We buy copper concentate at 20%min and any quantity is negotiable. The goods should comply with the following requirement:Cu : 20% MinPb : 6 % MaxZn: 2% MaxAs : 0.5 % Max F : 0.1% MaxCd : 0.05 % MaxHg : 0.01 % MaxSb: 0.15% MaxMgO: 7% MaxMoisture: (H2O) 5% MaxRadioactivity less or equal to 400nGy/h