Prospects for the Ferronickel Production Development from the Urals Oxidized Nickel Ores

Methods of ore processing are divided into hydro- and pyrometallurgical. The latter method is more common. Ferronickel is seeing high demand at present. It is produced by reducing electric smelting of previously calcined ore. This method is typically used because of the composition and quality of the products obtained (there is a particularly large market for Ferronickel of the standard ISO 6501:1988, containing at least 15% Ni). Processing technologies for converting poor oxidized nickel ores into ferronickel offer significant advantages, reducing the environmental impact and energy consumption, and increase the recovery of valuable metals. This study considers the processing technology of serpentinite ores, which includes: ore preparation (averaging, crushing and screening, drying); roasting a mixture of dried ore and crushed dolomite (flux) in tubular rotary kilns; melting of hot cinder with the addition of a reducing agent in an ore-smelting direct-current electric furnace to produce a rough ferronickel; refining ferronickel from impurities of carbon, silicon, sulfur, phosphorus, chromium was substantiated. During the industrial testing of electric smelting of calcined ores from the Ural deposits, ferronickel, containing (in wt. %) 8.9-15.5 Ni, 1.1 Cr, 0.17 Co, 0.1 S, 0.1 C was produced. Nickel extraction in ferronickel was 96.1 %, cobalt – 89.1 %. Keywords: ore, nickel, production, heating, roasting and reduction, phase transition

Structure of oxidative and sulphate-clorinating roasting products of nickel converter matte

The structure and phase composition of the nickel converter matte roasting products has been studied in the sulphate-chlorinating process stage. In stages of the converter matte oxidation in the "fluidized bed" and flash smelting remainder roasting together with silvinite the distribution of non-ferrous metals on the phase constituents has been estimated. In the article data from optical spectroscopy, as well as X-ray diffraction, microprobe and chemical analyze are used. As following from the composition of the phases formed during sulphate-chlorinating roasting and thermodynamic modeling data a number of reactions proceeding in the process is presented. © 2013 Allerton Press, Inc

The effect of the nickel sulphide alloys structure on their electrochemical oxidation parameters

The granulation of nickel sulphide alloys results in formation of the ultrafine structure because of their reactivity is increased in the hydrometallurgical processing The phase composition and phase size of nickel sulphide alloys granulated was studied by X-ray and optical microscopy methods It is shown the high cooling rate leads to the crystallization of non-equilibrium phase and dispersion of a metal component The parameters of the electrochemical oxidation of nickel sulfide granular alloys in sulfuric acid solution were estimated The initial potentials of phase components oxidation of nickel sulfide alloys granulated were defined The rate of electrochemical oxidation of nickel sulfide alloys granulated is higher than that at slow-rate cooling Copyright © 2013 IFAC.Russian Academy of Sciences, РАН: 12-I-3-103This research was supported by the Presidium of RAS project No. 12-I-3-103.and Metal Processing;Control (IFAC) - TC 6.2. Mining, Mineral;International Federation of Automatic;TC 6.1. Chemical Process Control;TC 6.3. Power and Energy System

Intermolecular interactions-photophysical properties relationships in phenanthrene-9,10-dicarbonitrile assemblies

Phenanthrene-9,10-dicarbonitriles show various luminescence behaviour in solution and in the solid state. Aggregation patterns of phenanthrene-9,10-dicarbonitriles govern their luminescent properties in the solid state. Single crystal structures of phenanthrene-9,10-dicarbonitriles showed head-to-tail intraplane (or quasi-intraplane) intermolecular interactions and π-stacking patterns with eclipsing of molecules when viewed orthogonal to the stacking plane. The π-stacking interactions were detected in the X-ray structures of phenanthrene-9,10-dicarbonitriles and studied by DFT calculations at the M06–2X/6–311++G(d,p) level of theory and topological analysis of the electron density distribution within the framework of QTAIM method. The estimated strength of the C⋯C contacts responsible for the π-stacking interactions is 0.6–1.1 kcal/mol. The orientation of molecules in crystals depends on the substituents in phenanthrene-9,10-dicarbonitriles. Distinct molecular orientation and packing arrangements in crystalline phenanthrene-9,10-dicarbonitriles ensured perturbed electronic communication among the nearest and non-nearest molecules through an interplay of excimer and dipole couplings. As a result, the intermolecular interactions govern the solid state luminescence of molecules

Structural data of phenanthrene-9,10-dicarbonitriles

In this data article, we present the single-crystal XRD data of phenanthrene-9,10-dicarbonitriles. Detailed structure analysis and photophysical properties were discussed in our previous study, "Intermolecular interactions-photophysical properties relationships in phenanthrene-9,10-dicarbonitrile assemblies" (Afanasenko et al., 2020). The data include the intra- and intermolecular bond lengths and angles. (c) 2019 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Фазовый состав и термические свойства окисленной никелевой руды Сахаринского месторождения

X-ray diffraction, optical microscopy and X-ray microanalysis were used to determine the composition and distribution of elements in the main mineral constituents of oxidized nickel ore at the Sakhalin deposit (goethite, hematite, serpentine, talc and chlorite). The main fraction of nickel is concentrated in iron oxides, where its content reaches 2,4 %, while in magnesium silicates it does not exceed 0,4 %. The sequence and temperature intervals of transformations were established when heating ore in inert and reducing media by means of thermal analysis methods combined with mass-spectrometric analysis of gases and subsequent X-ray phase analysis of products. The temperature regimes of ore roasting for the reduction of nickel and iron from their minerals were justified. The temperature regimes of sample heating are assumed to be close to the conditions implemented in industrial units (electric furnaces) where the rate of charge heating varies within 5—15 degrees/min, up to the melting point (1450 °С) of ferronickel and slag. It is proposed to use information on material composition, thermal properties and metal forms in ore to select regimes and technologies for their pyro-or hydrometallurgical processing. Nickel and iron recovery from oxides in CO environment occurs above 800 °С, while serpentines remain stable up to 1200 °С. The use of coke as a reducing agent allows reducing iron and nickel from serpentines at temperatures above 1250 °С. The obtained data were used to substantiate the operating conditions of roaster and electric furnaces during ferronickel smelting from oxidized ores. When roasting, resulting ferronickel particles will contain 2—4 % Ni. Completing recovery processes in the electric furnace will ensure metal recovery from magnesium silicates, which will slightly increase the nickel content in ferro-nickel.Методами рентгенографии, оптической микроскопии и рентгеноспектрального микроанализа определены составы и распределение элементов в основных минеральных составляющих окисленной никелевой руды Сахаринского месторождения: гетите, гематите, серпентине, тальке и хлорите. Основная доля никеля сосредоточена в оксидах железа, где его содержание достигает 2,4 %, в то время как в силикатах магния — не превышает 0,4 %. Методами термоанализа, совмещенного с масс-спектрометрическим анализом газов, и последующей рентгенографии продуктов установлены последовательность и температурные интервалы превращений при нагреве руды в инертной и восстановительной средах. Обоснованы температурные режимы обжига руды для восстановления никеля и железа из их минералов. Температурные режимы нагрева образцов приняты близкими к условиям, реализованным в промышленных агрегатах (электропечи), где скорость нагрева шихты колеблется в пределах 5—15 град/мин, вплоть до температур плавления (1450 °С) ферроникеля и шлака. Сведения по вещественному составу, термическим свойствам и формам нахождения металлов в руде предложено использовать при выборе режимов и технологий их пиро- или гидрометаллургической переработки. Восстановление никеля и железа из оксидов в среде СО происходит при температурах выше 800 °С, в то время как серпентины остаются устойчивыми вплоть до 1200 °С. Применение кокса в качестве восстановителя позволяет восстанавливать железо и никель из серпентинов при температуре выше 1250 °С. Полученные данные использованы для обоснования режимов работы обжиговых и электрических печей при выплавке ферроникеля из окисленных руд. При обжиге образующиеся частицы ферроникеля будут содержать 2—4 % Ni. Завершение восстановительных процессов в электропечи обеспечит извлечение металлов из силикатов магния, что позволит незначительно повысить содержание никеля в ферроникеле

РАСЧЕТ СКОРОСТИ ВОССТАНОВЛЕНИЯ МЕДИ, НИКЕЛЯ И КОБАЛЬТА ИЗ ОКСИДНЫХ РАСПЛАВОВ МОНООКСИДОМ УГЛЕРОДА

Supposing the electrochemical nature of the interaction of reducing gas (CO) with oxide melt containing transition metal ions, a kinetic equation is derived for calculation of the reduction process rate taking physical and chemical properties of the contacting phases. Satisfactory agreement between the calculated and experimental data is shown by the example of interaction of the CaO–SiO2–Al2O3 system melt, which contains up to 6.0 wt.% MenOm (NiO, CoO, Cu2O), blasted by gas phase of partial pressure РCO = (0,4÷5,0)·102 MPa at Т = 1623 K.В предположении электрохимической природы взаимодействия газа-восстановителя (СО) с оксидным расплавом, содержащим ионы металлов переходной группы, выведено кинетическое уравнение для расчета скорости восстановительного процесса, учитывающее физико-химические свойства контактирующих фаз. На примере взаимодействия оксидного расплава системы СаО–SiO2–Al2O3, содержащего до 6,0 мас.% MenOm (NiO, CoO, Cu2O), обдуваемого газовой фазой с парциальным давлением РСО = (0,4÷5,0)·102 МПа при Т = 1623 К показано удовлетворительное согласие расчетных и экспериментальных данных

Reactive Oxygen Species Production by Forward and Reverse Electron Fluxes in the Mitochondrial Respiratory Chain

Reactive oxygen species (ROS) produced in the mitochondrial respiratory chain (RC) are primary signals that modulate cellular adaptation to environment, and are also destructive factors that damage cells under the conditions of hypoxia/reoxygenation relevant for various systemic diseases or transplantation. The important role of ROS in cell survival requires detailed investigation of mechanism and determinants of ROS production. To perform such an investigation we extended our rule-based model of complex III in order to account for electron transport in the whole RC coupled to proton translocation, transmembrane electrochemical potential generation, TCA cycle reactions, and substrate transport to mitochondria. It fits respiratory electron fluxes measured in rat brain mitochondria fueled by succinate or pyruvate and malate, and the dynamics of NAD+ reduction by reverse electron transport from succinate through complex I. The fitting of measured characteristics gave an insight into the mechanism of underlying processes governing the formation of free radicals that can transfer an unpaired electron to oxygen-producing superoxide and thus can initiate the generation of ROS. Our analysis revealed an association of ROS production with levels of specific radicals of individual electron transporters and their combinations in species of complexes I and III. It was found that the phenomenon of bistability, revealed previously as a property of complex III, remains valid for the whole RC. The conditions for switching to a state with a high content of free radicals in complex III were predicted based on theoretical analysis and were confirmed experimentally. These findings provide a new insight into the mechanisms of ROS production in RC