【摘要】 采用废电池的锌皮为阳极,不锈钢板为阴极,Zn2+的浓度为40g/L,导电盐氯化铵的浓度为30g/L,晶粒细化剂糊精的浓度为3g/L,阴极电流密度为12A/dm2,在低速搅拌下,通过电沉积得到了1～4μm不规则形状的纯度为91.3%的锌粉,电流效率达91.1%。研究中发现:Zn2+浓度越大,锌粉粒径越大,团聚越严重;糊精和聚乙二醇能够起到细化晶粒和防止锌粉团聚的作用;阴极电流密度越大,锌粉粒径越小,但析氢也越严重;低速搅拌和超声分散能促进Zn2+的传质,能够有效抑制析氢。电化学研究表明:当电极电势比-1.8V(vsSCE)更负时,能造成H+和Zn2+浓差极化,得到锌粉而非镀锌层。更多还原

【Abstract】 Zinc powder was electrodeposited from the bath containing 40g/L Zn2+,30g/L NH4Cl as the conducting salt,3g/L dextrin as the refiner with some zinc shells of used dry cells as the anode and stainless steel plate as the cathode.Irregulerly shaped zinc powder 1～4 μm in size,91.3% in purity was obtained with a current efficiency up to 91.1% at a current density of 12A/dm2 and with low-speed agitation.The results show that,the higher Zn2+ concentration the larger the powder size and the severer the glomeration is;both dextrin and polyethylene glycol can act as the grain refiner and prevent the glomeration;the higher the cathode current density,the finer the zinc powder,the more hydrogen evolution is;low-speed agitation and ultrasonic wave can accelerate the mass transfer of Zn2+ and depress the hydrogen evolution.The results of electrochemical studies indicate that the concentration polarization of Zn2+ and H+ is great enough to obtain zinc powder instead of plate when the potential is more negative than-1.8V(vs SCE).更多还原