FCC废催化剂中的金属污染物及其环境风险

Pollution characteristics and risk of main metal pollutants in spent FCC catalysts in China

采集国内不同地区的19套流化催化裂化(FCC)装置产生的FCC废催化剂样品,分析其金属浓度及浸出浓度,探讨FCC废催化剂中的主要金属污染物、污染特性及潜在风险。结果表明:FCC废催化剂中主要金属为镍、钒、锑、钴和锌;不同装置采集的FCC废催化剂中主要金属浓度与浸出浓度差别较大,其中镍、钒、锑浸出浓度较高,分别为0.004~3.171、0.130~39.490、0.042~8.099 mg L;FCC废催化剂中金属浸出浓度不影响其作为危险废物填埋,而浸出pH过低需要进行预处理后才能进入危险废物填埋场;当FCC废催化剂长期堆存在地面时,锑会释放出来,危及地下水,存在一定健康风险,而镍没有类似影响。

The spent fluid catalytic cracking (FCC) catalysts generated from 19 FCC units in different regions of China were collected, the heavy metal contents and leaching concentrations analyzed, and the main metal pollutants, pollution characteristics and potential risks discussed. The results were as follows: The main metal pollutants in spent FCC catalyst were nickel, vanadium, antimony, cobalt and zinc. The total concentration and leaching concentration of main metal pollutants varied great among different facilities. The leaching concentration of nickel, vanadium and antimony were comparatively higher, which were 0.004-3.171, 0.130-39.490, 0.042-8.099 mg L respectively. The metals leaching concentrations from spent FCC catalyst could meet the criteria to enter the landfills as hazardous waste, whilst the pH in leaching solution was too low to enter hazardous waste landfill which need pretreatment. If a pile of spent FCC catalyst were not environmentally managed but stored on ground for a long period, the antimony would be released, thus endangering the groundwater and leading to certain potential health risk. The nickel had no similar effect.