为揭示Ca O对含As废渣烧结陶粒过程中As挥发和结构形态变化的影响规律,对添加Ca O前、后含As废渣在不同温度下烧结体中的As残留量、形貌、结构形态和环境释放行为的变化进行了研究.结果表明:1在400~1 000℃,Ca O对As的挥发有很强的抑制作用,As的固化率均大于85%;当温度〉1 000℃时,Ca O对As的挥发抑制作用减弱.2在400~1 000℃,Ca O对烧结体As的浸出释放抑制作用显著;当温度〉1 000℃时,Ca O对As的浸出释放抑制作用随温度升高显著降低.3在1 000℃时,Ca O与As化合生成了稳定的砷酸钙,残留于烧结体中,大幅降低了As的挥发和浸出释放特性,As的固化率最高可达95.14%;As的浸出浓度(以ρ计)也达到最小值,其中水平振荡法、硫酸硝酸法和TCLP法处理后的浸出值分别为1.33、130和0.85μgL;温度升至1 300℃时,砷酸钙消失,As以溶解度高的As2O3形式存在,导致As的浸出浓度增大.
To determine the impacts of CaO on species and release characteristics of arsenic during sintering of arsenic-containing waste residue, this paper studied the volatilization characteristics, leaching characteristics, morphology and mineral phases of sintered products before and after treatment of CaO at different sintcring temperatures. The resuhs showed that the inhibitory effect of CaO on the volatilization of arsenic was significant at temperatures ranging from 400-1000 ~C. The curing rate of arsenic was higher than 85% . However, the effect was reduced when the temperature was higher than 1000 ~C. The inhibitory effect of CaO on the leaching of arsenic was significant at temperatures ranging from 400-1000 ℃. The inhibitory effect was the strongest at the temperature of 1000 ℃. However, the inhibition was significantly reduced at temperatures above 1000 ℃. At temperatures between 400-1000 ℃ , XRD analysis showed that CaO and As combined and generated stable CaAs206, which remained As in the sintered products in the form of CaAs206. The volatilization and leaching of arsenic was highly reduced. The curing rate of arsenic was as high as 95. 14% , and the leaching mass concentration of arsenic also reached a minimum. After treatment with horizontal oscillation, sulfuric acid-nitric acid and TCLP method, the concentrations were 1.33, 130 and 0.85 μg/L, respectively. The volatilization and leaching of arsenic were highly reduced. At the temperature of 1300 ℃, CaAs206 disappeared and arsenic existed in the form of ASEO3 with high solubility, which increased the leaching concentration of arsenic.