Overview
ISO 2828:1973 specifies a spectrophotometric method for the determination of fluorine content in aluminium oxide primarily used for aluminium production. This standard is essential for quality control in the aluminium manufacturing industry, ensuring that fluorine levels are accurately measured when they exceed 0.003% (m/m). The method involves dissolving a sample with sulfuric acid under pressure, followed by distillation and complexation of fluorine for spectrophotometric analysis using alizarin complexone and lanthanum chloride reagents.
This internationally recognized test method, approved by ISO and the IUPAC, provides reliable, sensitive, and precise measurement of fluorine, critical for maintaining product purity and process control.
Key Topics
- Sample Preparation: Dissolution of aluminium oxide samples in sulfuric acid under controlled pressure conditions.
- Fluorine Separation: Distillation of fluorine from the solution at 150 ±1 °C using sulfuric acid, following the method described in ISO 1693.
- Complex Formation: Formation of a blue-colored complex between fluorine and a combined reagent of alizarin complexone and lanthanum chloride at a pH of 4.5 to 4.6.
- Acetone Addition: Use of acetone to enhance the stability and sensitivity of the fluorine complex for accurate analysis.
- Spectrophotometric Measurement: Quantification of the fluorine complex at a wavelength near 620 nm using a spectrophotometer.
- Calibration and Standards: Preparation of fluorine standard solutions and calibration curves for precise quantification.
- pH Control: Adjustment and maintenance of the solution pH for optimal complex stability and measurement accuracy.
Applications
- Quality Control in Aluminium Production: Ensures that aluminium oxide meets fluorine content specifications critical for downstream metallurgical processes.
- Chemical Analysis Laboratories: Provides a standardized method for laboratories to accurately determine fluorine in aluminium oxide samples.
- Industrial Process Monitoring: Supports monitoring and control of fluorine contamination, which can affect aluminium refining efficiency and product quality.
- Research and Development: Facilitates investigation into materials and chemical characteristics of aluminium oxide by providing reliable fluorine content measurement.
- Regulatory Compliance: Assists manufacturers in adhering to international regulations and quality standards for aluminium oxide purity.
Related Standards
- ISO 1693: Specifies the distillation method for fluorine separation used within ISO 2828.
- ISO 802: Details preparation and storage of aluminium oxide test samples.
- ISO 2073: Covers dissolution of aluminium oxide by hydrochloric acid under pressure, referenced for comparative methods.
- ISO 2828 aligns with best practices in chemical analysis standards for aluminium compounds and fluorine determination.
By adopting ISO 2828:1973, industries involved in aluminium oxide production gain access to a precise, internationally validated test method for fluorine content. This promotes consistency in quality assurance checks, boosts analytical confidence, and helps maintain compliance with global standards. The use of alizarin complexone and lanthanum chloride spectrophotometric analysis represents a sensitive and reliable approach for fluorine quantification in challenging materials like aluminium oxide.
Keywords: ISO 2828, aluminium oxide, fluorine determination, spectrophotometric method, alizarin complexone, lanthanum chloride, fluorine content, chemical analysis, aluminium production, ISO standards, fluorine measurement.
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