| Hydrometallurgy method was employed to recover copper resource from vast copper smelting slag in China. The copper in copper smelting slag was leaching by oxidation-ammonia leaching method. The influencing factors of leching rate were studied, including leaching time, leaching temperature, the amount of ammonia sulfate, the concentration of ammonia, particle size of slag, mixing speed and the mass ratio of liquid and solid. And the best operation conditions were achieved. Copper sulfide can be made according to reaction between ammonium sulfide and lixivium. The influencing factors of copper recovery rate and copper sulfide purity were also studied, including the amount of ammonia sulfate, temperature, mixing speed and reaction time. It’s determined that the best operation conditions to achieve high copper recovery rate and copper sulfide purity. The results of the experiment are as follows:(1)When the slag was10g, temperature was50℃, leaching time was120min, particle size was100mesh, mixing speed was400r/min, the (NH4)2S2O8was0.7times the mass of slag, the concentration of NH3H2O was10mol/L, the effect of the mass ratio of liquid and solid (m/m) on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal mass ratio of liquid and solid was4:1(m/m), and the corresponding leaching rate of copper and zinc were49.1%and0.32%respectively.(2)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), leaching time was120min, particle size was100mesh, mixing speed was400r/min, the (NH4)2S2O8was0.7times the mass of slag, the concentration of NH3·H2O was10mol/L, the effect of temperature on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal temperature was35℃, and the corresponding leaching rate of copper and zinc were53.5%and0.15%respectively.(3)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), temperature was35℃, particle size was100mesh, mixing speed was400r/min, the (NH4)2S2O8was0.7times the mass of slag, the concentration of NH3·H2O was10mol/L, the effect of leaching time on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal leaching time was180min, and the corresponding leaching rate of copper and zinc were58.3%and0.23%respectively.(4)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), temperature was35℃, leaching time was180min, mixing speed was400r/min, the (NH4)2S2O8was0.7times the mass of slag, the concentration of NH3·H2O was10mol/L, the effect of particle size on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal particle size was200mesh,, and the corresponding leaching rate of copper and zinc were79.2%and0.23%respectively.(5)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), temperature was35℃, leaching time was180min, particle size was200mesh, the (NH4)2S2O8was0.7times the mass of slag, the concentration of NH3·H2O was10mol/L, the effect of mixing speed on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal mixing speed was500r/min, and the corresponding leaching rate of copper and zinc were80.6%and0.19%respectively.(6)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), temperature was35℃, leaching time was180min, particle size was200mesh, mixing speed was500r/min, the concentration of NH3·H2O was10mol/L, the effect of (NH4)2S2O8mass on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal the (NH4)2S2O8was0.4times the mass of slag, and the corresponding leaching rate of copper and zinc were80.8%and0.27%respectively.(7)When the slag was10g, mass ratio of liquid and solid was4:1(m/m), temperature was35℃, leaching time was180min, particle size was 200mesh, mixing speed was500r/min, the (NH4)2S2O8was0.4times the mass of slag, the effect of concentration of NH3·H2O on copper and zinc leching of the copper smelting slag was studied. The results showed that the optimal concentration of NH3·H2O was11mol/L, and the corresponding leaching rate of copper and zinc were81.7%and0.13%respectively.(8)Testing the lixivium by the flame atomic absorption spectrometry, it can be determined that copper was the major metal in the lixivium, the content of copper was85.4mg/L, and the content of zinc was small (1.4mg/L). The leaching rate of copper and zinc were81.7%and0.13%respectively. There has no other metal been tested.(9)Taking the lixivium500mL, when temperature was25℃, mixing speed was200r/min, leaching time was20min, the effect of (NH4)2S mass on copper recovery rate and copper sulfide purity was studied. The results showed that the optimal (NH4)2S mass was1.6times of the theory mass. The corresponding recovery rate of copper was90.4%and copper sulfide purity was96.9%. And the effect of (NH4)2mass on copper sulfide purity was not significant.(10)Taking the lixivium500mL, when (NH4)2s mass was1.6times of the theory mass, mixing speed was200r/min, leaching time was20min, the effect of temperature on copper recovery rate and copper sulfide purity was studied. The results showed that the optimal temperature was about25℃,. The corresponding recovery rate of copper was91.1%and copper sulfide purity was98.7%. And the effect of temperature on copper sulfide purity was not significant.(11)Taking the lixivium500mL, when (NH4)2S mass was1.6times of the theory mass, temperature was about25℃, leaching time was20min, the effect of mixing speed on copper recovery rate and copper sulfide purity was studied. The results showed that the optimal mixing speed was100r/min. The corresponding recovery rate of copper was91.1%and copper sulfide purity was98.1%. And the effect of temperature on copper sulfide purity was not significant. (12)Taking the lixivium500mL, when (NH4)2S mass was1.6times of the theory mass, temperature was about25℃, mixing speed was100r/min, the effect of leaching time on copper recovery rate and copper sulfide purity was studied. The results showed that the optimal leaching time was15min. The corresponding recovery rate of copper was90.9%and copper sulfide purity was97.8%. And the effect of temperature on copper sulfide purity was not significant. That is, these are the optimal conditions for copper recovery rate and copper sulfide purity. The rate of copper resource recovery calculated according to the formula (4.7) was74%. |
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