GB/T 26416.1-2022Chemical analysis methods for rare earth ferroalloy—Part 1: Determination of total rare earth content (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 1 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 26416.1-2010 "Methods for Chemical Analysis of Dysprosium-Fe Alloys Part 1: Determination of Total Rare Earth Weight" Compared with GB/T 26416.1-2010, except for structural adjustment and editorial changes, the main technical changes are as follows.

a) The scope of application has been changed from "dysprosium-iron alloy" to "rare-earth iron alloy", the measurement range of method 1 oxalate gravimetric method (mass Score) changed from "70.00%~90.00%" to "10.00%~90.00%" (see Chapter 1, Chapter 1 of the 2010 edition);

b) The material of the crucible in method 1 has been changed (see 4.3.3, 4.3 of the 2010 edition);

c) Changed the sample weight of method 1 (see 4.5.1, 6.1 of the 2010 edition);

d) The amount of hydrogen peroxide and oxalic acid solution in method 1 has been changed (see 4.5.4.2, 6.4.2 of the 2010 edition);

e) Changed the oxalic acid precipitation and washing times of the beaker in method 1 (see 4.5.4.3, 6.4.3 of the 2010 edition);

f) Added method 1 for the determination of rare earth content in grass sediment filtrate (see 4.5.5);

g) The calculation formula of method 1 has been changed (see 4.6.1, Chapter 7 of the 2010 edition), and the determination results of holmium-iron alloy and yttrium-iron alloy have been added. Compensation calculation of results (see 4.6.2);

h) Added method 2 (disodium ethylenediaminetetraacetic acid) EDTA titration method (see Chapter 5);

i) Added method 3 inductively coupled plasma emission spectrometry (see Chapter 6);

j) Changed the "precision", and changed the "permissible difference" to "reproducibility" (see 4.7, 5.7, 6.8, 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. are used in iron and steel smelting. Chemical composition is an important assessment index of rare earth ferroalloys. GB/T 26416 integrates industry standards

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 The production and application of rare earth ferroalloys (including ferro-lanthanum, ferrocerium, ferro-lanthanum, ferro-ndium, ferro-dysprosium, ferro-gadolinium, ferro-holmium and ferro-yttrium, etc.) need to be considered in the production and application.

Standards for chemical analysis methods of nuclear indicators, including the detection of total rare earth content, rare earth impurity content, and non-rare earth impurity content. According to detection Due to differences in imaging and detection methods and substrates, 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 above-mentioned standards 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 26416.1 adds the EDTA titration method for the determination of the total amount of rare earths (method 2) and the inductively coupled plasma emission method.

Spectroscopic method (method 3) is used to determine the content of main rare earth elements, which not only provides users with more choices of testing methods, but also provides the total rare earth elements.

The selection of test objects with different amounts and amounts of each main rare earth element. The precision data of the 3 methods were compared by 6 laboratories in 2020 6 levels of samples with different contents were determined through joint experiments, and each laboratory independently determined the total amount of rare earths at each level under repeatable conditions.

Measured 11 times at once, the joint test data shall be statistically analyzed according to GB/T 6379.2.

1 Scope

This document specifies the methods for the determination of the total amount of rare earths in rare earth ferroalloys, including three methods. oxalate gravimetric method (method 1), EDTA Titration (method 2), inductively coupled plasma emission spectrometry (method 3).

This document is applicable to the determination of the total amount of rare earths in rare earth ferroalloys. Method 1 and method 2 are applicable to the determination of the total amount of rare earths in rare earth ferroalloys.

Determined, measuring range (mass fraction). 10.00%~90.00%; method 3 is applicable to main rare earth elements in lanthanum-iron alloys, cerium-iron alloys, and lanthanum-cerium-iron alloys Determination of element amount, determination range (mass fraction). 1.00%~20.00%. Method 1 is used as the referee method for the overlapping part of the determination range.

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

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

3 Terms and Definitions

This document does not have terms and definitions that need to be defined.

4 Oxalate gravimetric method (method 1)