GB/T 6730.25-2021Iron ores—Determination of total rare earth contents—Oxalate gravimetric method (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 of Standardization Documents" drafted.

This document is Part 25 of GB/T 6730. See Appendix A for the published part of GB/T 6730.

This document replaces GB/T 6730.25-2006 "Oxalate Gravimetric Method for Determination of Total Rare Earths in Iron Ore", and Compared with GB/T 6730.25-2006, in addition to structural adjustment and editorial changes, the main technical changes are as follows:

a) Change the measurement range to "1.00%~20.00%" (see Chapter 1, Chapter 1 of the 2006 edition);

b) the chapter "Apparatus and Equipment" was added (see Chapter 6);

c) Changed the amount of sodium hydroxide used when the sample is decomposed (see 8.4.1, 7.4.1 of the 2006 edition);

d) Add 0.5mL of hydrogen peroxide to dissolve salts by heating (see 8.4.2);

e) Changed the amount of hot oxalic acid solution added during oxalic acid precipitation and the precipitation aging time (see 8.4.3, 2006 edition of 7.4.3);

f) Added "General Handling of Analysis Results" (see 9.2).

Introduction

Iron ore is the main raw material for the steel industry. In the iron and steel industry standard system, the standard system for the determination of chemical composition of iron ore is A very important part of them plays an important role in ensuring the quality of iron ore products. This series of method standards serves the production of iron ore. production, trade and application, and provide technical support for the high-quality development of my country's iron and steel industry.

GB/T 6730 includes a series of standards for the determination of chemical composition of iron ore, which respectively stipulates moisture, total iron and metal in iron ore products.

Iron, ferrous, silicon, aluminum, calcium, magnesium, sulfur, phosphorus, manganese, titanium, total rare earth, barium, chromium, vanadium, tin, copper, cobalt, nickel, zinc, niobium, bismuth, potassium, sodium, carbon, lead, arsenic, Methods for the determination of chemical components such as cadmium, mercury, fluorine, chlorine, loss on ignition, and combined water.

In 1986, GB/T 6730 issued 51 national standards for the determination of chemical composition of iron ore for the first time.

According to the development of technology and the actual needs of production, after years of continuous formulation and revision work, a relatively complete standard system has been formed at present. The GB/T 6730 constituent documents are detailed in Appendix A.

GB/T 6730.25 provides a method for the determination of the total amount of rare earth in iron ore by oxalate gravimetric method. After this revision, it is in line with international standards. be consistent.

Caution - Persons using this document should have practical experience in formal laboratory work. This document does not address all possible security issues question. It is the user's responsibility to take appropriate safety and health measures and to ensure compliance with the conditions stipulated by relevant national regulations.

1 Scope

This document specifies the oxalate gravimetric method for the determination of the total amount of rare earths.

This document applies to the determination of the total amount of rare earths in natural iron ores, iron concentrates and lumps, including sintered products. Measurement range (mass points number). 1.00%~20.00%.

2 Normative references

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

GB/T 6379.1 Accuracy (correctness and precision) of measurement methods and results - Part 1. General provisions and definitions

GB/T 6379.2 Accuracy (correctness and precision) of measurement methods and results - Part 2. Determining repetition of standard measurement methods Basic Methods of Reproducibility and Reproducibility

GB/T 6682 Analysis Laboratory Water Specifications and Test Methods

GB/T 6730.1 Preparation of pre-dried samples for iron ore analysis

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

GB/T 10322.1 Iron ore sampling and sample preparation method

GB/T 12690.12 Method for Chemical Analysis of Non-Rare Earth Impurities in Rare Earth Metals and Their Oxides - Determination of Thorium Content by Arsazo III Spectroscopy Photometry and Inductively Coupled Plasma Mass Spectrometry

GB/T 12806 Laboratory glass instrument single-line volumetric flask

GB/T 12807 Laboratory glass instrument indexing pipette

GB/T 12808 Laboratory glass instrument single reticle pipette

3 Terms and Definitions

There are no terms and definitions that need to be defined in this document.

4 Principles

The sample was melted by sodium hydroxide and sodium peroxide, leached with dilute triethanolamine, and in the presence of hydroxylamine hydrochloride and ascorbic acid, the EDTA complexation separates interfering elements such as iron, manganese, aluminum, and calcium.

The oxalic acid precipitate was calcined at 900°C into oxides and weighed. The mass of the obtained oxide minus the amount of thorium dioxide is the amount of rare earth oxide.

5 Reagents

Unless otherwise specified, only use approved analytical reagents and secondary water in accordance with GB/T 6682 or its purity […]