Mining Institute of Kola Science Centre of RAS (Apatity, Russia)

Fomin A. V., Senior Researcher, PhD in Engineering Science, fomin5-49@mail.ru
Mitrofanova G. V., Leading Researcher, PhD in Engineering Science
Chernousenko E. V., Senior Researcher

This article presents the results of research focused on developing a technology to produce loparite and nepheline concentrates from the tailings of loparite ore processing. The study investigates the material composition of current tailings from the Karnasurt plant. The sample contained 0.9 % loparite and 52.8 % nepheline, with the mass fractions of Al₂O₃ and Nb₂O₅ being approximately 22 % and 0.14 %, respectively. More than 84 % of the Al₂O₃ was found in fraction –0.63 + 0.1 mm, while over 83 % of the Nb₂O₅ was located in material smaller than 0.315 mm. The degree of liberation for loparite did not exceed 60 %, while nepheline (including feldspar) exhibited a liberation degree of 95 %. Three stages of gravity separation using screw separators resulted in a rough loparite concentrate containing 1.3 % Nb₂O₅, recovering 47 % of the initial feed. Further refinement through table concentration increased the Nb₂O₅ content to 3.3 %. High-intensity wet magnetic separation of the table concentrate boosted the Nb₂O₅ content to 5 % by weight. Purification through electrical separation is required to achieve the desired loparite concentrate grade. The study also substantiated a set of optimized conditions for the regrinding and reverse flotation of screw separation tailings, allowing for the extraction of a nepheline concentrate with 28.1 % Al₂O₃ by weight. The combined gravity-magnetic-flotation process developed for the enrichment of loparite tailings successfully produces high-quality nepheline concentrate with 28.12 % Al₂O₃ and a recovery rate of 78.84 %, as well as loparite concentrate with 5.07 % Nb₂O₅ and a recovery of 40.96 %.

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