The impact of microbubbles on flotation efficiency has been studied for ultrafine ( < 12 μm) chalcopyrite recovery from chalcopyrite/quartz artificial mixtures using laboratory pneumomechanical and column flotation cells. The findings show that significant enhancement in the efficiency of ultrafine minerals beneficiation is ensured by using the method known as combined microflotation based on simultaneous use of both coarse air bubbles (conventionally produced in flotation cells) and microbubbles generated by a standalone generator in the form of air in water microdispersion. Introduction of microbubbles at the dosage of 8–16 L per 1 kg of chalcopyrite before its treatment in a pneumomechanical flotation cell increased the flotation rate by several times. In the case of column flotation, introduction of microbubbles at the dosage of around 50 L per 1 kg of chalcopyrite following pulp treatment in a static mixer for 60 s before feeding it into the column cell increased the copper recovery by more than 50%. Increasing the treatment time of the pulp in the static mixer to 80 s led to gains in copper recovery by more than 60%, even in the absence of cell aeration by coarse air bubbles (turbulent microflotation regime).

This paper discusses the results of flotation tests on finely dispersed Cu–Pb–Zn–Fe–sulphide ore of the in which microbubbles finer than 50 µm were used as carriers. It was found that volume dosage of microbubbles in the amount of 0.1 liter per kilogram of solids increased the flotation rate of various sulphide ore components by factors of 2–4 and recovery by 0.5–3%. An analysis of the recovery kinetics was performed using previously developed theory of combined microflotation. It was found that the major effect of using microbubble carriers, which has led to the gain in flotation rate efficiency, can be attributed to the fact that the effectiveness of particles and microbubbles hetero-aggregation exceeds the capture efficiency of particles by coarse bubbles by factors of more than 50–70 and the flotation rate of mineralised microbubbles by coarse bubbles by several times compared to the flotation rate of separate particles.

The article presents the results of laboratory research on the possibility of flotation processing of copper-containing technogenic raw materials. Studies were performed using a sample of copper-containing tailings obtained after the processing of copper ore from the Kazakhstan deposit and a composite flotation reagent. The application of a combination of various collectors allows for raising technological indicators of flotation. The purpose of the research is the increase extraction of copper at flotation of copper-containing technogenic raw materials with the application of a composite reagent. The studied sample of tailings contains 0.23% of copper. A mixture of sodium butyl xanthate and thionocarbamate in the ratio of 1:1 was used as a composite flotation reagent. Parameters of flotation of copper-containing tailings were worked out: degree of regrinding, charges of sodium butyl xanthate, blowing agent T-92, and a composite reagent. Composite flotation reagent was fed into the flotation process of copper-containing tailings in the form of emulsion produced in a T 18 digital ULTRA-TURRAX dispersant. The optimal emulsification time of the composite flotation reagent was 1 min. Without emulsification in the composite reagent the percentage of particles smaller than 1.192 µm is 55.047%. After emulsification of the composite reagent for 1 minute, the percentage of particles smaller than 1.192 μm is 91.134%. In optimum basic mode the rough copper concentrate with a copper content of 4.2% was obtained with the extraction of 61.56%. With the use of a composite reagent, a blister copper concentrate with a copper content of 4.5% and a recovery of 66.54% was obtained. Extraction of copper increases by 4,98%.

This article presents the results of cyanide leaching of gold-containing concentrate using the trichlorocyanuric acid (TCCA) oxidizer. Gold-containing concentrate was obtained from a gold tailings sample from a gold recovery factory (GRF) in one of the deposits of Kazakhstan that have not previously been studied for concentrability. According to X-ray phase analysis and energy dispersive spectrometry (DSM) data, the main compounds in the tailings sample under study are pyrite FeS₂, quartz SiO₂, calcite CaCO₃, albite NaAlSi₃O₈, muscovite KAl₂Si₃AlO₁₀(OH)₈, dolomite CaMg(CO₃)₂, and oxidized iron compounds. Microscopic studies of the concentrate have established the presence of ultrafine gold with sizes from Au 0.9 to 10.2 μm in pyrite. Obtaining the gold-containing concentrate with a gold content of 15.95 g/t is possible according to the enrichment scheme, which includes centrifugal separation, classification according to the fineness class −0.05 mm, additional grinding of hydrocyclone sands to a fineness of 90.0–95.0% of the class finer than 0.050 mm, and control centrifugal separation. Since pyrite in technogenic raw materials is the main gold-containing mineral, this paper presents studies on the oxidizability of pyrite with the TCCA oxidizer. The results of studies on the oxidation of pyrite using the TCCA oxidizer show the products of its hydrolysis oxidize pyrite with the formation of various iron compounds on its surface. Pretreatment of gold-containing concentrate with oxidizer TCCA for 3 h before the cyanidation process (20 h) allows for an increase in the recovery of gold in the solution by 5.8%.

The article presents the results of laboratory studies on the effect of the liquid-gas ratio and the foaming agent type on the average water-air micro dispersion size obtained from the foaming agent solution. The size of microbubbles significantly effects the efficiency of flotation and depends on the type and concentration of foaming agent used for their production. A generator was used to obtain water-air micro dispersion. The works were performed to work out the water-air micro dispersion parameters of at different liquid-gas ratio and different performance of the generator. The following foaming agents were used as objects of research: sodium butyl aero flot (BTF), flotanol C-7, butyl triethylenetetramine (B-TETA) at a concentration of 0.5 g/dm3. It has been established, that the optimal phase liquid-gas ratio was 1:1, the optimal capacity of the generator was 6-7.2 dm3/h with an average particle size of air-water micro dispersion- 33-41 mm for BTF solution, 103-107 mm for C-7 solution, 90-93 mm for B-TETA solution. The type of foaming agent used in flotation effects the size and stability of microbubbles. It is established that the flotation agents can be arranged in the following line with respect to their ability to create micro dispersion: IIBK→Senfroth 580→B-TETA→OPSB→Flotanol C-7→T-92→BTF. The best results are shown by BTF that creates micro dispersion of 43-58 μm (t 20-40 °С) and stability of 80 sec with concentration of 0.5 g/dm3.

It is already well established that the flotation efficiency of fine minerals can be significantly improved by adding a relatively small amount of microbubbles ( < 50 μm) to conventional coarse bubbles (>1 mm) normally used in flotation cells. To establish quantitative characteristics of this effect, the dependence of the flotation rate constant and recovery on microbubbles dosage was studied using fine quartz ( < 25 μm) samples in laboratory pneumomechanical and column flotation cells. It was found that, for pulp concentration in the range of 20–30 g L^− 1, the flotation rate constant of the pneumomechanical flotation process is directly proportional to the microbubbles dosage. It was also found that the introduction of 0.25 L kg^− 1 of microbubbles into the pulp before it is fed into the column flotation cell resulted in the recovery increasing from 77 to 89% for quartz concentration of 34 g L^− 1 and from 66 to 87% for the quartz concentration of 68 g L^− 1.