MgO对含砷废渣烧结过程砷的形态及释放特性影响

Species and Release Characteristics of Arsenic During Sintering of Arsenic-containing Waste with MgO

本文研究MgO对含砷废渣烧结陶粒过程中砷的形态及释放特性的影响，通过测定添加MgO后烧结体中砷的质量浓度得到砷的挥发特性、采用毒性试验研究砷的浸出特性、采用X射线衍射（XRD）研究烧结体矿物晶相。结果表明：在800～1100℃，MgO对砷的挥发有强烈的抑制作用；在400-1100℃，MgO对砷的浸出抑制作用显著，1300℃时，MgO对砷的浸出没有抑制作用。XRD分析表明，1100℃时，砷以稳定的砷酸钙和砷酸镁的形式存在，大大降低了砷的挥发及浸出，1300℃时，主要减少了砷酸钙矿物相，导致砷的浸出浓度增大。通过研究MgO对含砷废渣烧结过程砷的挥发、浸出及砷形态变化的影响，可为含砷废渣烧结制陶粒技术添加剂的选择提供依据。

An experimental work was carried out to investigate the species and release behavior of arsenic during sin- tering of arsenic-containing waste with MgO, studied the arsenic volatilization characteristics via testing mass concen- tration of arsenic in sintered products, studied the arsenic leaching characteristics by toxicity test, studied the mineral phases of sintered products via XRD. The results shows that the inhibitory effects of MgO on arsenic volatilization were greatly at 800- 1 100℃. The inhibitory effects of MgO on arsenic leaching were significantly at 400 - 1 100℃, howev- er, MgO had no inhibitory effects on arsenic leaching at 1 300℃. XRD analysis showed that arsenic existed in the form of stable Ca3（ AsO4 ）2 and MgssAs3O16 at 1 100℃ which highly reduced arsenic volatilization and leaching, however, the concentration of arsenic leaching was highly increased when Ca3 （ AsO4 ） 2 disappeared at 1 300℃. By studying the effect of MgO on arsenic volatilization, leaching and species during sintering of arsenic-containing waste, which can provide the basis for the selection of additive.