S. A. Kondrat’ev

Kinetics of calcium minerals flotation from Scheelite-carbonate ores

The laboratory and commercial tests of ore specimens with different content of tungstic oxide and calcite have been conducted, and basic patterns of flotation have been established. Based on the results of analytical and practical studies, the actual processing plant’s operating practice and processing flow sheet have been upgraded.

Justification and development of innovative technologies for integrated processing of complex ore and mine waste

The article presents the theoretical and experimental research findings aimed to create a basis for the development of innovative integrated processing technologies for complex ore and mine waste. It is found that introduction of nonmechanical energy treatment by an accelerated electron beam in the ore dressing circuits increases rebellious mineral processing data. The features of a flotation unit process are analyzed from the viewpoint of improvement of collecting and selecting abilities of a reagent and relationship between these abilities and molecular structure of the reagent. The authors define flotation activity of reagents and offer a flotation contact formation criterion. It is proved to be effective and promising to use magnesium- and manganese-bearing minerals for sorption purification of mine effluents in order to reduce metal loss in the wastewater discharge and to minimize damage of natural water bodies.

Some approaches to gold extraction from rebellious ores on the South of Russia’s Far East

Interpreted data of the phase analysis of the Far East ore bodies made it possible to characterize rebellious behavior of ores under study. The researchers propose the integrated flow sheet composed of gravitational preparation, flotation and metallurgical processing flow sheet for beneficiation of rebellious auric-arsenical ore and present the beneficiation parameters for ores of moderate sorption capacity.

Activity and Selectivity of Carboxylic Acids as Flotation Agents

The article proves that the strength of a flotation agent depends on the surface pressure of its molecules, or the ion-molecule associates, at the air-solution contact. Based on the found relationship of the flotation strength and surface pressure of a reagent, the author determines collecting activity and selectivity of the reagent, and suggests the method for enhancing quality of separation of minerals having akin surface properties.

Estimate of collecting force of flotation agent

The authors compare collecting activity of carboxylic acids and surface pressures of their films on water surface. It is found that these parameters correlate, and the surface pressure of the films depends on the length, saturation and branching of hydraulic radical and the availability of substituents. The problem on liquid removal from the film between air bubble and mineral particle is solved numerically. It is shown that the bulk force on the liquid in the film is conditioned by the surface pressure of molecules. The force of a flotation agent is defined as the force of the agent on the liquid in the film. The volumetric liquid flow from the film is related with the surface tension of agent forms active at the particle–bubble interface. The authors propose the method of estimating collecting activity of physically attached agents by the value of force the agent exerts on liquid in the film.

Mechanisms of nonsulfide mineral flotation with oleinic acid

By the analysis of oleinic acid flotation of fluorite and hematite, it is inconsistent to use thermodynamic approach to explain the flotation effect by the chemical adsorption of the reagent only. The authors propose a hypothesis that collecting ability of a flotation reagent relates with the activity of its physical adsorption at the air-liquid interface. The hypothesis is supported with the data on flotation of rutile, zircon and fluorite. Capability of surface pressure of film generated by molecules or ion-molecule associates as the criterion of collecting ability of a flotation agent is defined.

Collecting ability of easily desorbed xanthates

The analysis focuses on collecting ability of easily desorbed (ED-forms) ethyl and butyl xanthates. The authors give visual proof of “dry” spot extension on mineral surface when xanthates that are active relative to air–water interface are desorbed from it. It is shown that ED-forms of agents, being products of interaction between xanthates and heavy metal salts, can remove water from film between mineral particle and air bubble. The main force on water in the film is conditioned by surface tension nonuniformity at the moment of local rupture and by surface pressure of molecules in the film of agent ED-forms. The collecting ability of ED-forms of xanthate is determined as the rate of its influence on water in the film. The forces exerted on water in the film of ED-forms of ethyl and butyl xanthates are estimated numerically. The dependence of volumetric water flow from the film on the surface tension of agent ED-forms active at air–water interface is found. It is shown that collecting ability of an agent is dependent on surface tension of solution of its ED-forms and is governed by structure of hydrocarbon fragment of the collector.

Foam separation selectivity conditioned by the chemically attached agent

It is hypothesized that the critical thickness of rupture of a liquid film between air bubble and mineral particle depends on potential and size of area occupied by nanobubble. It is shown that the critical thickness of film equals the height of meniscus formed under rupture. The size and shape of meniscus are characterized by its neck radius and contact angle. The proposed hypothesis is based on the assumption that the size of initial meniscus neck is connected with the diameter of attachment area of nanobubble. There are no nanobubbles on the surface of hydrophilic minerals, and the liquid film rupture is hampered in this case. Since liquid film stability is mainly affected by hydrophobic interaction, the liquid film rupture thickness is larger on hydrophilic minerals than on hydrophobic minerals. Selectivity of foam separation of minerals, governed by the chemically attached agents, depends on the ratio of the critical rupture thicknesses of the liquid film.

Chudsko-Pskovskii Lake Complex: Monitoring and modeling phosphorus regime

The existing system for state monitoring of surface waters in the Russian part of the Chudsko-Pskovskii Lake Complex and its catchment is assessed. The ways for the improvement of the monitoring system are outlined. The phosphorus load onto the Chudsko-Pskovskii Lake Complex from the Russian territory is estimated. A balance model is used to calculate the dynamics of mean annual concentrations of total phosphorus in the northern and southern parts of the water body in 1990–2003. The possible use of simplest models for the assessment of the external phosphorus load onto the water body with the existing point and nonpoint sources of phosphorus taken into account is assessed.

Quantum-mechanics of pyrite flotation

The authors have carried out molecular modeling of clusters of simple structure and ring structure pyrite. It is suggested to analyze bonding of a collecting agent and cluster atoms using the collector capacity forecasting index. It is shown that butyl dixanthate more vigorously connects to cluster atoms than thionocarbamates, e.g., Z 200 and IETNC. Analysis of the charge transfer during interaction of pyrite with the listed collecting agents shows that in monodentate bonding the charge is transferred from the mineral to the collector sulfur atoms and in bidentate bonding the classical transfer of the charge from the collector donor to the mineral acceptor is observed. It is supposed that ferrum xanthate decompounding in an acid medium results in inception of dixanthates that govern pyrite flotation. Pyrite oxidation and elemental sulfur formation also favor pyrite flotation but complicate pyrite depression in an alkaline medium.