LAUSR

—Using UV-visible spectrophotometry, it is found that old tailings of Solnechny Mining and Processing Plant are characterized with high absorptive capacity relative to sodium dibutyl dithiocarbamate (DBDTC) and require high consumption of collecting agents in flotation. The optical and scanning electron microscopy tools revealed gypsum-cemented finely dispersed fractions (smaller than 20 μm) coating larger mineral particles (60–80 μm). Minerals are represented by chalcopyrite, pyrrhotine, pyrite, sphalerite, jamesonite and cassiterite; rocks are quartz and silicates. A feature of these old tailings is supergene mineralization and sulphide oxidation products. Alongside with cassiterite, varlamovite is present as a typical product of stannite-group tin sulfosalts modification. New experimental data on flotation of Solnechny MPP tailings with DBDTC are obtained. The flotation experiments show that DBDTC addition to butyl xanthate (at ratio of 1: 3) enables increased recovery of copper, lead, zinc and silver in bulk concentrate and reduces loss of these minerals in slime.