Abstract: The optimization of process parameters of iron removal for leachable liquid which is from calcined production of the fly ash and ammonia sulfate was described. The corresponding mathematical model on iron removal by ammonium jarosite method and goethite method were established，respectively. In the above process， the reaction temperature， pH value and adding amount of seed precipitation were variable， and the concentration of aluminum ions and iron ions were corresponding variables. The affecting factors were analyzed at the same time. The models are checked by experiment， and the error is less than 5%， which indicates the models are reliable. After the solution of the models， the best process condition of iron removal is given via ammonium jarosite method and goethite method respectively.

Key words: response surface methodology(RSM), removal of iron by ammonium jarosite method, removal of iron by goethite method, process condition