Selection of collectors for lepidolite flotation

Lithium is the lightest metal element with very strong metallic activity. As a high-energy metal, it is mainly used in the nuclear industry, battery industry and solid fuel industry, and is also used in aerospace, ceramics, metallurgy, chemical industry, lubrication, glass and medicine.

As a lithium-containing mineral with large reserves in my country, lithium mica is one of the most important resources for extracting lithium elements

1. Factors affecting lithium mica flotation

Lepidolite ore is mostly fine-grained interbedded type, and lithium mica is mainly intergrowth with gangue minerals such as quartz and feldspar. Since lithium mica is a silicate mineral, the ore is mainly flaky or scaly after monomer dissociation. Coarse-grained lithium mica is generally enriched by hand selection, wind selection or friction selection, and fine-grained lithium mica is more effectively recovered by flotation.

Most lithium mica beneficiation processes use flotation, and the research on reagent system is mainly about the research on collectors. There are several problems with lithium mica flotation collectors 

(1) Fe ions are often introduced into lithium mica ores during the crushing stage. Fe ions inhibit the target minerals or activate gangue minerals, deteriorating the separation of lithium mica from gangue minerals; some scholars believe that Fe ions increase the surface charge of mica, which is conducive to the gangue ore mud covering the lithium mica surface, thus affecting the flotation of lithium mica.

(2) In actual production, the collectors for flotation of lithium mica are mostly traditional oxide ore collectors, which have weak selectivity and collection ability and are difficult to adapt to lithium mica ores with low Li2O grade and high ore mud content; and new lithium mica collectors are mostly used in the laboratory stage, without considering environmental and reagent cost issues.

(3) Amine collectors are sensitive to the temperature of the ore pulp and are easy to solidify at low temperatures. A large amount of acid needs to be added when used, which can easily cause corrosion to the equipment and pollute the environment, and the cost of wastewater treatment is high; the reagent system of fatty acid collectors is complex and the production cost is high; although the combined collector has strong selectivity and collection ability, it needs to be used with a large amount of inhibitors or dispersants, which can easily cause difficulties in subsequent filtration operations. 

2 Lepidolite Collectors

Common lepidolite flotation reagent systems include: amine collectors are used to float lepidolite under acidic conditions, and fatty acid collectors or combined collectors are used to float lepidolite under alkaline conditions.

Since lepidolite is a silicate mineral with negative surface charge, anionic fatty acid collectors can only collect activated lepidolite, and unactivated lepidolite is almost impossible to float;

Cationic amine collectors have good collection ability for lepidolite in a wide pH range, but the selectivity is not ideal;

Anionic and cationic combined collectors can effectively improve the grade and recovery rate of lepidolite concentrate by utilizing the synergistic effect of reagents; The research and development and testing of new lepidolite collectors are in the initial stage, and there are few actual applications. At present, most lepidolite production still uses single amine collectors or combined collectors to float lepidolite.