Thermal analysis and kinetics of the chalcopyrite-pyrite concentrate oxidation process

The paper presents the results of experimental investigation of the chalcopyrite-pyrite concentrate oxidation in the air. Characterisation of the initial sample and oxidation products was done by ICP-AES, XRD, EDXRF methods. Phase stability diagrams were constructed for Cu-Fe-S-O system at 25, 450, 650 and 900 °C. Equilibrium composition of the charge for the optimal oxidation process was calculated. DTA-TG analysis was used for monitoring the oxidation process. Kinetic parameters in non-isothermal conditions were determined, based on Kissinger and Ozawa methods.Values of activation energies showed that all stages of the oxidation process occur in the kinetic field

EXAMPLES OF LCA METHODOLOGY IMPLEMENTATION IN STEEL INDUSTRY

Steel industry kept pace with actual trends for environmental protection in many ways – through different technological improvements considering environment protection, important share of recycling in the steel production, design of so called “eco-steels”, materials designed according to recent environmental directives and legislatives, etc. In the frame of steel production monitoring, LCA methodology is very important for obtaining an accurate environmental picture of a process, due to the fact that the process should be evaluated over its entire life cycle. A number of tools and methodologies have been developed in recent years to assess the potential environmental impacts associated with a product, process or activity during its entire life cycle. The examples of Life Cycle Assessment (LCA) are used by large steel industrial companies as potentially helpful tool for improving the production processes, efficiency of resource utilization and significantly reduction of waste generation and emissions are presented in this paper

Phase diagram investigation and characterization of alloys in Bi-Ga10Sb90 section of Ga-Bi-Sb system

The results of phase equilibria investigation and characterization of the alloys in the Bi-Ga10Sb90 section of Ga-Bi-Sb system are presented in this paper. Phase diagram of the mentioned section has been calculated according to CALPHAD model, using Pandat software. In the frame of alloys characterization, structural, mechanical and electrical characteristics were determined using SEM-EDX analysis, microhardness and electroconductivity measurements

Characterization of the Ga-InSb system: experimental investigation of thermal, structural, mechanical and electrical properties

The materials based on gallium-antimonide are widely used in electronic industry in the production of various electronic devices. The results of characterization of selected alloys in the Ga-InSb system obtained by experimental investigation of some thermal, structural, mechanical and electrical properties are presented in this paper. Applied experimental techniques included: differential thermal analysis, light optical microscopy, scanning electron microscopy with EDX, hardness, micro hardness and electrical conductivity measurements

Convective response to large-scale forcing in the tropical western Pacific simulated by spCAM5 and CanAM4.3

Changes in the large-scale environment during convective precipitation events in the tropical western Pacific simulated by version 4.3 of the Canadian Atmospheric Model (CanAM4.3) are compared against those simulated by version 5.0 of the super-parameterized Community Atmosphere Model (spCAM5). This is done by compositing sub-hourly output of convective rainfall, convective available potential energy (CAPE), CAPE generation due to large-scale forcing in the free troposphere (dCAPELSFT) and near-surface vertical velocity (ω) over the time period May–July 1997. Compared to spCAM5, CanAM4.3 tends to produce more frequent light convective precipitation (&lt;0.2&thinsp;mm&thinsp;h−1) and underestimates the frequency of extreme convective precipitation (&gt;2&thinsp;mm&thinsp;h−1). In spCAM5, 5&thinsp;% of convective precipitation events lasted less than 1.5&thinsp;h and 75&thinsp;% lasted between 1.5 and 3.0&thinsp;h, while in CanAM4.3 80&thinsp;% of the events lasted less than 1.5&thinsp;h. Convective precipitation in spCAM5 is found to be a function of dCAPELSFT and the large-scale near-surface ω with variations in ω slightly leading variations in convective precipitation. Convective precipitation in CanAM4.3 does not have the same dependency and instead is found to be a function of CAPE.</p

Phase diagram investigation and characterization of alloys in Bi-Ga10Sb90 section of Ga-Bi-Sb system

The results of phase equilibria investigation and characterization of the alloys in the Bi-Ga10Sb90 section of Ga-Bi-Sb system are presented in this paper. Phase diagram of the mentioned section has been calculated according to CALPHAD model, using Pandat software. In the frame of alloys characterization, structural, mechanical and electrical characteristics were determined using SEM-EDX analysis, microhardness and electroconductivity measurements

Electrochemical behavior of AgCu50 in alkaline media in the presence of chlorides and 2-mercaptobenzothiazole

Electrochemical behavior of an alloy AgCu50, pure copper, and pure silver, respectively, was investigated by measuring the open circuit potentials using anodic potentiodynamic polarization and potentiostatic method in 0.1 moldm-3 NaOH + 0.02 moldm-3 NaCl solution, without and with adding 2-mercaptobenzothiazole in various concentrations (0.00001 - 0.001 moldm-3). Anodic polarization curves for AgCu50 alloy, showed four current peaks. Potentiostatic curves showed that values of the stationary current densities drop down with the increase of 2-mercaptobenzothiazole concentration in the electrolyte. The electrode surface was analyzed by optical microscopy after the potentiostatic oxidation. Micrographs confirmed that 2-mercaptobenzothiazole has got the inhibitory effect by forming the film of CuMBT and AgMBT which protect the electrode surface from corrosion. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON.172060

Investigation of archaeometallurgical findings from Felix Romuliana locality

Remains of metallurgical activities have been discovered recently at the locality Felix Romuliana near Zaječar (Eastern Serbia), with a lot of slag occurrences and metal findings. Samples, taken from this locality, have been investigated using different characterization methods - chemical analysis, XRD and SEM-EDX, in order to clarify the Early Byzantine metallurgical activities at Felix Romuliana