Papers by Keyword: Copper Recovery

Abstract: This paper mainly introduces a novel route for copper recovery from waste printed circuit boards (WPCBs) via mechanochemistry. Copper in the crust is most commonly present as copper-iron-sulfide and copper-sulfide minerals (about 80%) and there exist many methods to extract copper from cooper ores in mineral engineering. It seems an alternative to transform the metallic components in obsolete materials to their corresponding compounds common in nature. By means of mechanochemistry, copper and sulfur were verified to form into copper sulfide in the model experiment, where, meanwhile, the optimal ball milling time was determined (20 minutes). In the real experiment, WPCB fragments and sulfur were mixed and ground for 20 minutes, no copper was detected by XRD analysis but copper sulfide was left. After leaching in sulfuric acid (3M) and hydrogen peroxide (30 wt%), the yield of copper reached nearly 95% and, also, resin was conserved for further utilization. This paper, for the first time, reports the green recovery route combining mechanical activation and sulfurization and may provide an alternative in other studies of metal recovery.

Abstract: Electrodeposition method was applied to recover copper from the simulation of copper-containing electroplating wastewater. Stainless steel plate is used as the cathode and the anode is made of titanium plate coated with RnO2+IrO2, titanium mesh coated with RnO2+IrO2 or stainless steel plate. The electrode potential of copper in electrolyte was calculated, and the effect of initial concentration of copper ions, temperature of electrolyte, voltage, electrode spacing, initial pH value and additive concentration on the recovery of copper was studied in detail. The experimental results showed that the proper anode is titanium plate coated with RnO2+IrO2.Under the condition ofinitial concentration of copper ions 25g/L, temperature of electrolyte 40°C, voltage 3.8V, electrode spacing 25mm, initial pH value 3.60, additive concentration 7.1g/L,the recovery rate of copper can achieve 99.4% and the current efficiency can achieve 88.5%.

Abstract: Low grade copper ores containing chalcopyrite are increasingly used for copper recovery via biomining. Since metal sulfide oxidation is an exothememic process, bioleaching activity can be measured due to the heat output by microcalorimetry, which is a non-destructive and non-invasive method. The bioleaching activity of pure cultures of Sulfolobus metallicus, Metallosphaera hakonensis and a moderate thermophilic enrichment culture on high grade chalcopyrite was evaluated. Chalcopyrite leaching by microorganisms showed a higher copper recovery than sterile controls. Chemical chalcopyrite leaching by acid produced heat due to the exothermic reaction, the heat output was increased while metal sulfide oxidation by microorganisms.

Abstract: The recovery of vanadium and copper from the precipitate and the waste water formed in the removing vanadium from crude TiCl₄ with copper wire was investigated. For the processing of the precipitate, the brief flow includes dechlorinating, H₂SO₄ leaching copper, crystallization blue vitriod, as well as NaOH leaching vanadium, followed by ion exchange enrichment vanadium; the copper and vanadium leaching percent was 88.4% and 84.3%, respectively. For the processing of the waste water, the coprecipitation process was used, after that the discharged wastewater could meet with the National Standards. The precipitate formed in coprecipitation process was first leached by NaOH solution for recovery of vanadium, and then the leach cake containing copper was leached by H₂SO₄ solution for recovery of copper; the overall vanadium and copper recovery was 79.5% and 86.8%, respectively.

Abstract: The electrowinning method for treating high copper cyanide solution was investigated by thermodynamics analysis and experiment. The influences of copper concentration, solution temperature, electrolysis time, current density and flow rate on copper recovery and current efficiency was studied in detail and the suitable operation parameters were chosen. Copper electrowinning from the industrial barren solution with copper concentration of 12.40g/L was performed under the condition of current density of 75 mA/cm2, flow rate of 30mL/min and 50°C for 8 hours. An alloy with copper concentration of 99.87% was obtained at the cathode with total energy consumption 2938KWh/t. The used electrolysis solution added with some fresh cyanide sodium solution can be recycled to leaching process.