Mirny Polytechnic Institute (Branch), Ammosov North-Eastern Federal University, Mirny, Russia:

G. P. Dvoychenkova, Leading Researcher, Professor, Candidate of Engineering Sciences, dvoigp@mail.ru

Yakutniproalmaz Institute, ALROSA:
I. V. Zyryanov, Deputy Director of Scientific Work, Doctor of Engineering Sciences

Geological Exploration Company, PJSC ALROSA, Mirny, Russia:
O. E. Kovalchuk, Deputy Director for Innovation

Melnikov Institute for Comprehensive Exploitation of Mineral Resources, Russian Academy of Sciences, Moscow, Russia:
A. S. Timofeev, Researcher, Candidate of Engineering Sciences

Key kimberlite reserves in West Yakutia feature high (up to 45 %) content of diamond size grade –5 mm. This fact governs importance of increasing recovery of diamond size grade –5+0.2 mm, which calls for the required level processing of diamond-bearing raw material. To this effect, the method is proposed for intensifying high-level processing of rebellious kimberlite ore by means of electrochemical modification of diamond surface properties. This method involves diaphragm-free electrochemical conditioning of mineralized recycling water, which provides the wanted ion content and physicochemical properties of liquid phase in slurry. Technical efficiency of the developed structures and parameters of diaphragm-free electrochemical conditioners for mineralized recycling water was tested in full-scale processing of kimberlite ore in Mir and Internatsionalny mines. The processes of electrochemical conditioning of mineralized water were investigated in grease and froth separation of rebellious kimberlite ore from the aforesaid mines. The properties of mineralized water and their diaphragm-free electrolysis during grease and froth separation, as well as quality and composition of products of grease and froth separation were examined. The regular variations in properties of recycling water under diaphragm-free treatment of highly mineralized chloride-bearing water are experimentally determined. It is shown that diaphragm-free electrolysis reduces concentrations of carbonate and calcium ions in recycling water as well as pH values of liquid phase, which improves capability of water to dissolve carbonate minerals. It is experimentally found that ore slurry is maximally saturated with fine-dispersion electrolysis gases—hydrogen, oxygen and chlorine, which enhances efficiency of froth separation of diamond-bearing material. The proof test data show the increase in the diamond recovery by 4–4.2 % in the grease separation concentrate and by 5.2–8.8. % in the froth separation concentrate at the decreased consumption of reagents.
The study was carried out in the framework of the Plan for R&D of the Research Institute for Comprehensive Exploitation of Mineral Resources, Russian Academy of Sciences, No. 0138-2014-0002, under the direction of Academician V. A. Chanturia.

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