Preparation And Properties Of Fly Ash-Ferronickel Slag Geopolymer

Geopolymer is a high-performance new type of cementing material,with corrosionresistant,anti-penetration,high temperature and other special physical and chemical properties.Compared with ordinary Portland cement,geopolymer has many advantages,such as wide range of raw materials,low prices,green simple preparation process.So much excellent performance has made geopolymer became a hot research at home and abroad with a broad development and application space.In this paper,the geopolymer cementitious materials were prepared by using fly ash and ferronickel slag as raw materials under the action of alkaline activator.The effects of technological parameters such as water glass modulus,basic activator content and water-cement ratio on the properties of geopolymer materials were studied.And the durability of the prepared geopolymeric materials was studied,including frost resistance,high temperature resistance and chemical resistance.The main research work and achievements are as follows:Using fly ash as raw material and water glass and NaOH as alkaline activator prepared fly ash geopolymer cementitious material.The results of orthogonal experiments showed that the optimum preparation parameters of fly ash geomaterials are water glass module 1.4,the content of alkaline activator 14%,water-cement ratio 0.24.In the four kinds of conservation methods: standard conservation,natural conservation,film conservation and water conservation,film curing was the most ideal way of maintenance of fly ash geological polymer.The compressive strength of the fly ash geopolymer at 28 days was 60.33 MPa with the best technological parameters.Using ferronickel slag as raw material prepared geopolymer by alkaline excitation.The effect of grinding time on the fineness,specific surface area and activity of ferronickel slag was studied by grinding.Select the ferronickel slag of grinding 70 min with the specific surface area of 461m2/kg,45?m sieve 7.03% as the follow-up experiment raw materials.The results showed that the excitation effect of water glass on ferronickel slag was the best.The optimum technological parameters for the preparation of ferronickel slag geopolymer were as follows: water glass module 2.2,alkali excipient dosage 12% and water-cement ratio 0.28.The compressive strength of ferronickel slag geopolymer cemented material prepared by the optimum technological parameters was up to 110.32 MPa,and it had good thermal stability and durability.After 30 freeze-thaw cycles,the mass loss rate of the sample was less than 2% and the compressive strength is still 83.93 Mpa.When the heat treatment temperature was 800 ?,the mass loss rate of the nickel iron slag geological polymer sample was 18.2%,which reaches the maximum value and the compressive strength reduced to 59.61 MPa.In the typical chemical resistance test,the mass loss of the ferronickel slag geopolymer sample in the 5% HCl solution was the greatest.After been soaked 60 days,the mass loss rate was 9.7%,but the compressive strength was still up to 73.25 MPa,which decreased 31.7%.Using fly ash and ferronickel slag as raw material and water glass and NaOH as alkaline activator prepared geopolymer cementitious material.The effect of fly ash content on the compressive strength of fly ash-ferronickel slag geopolymer was studied.The results showed that the compressive strength of fly ash-ferronickel slag geopolymer material decreased with the increasing of fly ash content.When the content of fly ash was50%,the compressive strength of fly ash-ferronickel slag geopolymer can reach 71.83 MPa with good thermal stability and durability,which was much higher than that of the pure fly ash geopolymer prepared under the best technological parameters.After 30 freeze-thaw cycles,the mass loss rate of the sample was less than 2% and the compressive strength was still 54.93 Mpa.When the heat treatment temperature was 800 ?,the mass loss rate of the nickel iron slag geological polymer sample was 17.3%,which reaches the maximum value and the compressive strength reduced to 38.76 MPa.In the typical chemical resistance test,the mass loss of the ferronickel slag geopolymer sample in the 5% HCl solution was the greatest.After been soaked 60 days,the mass loss rate was 9.7%,but the compressive strength was still up to 57.31 MPa,which decreased 19.5%.