Effect of Jet Flow between Electrodes on the Cathode Quality in Copper Electrorefining with High Current Density

Increasing current density is one of the main methods for improving the productivity of copper electrorefining. However, in the conventional bottom-inlet/top-outlet mode, an increase in current density leads to a deterioration of the surface quality of the cathode copper. This paper describes an experimental study of the influence of the jet flow between electrodes on the cathode quality. The surface roughness and the standard deviation of the cathode copper were used to evaluate the cathode quality. The results showed that in the single-side jet inlet mode, the electrolyte circulation rate has great influence on the surface roughness of the cathode copper, which is inversely correlated. However, when the electrolyte circulation rate is small, the surface roughness of the cathode copper is not uniform. The farther the position at the surface of the cathode copper is to the jet region, the coarser the cathode copper surface, and vice versa

Numerical Simulation of Electromagnetic Field in Round Bloom Continuous Casting with Final Electromagnetic Stirring

A 3D mathematical model was developed to simulate the electromagnetic field in Φ600 mm round bloom continuous casting with final electromagnetic stirring (F-EMS), and the model was verified using measured data for the magnetic flux density in the stirrer centre. The distribution of electromagnetic force and the influence of current intensity and frequency were investigated. The results show that the Joule heat generated by F-EMS is very small and its influence on secondary cooling heat transfer in the stirring zone can be ignored. With an increase in current frequency, the electromagnetic force density at R/2 and R/3 of the Φ600 mm round bloom first increases and then decreases, reaching a maximum at 10 Hz

Kinetic and Thermodynamic Studies on the Phosphate Adsorption Removal by Dolomite Mineral

The efficiency of dolomite to remove phosphate from aqueous solutions was investigated. The experimental results showed that the removal of phosphate by dolomite was rapid (the removal rate over 95% in 60 min) when the initial phosphate concentration is at the range of 10–50 mg/L. Several kinetic models including intraparticle diffusion model, pseudo-first-order model, Elovich model, and pseudo-second-order model were employed to evaluate the kinetics data of phosphate adsorption onto dolomite and pseudo-second-order model was recommended to describe the adsorption kinetics characteristics. Further analysis of the adsorption kinetics indicated that the phosphate removal process was mainly controlled by chemical bonding or chemisorption. Moreover, both Freundlich and Langmuir adsorption isotherms were used to evaluate the experimental data. The results indicated that Langmuir isotherm was more suitable to describe the adsorption characteristics of dolomite. Maximum adsorption capacity of phosphate by dolomite was found to be 4.76 mg phosphorous/g dolomite. Thermodynamic studies showed that phosphate adsorption was exothermic. The study implies that dolomite is an excellent low cost material for phosphate removal in wastewater treatment process