银的治炼 Ag2S+4NaCN=Na[Ag(CN)2]+Na2S 4Ag +8NaCN+2H2O+02=4Na[Ag(CN)2]+4NaOH 4Au+8NaCN+2H2O+02=4Na[Au(CN)2]+4NaOH 2Na[Ag(CN)2]+Zn 2Ag 4Naz[Zn(CN)4] 银器表面会有黑色锈迹(Ag2S) 4Ag+2H2S+02=2Ag2S+2H20 (1)HNO3 2Ag2S+2N03+8H+=3S+2N0+6Ag++4H20 (2)NaCN 2Ag2S+2CN-=[Ag(CN)2]+S2- (3)Zn 2Ag2S+Zn +40H-=2Ag [Zn(OH)]2-+S2- 银的冶炼 Ag2S+ 4NaCN= Na[Ag(CN)2 ] + Na2S 4Ag + 8NaCN + 2H2O + O2 = 4Na[Ag(CN)2 ] + 4NaOH 4Au+8NaCN+2H2O+O2 = 4Na[Au(CN)2 ] + 4NaOH 2Na[Ag(CN)2 ] + Zn = 2Ag + 4Na2 [Zn(CN)4 ] 银器表面会有黑色锈迹 (Ag2S) 4Ag＋2H2S+O2= 2Ag2S+2H2O (1) HNO3 2Ag2S + 2NO3 - + 8H+ = 3S + 2NO + 6Ag+ + 4H2O (2) NaCN 2Ag2S + 2CN- = [Ag(CN)2 ] - + S2- (3) Zn 2Ag2S + Zn + 4OH- = 2Ag + [Zn(OH)4 ] 2- + S2-