Study On Preparation Of Geopolymer With Fly Ash

With the development of the society, people’s requirements and awareness for environment protection have become increasingly high. However, energy consumption also grows considerably. The production of fly ash which is the by-product of the energy industry also grows simultaneously. After these years rapid development, Chinese government has being paying more attention to reuse solid waste of fly ash. However, compared with western developed countries, China’s fly ash utilization rate is not high. In order to improve the utilization rate and ways of fly ash in China, metakaolin and fly ash of Huadian Power Generation Co., Ltd. Datong Qinghai were made into geopolymer by alkali activated and phosphoric acid-activated ways. Then geopolymeric specimens were detected by press machine, Infrared spectroscopy analyzer, DTA-TG thermal analyzer and so on. The best geopolymer as the porous material matrix was made into different porous materials and tested. Eventually, according to the test results, porous material was modified by adding glass fiber. The main conclusions are as follows.(1)Phosphoric acid-activated and alkali activated formulas. Phosphoric acid-activated formula of mass ratio is : fly ash :water :phosphoric acid =100:25.71:44.54. The compress strength of the geopolymer specimen made by the formula got to 28.10 MPa. Alkali activated formula of mass ratio is: fly ash: NaOH: water: sodium silicate=100:9.11:15:42.37. The compress strength of the geopolymer specimen made by the alkali activated formula reached 41.65 MPa.(2)Preparation of phosphoric acid-metakaolin based geopolymer and mixing fly ash experiment. Phosphoric acid-metakaolin based geopolymer formula of mass ratio is:metakaolin: water: phosphoric acid=100: 43: 74.01. The compress strength of the geopolymer specimen made by this formula was up to 166.73 MPa. After mixing with fly ash, the compress strength of geopolymer specimen was dropped dramatically. Adding fly ash to metakaolin is harmful to the compress strength of geopolymer specimen.(3)Foaming experiment of Mechanical foaming-chemical foaming way. The optimum of mass ratio is: SDS: PEG: Al=4:1:0.1. The parameters of the porous geopolymer specimen made by this formula were: compress strength 0.93 MPa, bulk density 0.45 g·cm-3, thermal conductivity 0.1619 W·m-1·K-1.(4) Experiment of modification of porous materials. The best formula is: glass fiber adds in alkaline solution, the length of glass fiber was 5.00 mm, the dosage of glass fiber was 3.00 g. According to this process, the determination results of the porous material were: bulk density 0.48 g·cm-3, compress strength 1.62 MPa, thermal conductivity 0.1206W·m-1·K-1...