医疗废物焚烧飞灰中锌回收价值分析

Recovery value analysis of zinc from medical waste incineration fly ash

  • 摘要: 聚焦医疗废物焚烧锅炉灰和飞灰中锌元素的回收价值,提出一种氧化锌化学浸出回收工艺。通过预处理、柠檬酸溶液浸出、沉淀分离、烘干及煅烧等步骤实现锌提取。分析了工艺流程各阶段样品元素含量及pH对氧化锌产率和含量影响,并从技术经济性角度评估工艺可行性。结果表明,随着pH的增加,氧化锌产率和含量逐渐减小,最佳工艺条件pH为2,酸洗温度为25 ℃,酸洗时长为12 h,煅烧温度为400 ℃,煅烧时长为2 h。此工艺参数组合下,氧化锌的提取效率较高且成本较低,锅炉灰中氧化锌产率约为0.077 kg/kg,飞灰中氧化锌产率约为0.036 kg/kg,回收效率在70%以上。经济性分析表明,从锅炉灰中回收氧化锌成本约为12.33元/kg,从飞灰中回收氧化锌成本约为10.78元/kg,总盈利可达2 400元/t,投资回收期约3.63年,经济效益显著。研究结果为医疗废物焚烧飞灰的资源化利用提供了参考。

     

    Abstract: This study focused on the recovery value of zinc from both boiler ash (BA) and fly ash (FA) in medical waste incineration systems and put forward a chemical leaching procedure for recovering zinc oxide (ZnO). The procedure included sequential steps of pretreatment, citric acid leaching, precipitation separation, drying, and calcination. The element contents at each stage and the effect of pH value on ZnO yield and content were analyzed, and the feasibility was evaluated from the technical and economic viewpoints. The result showed that with the increase of pH, ZnO yield and content decreased gradually. The optimal parameters were identified as follows: pH value 2, pickling temperature 25 ℃, pickling duration 12 h, calcination temperature 400 ℃, and calcination duration 2 h. Under these conditions, the extraction efficiency was relatively high while the cost remained low, yielding 0.077 kg ZnO per kg BA and 0.036 kg ZnO per kg FA, with a recovery efficiency reaching 70% or higher. Economic analysis indicated that the recovering cost of 12.33 CNY/kg ZnO from BA and 10.78 CNY/kg ZnO from FA. The total profit could reach up to 2 400 CNY per ton, with an investment payback period of approximately 3.63 years, demonstrating significant economic benefits. These findings provide critical references for the resource utilization of medical waste incineration residues.

     

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