicon, manganese, aluminum, calcium, chromium and iron content by wavelength dispersive X-ray fluorescence spectrometry (fused glass plate method). Head The purpose is to measure the content of silicon, manganese, aluminum, calcium, chromium and iron in ferrosilicon, using wavelength dispersive X-ray fluorescence spectrometry (molded glass film method).

---Determination of silicon-iron-chromium content by diphenylcarbazide spectrophotometry. The purpose is to measure the chromium content in ferrosilicon, using two Phenylcarbazide spectrophotometry.

---Determination of ferrosilicon and sulfur content by infrared absorption method and chromatography barium sulfate gravimetric method. The purpose is to measure the sulfur content in ferrosilicon Quantity, using infrared absorption method and chromatography barium sulfate gravimetric method.

---Determination of calcium ferrosilicon content by flame atomic absorption spectrometry. The purpose is to measure the calcium content in ferrosilicon, using flame atoms Absorption spectroscopy.

---Determination of silicon, iron and carbon content by infrared absorption method. The purpose is to measure the carbon content in ferrosilicon, using infrared absorption method.

Determination of ferrosilicon and phosphorus content Bismuth phosphomolybdenum blue spectrophotometry Warning---Personnel using this document should have practical experience in regular laboratory work. This document does not address all possible security issues question. Users are responsible for taking appropriate safety and health measures and ensuring compliance with the conditions stipulated in relevant national regulations.

1 Scope

This document describes a method for the determination of phosphorus content in ferrosilicon using the bismuth phosphomolybdenum blue spectrophotometric method.

This document is applicable to the determination of phosphorus content in ferrosilicon. The measurement range (mass fraction) is. 0.010%~0.060%.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 4010 Collection and preparation of samples for chemical analysis of iron alloys

GB/T 6379.1 Accuracy of measurement methods and results (correctness and precision) Part 1: General principles and definitions

GB/T 6379.2 Accuracy of measurement methods and results (correctness and precision) Part 2: Determination of repeatability of standard measurement methods Basic methods of sex and reproducibility

GB/T 6682 Specifications and test methods for water used in analytical laboratories

GB/T 7729 General rules for chemical analysis of metallurgical products by spectrophotometry

GB/T 8170 Numerical rounding rules and representation and determination of limit values

GB/T 12806 Laboratory glassware single-marked volumetric flasks

GB/T 12807 Graduated pipettes for laboratory glass instruments

GB/T 12808 Single-marked pipette for laboratory glass instruments

3 Terms and definitions

There are no terms or definitions to be defined in this document.

4 Principles

The sample is dissolved with nitric acid or hydrofluoric acid, smoked with perchloric acid or sulfuric acid, reduced with sodium thiosulfate to mask the influence of pentavalent arsenic, phosphorus and bismuth, molybdate Ammonium forms a yellow heteropoly acid complex, which is reduced to bismuth phosphomolybdenum blue with ascorbic acid, and its absorbance is measured at a wavelength of 690 nm with a spectrophotometer.

5 Reagents and materials

Unless otherwise stated, only approved reagents of analytical grade or above and secondary distillation or higher in compliance with GB/T 6682 are used in the analysis. Water or water of comparable purity.

5.1 Nitric acid, density rho is about 1.42g/mL