Experimental Study On Gold Recovery From Solution With Electrodeposition Technology

At present in the electroplating industry, the gold plating wastewater containing cyanide for gold plating ornaments and decoration was using bullion dissolved in potassium cyanide, generated such as potassium cyanide-gold complex, after plating, to produce a cyanide Gold-plated liquid waste, which contained the gold content about 0.1 g/L, with very high recycling value.The thesis gives a review of the sources of gold solution and the recovery methods, including replacement of zinc, carbon adsorption, ion exchange, solvent extraction, electrodeposition and other methods. The gold-bearing solution of this experimentation is provided by the gilded corporate wastewater, which is done through the factory initial recycling, and gold concentration is 80mg/L, through the analysis of several recovery methods, the experimentation to be adopted electrodeposition.Experimentation in single-cell within the box, which is made of plexiglass, Size: 50 mm×100mm×100mm, the total volume: 500 mL, the actual volume for effective electrolytic 300 mL, cathode material for the ACF, anode for plating ruthenium titanium mesh, polar distance of 3 cm. During the whole experiment at room temperature, gold-bearing solution for each 1000 mL , relying on artificial continuous cycle through the cell. Main contents and conclusions are:(1) Cathode material selection. Through the three cathode materials that were tested, the most obvious effect of recovery with activated carbon fiber, so selection of activated carbon fiber as a cathode.(2) Orthogonal and single factor experiments. Experiment overall investigated the Effect of gold electrodeposition rate of several factors with current density, pH, sodium sulfite solution and velocity , and the regularity of deposition rate of various factors for different levels. Final the best conditions of electrodeposition are as follows: density of 83.3 A/m², solution flow rate of 35 mL/min, pH value of 11.5, the sulfite of 2g/L. Under these conditions, the current efficiency with the deposition rate of increase lower, but the deposition rate is the faster decline in the current efficiency. (3) To the best conditions for the foundation, experiment investigated respectively the effect of various factors. Obtained through the experiment: the current density is the main factors of the deposition rate, the current density greater deposition rate will sooner, but velocity and pH value of the deposition rate less affected; Na₂SO₃ additive is an important factor, and adding 2 g / L of Na₂SO₃ to the solution, electrodeposition significantly improve efficiency.(4) The electrochemical dynamic analysis and study on mechanism on the gold electrolysis process.