GB/T 6150.1-2023Methods for chemical analysis of tungsten concentrates—Part 1: Determination of tungsten trioxide content—Ammonium tungstate igniting gravimetric method (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020 Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents.

This document is part 1 of GB/T 6150 Methods for chemical analysis of tungsten concentrates. GB/T 6150 has published the following parts.

-- Part 1: Determination of tungsten trioxide content - Ammonium tungstate igniting gravimetric method;

-- Part 2: Determination of tin content - Potassium iodate titrimetry and inductively coupled plasma atomic emission spectrometry;

-- Part 3: Determination of phosphorus content - The phosphorus molybdenum yellow spectrophotometry and inductively coupled plasma atomic emission spectrometry;

-- Part 4: Determination of sulfur content - High frequency-infrared absorption method and combustion-iodometric method;

-- Determination of calcium content - EDTA volumetric method and flame atomic absorption spectrometric method;

-- Part 6: Determination of moisture content - Gravimetric method;

-- Determination of tantalum content and niobium content - Inductively coupled plasma emission spectrometry and spectrophotometry;

-- Part 8: Determination of molybdenum content - Thiocyanate spectrophotometry method;

-- Determination of copper content - Flame atomic absorption spectrometry;

-- Part 10: Determination of lead content - Hydride generation atomic fluorescence spectrometry and flame atomic absorption spectrometry;

-- Determination of zinc content - Flame atomic absorption spectrometric method;

-- Part 12: Determination of silicon dioxide content - Silicomolybdenum blue spectrophotometry and gravimetry;

-- Part 13: Determination of arsenic content - Atomic fluorescence spectrometry and the silver diethyldithiocarbamate (DDTC-Ag) spectrophotometry;

-- Determination of manganese content - The ammonium ferrous sulfate volumetric method and flame atomic absorption spectrometric method;

-- Part 15: Determination of bismuth content - Hydride generation atomic fluorescence spectrometry and flame atomic absorption spectrometry;

-- Determination of iron content - The sulfosalicylic acid spectrophotometry;

-- Part 17: Determination of antimony content - Atomic fluorescence spectrometry;

-- Part 18: Determination of barium content - Inductively coupled plasma atomic emission spectrometry.

This document replaces GB/T 6150.1-2008 Methods for chemical analysis of tungsten concentrates - Determination of tungsten trioxide content - The ammonium tungstate igniting gravimetric method. Compared with GB/T 6150.1-2008, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) The scope of application and measurement range of the method have been changed (see Chapter 1; see Chapter 1 of the 2008 edition);

b) The chapter "Terms and definitions" has been added (see Chapter 3);

c) The chapter "Instruments and equipment" has been added (see Chapter 6);

d) The amount of hydrochloric acid used for sample decomposition and the types of samples that require EDTA addition in the method have been changed (see 8.3.1; see 5.3.1 of the 2008 edition);

e) The metered volume for residue colorimetry in the method has been changed [see 8.3.6a); see 5.3.6.1 of the 2008 edition];

f) The chapter "Precision" has been changed (see Chapter 10; see Chapter 7 of the 2008 edition);

g) The chapter "Quality assurance and control" has been deleted (see Chapter 8 of the 2008 edition);

h) The chapter "Test report" has been added (see Chapter 11).

1 Scope

This document describes the method for the determination of tungsten trioxide content in tungsten concentrates.

This document is applicable to the determination of tungsten trioxide content in tungsten concentrate with a molybdenum content of less than 0.3% and a phosphorus content of less than 0.3%. The determination range of tungsten trioxide (mass fraction). not less than 20%.

2 Normative references

The provisions of the following documents constitute the essential clauses of this document through normative references in this text. Among them, for referenced documents with dates, only the versions corresponding to the dates are applicable to this document; for referenced documents without dates, the latest versions (including all amendments) are applicable to this document.

GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values

GB/T 17433 Foundation terms for chemical analysis of metallurgical products

3 Terms and definitions

The terms and definitions defined in GB/T 17433 apply to this document.

4 Principle

The sample is dissolved in hydrochloric acid, nitric acid, and perchloric acid in the presence of a small amount of ammonium fluoride, and concentrated until white smoke is emitted to drive off fluoride ions and nitrate ions. Tungsten is precipitated as tungstic acid, filtered to separate it from most of the coexisting elements, and then tungstic acid is dissolved in ammonia water. The filtrate is evaporated and burned, and then desiliconized with hydrofluoric acid and burned again, and the mass of tungsten trioxide is weighed. The mass of tungsten trioxide in the residue is determined by spectrophotometry, and the result is corrected.

5 Reagents or materials

Unless otherwise stated, only confirmed analytical reagents and distilled water are used in the analyses.

5.1 Ammonium fluoride.

5.2 Sodium peroxide.

5.3 Disodium ethylenediaminetetraacetate (Disodium EDTA).

5.4 Hydrochloric acid (rho=1.19 g/mL).

5.5 Perchloric acid (rho=1.67 g/mL).

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

5.7 Anhydrous ethanol.

5.8 Hydrofluoric acid (rho=1.15 g/mL).

5.9 Perchloric acid cleaning solution (1+199).

5.10 Ammonia water (1+4).

5.11 Sodium hydroxide solution (48 g/L).

5.12 Potassium thiocyanate solution (350 g/L).

5.13 Titanium trichloride-hydrochloric acid mixed solution. Pipette 0.5 mL titanium trichloride solution (150 g/L), dilute to 100 mL with hydrochloric acid (2+3), and mix well.

6 Instruments and equipment

6.1 Spectrophotometer.

6.2 High temperature furnace.

7 Samples

7.1 The sample particle size shall not be greater than 0.074 mm.

8 Test steps

9 Experimental data processing

The tungsten trioxide content is expressed as the mass fraction w of tungsten trioxide and is calculated according to formula (1).

10 Precision

11 Test report

The test report shall at least include the following contents. […]

Appendix A (Informative)

Raw data of the precision test The precision data in this appendix were determined by 12 laboratories conducting joint tests on 8 samples with different levels of tungsten trioxide content in 2022.Each laboratory independently measured the tungsten trioxide content at each level 11 times under repeatability conditions. The statistical results are shown in Table A.1. […]