炼铁高炉共处置危险废物过程中Zn、Cd的挥发特性

Volatile characteristics of zinc and cadmium during co-processing hazardous waste in blast furnace

为探究炼铁高炉共处置危险废物过程中重金属Zn、Cd的挥发特性,选择Zn Cl2、Cd Cl2?2.5H2O来模拟危险废物中的重金属,开展了Zn Cl2、Cd Cl2?2.5H2O与高炉炼铁原料混合后的共处置煅烧实验,分析了共处置煅烧时挥发烟气及煅烧产物中重金属Zn、Cd的总量.结果表明,Zn、Cd的挥发特性相似,在煅烧初期,二者的挥发率都是随着时间的增加而逐渐增大,当煅烧超过一定时间后,挥发率趋于稳定.在1400℃条件下煅烧60min后,Zn、Cd的挥发率分别为93.55%、99.96%.对Zn、Cd的挥发规律进行了动力学模拟,得出其挥发反应表观活化能E分别为59.37,49.68k J/mol,挥发的动力学方程则分别为α=f(T,t)=1-exp(-13.60exp(-7141/T)t)、α=f(T,t)=1-exp(-8.64exp(-5975/T)t).

ZnCl2 and CdCl2·2.5 H2O were chosen to simulate heavy metals in hazardous waste and study the volatile characteristics of zinc and cadmium during co-processing hazardous wastes in blast furnaces. The blast furnace raw materials mixed with ZnCl2 and CdCl2·2.5 H2O were calcined, and the total contents of Zn and Cd in the flue gas and calcined product were analyzed. The results showed that the volatile characteristics of Zn was similar to Cd, and their volatilization ratios increased with the increase of time at the beginning of calcination, but tended to be stable when the calcination time exceeds a certain value. The volatilization ratios of Zn and Cd, when calcinined for 60 minutes at 1400℃, were 93.55% and 99.96%, respectively. The volatile rules of Zn and Cd were simulated by chemical reaction kinetic. The apparent activation energy（E） of the volatile reaction of Zn and Cd were 59.37, 49.26 k J/mol, respectively. And the volatile reaction kinetic equations of Zn and Cd were α=f（T, t）=1-exp（-13.60exp（-7141/T） t） and α=f（T, t）=1-exp（-8.35exp（-5925/T）t）, respectively.