Overview
ISO 7723:1984 specifies a spectrometric method using 4,4'-diantipyrylmethane for the determination of titanium content in manganese ores and concentrates. The method applies to products with titanium contents from 0.01 to 0.5 % (m/m) and is intended to be read in conjunction with ISO 4297 (general instructions) and the ISO sampling/preparation standards for manganese ores.
Key topics and technical requirements
- Scope and sample: Test sample crushed to ≤100 µm and air-dried; typical test portion is 1 g.
- Analytical principle:
- Decompose the sample with hydrochloric, nitric and sulfuric acids.
- Separate insoluble residue; ignite the filter residue and fuse with potassium disulfate (K2S2O7).
- Dissolve the melt, combine with the main solution, reduce iron with ascorbic acid, develop colour with 4,4'-diantipyrylmethane, and measure absorbance at 385 nm.
- Reagents and standards: Includes specified grades/strengths of HCl, HNO3, H2SO4, HF, ascorbic acid, and 4,4'-diantipyrylmethane. Procedures for preparing titanium standard solutions (100 mg/L and 20 mg/L) from TiO2 or metallic Ti are given.
- Apparatus: Routine laboratory glassware, platinum crucible, and a spectrometer suitable for 385 nm with cell path lengths of 10–30 mm.
- Calibration and measurement: Construct a calibration graph from a series of titanium standard solutions; run blank tests; select aliquots according to expected Ti content. Measure net absorbance (sample minus blank) and convert to Ti % by the calibration curve.
- Quality/precision: Permissible tolerances for parallel determinations are provided for different titanium concentration ranges (e.g., tolerances listed for two- and three-parallel determinations).
Practical applications and users
- Quality control laboratories in mining and mineral processing for monitoring titanium as an impurity in manganese ores and concentrates.
- Commercial assay and analytical laboratories performing contract analysis for buyers/sellers and compliance testing.
- Process control in beneficiation plants where Ti content influences downstream processing or product specifications.
- Materials characterization for metallurgy and research where accurate Ti quantification in manganese matrices is required.
Related standards
- ISO 4297 - Manganese ores and concentrates: Methods of chemical analysis - General instructions (referenced for general laboratory procedure).
- ISO sampling and preparation standards for manganese ores (e.g., ISO 4296 series) referenced for correct sampling and sample preparation.
Keywords: ISO 7723:1984, manganese ores, titanium determination, 4,4'-diantipyrylmethane, spectrometric method, spectrophotometric analysis, sample preparation, calibration, titanium standard solution.
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