A Convenient One-Pot –Three Component Syntheses of a New Diaminophosphonate via Heterogeneous Organo-Catalyst, and Its Application for Titanium Recovery: Design, Optimization and Kinetic Aspects

A novel diaminophosphonate derivative (DAmPh) has been synthesized using one-pot-three-component method tailored for the extraction of titanium from Egyptian Rosetta ilmenite concentrate. The structure of DAmPh was elucidated through a combination of analytical techniques, including XPS, FT-IR, 1H-NMR, 31P-NMR, 13C-NMR and EI/MS analysis. The identification of the final product, TiO2 in rutile phase was confirmed using XRD, ICP/OES, and SEM/EDS techniques. Experimental factors such as pH, agitation time, DAmPh dose, co-ions, temperature, and stripping agents were optimized. Under specific conditions (25°C, pH 0, 20 minutes of agitation, and 900 mg/L titanium ions), the solution of 0.0172 mol/L DAmPh/n-hexane exhibited a maximum retention capacity of 225 mg Ti/g DAmPh. From the slope regression analysis, DAmPh-Ti neutral chelate was formed with stability constant (log β) equals 0.3641 at pH 0. Based on the optimized conditions, the McCabe-Thiele extraction-stripping isotherm suggests that approximately two theoretical extraction stages are necessary to extract nearly all titanium ions at an A/O ratio of 1/1. Conversely, three theoretical stripping stages are required to completely remove all extracted titanium ions using the loaded strip liquor at an A/O ratio of 1/2. Regarding kinetic modeling, the pseudo-second-order proves suitable for evaluating practical data. The calculated value of qe, derived through mathematical analysis, closely aligns with the realistic uptake of 225 mg/g, standing at 227.27 mg/g. Thermodynamic analysis reveals that the extraction process is exothermic, spontaneous, and advantageous at low temperatures. Factors such as ΔS (-0.0332 KJ/mol), ΔH (-13.25 KJ/mol), and ΔG were evaluated, ranging from -3.356 KJ/mol at 298 K to -1.948 KJ/mol at 338 K. Titanium ions can be efficiently stripped from the loaded DAmPh using 2M H2SO4 with a 99% efficiency. Furthermore, it was observed that the DAmPh ligand demonstrates a favorable separation factor (S.F.) for Ti3+ ions compared to other co-ions like Fe2+, Mn2+, V2+, and Cr2+.The synthesized DAmPh facilitated the creation of a high-purity TiO2 concentrate (rutile phase) with a titanium content of 59.9% and a purity reaching 99.99%.