镍渣的重金属浸出特性

在分析镍渣的矿物相组成和重金属元素含量的基础上,鉴定了镍渣样品的浸出毒性,并考察了pH、液固比和浸出时间等条件对镍渣样中铬、铅、铜和锌等重金属浸出特性的影响。结果表明,镍渣中的重金属总量约为渣样的0.9%,且铬、铜和锌的含量较高,需进行安全管理。实验所用镍渣样品为第Ⅰ类一般工业固体废物。在强酸条件下镍渣中重金属浸出浓度较大,pH3后浸出浓度显著降低;液固比40 L/kg时,镍渣中重金属不断溶出,液固比40 L/kg后,浸出达到饱和,浸出浓度趋于平衡;随着浸出时间的增加,重金属离子的浸出浓度先增加后减少,但由于各重金属性质不同,各重金属达到最大浸出浓度的时间不同。

Leaching characteristics of heavy metals from nickel slag

On the basis of analyzing mineral phase and heavy metal element contents from nickel slag, the leaching properties were identified and the effects of conditions such as pH, liquid-solid ratio and leaching time were investigated. The results showed that the total fraction of the main heavy metals was about 0.9% in the nickel slag, with Cr, Cu and Zn accounting for higher fractions and environmental risks. The nickel slag belonged to the first general industrial waste. The leaching concentrations were higher when the leaching acid was stronger, but decreased markedly when pH>3. When the liquid-solid ratio was less than 40 L/kg, the heavy metals were dissolved into the liquid, and when exceeded, they were satiated and balanced. The leaching concentrations increased in the beginning and then decreased, but leaching times reaching the maximum were varied due to the nature of heavy metals.