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Article
Electrical Conductivity of Rhenium-Containing Ammonium Carbonate Solutions and the Calculation of Its Activation Energy
The conductometric method is used to study the dependences of the electrical conductivity (EC) of aqueous solutions of ammonium carbonate and solutions of the ammonium carbonate–ammonium perrhenate system on t...
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Article
Electrochemical Processing of the Wastes of Heavy Tungsten Alloys in Ammonium Carbonate Solutions
The electrochemical behavior of tungsten and a VNZhK alloy (wt %: 90 W, 7.2 Ni, 1.8 Fe, 1 Co) in 0.5–1.5 M solutions of ammonium carbonate is studied by linear voltammetry in the potentiodynamic mode. An incre...
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Article
Electrical Conductivity of Ammonium Perrhenate Solutions and the Calculation of Its Activation Energy
The electrical conductivity of the aqueous solutions of ammonium perrhenate is studied in the reagent concentration range 0.01–0.2 mol/L based on metal at aqueous solution temperatures of 20–50°C. The electric...
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Article
Formation of Elemental Sulfur during the Oxidation Leaching of Chalcocite
Nonstoichiometric minerals form during the leaching of chalcocite; they form the following sequential row between chalcocite and covellite: djurleite (Cu1.93–1.96S), roxbyite (Cu1.72–1.82S), digenite (Cu1.75–1.78
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Article
Electrochemical Processing of a Heavy W–Ni–Fe Alloy by Direct and Alternating Currents in Ammonia–Alkali Solutions
The electrochemical behavior of a heavy tungsten alloy W–Ni–Fe ((wt %): 78.8 W, 15.2 Ni, 6.0 Fe) in solutions of sodium hydroxide (2–6 M) and ammonium hydroxide (0–6 M) is studied by linear voltammetry in the ...
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Article
Electrical Conductivity of Ammonium Heptamolybdate Solutions and the Calculation of Its Activation Energy
The electrical conductivity (EC) of ammonium heptamolybdate solutions in the concentration range 0.01–0.6 mol/L (based on Mo(IV)) is studied as a function of the reagent content in the solution and its tempera...
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Article
Substantiation of the Possibility to Organize a Complex Two-Stage Sulfuric Acid Leaching Technology for Pyrrhotine Middlings
A two-stage technological scheme is proposed for the processing of pyrrhotine middlings and poor copper–nickel raw materials. The hydrolytic cleaning of cycling leaching solutions from iron is separated as a p...
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Article
On the Assumed Mechanism of the Pressure Oxidation of Pyrrhotine during the Pressure Oxidation Leaching of a Low-Nickel Pyrrhotine Product Using Iron(III) Ions as an Oxidant
Abstract—The influence of the Fe(III) content in the solutions of the sulfuric acid leaching of a pyrrhotine concentrate on the features of the reaction mechanism of its desulfurization is analyzed. Owing to the ...
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Article
Electrical Conductivity of Tungsten-Containing Ammonia Solutions and Calculation of Its Activation Energy
Abstract—The activation energy of the electrical conductivity of ammonium hydroxide–tungstate ion solutions is determined in the NH4OH concentration ranges 0.01–6 and 0.01–0.2 mol/L (based on the metal). For all ...
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Article
Leaching of Rapidly Cooled Copper–Nickel Converter Mattes
Abstract—Physicochemical studies aimed at increasing the technological efficiency of the hydrometallurgical sulfuric acid processing of copper–nickel converter mattes are presented. The influence of preliminary q...
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Article
Electrical Conductivity of Tungsten-Containing Ammonium Hydroxide Solutions
The electrical conductivity of ammonium hydroxide–tungstate ion solutions is studied in the concentration range 0.01–6 M NH4OH and 0.01–0.2 M W (based on metal) as a function of the reagent content in a solution ...
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Article
Combined Flotation Hydrometallurgical Technology for the Beneficiation and Processing of Disseminated Copper–Nickel Ores
The possibilities of extracting valuable components and producing selective good-quality concentrates from hard-to-beneficiate crude ores are considered for the disseminated copper–nickel ores from the Norilsk...
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Article
Substantiation of the Possibility of Hydrometallurgical Processing of a Copper–Nickel Converter Matte
The hydrometallurgical processing of industrial converter mattes with the copper-to-nickel concentration ratios (Ni : Cu) of 2 : 1 and 3 : 4 is studied in order to demonstrate the advantages of hydrometallurgi...
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Article
Behavior of Nickel and Copper Sulfides and Their Mixtures in Sulfuric Acid Solutions
The behavior of nickel sulfide (Ni3S2), copper sulfide (Cu2S), and their mixture (Ni3S2 : Cu2S = 1 : 1) is studied under the leaching conditions in sulfuric acid solutions. The effects of the acid concentration, ...
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Article
Improved Electrodialysis Synthesis of Perrhenic Acid from the Electrolytes of Processing the Wastes of Tungsten–Rhenium Alloys
The voltage drops across the elements of a three-chamber electrolytic cell are measured during the synthesis of perrhenic acid from potassium perrhenate, and the main contribution to the total bath voltage is ...
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Article
Electrical Conductivity of Ammonia–Alkali Solutions and Its Activation Energy
The electrical conductivity of sodium hydroxide–ammonium hydroxide solutions in the concentration ranges 1–3 M NaOH and 2–6 M NH4OH is studied in accordance with the content of the reagents in the solution and it...
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Article
Electrochemical Oxidation of a Heavy Tungsten-Containing VNZh-Type Alloy and Its Components in Ammonia–Alkali Electrolytes
Linear voltammetry in the potentiodynamic mode is used to study the electrochemical behavior of a heavy tungsten-containing VNZh alloy (in wt %: 90 W, 7 Ni, 3 Fe) and its components in ammonia–alkali electroly...
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Article
Some Features of the Cathodic and Anodic Nickel Depassivation during DC Polarization in Sulfuric Acid Solutions
A comparative analysis of the formation and decomposition processes and the component composition of the phases of films that passivate a nickel electrode during its dc polarization in sulfuric acid solutions ...
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Article
Some Features of the Nickel Passivation Mechanism during Direct Current Polarization in Sulfuric Acid Solutions
The chemical compositions of the films on the nickel surface are examined by X-ray photoelectron spectroscopy during direct current polarization in aqueous and acidic electrolytes, which determine the mechanis...
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Article
Effect of Cathodic Polarization on the Depassivation of Oxidized Nickel
The dissolution of nickel in sulfuric acid (100 g/L) is studied by cyclic voltammetry using intermediate cathodic polarization between cycles. The main laws of the joint effect of the potential (from –2.0 to ‒...
