Selection of reagent compositions for modifying spectral characteristics of weakly and anomalously luminescent diamonds in the process of X-ray luminescence separation

Abstract

The feasibility of targeted modification of the spectral properties of weakly and anomalously luminescent diamonds by modifying reagents containing luminophores based on sulfides and zinc orthosilicate, characterized by medium and low deviation of the luminescence signal from that of natural diamond. It was found that the hydrophobic treatment of inorganic luminophores with potassium butyl xanthate could increase the recovery of anomalous luminescent diamonds in the process of X-ray luminescence separation up to 80%. Organic collectors (optically transparent oil products with high extractability for luminophores and adhesion to diamonds) based on technical-grade diesel fuel and catalytically cracked heavy gas oil are recommended for the luminophorecontaining compositions. The feasibility of reducing the fixation of luminophores on the surface of kimberlite grains using sodium hexametaphosphate, sulfonol, carboxymethylcellulose and liquid glass was demonstrated. The application of these reagents in low-salinity water provides decreasing coating of kimberlite grains with luminophores while maintaining the required concentration of luminophores on the surface of diamonds. Semi-industrial tests with an LS-D-4-03N separator proved the possibility of complete recovery of weakly and anomalously luminescent diamonds after treatment of XRS tailings with the modifying reagents.