Institute of Comprehensive Exploitation of Mineral Resources, Russian Academy of Sciences (Moscow, Russia):
Chanturia V. A., Chief Researcher, Doctor of Engineering Sciences, Academician of RAS
Morozov V. V., Professor, Doctor of Engineering Sciences, Professor
Dvoichenkova G. P., Chief Researcher, Doctor of Engineering Sciences, Associate Professor, dvoigp@mail.ru
Timofeev A. S., Senior Researcher, Candidate of Engineering Sciences

Reduced performance of control X-ray luminescence separation of diamond-bearing kimberlites is caused by the loss of anomalously and weakly luminescent diamonds, which do not have the necessary contrast of the X-ray luminescence signal in relation to the kimberlite minerals. The paper substantiates the necessity and possibility of increasing the performance of X-ray luminescence separation through targeted modifications of the spectral and kinetic characteristics of unrecoverable diamonds using luminophors. Criteria for evaluating the X-ray luminescence signal are proposed, which ensure effective detection of anomalous and weakly luminescent diamonds. The efficiency of the FL-530 luminophor, characterized by the presence of a pronounced slow signal component, and anthracene luminophors with a large amplitude of the fast component has been confirmed for modifying spectral characteristics of diamonds. The use of diesel fuel as an organic phase in a luminophor-containing emulsion for its effective attachment to diamonds has been substantiated. The advisability of introducing additives to the organic and aqueous phases has been experimentally confirmed for the F-5 fuel oil emulsion, sodium alkyl sulfonate, and sodium oleate that improve adhesion and retention capacity of the organic phase with respect to diamonds and luminophors, as well as for the sodium hexametaphosphate additive that significantly weakens the adhesion of luminophors to kimberlite minerals. The efficiency of processing diamond-containing products with an emulsion of the proposed composition for modifying the spectral and kinetic characteristics of anomalously luminescent diamonds upstream of control X-ray luminescence separation for their additional recovery has been confirmed by tests using a Polyus-M separator.
The work was carried out with the support of the Russian Science Foundation (grant No. 21-17-00020).

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