The objective of this study is to introduce a treatment sequence enabling straightforward and effective recovery of hazardous trace elements from recovery boiler fly ash (RBFA) by a novel method, and to demonstrate the subsequent removal of Cl and K with the existing crystallization technology. The treatment sequence comprises two stages: dissolution of most other RBFA components than the hazardous trace elements in water in Step 1 of the treatment, and crystallization of the process chemicals in Step 2. Solid-liquid separation has an important role in the treatment, due to the need to separate first the small solid residue containing the trace elements, and to separate the valuable crystals, containing Na and S, from the liquid rich in Cl and K. According to the results, nearly complete recovery of cadmium, lead and zinc can be reached even without pH adjustment. Some other metals, such as Mg and Mn, are removed together with the hazardous metals. Regarding the removal of Cl and K from the process, in this non-optimized case the removal efficiency was satisfactory: 60–70% for K when 80% of sodium was recovered, and close to 70% for Cl when 80% of sulfate was recovered.

这项研究的目的是介绍一种处理程序，该处理程序能够通过一种新颖的方法从回收锅炉粉煤灰（RBFA）中直接有效地回收有害微量元素，并演示随后利用现有的结晶技术去除Cl和K的方法。处理顺序包括两个阶段：在处理的步骤1中，除有害微量元素以外的其他大多数RBFA组分在水中的溶解；在步骤2中，工艺化学品的结晶。固液分离在处理中起着重要的作用，这是因为首先需要从含有微量元素的小固体残渣中分离出来，并从富含Cl和K的液体中分离出含有Na和S的有价值的晶体。根据结果，几乎完全回收了镉，即使不调节pH值也可以达到铅和锌。某些其他金属（例如Mg和Mn）也与有害金属一起被去除。关于从工艺中去除Cl和K的问题，在这种非优化的情况下，去除效率令人满意：当回收了80％的钠时，K的去除率为60-70％，而当回收80％的硫酸盐时，Cl的去除率接近70％。恢复了。