低温热解技术在中试条件下修复汞污染土壤的研究

A study on a pilot-scale remediation employing low-temperature pyrolysis technology for mercury contaminated soil

本文在总结已有实验结果的基础上,扩大低温热解处理规模,验证低温热解技术在中试条件下(处理规模约150kg/h)修复汞污染土壤的可行性。实验结果表明,汞污染土壤在热解温度为350℃,热解时间为30min的条件下,土壤中汞的去除效率可达79.75%。经修复后土壤粉砂粒含量增加,而粘粒含量降低,土壤质地由粘质壤土变为砂壤;修复后土壤p H、有机质、全氮、碱解氮、全磷、全钾等指标与修复前相当,有效磷的含量增加了144.34%,而速效钾降低了55.29%,阳离子交换量(CEC)降低了36.05%,但修复后土壤仍然满足农耕要求。

Based on existed experimental results,this study further expands the experiment scale to pilot-scale( processing capacity of about 150kg/h) with the purpose to verify the feasibility for remediating mercury contaminated soil with low-temperature pyrolysis technology under such a condition. The experimental results show that the removal efficiency of mercury from soil reaches 79. 75%as the treating temperature is controlled at 350℃ and the pyrolysis time is set at 30 min. After remediation,changes of soil texture can be observed,with an increase of silt and a decrease of clay,indicating soil changes from clayey loam to sandy loam. The p H,organic matter,total nitrogen,total phosphorus and total potassium are kept almost at the same level as that before remediation,while available phosphorus content is increased by 144. 34%. The available potassium content and cation exchange capacity( CEC) are however decreased by 55. 29% and 36. 05% respectively. The remediated soil can meet farming requirements though some soil nutrients losses are witnessed.