Study On The Influence Of Activator On The Properties Of Coal Gasification Slag Micro-powder Cementitious System

With the development of industrialization,environmental protection has been paid more and more attention.Coal gasification slag as a kind of waste residue,if it can not be effectively utilized,it will lead to serious environmental pollution and social burden.At present,the way to deal with it is generally buried or accumulated..The long-term storage of coal gasification slag will occupya large amount of land resources and even cause pollution of land and water resources.Meanwhile,some very fine particles in coal gasification will cause sand and even sandstorm under the action of wind,causing air pollution.In order to make good use of coal gasification slag,this paper studies the effect of activator on the properties of coal gasification slag powder cementing system and the feasibility of its application in cement concrete,and discusses its hydration mechanism.Through the analysis of mineral composition and microstructure of coal gasification slag,it is found that it has potential pozzolanic activity.The reasonable grinding time of coal gasification slag is determined by the strength test of mortar and particle size analysis: the initial grinding time of 500 mm × 500 mm ball mill is 45 minutes,and then it is grinded in QM-BP planetary ball mill for 20 minutes.Select appropriate excitation agent for coal gasification slag powder active excitation,by adopting the orthogonal experiment method to 5 kinds of single-component exciting agent,the optimum composite component optimization design,determine the coarse whiting in compound excitation agent,sodium carbonate,sodium sulfate,modified single chemical,polymer polyol content were 2.5%(according to the coal gasification slag powder content,hereinafter the same)、0.1%、0.1%、0.06%、0.04%.The cementitious properties of coal gasification slag powder cementitious system before and after activation were studied through cementitious strength,hydration heat,drying shrinkage and abrasion resistance.The results showed that the cementitious strength of coal gasification slag powder cementitious system after stimulationincreased by 26.4% and 14.9% respectively in 3d and 28 d at the same water-binder ratio and content,and the hydration heat temperature and exothermic rate increased significantly.Dry shrinkage and wear resistance were improved.XRD,SEM and EDS were used to analyze the types and morphologies of hydration products of coal gasification slag micro-powder cementing system before and after excitation.The results show that the diffraction peaks of ettringite and calcium hydroxide in hydration products of coal gasification slag micro-powder cementing system after excitation are more significant than those before excitation.Compared with that before excitation,the hydration products of coal gasification slag micro-powder cementing system after excitation are 3 days.The crystallinity of the product is high,and a large number of hexagonal columnar CH crystals are formed by hydration products 28 days after excitation,which are closely arranged.Pure cement,mixed with fly ash,was studied before and after gasification slag powder four gel system of C40 concrete compressive strength,abrasion resistance,resistance to chloride ion penetration,the results show that the excitation powder coal gasification slag concrete compared with before 3d and 28 d compressive strength increased by 13.4% and 10.0% respectively,abrasion resistance and chloride ion penetration resistance is improved.According to the above conclusions,on the basis of controlling the carbon content of coal gasification slag,it can be ground to a certain fineness and stimulate its activity.It can be used as an auxiliary cementing material in cement concrete to provide a reference for the comprehensive utilization of coal gasification slag.