Industrial Matte Research Articles

Thermal Conductivity of Solidified Industrial Copper Matte and Fayalite Slag

The thermal conductivity of various copper matte and fayalite slag was measured using laser flash analysis, a non-steady state measurement method. Industrial matte and slag samples were taken in such a way that their composition represented typical process conditions. Thermal conductivities for solid copper matte (average 64% Cu) were found to be from 1.2 W m−1 K−1 at 300°C to 2.1 W m−1 K−1 at 900°C. Because arsenic is one of the most important impurities in copper matte, its effect on thermal conductivity was investigated with As-doped matte samples up to 0.59% As. The results showed substantially lower thermal conductivity, between 0.5 W m−1 K−1 and 1.3 W m−1 K−1 at 300–900°C with low As matte, behavior that is analogous to that of a semiconductor. The data obtained showed that the thermal conductivity of copper matte increased linearly with temperature, but the gradient was small. The thermal conductivity of slags was found to be between 1.6 W m−1 K−1 and 1.9 W m−1 K−1, values that are consistent with earlier studies.

A RQPSO Algorithm for Multiphase Equilibrium Calculation in the KIVCET Process

The prediction of phase configurations and the optimization of operating parameters in the metallurgical process are normally achieved by the multiphase equilibrium calculation (MEC), which is formulated as a constrained optimization problem based on the principle of Gibbs free energy minimization. A revised quantum-behaved particle swarm optimization (RQPSO) algorithm has been proposed to solve the optimization problem using three-part improved strategies. Based on the KIVCET smelting characteristics, a MEC model for the KIVCET process is established and solved using the RQPSO algorithm. The calculated and industrial data of the lead grade are 96.20% and 96.33%, respectively, those of the matte grade are 19.39% and 19.68%, and the mass fractions of Pb in the predicted and industrial matte are 3.96% and 3.34%, respectively. The calculated results of the phase configuration are consistent with the actual production data, which indicates that the MEC model and RQPSO algorithm are accurate and reliable.

Interactions of MgO·Al2O3 spinel with Cu, Cu2O and copper matte at high temperature

Magnesia-chrome refractory has been used in the copper industry for decades, and the chromium in the used refractory has been proved to have the risk to harm the environment. A reliable chromium-free refractory is urged to replace the chromium-containing refractory in the future. In the present study, MgO·Al2O3 spinel was systematically tested with Cu, Cu2O, and industrial matte respectively at 1300 °C. All samples were directly quenched into the water after the experiments and examined by electron probe X-ray microanalysis. The molten Cu and MgO·Al2O3 spinel did not react and showed a low wettability, while limited reactions between the spinel and matte were detected. However, severe reactions occurred between the spinel and Cu2O at 1300 °C. The possible applications of the spinel in the copper-making industry are discussed based on the experimental results.

High temperature reactions between Si3N4 bonded SiC materials and Cu, Cu2O and matte

Si3N4 bonded SiC (Si3N4-SiC) is a conventional refractory material and has broad applications. In the present study, Si3N4-SiC refractory materials were systematically investigated in the copper-making environment. Si3N4-SiC was reacted with Cu, Cu2O, industrial matte, Cu2S and FeS melts at 1200°C in argon gas atmosphere, and all samples were directly quenched in water after the experiments. Phase changes and compositions of the phases were measured by electron probe X-ray microanalysis. The present investigations demonstrate that Cu and Cu2S do not react with Si3N4-SiC at high temperatures and the wettability between this material and the melts is low. However, significant reactions occur between Si3N4-SiC and Cu2O, industrial matte and FeS. The results imply that Si3N4-SiC material has limited oxidation-resistance and can only be used under reducing conditions.

Compatibility of graphite with primary platinum group metals industrial matte

Wear resistance of synthetic graphite against liquid industrial platinum group metals furnace matte (Cu–Fe–Ni–S) was investigated from 800°C to 1450°C at a contact time of 1 hour. Graphite resistance was measured by the extent of liquid-matte penetration through the graphite, using X-ray microtomography. The matte was molten at 900°C, and it penetrated through cracks in the graphite wall. The matte penetration depth into the graphite did not increase with temperature. The matte loss in the gas phase increased with temperature. During melting, the volume of the industrial matte expanded. As the matte expanded, it pushed against the wall of the graphite and penetrated through cracks in the graphite wall. Where the crucible volume was large enough to accommodate the expanded matte, the matte did not penetrate through the graphite. Graphite exhibited poor resistance against penetration by the liquid industrial platinum group metals furnace matte.

Phase Relations, Activities and Precious Metal Distribution in the Cu-Fe-S-Sb System Saturated with Carbon at 1200°C

As a fundamental study to develop a new process for eliminating detrimental antimony, recovering precious metals from the antimony-rich matte produced from the copper concentrate, and treating the occasionally generated speiss in nonferrous smelting processes, the phase relations in the Cu-Fe-S-Sb system saturated with carbon and the distribution of some minor elements between the phases in the miscibility gap, where three equilibrated phases of iron-rich alloy, copper-rich alloy and matte coexist, were investigated at 1200°C by using a quenching method. The experimental results were compared with the results for the Cu-Fe-S-As-C system and discussed on the basis of activity coefficient of antimony in the matte phase at different matte grades. By utilizing the obtained data, material balance calculations concerning to the treatment of antimony-rich matte produced in copper smelting by adding the pig-iron was elaborated and also laboratory scale experiments using industrial matte were carried to corroborate the calculations. By using the phase separation, the cleaning of complex matte, the recovery of valuable copper, silver and gold into the copper-rich alloy and matte phases as well as the elimination of iron and an acceptable amount of antimony into the iron-rich alloy phase for discarding as a harmless and smaller deposit might be feasible.

Cobalt distribution during copper matte smelting

Many smelter operators subscribe to the “precautionary principle” and wish to understand the behavior of the metals and impurities during smelting, especially how they distribute between product and waste phases and whether these phases lead to environmental, health, or safety issues. In copper smelting, copper and other elements are partitioned between copper matte, iron silicate slag, and possibly the waste gas. Many copper concentrates contain small amounts of cobalt, a metal of considerable value but also of some environmental interest. In this work, the matte/slag distribution ratio (weight percent) of cobalt between copper matte (55 wt pct) and iron silicate slag was thermodynamically modeled and predicted to be approximately 5. Experiments were performed using synthetic matte and slag at 1250 °C under a low oxygen partial pressure and the distribution ratio was found to be 4.3, while between industrial matte and slag, the ratio was found to be 1.8. Both values are acceptably close to each other and to the predicted value, given the errors inherent in such measurements. The implications of these results for increasingly sustainable copper production are discussed.

Phase Relations, Activities and Minor Element Distribution in Cu-Fe-S and Cu-Fe-S-As Systems Saturated with Carbon at 1473 K

As a fundamental study to develop a new process for eliminating detrimental arsenic, recovering precious elements from the arsenic-rich matte produced from the copper concentrate, and treating the occasionally generated speiss in nonferrous smelting processes, the phase relations in the Cu-Fe-S and Cu-Fe-S-As systems saturated with carbon and the distribution of some minor elements between the phases in the miscibility gap, where three equilibrated phases of iron-rich alloy, copper-rich alloy and matte coexist, were investigated at 1473 K by using a quenching method. The experimental results were discussed on the basis of activity coefficient of arsenic in the matte phase at different matte grades. By utilizing the obtained data, material balance calculations concerning to the treatment of arsenic-rich matte produced in copper smelting by adding the pig-iron was elaborated and also laboratory scale experiments using industrial matte were carried to corroborate the calculations. By using the phase separation, the recovery of valuable copper, silver and gold into the copper-rich alloy and matte phases as well as the elimination of iron and arsenic into the iron-rich alloy phase for discarding as a harmless and smaller deposit might be feasible. [doi:10.2320/matertrans.47.2963]