GB/T 26416.6-2023Chemical analysis methods for rare earth ferroalloy—Part 6: Determination of molybdenum, tungsten and titanium 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 6 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;

--- 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.

Introduction

The rare earth ferroalloy referred to in this document refers to the master alloy composed of iron and one or more rare earth elements, generally adopts the molten salt electrolysis method or It is prepared by fusion method, and is mainly used as an additive in NdFeB permanent magnet materials, magnetostrictive materials, optical and magnetic recording materials and other magnetic materials or as It is used as a deoxidizer, additive, etc. in iron and steel smelting. Chemical composition is an important assessment index of rare earth ferroalloys. GB/T 26416 integration The industry standard XB/T 616-2012 "Chemical Analysis Method of Gadolinium Iron Alloy", XB/T 621-2016 "Chemical Analysis Method of Holmium Iron Alloy",

XB/T 623-2018 "Cerium-Fe Alloy Chemical Analysis Method", XB/T 624-2018 "Yttrium-Fe Alloy Chemical Analysis Method", established for the current All rare earth ferroalloys (including ferro-lanthanum, ferrocerium, ferro-lanthanum, ferro-ndium, ferrodysprosium, ferro-gadolinium, ferro-holmium and ferro-yttrium) that have been produced on a large scale are in production, The standards of chemical analysis methods for the indicators that need to be assessed in the application include the detection of the total amount of rare earths, the content of rare earth impurities, and the content of non-rare earth impurities.

According to the different detection objects and detection methods, as well as the differences in 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 above-mentioned standards have clarified the scope of application, standardized reagents, materials, test equipment and procedures, and have undergone repeated trials by many laboratories.

The precision data given by the test and verification enhances the consistency and comparability of data between different laboratories, and establishes a standard for the quality verification of rare earth ferroalloys. Rigorous and standardized basis for standardization work.

This document specifies the determination of non-rare earth impurities molybdenum, tungsten, and

In the condition test, the amount of nitric acid and hydrofluoric acid used to decompose the sample, the inhibitory effect of the acidity of nitric acid on the signal intensity, and the spectral line The selection, interference of co-existing elements (spectrum interference), iron matrix effect and other influences have been verified and verified. The determined standard method is accurate, simple, and Fast, low-cost features.

The precision data in this document is in 2022. Seven laboratories tested six different levels of molybdenum, tungsten and titanium in six rare earth ferroalloys.

Determined by collaborative tests on flat samples, each laboratory tested each level of molybdenum, tungsten, and titanium content in the six rare earth iron alloys under repeatable conditions.

11 times of independent determination, the test data shall be statistically analyzed according to GB/T 6379.2.

1 Scope

This document describes the rare earth ferroalloys (lanthanum ferroalloy, cerium ferroalloy, lanthanum ferrocerium alloy, neodymium ferroalloy, dysprosium ferroalloy, gadolinium ferroalloy, holmium ferroalloy Determination method of molybdenum, tungsten and titanium content in alloy, yttrium-iron alloy).

This document is applicable to rare earth iron alloys (lanthanum-iron alloy, cerium-iron alloy, lanthanum-cerium-iron alloy, neodymium-iron alloy, dysprosium-iron alloy, gadolinium-iron alloy, holmium-iron alloy Determination of molybdenum, tungsten and titanium content in alloy, yttrium-iron alloy). Determination of elements and range (mass fraction). tungsten is 0.010%~0.20%; molybdenum is 0.0050%~0.10%; titanium is 0.0050%~0.10%.

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 Method Summary

Rare earth ferroalloy samples were dissolved in nitric acid and hydrofluoric acid, fluorinated to separate the rare earth matrix, excited by argon plasma light source, and spectroscopically determined.

5 Reagents or Materials

Unless otherwise specified, in the analysis, only the reagents confirmed as superior grade and above and the secondary water in accordance with the provisions of GB/T 6682 of the laboratory are used.

Distilled water or deionized water or water of equivalent purity, and liquid reagents are stored in plastic bottles. Prefer certified standard solutions.

5.1 Potassium pyrosulfate.

5.2 Sodium hydroxide.

5.3 Nitric acid (rho=1.42g/mL).

5.4 Hydrofluoric acid (rho=1.14g/mL).

5.5 Nitric acid (1 1).

5.6 Ammonia (1 3).