复掺粉煤灰吸附剂碳化固碳反应及对重金属浸出特性的影响

针对复掺方法提高粉煤灰矿物固碳效率和重金属析出钝化作用，采用粉煤灰掺入不同比例的消石灰和氧化铝制备了固碳吸附剂，利用三相高压反应釜模拟碳酸化固碳反应，利用热重-差热测试分析了不同配比固化剂CO2固定量和固定效率，对碳酸化反应前后固化剂的化学成分进行了分析，揭示了复掺粉煤灰吸附剂固碳机理，对碳酸化反应前后固化剂材料中重金属浸出毒性进行了实验模拟。结果表明，粉煤灰基固化剂复掺消石灰后，增加了固化材料中CaO量，显著提高了碳酸化体系中pH值，当粉煤灰与消石灰质量比为1：1时，碳固定效率最高，达到6.98%。当消石灰的投加量为50%时，As、Cd、Cu、Pb、Cr受到了较强的抑制效果，Ni、Zn的浸出浓度没有变化。因此，复掺消石灰、氧化铝的粉煤灰基碳固化材料可有效改善纯粉煤灰碳酸化固定CO2的效率，并可降低粉煤灰碳酸化后重金属的浸出毒性。

Carbonation for carbon sequestration by coal fly ash adsorbent with additives and impacts on leaching characteristics of heavy metals

In an effort to improve the mineral carbonation efficiency of coal fly ash (CFA)for carbon sequestration as well as to alleviate heavy metal leaching,compounding adsorbents made of CFA,slaked lime,and alumina were prepared. Mineralization reaction experiments were conducted using a high-pressure triple-phase reactor. Carbonation contents and the efficiency of adsorbents with different CFA slake lime ratios were quantified by T-G analysis. Moreover,chemical components of the adsorbents were analyzed before and after the mineralization reaction. The carbon sequestration mechanism of CFA adsorbents is critically discussed. The leaching toxicity of heavy metals in adsorbents was tested before and after the carbonation reaction as well. The results indicate that CFA-based adsorbents mixed with slaked lime increase the addition of CaO amount and the pH value is significantly elevated. The highest carbonation efficiency (6.98%) was observed at the CFA-lime ratio of 1:1. When the additive ratio of slaked lime was 50%,the leaching amounts of As,Cu,Cd,Pb,and Cr in CFA were strongly inhibited. Therefore,it is reliable to improve carbonation efficiency of CFA adsorbents and reduce the leaching toxicity of heavy metals by mixing with slaked lime and alumina.