Abstract:In response to the high hardness of discharged water (350~900 mg/L CaCO3), seasonal water scarcity, and pipeline scaling risk at Wushan Copper Mine in Jiangxi, this study developed a softening and reuse process based on ion exchange resin. Laboratory-scale tests were conducted to select a domestic Zhengguang (working exchange capacity 550~600 mmol/L). Operating parameters were optimized (flow rate 12 m/h, regenerant concentration 6%~8% NaCl), and the feasibility was verified at an industrial scale of 120 m3/h. Results showed that the softened water hardness was stably controlled at 0~130 mg/L CaCO3, with a Ryznar stability index of 6.0~7.3. Regenerant salt consumption was 210~245 g/mol, and treatment cost per ton of water was 0.686 RMB/ton, of which the salt cost was 0.684 RMB/ton. Resin cost per cubic meter of softened water was 0.069 RMB/m3, and the average electricity cost for recycled water was 0.002 RMB/m3, comparable to current water intake cost. Concentrations of heavy metals in the regeneration waste complied with the GB 25467—2010 discharge standards (Pb<0.37 mg/L, Zn<0.45 mg/L). This technology addressed the production risk caused by seasonal water interruptions of the Nanyang River, achieved 100% wastewater reuse, and provided a solution for treating high-hardness mine wastewater.