电镀污泥的还原焙烧-酸浸

Reduction roasting-sulphuric acid leaching of electroplating sludge

将电镀污泥作为一种重要的重金属资源加以回收利用,逐渐成为了国内外研究的重点。以电镀污泥为研究对象,在不同的温度及不同的焙烧时间下进行直接焙烧和还原焙烧,并对焙烧底渣进行酸浸,分别研究了污泥减量率以及Cu、Ni、Zn和Cr 4种重金属的含量和浸出率,并探索了还原剂(煤粉)和催化剂(CaCO3)投加量的影响。实验结果表明,原始电镀污泥中,Cu含量最高,达到10.05%,因此,电镀污泥中Cu具有回收价值;焙烧后电镀污泥得到了减量化,同时污泥中的金属得到了富集;还原焙烧比直接焙烧更有利于Cu的选择性浸出,当煤粉投加量为10%,CaCO3投加量为0.5%,在700℃下焙烧20 min时,Cu的浸出率达到98.73%,Cu的含量达到15.07%。

To recycle the heavy metal as an important resource in electroplating sludge gradually became the focus of studies at home and abroad. Electroplating sludge, as the research object, was direct roasted and reduction roasted under different temperature and roasting time conditions. Then the electroplating sludge roasted was leached by using sulphuric acid. Some parameters were assayed, such as weight loss percentage, the concentration and leaching rate of copper, nickel, zinc and chromium in roasted sludge. The addition of reducer（coal powder） and catalyzer（CaCO3） in reduction roasting were analyzed. The results showed that the copper content was the highest in the original electroplating sludge, up to 10.05%, so copper had the value of being recycled. The weight of electroplating sludge decreased and the metal content increased after being roasted. Relative to direct roasting, reduction roasting was more beneficial to the selective leaching of copper from electroplating sludge. The leaching rate of copper achieved 98.73% and the copper content in roasted sludge achieved 15.07% when the addition of coal powder became the rate of 10% and of CaCO3 became the rate of 0.5% under the roasting temperature of 700℃ and the roasting time of 20 min.