Extraction Of Copper From Highly Alkaline Gangue And Low-Grade Copper Oxide Ore

This article focuses on the "three highs and one low" characteristics of a high-alkaline gangue low-grade copper oxide ore with high calcium and magnesium content,high mud content,high oxidation rate and low grade,based on the idea of low-ammonia leaching or non-ammonia leaching.,The thermodynamic calculation and leaching process experimental research on the main minerals of ammonia-ammonium sulfate leaching,and studied the EDTA·2Na leaching process of high-alkaline gangue low-grade copper oxide,and obtained the following main conclusions:(1)For copper oxide(CuO)and basic copper carbonate(Cu2(OH)2CO3),a thermodynamic model of Cu(II)-(NH4)2SO4-NH3-H2O is established in the constructed leaching system;calculations show that Cu(II)-(NH4)2SO4-NH3-H2O system Cu(OH)2,CuCO3 and Cu3(OH)2(CO3)2 are unstable solid phases,[NH3]is affected by c(NH3)and c[(NH4)2SO4]is jointly controlled,but mainly provided by c(NH3),c[(NH4)2SO4]plays a very small role,c(NH3)promotes the increase of pH,c[(NH4)2SO4]The increase in pH has an inhibitory effect.Increasing the concentration of(NH4)2SO4 is conducive to the dissolution of CuO,and it is difficult to dissolve CuO in pure ammonia;the turning points of the change curves of c(Cu2+)T and c[(NH4)2SO4]under different ammonia concentrations are constantly changing.Iteratively,the relationship between c[(NH4)2SO4]and c(NH3)and the relationship between c(Cu2+)T and c(NH3)under a better ammonia-ammonium ratio are obtained,that is,the ammonium sulfate concentration is 0.6 mol/L,and the ammonia concentration is at 1.3 mol/L,the copper leaching rate is higher.(2)Ammonia-ammonium sulfate system leaching high-alkaline gangue low-grade copper oxide ore technology research shows that the leaching rate of copper is mainly affected by factors such as temperature,liquid-to-solid mass ratio and the concentration of ammonia and ammonium sulfate.This system is suitable The process conditions are as follows:ammonia concentration is 1.2 mol/L,ammonium sulfate concentration is 0.6 mol/L,stirring intensity is 250 r/min,liquid-to-solid mass ratio is 3:1,temperature is 25℃,and leaching time is 4 h.The copper leaching rate is 69.4%.The leaching process conditions are basically consistent with the results of higher copper leaching rate when the ammonium sulfate concentration is 0.6 mol/L and the ammonia concentration is 1.3 mol/L during the dissolution process of Cu2(OH)2CO3 calculated by thermodynamics in Chapter 3.(3)AD 100 is used to extract copper ions in the ammonia-ammonium sulfate leaching solution.The process of AD 100 extraction of copper ions is affected by the volume concentration of the extractant,different initial pH values,oscillation time and temperature,and comparison(O/A).The copper ion extraction rate and extraction rate are mainly affected by the volume concentration of the organic phase and the ratio(O/A).The suitable process conditions are:AD 100 volume concentration 7%,time 5 min,ratio(O/A)2:1.The pH value is 9.35.Under these conditions,the extraction rate of copper ions is 96.9%.The suitable process conditions for sulfuric acid stripping to load copper ions in the organic phase are:temperature 25℃ sulfuric acid concentration 1.5 mol/L,and stripping ratio(O/A)is 1:1 and the time is 10 min.Under this condition,the stripping rate of copper ions can reach 97.4%;after the copper sulfate solution after stripping is concentrated and crystallized,the main phase in the sample is CuSO4·5H2O,And the sample purity is better,and the impurity content is less.(4)Using EDTA·2Na to leaching high-alkaline gangue low-grade copper oxide ore,the effects of EDTA·2Na concentration,stirring speed,temperature,leaching time,liquid-to-solid mass ratio and other reaction conditions on the copper leaching rate were studied.The suitable leaching process conditions are as follows:stirring speed is 250 r/min,EDTA·2Na concentration is 0.3 mol/L,leaching time is 3 h,temperature is 25℃,and liquid-to-solid mass ratio is 3:1.The copper leaching rate is 68.1%.By observing the surface morphology and energy spectrum of the leached minerals,the minerals are corroded by the EDTA·2Na solution,which causes the mineral surface to be rough and uneven,but the size of the mineral particles basically does not change.