Granulometric Characteristics Study for the Particles of the Cu2-xS - Fex+1S System

The electrolysis of granular matte is a new alternative method for processing sulphide copper materials with the production of cathode copper and the conversion of sulfur to the elemental state. For the first time were established the regularities for the Cu2-xS – Fex+1S granules distribution by the size classes of obtained granulations for the Cu - Fe - S melt at temperatures of 1200, 1250, 1300 and 1350 °C. The maximum amount of Cu2-xS – Fex+1S material of size class 5.0 + 2.5, -2.5 + 1.6 and-1.6 + 1.0 mm, which corresponds to the conditions of following electrochemical processing and estimated as 72.5%, was obtained by granulation of the melt at 1200 °C. The granulometric characteristics of Cu2-xS – Fex+1S granules were estimated. With an increase in the overheating temperature of the Cu - Fe - S melt, granules with a large value of the average diameter were obtained, also the root-mean-square deviation of the particle size from the average value increases and the degree of polydispersity of the granules decreases. The duration of cooling for Cu2-xS – Fex+1S granules from the melt temperatures at 1200, 1250, 1300 and 1350 °C was calculated. In the entire considered temperature range, the particle cooling time is much longer than the spheroidization time, which contributes to the formation of spherical particles.

Assessing Water Footprint of Copper Production by Pyrometallurgy

As an important tool for water resource environmental impact assessment, the application of water footprint assessment method in copper production process is conducive to more accurate assessment of water resource environmental impact in copper production process. The water footprint assessment method released by the Water Footprint Network was used to study the water footprint of the production process of cathode copper products produced by pyrometallurgy. It was found that the water footprint of 1 ton of copper produced by pyrometallurgy was 242m3, of which the blue water footprint accounted for 60%, the grey water footprint accounted for 40%. The direct water footprint accounted for 67% and the indirect water footprint accounted for 33%. The characteristics of water footprint contribution at each process were compared, which provided data support and reference for enterprises to better understand the water resource environmental impact of copper by pyrometallurgy and to choose the water resource utilization mode with their own production characteristics.

Effect of Cd2+ on Electrodeposition of Copper in Cyclone Electrodeposition

A strategy to determine the effect of Cd2+ on the electrodeposition of copper from a copper electrolyte by cyclone electrowinning is presented. The concentration of Cu2+ in the copper electrolyte with different Cd2+ concentrations was determined by atomic absorption spectrometry (AAS). It indicated that the current efficiency, the rate of electrodeposition, and the rate copper electrodeposition decreased with the addition of Cd2+ in the three stages of electrodeposition. The current efficiency declined from 99.6 to 79.2% and the copper electrodeposition rate declined from 52 to 40% in the first electrodeposition. The current efficiency had no significant change, and the copper electrodeposition rate declined from 88 to 77% in the second electrodeposition. The current efficiency declined from 72.6 to 40.3%, and the copper electrodeposition rate was all at 99% in the third electrodeposition. The influences of the Cd2+ concentration on the purity and morphology of cathode copper were investigated. The effect of Cd2+ concentration on the purity and morphology of cathode copper was also studied. In the three-stage electrodeposition, the addition of the Cd2+ concentration mainly affected the microstructure of the cathode copper, but it had little effect on the purity of the cathode copper. The higher the amount of Cd2+, the rougher the morphology of the cathode copper and the larger the gap between the grains; the higher the amount of Cd2+, the lower the electrodeposition rate and current efficiency, though the reduction was small.

Behaviour of selenium and tellurium in copper electrowinning process

The revamping project to be implemented at Norilsk Nickel’s refining facilities includes commissioning of a nickel plant and increasing the output of copper obtained by electrowinning from liquors produced in matte leach processes. At the revamped facility, a major portion of selenium and a considerable share of tellurium will be transferred with calciner gases to a sulphuric acid facility. The microimpurities that remain after calcination get distributed between the leachates. Considering that semiproducts keep circulating between the nickel and copper plants, selenium and tellurium can accumulate in the product solutions and thus affect the quality of finished metals. This paper examines the behaviour of selenium and tellurium in copper electrowinning process and formulates certain requirements for copper electrolyte that will ensure production of high-purity copper cathodes for commercial application. It is shown that, at low concentrations of selenium (IV) and tellurium (IV) in the copper electrolyte, their discharge follows the laws of diffusion kinetics, i.e. occurs at maximum current, together with cathode reduction of copper, and the concentrations of selenium and tellurium in copper change in correlation with the concentration of chalcogenides in the solution. Simultaneously with cathode reduction on a lead anode, selenium (IV) and tellurium (IV) get oxidized to selenium (VI) and tellurium (VI) that are not precipitable with copper and get accumulated in circulating solutions. It is shown that the concentration of chalcogenides has a negative first order from the removal of copper per unit volume of electrolyte. That’s why the contamination of cathode copper with selenium and tellurium rapidly decreases with an increase in copper removal. The paper provides data that can be used to estimate the allowable concentration of toxic microimpurities in the feed electrolyte that would not affect the desired copper purity level.

Centrifugation of Interphase Suspension with the Use of Surfactants

Currently, in non–ferrous metallurgy, hydrometallurgical methods are practiced for metal recovering from copper ore in addition to pyrometallurgy, for example, SX–EW (solvent extraction–electrowinning). Although this technology gives the opportunity to get cathode copper from oxidized ores without thermal impact on the material, it has several disadvantages, one of which is the formation of interphase suspension or “crud” in the extraction process. The interphase suspension impedes and worsens extraction process performances and carries away the large number of valuable components, such as extractant, diluent and copper–containing solution. At present, this interphase suspension is not recycled, instead it is drained from the extractor and stored. Interphase suspension recycling is a highly relevant problem of hydrometallurgical production.

Recycling of Gas Cleaning Off-test Products when Producing Copper at "Kolskaya GMK" JSC

The procedures aimed to recycle off-test products of the dust-and-gas phase when producing copper at the industrial complex “Severonikel” of “Kolskaya GMK” JSC have been developed. Introduction of the proposed procedures into production will allow substantial reducing the environmental impact from cathode copper manufacture thanks to decrease of the gas phase dust content and exclusion of off-test products from the technological cycle. The advantages of the proposed procedures are low capital expenditures during implementation, increase in complexity of raw material usage, and fitness of the recycling procedures to the main technology of cathode copper manufacture.