Study on defluorination process of secondary aluminum ash wet process and conversion behavior of fluoride
In order to study the influence of wet defluorination factors(liquid-solid ratio,time,temperature,solution type and solution concentration)on the fluoride leaching efficiency and the fluoride leaching of the bottom slag during the wet treatment of secondary aluminum ash,a single factor experiment was used to determine the fluoride content of the bottom slag and its leaching solution before and after wet leaching.At the same time,XRD and SEM-EDS were used to characterize the original aluminum ash and the bottom slag after wet treatment.The results showed that the above five factors affected the fluoride leaching efficiency under the two leaching media conditions.Under the condition of constant temperature and wet leaching,the fluoride removal effect of NaOH solution was better than that of deionized water.The optimal parameters of de-ionized water leaching fluoride were as follows:ratio of liquid to solid(mL/g)of 30,hydrolysis time of 4 h,hydrolysis tem-perature of 90 ℃,and leaching rate of fluoride of 12.98％.Under normal temperature conditions,the optimal parameters were as follows:ratio of liquid to solid(mL/g)of 10,concentration of NaOH solution of 1.5 mol/L,hydrolysis time of 30 min,and leaching rate of fluoride of 65.85％.XRD results showed that the content of AlN in the secondary aluminum ash was re-duced to different degrees after wet treatment,and SEM-EDS results showed that the content of fluoride in the bottom slag was reduced correspondingly after wet treatment.The above research results provided a scientific basis for the removal of fluoride in the wet treatment of secondary aluminum ash.
万方数据
维普
