A potential method for modifying saponite (intercalation) ensuring its high sorption capacity for gold was theoretically and experimentally substantiated. Saponite isolated from recycled water of processing plant tailings dam is modified by mixing a suspension of the mineral and acetone with the surfactant hexadecyltrimethylammonium bromide (CTAB) followed by four washings with ethanol and distilled water, and drying. The intercalation mechanism of saponite-containing product involves the introduction of positively charged cations of organic compounds into the interlayer space through cation exchange or adsorption, which leads to expansion of mineral layers and an abrupt shift in zeta potential toward the positive side. The appearance of bands in the IR spectral ranges of 1460-1490 and 2850-2920 cm–1 related to the deformation and stretching vibrations of the CH2 group, respectively, confirms the successful incorporation of CTAB molecules into the mineral structure. Studies of the maximum sorption capacity of modified saponite revealed that at initial gold concentration 22.6 mg/l, complete extraction is achieved after 7.5 min. The maximum static exchange capacity of modified saponite was achieved after contact with the third portion of fresh gold-bearing solution and amounted to 100.5 mg/g. Gold sorption isotherms correspond to the Langmuir model which presumes that a monomolecular sorption layer forms on the surface of the modified saponite, and all active sites have equal energy and enthalpy of sorption. The kinetic dependences of sorption are best described by a pseudo-second order model, which presumes that the chemical exchange reaction limits the sorption process. It was found that saponite intercalation with hexadecyltrimethylammonium bromide ensures a more efficient sorption of negatively charged gold complex ions ([AuCl4]–). The calculated equilibrium static exchange capacity of modified saponite was 92-119 mg/g, while the experimentally determined value was 102 mg/g.
Based on a package of modern analysis methods, the influence of various acids and energy effects on the morphology, elemental composition, structural and chemical transformations of the mineral surface, and the efficiency of eudialyte concentrate leaching was studied. The mechanism and the optimal conditions and specific features of the destruction of eudialyte and rock minerals and the extraction of zirconium and REE under the influence of various acids, powerful nanosecond pulses, dielectric barrier discharge, electrochemical processing, mechanochemical activation and ultrasound were revealed. The mechanism of formation and the optimal conditions for the dispersion of silica gel, depending on the methods and parameters of energy effects, was theoretically and experimentally substantiated. A combined three-stage circuit of nitric acid leaching of eudialyte concentrate with ultrasonic treatment of the suspension, providing 97.1 % extraction of zirconium and 94.5 % REE, were scientifically substantiated and tested. The conditions for the selective deposition of zirconium and REE were theoretically and experimentally substantiated.
In 2001-2002, the Talnakh Concentrator (Talnakh Concentrator) of the Polar Division of MMC Norilsk Nickel implemented a number of measures aimed at improving the ore concentration technology at the Talnakh and Oktyabrskoye deposits in order to improve the quality of nickel and copper concentrates. A side effect of the implementation was a significant reduction in the amount of pyrrhotite concentrate (PC) supplied for processing to the hydrometallurgical production (HMP) of the Nadezhda Metallurgical Plant (NMZ). In 2003, a method of improving the autoclave-oxidation technology for processing PC with high pyrrhotite content was introduced into industrial production, which provides for the involvement of intermediate products of ore enrichment at Talnakh Concentrator into the HMP of NMP. This allowed to increase the output of non-ferrous and precious metals from "off-balance" raw materials while optimizing the utilization of the existing capacities of the NMP; to increase the stability of the oxidative leaching process of high-sulfur coarse-dispersed PCs and to improve the technological performance of the Talnakh Concentrator and the NMP. The actual economic effect obtained during 5 months of the development utilization amounted to 176 mln rub.
