A novel process based on gas filled memb

In the last ten years, the operational costs in the gold and silver cyanidation processes have increased, fundamentally, due to the treatment of ores which contains high cyanide soluble metals, such as zinc, copper, and nickel, among others, increasing the cyanide consumption along with the increase in cyanide price. Additionally, the high cyanide consumptions in gold operations have increased the cyanide contents in leach tailings, forcing the inclusion of processes to recover or eliminate cyanide. For these reasons, a membrane contactor operation to recover cyanide from gold mining, using gas filled membrane absorption is proposed in this study, performing laboratory tests in order to determine the throughput of this process and the most relevant parameters, which affect the cyanide recovery. Gas Filled Membrane Absorption (GFMA) process can extract cyanide, using an absorption solution of NaOH. In this process, previously reported for wastewater treatment, a hydrophobic membrane with its pores filled with air separates an aqueous stream containing cyanide and receives a solution with a high pH value. These aqueous solutions cannot penetrate into the membrane pores, promoting the cyanide transfer from the cyanidation solution to the receiving solution. The experimental results showed that, in the optimal conditions established, a cyanide extraction of 70% was achieved, obtaining an average diffusivity of 10 kg m−2 h−1 and identifying the pH, feed flow rate and copper concentration as the most influential parameters on the performance of the process.