title: Influence of NaOH concentrations on synthesis of pure-form zeolite A from fly ash using two-stage method.
abstract: Synthesis of pure-form zeolite A were investigated using four concentrations of NaOH solution to dissolve Si source form fly ash, and with the addition of Al source, to prepare initial gel. Experimental results demonstrated, for two-stage method, that NaOH concentrations in initial gel played an important role in synthesis of pure-form zeolite A using fly ash as raw materials. Generally, pure-form zeolite A could be synthesized when following conditions were used: NaOH concentrations, 1.67, 5 and 6.67 M; the synthesis temperature, 100 degrees C; the corresponding crystallization time, 340, 250 and 190 min. However, a mixture phases of zeolites A and X were obtained at the condition of 3.33 M NaOH solution during various crystallization times. It was found that the higher NaOH concentration was used, the shorter crystallization time of zeolite A was required and the narrower particle size distribution of zeolite A was achieved. In addition, zeolite A submicron-crystals were first synthesized from fly ash using two-stage method in our study.
authors.affiliation: School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Wang
authors.forename: Jian-Sheng
authors.initials: JS
authors.lastname: Li
authors.forename: Lian-Jun
authors.initials: LJ
authors.lastname: Wang
authors.forename: Xiu-Yun
authors.initials: XY
authors.lastname: Sun
mesh_terms: D002244:Carbon / Q000737:chemistry*; D060729:Coal Ash; D003247:Conservation of Natural Resources / Q000379:methods*; D003460:Crystallization; D007220:Industrial Waste; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry*; D018505:Waste Management / Q000379:methods*; D017641:Zeolites / Q000737:chemistry*
chemical_list: D060729:Coal Ash; D007220:Industrial Waste; D052638:Particulate Matter; D017641:Zeolites; D012972:Sodium Hydroxide; D002244:Carbon