GB/T 14635-2020 PDF English
GB/T 14635: Historical versions
| Standard ID | USD | BUY PDF | Delivery | Standard Title (Description) | Status |
| GB/T 14635-2020 | 205 | Add to Cart | Auto, 9 seconds. | Rare Earth Metals and Their Compounds - Determination of Total Rare Earth Content | Valid |
| GB/T 14635-2008 | 160 | Add to Cart | Auto, 9 seconds. | Rare earth metals and their compounds -- Determination of total rare earth contents | Obsolete |
| GB/T 14635.1-1993 | 199 | Add to Cart | 2 days | Rare earth metals and their compounds. Determination of total rare earth contents. Rare earth oxalate gravimetric method | Obsolete |
Similar standards
GB/T 14635-2020: Rare Earth Metals and Their Compounds - Determination of Total Rare Earth Content
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT14635-2020
GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 77.120.99 H 14 GB 14635-2020 Replacing GB/T 14635-2008 Rare Earth Metals and Their Compounds - Determination of Total Rare Earth Content Issued on. NOVEMBER 19, 2020 Implemented on. OCTOBER 01, 2021 Issued by. State Administration for Market Regulation; Standardization Administration of PRC.
Table of Contents
Foreword... 3 1 Scope... 6 2 Method-1.Oxalate Gravimetric Method... 7 3 Method-2.EDTA Titration Method... 14 4 Quality Assurance and Control... 211 Scope
This Standard specifies the determination method of total rare earth content in the rare earth metals and their compounds. This Standard is applicable to the determination of the total rare earth content in rare earth metals and their compounds. This Standard contains two methods. Method-1 is oxalate gravimetric method, and Method-2 is EDTA titration method. Method-1 is applicable to the determination of the total rare earth content in single and mixed rare earth metals and their compounds; the determination range is shown in Table 1; it is not applicable to the determination of the total rare earth content in single and mixed rare earth metals and their compounds mainly based on erbium, thulium, ytterbium, and lutetium or the individual content of thorium and lead is greater than 0.1%. Method- 2 is applicable to the determination of the total rare earth content in the single rare earth metals and mixed rare earth metals and their compounds mainly based on heavy rare earth holmium, erbium, thulium, ytterbium, and lutetium; the determination range is shown in Table 2; it is not applicable to the determination of the total rare earth content in the single rare earth with relative purity less than 99.5%, as well as in a single rare earth metal and its compounds with other impurity elements greater than 0.5%; it is also not applicable to the determination of the total rare earth content in materials with individual content of thorium, scandium, and zinc greater than 0.1%. 2 Method-1.Oxalate Gravimetric Method 2.1 Principle of method After the specimen is decomposed by acid, the rare earth is precipitated in ammonia water to separate calcium and magnesium. 2.2 Reagents and materials 2.2.1 Perchloric acid (ρ=1.67g/mL). 2.2.2 Hydrogen peroxide (30%). 2.2.3 Hydrochloric acid (1+1). 2.2.4 Nitric acid (1+1). 2.2.5 Ammonia water (1+1). 2.2.6 Oxalic acid solution (50g/L). 2.2.8 Oxalic acid lotion (2g/L). 2.3 Apparatus 2.4 Specimen 2.4.1 The oxide layer on the surface shall be removed from the metal specimen and weigh immediately after sampling. 2.5 Analytical procedures 2.5.1 Testing materials Weigh the specimen (2.4) according to Table 4, accurate to 0.0001g. 2.5.2 The number of determinations Weigh two portions of testing materials for parallel determination, and take the average value. 2.5.3 Determination 3 Method-2.EDTA Titration Method 3.1 Principle of the method The testing materials are dissolved in acid; and sulfosalicylic acid is used to mask the ions e.g., ferric ion, etc. Under the condition of pH 5.5, xylenol orange is used as an indicator; and use the EDTA standard solution to titrate the rare earth. 3.2 Reagents 3.3 Specimen 3.3.1 The surface oxide layer shall be removed from the metal specimen; and weigh immediately after sampling. 3.3.2 There are many types of rare earth compounds and their chemical properties are different. The basic state of the different compound specimen to determine the total rare earth content is difference. The basic state of measurement for each different compound is shown in Table 8.There are usually 3 ways. 3.4 Analysis procedures 3.4.1 Testing materials Take the specimen (3.3) according to Table 9, accurate to 0.0001g. 3.4.2 The number of determinations Weigh two specimens for parallel determination, and take the average value. 3.4.3 Determination 3.4.3.1 Dissolution of the testing materials 3.4.3.1.5 Dissolution of rare earth chloride. place the testing materials (3.4.1) in a 200mL beaker; add 20mL of water, 10mL of hydrochloric acid (3.2.5); cover with a watch glass; and take it off and cool to the room temperature after heating at low temperature to dissolve completely. Transfer the solution into a 200 mL volumetric flask; dilute to the mark with water, and mix well. 3.5 Calculation and expression of analysis results 3.5.1 Calculation and expression of the total rare earth content in rare earth metal testing materials 3.5.2 Calculation and expression of the total rare earth content in the rare earth compound testing materials The determination results of the total rare earth content in each rare earth compound are all the total rare earth content in the specimens with corresponding measurement basic state. The total rare earth content is calculated by the mass fraction w (REO) of rare earth oxide (REO), which is calculated as per Formula (5). 3.5.3 The calculation and expression of the total rare earth content in the mixed rare earth metal testing materials with heavy rare earth holmium, erbium, thulium, ytterbium and lutetium as the main body 3.5.4 The calculation and expression of the total rare earth content in the mixed rare earth compound testing materials with heavy rare earth holmium, erbium, thulium, ytterbium, and lutetium as the main body 3.6 Precision 3.6.1 Repeatability For the measured values of two independent test results obtained under repeatability conditions, within the average range given below, the absolute difference between the two test results does not exceed the repeatability limit (r); 3.6.2 Tolerance The difference between the analysis results among laboratories shall be no greater than the tolerance listed in Table 11.4 Quality Assurance and Control
Regularly use self-made control standard sample (if there is a national or industry-level standard sample, it should be used first) to check the effectiveness of this standard analysis method once. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
