Occurrence of beryllium and its microscale interactions with coexisting phases in beryllium-containing sludge

Beryllium-containing sludge (BCS) is a typical hazardous waste from Be smelting, which can cause serious harm to ecology and human health by releasing harmful Be if it is stored long-term in environment. Nonetheless, the occurrence of Be in BCS is unclear, which seriously hinders the development of pollution control technologies. In order to enhance the understanding of BCS, the occurrence of Be and the microscale interactions with coexisting phases were investigated for the first time. It was found that CaSO₄·2H₂O and amorphous SiO₂ are the primary phases of BCS. The simulated experiments of purified materials showed that Be interacted with CaSO₄·2H₂O and amorphous SiO₂. Be can enter into the lattice of CaSO₄·2H₂O mainly as free Be²⁺. Amorphous SiO₂ can adsorb Be²⁺ particularly at a pH range of 3-5. The dissolution behavior experiment of BCS shows that about 52 % of the Be is readily extracted under acidic conditions, which refers to the Be of independent occurrence. In contrast, the remaining 48 % of Be can be extracted only after the CaSO₄·2H₂O has completely dissolved. Hence, CaSO₄·2H₂O is identified as the key occurrence phase which determines the highly efficient dissolution of Be. As a result, this study enhances the understanding of BCS and lays the foundation for the development of Be separation technologies.