Perxanthate determination in flotation solutions by ultraviolet spectrophotometry

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Mineral Processing

Background:

• Alkyl perxanthates are crucial reagents in mineral flotation.
• Accurate quantification of alkyl perxanthates is essential for process control and optimization.
• Existing analytical methods may have limitations in complex industrial matrices.

Purpose of the Study:

• To develop and validate a robust spectrophotometric method for determining alkyl perxanthates.
• To compare direct spectrophotometry with solvent extraction for perxanthate analysis.
• To establish the analytical parameters, including molar absorptivity and detection limits.

Main Methods:

• Direct ultraviolet spectrophotometry of alkaline solutions (pH > 8) at 348 nm.
• Solvent extraction into chloroform after acidification (pH < 2).
• Spectrophotometric analysis of the organic extract at 302 nm.

Main Results:

• Direct method: molar absorptivity of 1.042 x 10^4 l.mole^-1.cm^-1, Beer's law up to 25 mg/l, detection limit 0.2 mg/l.
• Extraction method: molar absorptivity of 5.47 x 10^3 l.mole^-1.cm^-1, Beer's law up to 25 mg/l, detection limit 0.2 mg/l.
• Minimal interferences observed for both methods, with specific thresholds noted for nickelocyanide, mercaptobenzothiazole, sodium sulphite, and cuprocyanide.

Conclusions:

• Both direct and extraction-based UV spectrophotometry are effective for alkyl perxanthate determination.
• Direct method is suitable for clear solutions, while extraction enhances applicability for complex matrices.
• The validated methods provide accurate and sensitive quantification of alkyl perxanthates in industrial settings.