The article proves the promising nature of using functionalized magnetic nano particles in extraction of metals from process solutions and in treatment of industrial effluents. The experimental ...copper extraction from solutions using a magnetic nanosorbent made of lipoic acid-functionalized magnetite is described. Sorption efficiency is determined as function of the initial concentration of solutions as compared with non-functionalized nano-size magnetite. The copper-bearing sedimentation mechanism includes chemosorption at active centers of lipoic acid, adsorption at clean magnetite surface and re-crystallization of sorbate in intrinsic copper-bearing phases. The phase composition of copper in the sediments is examined, and the copper extractability is illustrated. The conditioning technology is proposed for copper-bearing solutions. The stage-wise use of the magnetic nanosorbent enables process solution purification up to the maximum allowable concentration at simultaneous production of a concentrate suitable for hydrometallurgical processing.
The authors compare the effect exerted by copper ions and sulphide copper nanoparticles on flotation of Gorevka deposit sphalerite using potassium n-butyl xanthate and in reagent-less regime. ...Covelline-like colloid particles 4–8 nm in size, obtained in interaction of copper (II) and sulfide ions in aqueous solutions, are characterized using the methods of dynamic light scattering, electron microscopy and diffraction. Sphalerite surface after reaction with copper ions and CuS dispersoid solutions are described by zeta-potential measurements and X-ray photoelectron spectroscopy. It is found that sphalerite flotation after activation with nanoparticles is lower than with copper ion solutions of the same concentrations, and improves with increasing duration of activation and flotation processes. The mechanism of CuS nanoparticles consists in creation of active centers for the collector to attach to, which intensifies the hydrophobic behavior and adsorption of the collector. Moreover, CuS nanoparticles promote formation of a special microrelief of the solid–liquid interface, which ensures rupture of liquid film and attachment of sphalerite particles to air bubbles when they collide.
The authors analyze collecting capacity of desorbable species of xanthates. Desorbable species of the reagent are understood as the species capable to transfer from a mineral particle to air bubble, ...i.e. to gas–liquid interface, at the moment of rupture of an interlayer between these interacting objects. Flotation process performance is evaluated at the presence of a mixed coating resulting from physical and chemical adsorption and in the presence of a chemisorption coating only. The rates of spreading products of interaction between butyl ethyl xanthates and lead nitrate over water surface are found. The spreading rates and collecting capacities of the mentioned reagents are correlated. It is found that an increase in the length of the hydrocarbon fragment increases collecting capacity of a reagent and the rate of spreading of its products on water surface.
The experimental data on modification of magnetic properties of gold-bearing sulfide ore using magnetic colloids are reported. The magnetic product of the high-gradient separator has the increased ...gold content by 2.52% at the higher recovery by 1.67%.
The results of the studies on the use of collector reagents in the form of a reverse microemulsion (RME) of the water-in-oil type (i.e., water droplets are suspended in the oil phase) for the ...flotation extraction of lead and zinc minerals are presented. Lead and zinc concentrates and a lead–zinc ore are used as the initial samples for flotation. The concentration of galena in the lead concentrate is 74.7%, and the concentration of sphalerite in the zinc concentrate is 78.7%. Basic collector reagents in the composition of the RME are potassium butyl xanthate (PBX) and kerosene. A nonionic surfactant (NSA) is used to stabilize the RME. Casein is used as additives to the main reagents to eliminate the negative effect of osmotic pressure upon preparing the RME. The transformation of casein to the active soluble form is carried out using sodium sulfide. The particle size in the reverse microemulsion is 12.38 nm. The following options for supplying reagents to the flotation pulp are studied in flotation tests: RME, RME + foaming agent, and potassium butyl xanthate + foaming agent. A T-92 reagent is used as the foaming agent. The consumption of PBX in the composition of the RME and in the classical supply is 26 g/t. The results of laboratory tests show that the method of supplying flotation reagents in the form of an RME leads to an increase both in the flotation rate of lead and zinc sulfides and in their recovery into a foam product. Tests with the use of an RME in the collective flotation cycle of a lead–zinc ore show an increase in the extraction of lead into the total concentrate by 10.8% and zinc by 38.5% in comparison with the classical supply of reagents (collector + foaming agent) in addition to an increase in the flotation rate. An increased selectivity of the action of an RME in relation to zinc sulfides in comparison with lead sulfides is noted. The flotation rate coefficient of sphalerite is 7.8-fold higher when compared to galena. The gain in the extraction into the total zinc concentrate is also higher and is 16.78%, while the gain into the lead concentrate is 1.9% under the same conditions.
Lumpy ore after semi-autogenous milling in Copper–Nickel ore processing at the Talnakh factory is studied. The lumpy ore is mainly presented by sizes −80+40 and −40+20 mm. The X-ray radiometric ...separation tests of the lumpy ore prove their efficiency in production of concentrate and tailings. The strength characteristics and the Bond work index of the concentrate are determined. The results of flotation of the X-ray radiometric concentrate are described.
This paper proposes a method for quickly estimating the average flotation capacity of minerals according to the kinetic experiment without finding the flotation spectrum at which the first moments of ...distribution are calculated by the coefficients of the polynomial approximation of the logarithmic form of the kinetics. Using the example of copper-nickel ore, it is shown that the application of this method is effective in the multiparameter problem of comparative assessment of reagents. The ten parameters assessed included the average floatability of the target minerals (chalcopyrite and pentlandite), pyrrhotite and rock; the flotation selectivity coefficients of target minerals relative to pyrrhotite and rock; and the levels of copper and nickel losses from bulk flotation tailings. A visual representation of the interdependencies of parameters is achieved using diagrams showing the effect of flotation reagents on groups of parameters: average flotation, selectivity coefficients, metal losses, and selectivity relative to rock. The influence of butyl xanthate, Aeroflot, diesel fuel, and waste rock depressants—carboxymethyl cellulose (CMC) and acidified water glass (with a total consumption of 130 g/t collectors, 5–10 g/t diesel fuel, 200 g/t CMC, acidified water glass—500 g/t)—on the estimated parameters under conditions of collective flotation is determined. It is found that the addition of Aeroflot and diesel fuel to the main reagent collector xanthate increases the selectivity of pentlandite and chalcopyrite flotation relative to pyrrhotite and rock-forming component. The introduction of acidified liquid glass into the reagent mode increases the selectivity of the flotation of nickel and copper sulfides relative to the rock. CMC additives impair the selectivity of copper flotation. The quantitative effects of each individual parameter are taken into account in the integral rating assessment of the prospects of using reagent combinations for copper-nickel ore in terms of a set of ten parameters. The proposed method can be further used for a mass comparative evaluation of flotation reagents.
The research results on floatability of old gold-bearing tailings are presented. The complex material composition and process features of processing waste are governed by difference in treatment of ...various ore types (sulfide, oxidized and mixed) at processing plant, as well as with supergene processes in the tailings pond. Feasibility of re-flotation of tailings is discussed. It is found that short-term mechanical activation of tailings in a mill with the subsequent flotation (at the adjusted reagent mode as against the current technology) results in gold recovery of 29.0 to 45.4% in flotation concentrate at the residue content of metal in rejects at the level of 0.2–0.3 g/t.
Under discussion is collectability of ethyl and butyl xanthate species resulted from nonstoichiometric interaction with oxidizer. It is visually proved that solution contains fine micro-drops ...stabilized by negative charge. The size and ζ–potential of micro–drops are determined together with the spreading velocity of emulsion over water surface. The mentioned velocity is higher than the spreading velocity of products of non-stoichiometric interaction between xanthate and heavy metal salt. The products of interaction between xanthates and oxidizers are known as desorbable species (DS), as at the moment of rupture of water film between mineral particle and air bubble they can detach from particle surface and attach to air–water interface. Spreading of DS over the interface forces water out of the film. The forces applied to liquid in the film from the side of DS of ethyl and butyl xanthates are evaluated. The volume–flow rate of water from the film is related with the surface pressure of reagent species active at the air–water interface. The surface pressure of dixanthogen–xanthate emulsion is evaluated as a function on initial concentration of xanthate. Collectability of the reagent depends on the surface tension of DS solution and is governed by the structure of hydrocarbon fragment of the agent.
Under discussion is the particle and bubble interaction in froth flotation. Water flow from an interlayer between a particle and a gas bubble under effect of hydrophobic component of wedging pressure ...is studied. It is assumed for a mineral to be extracted, that electrostatic interaction slightly influences the particle and bubble contingence and the liquid interlayer thinning. For this reason, particular attention is given to the effect exerted by mineral particle surface hydrophobicity on water flow rate from the interlayer. It is found that water flow rate under influence of hydrophobic component of wedging pressure is less than water flow rate under physical adsorption of a reagent. The authors hypothesize that hydrophobization creates areas on the mineral particle surface, where the reagent species active relative to gas–water interface attach in accordance with the polarity equalizing rule. Physically adsorbed reagent species pull out water from the interlayer after the interlayer rupture and, thus, remove the kinetic constraint of the particle–bubble attachment.
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