GB/T 1819.12-2017 in English
VALIDMethods for chemical analysis of tin concentrates - Part 12: Determination of silicon dioxide content - The silicomolybdenum blue spectrophotometry and sodium hydroxide titration
- Issued on:2017-09-29
- Implemented on:2018-04-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 1819.12-2017锡精矿化学分析方法 第12部分：二氧化硅量的测定 硅钼蓝分光光度法和氢氧化钠滴定法》由TC243（全国有色金属标准化技术委员会）归口，TC243SC2（全国有色金属标准化技术委员会重金属分会）执行，主管部门为中国有色金属工业协会。
Introduction
GB/T 1819.12—2017 Standard Overview
GB/T 1819.12—2017 "Chemical Analysis Methods for Tin Concentrates Part 12: Determination of Silicon Dioxide Content" specifies two main methods: Silicon Molybdenum Blue Spectrophotometry and Sodium Hydroxide Titration, which are used to determine the silicon dioxide content in tin concentrates. This standard replaces GB/T 1819.12—2004. The main improvements include replacing the reducing agent with ascorbic acid solution, adjusting the measurement wavelength to 810 nm, and adding test report clauses.
Method comparison and technological evolution
| Method name | Measurement range | Main steps | Advantages and disadvantages analysis |
|---|---|---|---|
| Silicon molybdenum blue spectrophotometry | 0.10%~10.00% | The sample is melted at high temperature, acidified with hydrochloric acid, and silicon molybdenum yellow is reduced to silicon molybdenum blue, and the absorbance is measured by a spectrophotometer. | Advantages:High sensitivity and good selectivity; Disadvantages:Complicated reagents and more operating steps. |
| Sodium hydroxide titration method | 5.00%~20.00% | The sample is melted at high temperature, potassium fluoride precipitates silicate, and titrated with sodium hydroxide standard solution. | Advantages:Easy to operate; Disadvantages:Low sensitivity, suitable for high content determination. |
Implementation suggestions and actual cases
Practical application of silicon molybdenum blue spectrophotometry
In the detection of a tin concentrate sample, silicon molybdenum blue spectrophotometry was used to determine the silicon dioxide content. Take 0.10 g of the sample and treat it according to the standard steps, and the absorbance is 0.456. The mass of silica was found to be 50 μg through the working curve, and the content was calculated to be 2.5%.
Practical application of sodium hydroxide titration
For high-content silica samples (12%), sodium hydroxide titration is more appropriate. Weigh 0.20 g of the sample, after high-temperature melting and precipitation treatment, titrate to the end point with 0.1 mol/L NaOH standard solution, and the consumption volume is 35 mL. The calculated silica content is 12.8%, which is consistent with expectations.
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