GB/T 12690.7-2021 in English

VALID

Chemical analysis methods for non-rare earth impurities of rare earth metals and their oxides—Part 7: Determination of silicon content

Issued on:2021-10-11
Implemented on:2022-05-01
File Format:PDF
Delivery:Via email within 1~3 business days

Price(USD)： $240.00
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Standard No:	GB/T 12690.7-2021
Document status:	VALID
Title in English:	Chemical analysis methods for non-rare earth impurities of rare earth metals and their oxides—Part 7: Determination of silicon content
Title in Chinese:	稀土金属及其氧化物中非稀土杂质化学分析方法第7部分：硅量的测定
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 1~3 business days
Issued on:	2021-10-11
Implemented on:	2022-05-01
Superseding:	GB/T 12690.7-2003 Neodymium and neodymium oxide-Determination of lanthanum oxide, cerium oxide, praseodymium oxide, s
ICS Classification:	77.120.99-Other non-ferrous metals and their alloys
Chinese Classification:	H14-Rare metals and their alloys analysis method
Professional Classification:	GB-National Standard
Related Keywords:	rare earth metals icp-oes method rare earth matrix rare earth detection technology rare earth enterprise rare earth elements
Related Topics:	rare earth rare earth metal oxides Rare Earth Standard Rare Earth Standard Gold Chemicals rare earth cluster rare earth oxide Soil Chemical Analysis Impurity standardization method Chemical analysis method for non-rare earth impurities in rare earth metals and their oxides rare earth capacity method Impurity standardization method Metal Oxidation Analysis Chemical analysis methods of rare earth metals and their oxides for non-rare earth impurities Rare earth+ rare earth iron oxide Rare earth impurities Hybrid silicon Hybrid silicon non-metal oxide Rare Earth Analyzer full oxide Rare Earth Capital central africa Rare earth inspection Rare earth colored quality analysis of its Rare earth impurities Metal Impurity Analysis Rare earth inspection soil metal oxides soil metal oxides soil metal oxides Foreign rare earth analysis methods rare earth oxide Rare earth mining rare earth quality Substance Metal Analysis Mass Spectrometry Rare Earth Analysis of plutonium and its impurities GBT12690.7 GB/T 12690.7-1990 GB/T 12690.7-2003 GB/T 12690.7-2021 Rare earth metals and their oxides About rare earth Primary Trace Rare Earth Analysis ICPoes detects impurities in gold Metal silicon industry quality Detection of bulk metal impurities in silicon wafers Rare earth titration analysis method Determination of Rare Earth International Determination method of total rare earth content in tea Rare earth extraction rate analysis method Trace Rare Earth Analysis Chemical testing of metallic silicon Silica quality Seawater Trace Rare Earth Testing Silica Quality

《GB/T 12690.7-2021稀土金属及其氧化物中非稀土杂质化学分析方法第7部分：硅量的测定》由TC229（全国稀土标准化技术委员会）归口，主管部门为国家标准化管理委员会。

Introduction

Core changes in the standard revision

Technical parameters	2003 edition	2021 edition
Method system	Molybdenum blue spectrophotometry only	New ICP-OES method
Detection range	0.0010%-0.20%	Molybdenum blue method0.0010%-0.20% ICP method0.010%-0.20%
Wavelength selection	Unspecified	830nm (Molybdenum Blue Method) 251.611nm, etc. (ICP Method)

Technical Details of the Method

1. Key Improvements of Molybdenum Blue Spectrophotometry

Acidity Control: Clearly require 0.12-0.25mol/L acidic medium
Color Developing System: Ascorbic acid solution concentration adjusted to 50g/L
Wavelength Optimization: Changed from visible light region to near infrared region (830nm)

Actual Application Case

When a rare earth enterprise detected the silicon content in yttrium oxide, it used visible light spectrophotometer at 830 nm, and the interference of rare earth elements was eliminated by matrix matching, with RSD < 1.5%.

2. New points of ICP-OES method

Rare earth matrix	Recommended analysis line (nm)	Dissolution method
Cerium oxide	251.611	Nitric acid + hydrogen peroxide
Terbium oxide	288.158	Nitric acid + hydrogen peroxide

Implementation suggestions

Method selection: Molybdenum blue method is preferred for arbitration analysis
Sample processing: Rare earth metals need to remove the surface oxide layer
Quality control: Each batch comes with matrix blanks and standard substances

Technology evolution analysis

The standard has been revised three times in 1988, 2003 and 2021, and the detection limit has been increased from 0.01% to 0.001%, reflecting the leap of my country's rare earth detection technology from traditional chemical analysis to instrumental analysis.

More samples: DL/T 5154-2012 QC/T 942-2021 JGJ 94-2008

Sample only — not a preview of GB/T 12690.7-2021

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