Institute of Biocolloid Chemistry, National Academy of Sciences of Ukraine, Kiev, Ukraine:

N. N. Rulev, Head of Department, e-mail: nrulyov@gmail.com

Institute of Metallurgy and Ore Beneficiation, Almaty, Republic of Kazakhstan:
D. K. Turysbekov, Leading Researcher, e-mail: dula@mail.ru
L. V. Semushkina, Leading Researcher, e-mail: syomushkina.lara@mail.ru
S. M. Narbekova, Researcher, e-mail: s.narbekova@mail.ru

The paper presents the combined microflotation theory, which adequately describes the flotation kinetics of fine dispersed minerals where coarse bubbles and small amounts of fine bubbles are introduced into flotation cell at the start of the process in the form of air-in-water dispersion. On the basis of this theory, the analysis of experimental findings of the combined microflotation of fine Pb – Zn-sulphide ore enrichment tailings of Shalkia deposit (Kazakhstan) allowed to estimate the capture efficiency of particles and fine bubbles by coarse bubbles and also the efficiency of particles and fine bubbles heterocoagulation in the non-uniform hydrodynamic field of flotation cell. Flotation tailings, produced during ore enrichment in the Shalkia deposit, had 1.1% of lead and 2.2% of zinc. Dispersion analysis showed that the major part of valuable components, specifically lead (71.96%) and zinc (71.4%), was present in fractions 0-30 μm. The differential functions of lead and zinc distribution by dimensional fractions in the feeds supplied on the rougher and scavenging lead and zinc flotation were calculated. The feed on the scavenging stage was sufficiently more finely dispersed and this significantly decrease the flotation efficiency overall. To overcome this problem, the technology of the combined microflotation was applied at the stage of scavenging flotation. This technology employs introduction of limited amount of air-in-water dispersion containing air bubbles smaller than 50 μm into flotation cell before flotation starts. The major effect from microbubbles application comprising the significant increase of flotation rate and recovery is due to the fact that the efficiency of particles and microbubbles heteroaggregation is by 8–15 times higher compared to the capture efficiency of particles by coarse bubbles, besides microbubbles can capture particles which coarse bubbles can not catch.

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