GB/T 26416.2-2022Chemical analysis method for rare earth ferroalloy—Part 2: Determination of rare earth impurity contents—Inductively coupled plasma emission spectrometry (English PDF)

Foreword

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

This document is part 2 of GB/T 26416 "Methods for Chemical Analysis of Rare Earth Ferroalloys". GB/T 26416 has issued the following part.

--- Part 1: Determination of the total amount of rare earth;

--- Part 2: Determination of rare earth impurity content Inductively coupled plasma emission spectrometry;

--- Part 3: Determination of calcium, magnesium, aluminum, nickel, manganese content Inductively coupled plasma emission spectrometry;

--- Part 4: Determination of iron content Potassium dichromate titration method;

--- Part 5: Determination of oxygen content pulse - infrared absorption method.

This document replaces GB/T 26416.2-2010 "Methods for Chemical Analysis of Dysprosium-Fe Alloys Part 2: Determination of Rare Earth Impurity Content Inductively coupled plasma emission spectrometry", compared with GB/T 26416.2-2010, except for structural adjustment and editorial changes, the main technical changes as follows.

a) Change the measurement range of each rare earth impurity (see Chapter 1, Chapter 1 of the 2010 edition);

b) Changed the preparation of dysprosium matrix solution (see 5.24, 3.18 of the 2010 edition);

c) Changed the equipment (see Chapter 6, Chapter 4 of the 2010 edition);

d) Changed the weighing amount of the sample, from 2.7g to 2.5g (see 8.1, 6.1 of the 2010 edition);

e) Added a blank test (see 8.3);

f) Changed the preparation of a series of standard solutions (see 8.5, 6.4 of the 2010 edition);

g) Changed the wavelengths of some analytical spectral lines, and increased the analytical spectral line wavelengths of iron-lanthanum, ferrocerium, iron-gadolinium, iron-holmium, and iron-yttrium alloys (see 8.6.1, 6.5.1 of the 2010 edition);

h) The calculation formula of the analysis results has been changed (see Chapter 9, Chapter 7 of the 2010 edition);

i) Changed "precision" and changed "allowable difference" to "reproducibility" (see Chapter 10, Chapter 8 of the 2010 edition).

Introduction

The rare earth iron alloy referred to in this document refers to the master alloy composed of iron and one or more rare earth elements, which is generally adopted by molten salt electrolysis or fusion It is mainly used as an additive for magnetic materials such as NdFeB permanent magnet materials, magnetostrictive materials, optical and magnetic recording materials, or as a deoxidizer, Additives, etc.

XB/T 616-2012 "Chemical Analysis Methods of Gadolinium-Fe Alloys", XB/T 621-2016 "Chemical Analysis Methods of Holmium-Fe Alloys", XB/T 623-2018 "Cerium-Fe Alloy Chemical Analysis Method", XB/T 624-2018 "Yttrium-Fe Alloy Chemical Analysis Method", established for all current implementation standards Rare earth ferroalloys (including ferro-lanthanum, ferrocerium, ferro-lanthanum, ferro-dysprosium, ferro-dysprosium, ferro-gadolinium, ferro-holmium and ferro-yttrium, etc.) produced by modeling require The standard of chemical analysis method for the assessment indicators, including the detection of the total amount of rare earth, the content of rare earth impurities, and the content of non-rare earth impurities. According to detection Due to differences in objects and detection methods and substrates, etc., GB/T 26416 is proposed to be composed of 9 parts.

--- Part 1: Determination of the total amount of rare earth;

--- Part 2: Determination of rare earth impurity content Inductively coupled plasma emission spectrometry;

--- Part 3: Determination of calcium, magnesium, aluminum, nickel, manganese content Inductively coupled plasma emission spectrometry;

--- Part 4: Determination of iron content Potassium dichromate titration method;

--- Part 5: Determination of oxygen content - pulse-infrared absorption method;

--- Part 6: Determination of molybdenum, tungsten and titanium content Inductively coupled plasma emission spectrometry;

--- Part 7: Determination of carbon and sulfur content High-frequency-infrared absorption method;

--- Part 8: Photometric method for the determination of the amount of silicon;

--- Part 9: Determination of phosphorus content Bismuth phosphomolybdenum blue spectrophotometry.

The standards for each part of the above have clarified the scope of application, standardized reagents, materials, test equipment and procedures, and have been repeatedly tested by many laboratories.

The test and verification give precision data, which enhances the consistency and comparability of data between different laboratories, and provides a basis for the quality verification of rare earth ferroalloys. Establish a rigorous and standardized standardization work foundation.

This revision to GB/T 26416.2 mainly adopts inductively coupled plasma optical emission spectrometry (ICP-OES), by approximating the matrix The matching method is used to realize the determination of the rare earth impurity content in the rare earth iron alloy. The approximate matrix matching method can effectively solve physical property interference, eliminate It has the characteristics of desalting effect, expanding the lower limit of determination, simple and fast operation, etc. This revision has fully considered the amount of sample weighing, the use of hydrochloric acid and nitric acid for sample decomposition In order to determine the influence of quantity, spectral line selection, coexisting ion interference, matrix concentration and matrix change on the determination, a comparative experiment was carried out, taking into account various energy It has the characteristics of accuracy, simplicity, speed and low cost.

The changes in the various rare earth ferroalloy substrates considered in this document are as follows.

The lanthanum content range (mass fraction) in lanthanum-iron alloy is 9%~21%, the cerium content range (mass fraction) in cerium-iron alloy is 9%~21%, The gadolinium content range (mass fraction) in the gadolinium-iron alloy is 68%~76%, the dysprosium content range (mass fraction) in the dysprosium-iron alloy is 74%~86%, and the holmium-iron alloy is The holmium content range (mass fraction) in gold is 79%~84%, the yttrium content range (mass fraction) in yttrium-iron alloy is 59%~66%, and the content range (mass fraction) in various ferroalloys The iron content is the balance of the total amount of elements, the main rare earth content and the content of each impurity.

The precision data in this document is in 2020, by 6 laboratories for 5 different rare earth impurity contents in 6 rare earth ferroalloys.

The levels of samples are determined by a common test, and each laboratory is responsible for the repeatability of each level of each rare earth impurity content in the 6 rare earth ferroalloys.

11 independent measurements under the same conditions, and the joint test data were statistically analyzed according to GB/T 6379.2.

1 Scope

This document specifies the rare earth elements in rare earth ferroalloys (lanthanum ferroalloy, cerium ferroalloy, gadolinium ferroalloy, dysprosium ferroalloy, holmium ferroalloy, yttrium ferroalloy) Determination method of impurity content.

This document is applicable to rare earth in rare earth ferroalloys (lanthanum ferroalloy, cerium ferroalloy, gadolinium ferroalloy, dysprosium ferroalloy, holmium ferroalloy, yttrium ferroalloy)

Determination of impurity content. Determination of elements and range (mass fraction) are shown in Table 1.

2 Normative references

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

GB/T 6682 Analytical laboratory water specifications and test methods