GB/T 6150.8-2023Methods for chemical analysis of tungsten concentrates—Part 8: Determination of molybdenum content—Thiocyante spectrophotometry method (English PDF)

Foreword

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

This document is Part 8 of GB/T 6150 "Chemical Analysis Methods for Tungsten Concentrates". GB/T 6150 has released the following parts.

---Part 1: Determination of tungsten trioxide content by ammonium tungstate ignition gravimetric method;

---Part 2: Determination of tin content by potassium iodate titration and inductively coupled plasma atomic emission spectrometry;

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

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

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

---Part 6: Gravimetric method for determination of wet water content;

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

---Part 8: Determination of molybdenum content by thiocyanate spectrophotometry;

---Determination of copper content by flame atomic absorption spectrometry;

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

---Determination of zinc content by flame atomic absorption spectrometry;

---Part 12: Determination of silica content by silicon-molybdenum blue spectrophotometry and gravimetric method;

---Part 13: Determination of arsenic content by atomic fluorescence spectrometry and DDTC-Ag spectrophotometry;

---Determination of manganese content by ferrous ammonium sulfate volumetric method and flame atomic absorption spectrometry;

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

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

---Part 17: Determination of antimony content by atomic fluorescence spectrometry;

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

This document replaces GB/T 6150.8-2009 "Methods for chemical analysis of tungsten concentrates - Determination of molybdenum content by thiocyanate spectrophotometry" and is consistent with Compared with GB/T 6150.8-2009, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) The method measurement range has been changed from "0.005%~1.00%" to "0.0050%~4.50%" (see Chapter 1, 2009 edition of Chapter 1);

b) Added "Terms and Definitions" (see Chapter 3);

c) The sample weighing amount has been changed (see 8.1, 6.1 of the 2009 version);

d) The material of the crucible has been added, changed from "high aluminum crucible" to "high aluminum crucible or iron crucible" (see 8.4.1, 6.4.1 of the 2009 version);

e) The drawing of the working curve has been changed from segmented drawing to whole segment curve drawing (see 8.5, 6.5 of the 2009 version);

f) "Precision" has been changed (see Chapter 10, Chapter 8 of the 2009 edition);

g) Quality Assurance and Control has been deleted (see Chapter 9 of the 2009 edition).

Introduction

Tungsten concentrate is an important strategic resource. Tungsten and tungsten alloys produced from tungsten concentrate as an important industrial raw material have high melting point, high specific Due to its heavy weight and high hardness, it is widely used in mechanical processing, metallurgy, mining, electronic telecommunications, construction industry, weapons industry, aerospace and other fields.

GB/T 6150 aims to establish through experimental research a set of complete, practical and chemical chemistry that is suitable for the production and trade of tungsten concentrate products.

Methodological standards for compositional analysis. Limited by the length of the document, usage requirements, scope of application, and technical independence between each analysis method, etc. Therefore, GB/T 6150 is planned to consist of 20 parts.

---Part 1: Determination of tungsten trioxide content. Ammonium tungstate ignition gravimetric method. The purpose is to establish the determination of tungsten trioxide content method.

---Part 2: Determination of tin content by potassium iodate titration and inductively coupled plasma atomic emission spectrometry. The purpose is to ensure Determination method of tin content.

---Part 3: Determination of phosphorus content by phosphomolybdenum yellow spectrophotometry and inductively coupled plasma atomic emission spectrometry. The purpose is To establish a method for determining phosphorus content.

---Part 4: Determination of sulfur content by high-frequency induction infrared absorption method and combustion-iodometric method. The purpose is to establish the determination of sulfur content method.

---Part 5: Determination of calcium content by EDTA volumetric method and flame atomic absorption spectrometry. The purpose is to establish the measurement of calcium content Determine the method.

---Part 6: Gravimetric method for determination of wet water content. The purpose is to establish a method for determining wet water content.

---Part 7: Determination of tantalum and niobium content by plasma emission spectrometry and spectrophotometry. The purpose is to establish that tantalum and niobium contain Quantity measurement method.

---Part 8: Determination of molybdenum content by thiocyanate spectrophotometry. The purpose is to establish a method for determining molybdenum content.

---Part 9: Determination of copper content by flame atomic absorption spectrometry. The purpose is to establish a method for measuring copper content.

---Part 10: Determination of lead content by hydride generation atomic fluorescence spectrometry and flame atomic absorption spectrometry. The purpose is to ensure Method for determination of vertical lead content.

---Part 11: Determination of zinc content by flame atomic absorption spectrometry. The purpose is to establish a method for determining zinc content.

---Part 12: Determination of silica content by silicon molybdenum blue spectrophotometry and gravimetric method. The purpose is to establish the silica content method of determination.

---Part 13: Determination of arsenic content by atomic fluorescence spectrometry and DDTC-Ag spectrophotometry. The aim was to establish the arsenic content method of determination.

---Part 14: Determination of manganese content by ferrous ammonium sulfate volumetric method and flame atomic absorption spectrometry. The aim is to establish the manganese content method of determination.

---Part 15: Determination of bismuth content by hydride generation atomic fluorescence spectrometry and flame atomic absorption spectrometry. The purpose is to ensure Method for determination of bismuth content.

---Part 16: Determination of iron content by sulfosalicylic acid spectrophotometry. The purpose is to establish a method for determining iron content.

---Part 17: Determination of antimony content by atomic fluorescence spectrometry. The purpose is to establish a method for determining antimony content.

---Part 18: Determination of barium content by inductively coupled plasma atomic emission spectrometry. The purpose is to establish the determination of barium content method.

---Part 19: Determination of fluorine content by ion selective electrode method. The purpose is to establish a method for measuring fluorine content.

---Part 20: Determination of mercury content by spectrophotometry. The purpose is to establish a method for measuring mercury content.

Molybdenum in tungsten concentrate products is a valuable element in transactions, and the data is reported by the supplier, which has extremely high economic value. Tungsten concentrate product standards It was revised in 2015 (YS/T 231-2015), adding high-impurity tungsten concentrate products, and its various technical indicators have undergone new changes.

The medium molybdenum content increased from 1% to 4.5%. In view of this, it is indeed necessary to revise GB/T 6150.8-2009 to ensure that the standard adapts to the industry changes and market demands.

This document expands the measurement scope of the method and increases the use of iron crucibles, which is more in line with the actual needs of the tungsten industry for product testing. This document enters It further improves the applicability of the standard and plays an important role in improving the quality of tungsten concentrate products, promoting its production, trade and expanding application demand. significance.

1 Scope

This document describes a thiocyanate spectrophotometric method for the determination of molybdenum content in tungsten concentrates.

This document is applicable to the determination of molybdenum content in tungsten concentrate. The determination range (mass fraction) is. 0.0050%~4.50%.

2 Normative reference documents

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

GB/T 6682 Specifications and test methods for water used in analytical laboratories

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

GB/T 17433 Basic terminology for chemical analysis of metallurgical products

3 Terms and definitions

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

4 Principles

The sample is melted with sodium peroxide in the crucible and leached with water to separate the molybdenum from most of the iron, manganese, copper, bismuth, calcium, etc. Mask with citric acid Tungsten, using copper salt as a catalyst, in dilute sulfuric acid, uses thiourea to reduce molybdenum to pentavalent, and then forms an orange-red complex with thiocyanate, which is visible in the spectrometer The absorbance is measured with a photometer at a wavelength of 460nm, and the molybdenum content is calculated through the working curve.

5 Reagents or materials

Unless otherwise stated, only reagents confirmed to be of analytical grade are used in the analysis.

5.1 Water, GB/T 6682, Level 2.

5.2 Sodium peroxide.

5.3 Absolute ethanol.

5.4 Sulfuric acid (1 1).

5.5 Sodium hydroxide solution (50g/L).

5.6 Ferric ammonium sulfate solution (30g/L). Add a few drops of sulfuric acid (5.4) when preparing.

5.7 Sulfuric acid-citric acid-copper sulfate solution. Weigh.200g of citric acid, place it in a 1000mL beaker, add 400mL of water, and wait until it is completely dissolved Then, add 330mL sulfuric acid (5.4) and 0.20g copper sulfate, transfer to a 1000mL volumetric flask, dilute to the mark with water, and mix.