The Study On Effect Of Fiber/EPS Grain On Performance Of Desulfurization Gypsum

With the rapid development of industry,human demand for energy is increasing day by day,combustion equipment and scale are also expanding.In order to reduce environmental pollution,the discharge of sulfide can be greatly reduced by the wet desulfurization method,but the wet desulfurization method produces a large amount of desulfurization gypsum.Due to its low utilization rate,a large amount of desulfurization gypsum is accumulated,and the unreasonable allocation of resources leads to serious waste of resources.EPS has the advantages of light weight,heat preservation,heat insulation and good water resistance.It is widely used in product packaging,logistics and transportation.However,EPS is difficult to degrade and reuse,and is often discarded everywhere after use,leading to the continuous accumulation of a large number of discarded EPS plates,and gradually forming the"white pollution"that deteriorates the environment.In order to solve the above resource problems,the calcined desulfurization gypsum is used as the main cementitious material,the discarded EPS board broken grain is used as light aggregate,and fiber is added to strengthen and toughen the material,and some additives are added to make the green,energy saving,light weight and environmental protection new building materials.Taking the calcined desulfurization gypsum as the main raw material,EPS grain was mixed in the single mixing test.According to the changing trend of mechanical properties and the difficulty of forming the test block,when the content of EPS grain was 0.9%of the mass of cementing material,the mass could be reduced by 37.98%,and the material lightness could be realized.However,due to the light weight,smooth appearance and hydrophobic properties of EPS grain,EPS grain appears to float up in desulfurized gypsum slurry,resulting in the uneven distribution of EPS grain in gypsum is more serious.Based on the characteristics of basalt fiber,PVA fiber and lignocellulose,EPS grain was mixed into desulfurization gypsum separately to improve the strength and inhibit the EPS grain floating.When the basalt fiber content is 1.6%,the compressive strength of EPS grain/desulfurization gypsum under dry condition can be increased by 35.98%.When the content of PVA fiber is 1.2%,the flexural strength of EPS grain/desulfurization gypsum under dry and saturated conditions of water absorption is increased by 121.94%and 71.93%,respectively.When the lignocellulose content was 1.4%,the compressive strength of EPS grain/desulfurization gypsum under water absorption and saturation condition was increased by 14.83%.Based on the optimal content of single fiber,the effects of two different fibers and three different fibers on the properties of EPS grain/desulfurization gypsum were studied.When two different kinds of fibers were mixed,the optimal content of PVA fiber and basalt fiber(2:1),PVA fiber and lignocellulose(2:1),basalt fiber and lignocellulose(2:1)were 1.2%,1.2%,1.6%,respectively.The effect of mixed fiber is better than that of single fiber,and the effect of mixed PVA fiber and basalt fiber on the strength improvement of EPS grain/desulfurization gypsum is the best.According to the performance comparison of the two kinds of fibers mixed in EPS granule/desulfurization gypsum,the optimum fiber content is 1.2%.Based on this,PVA fiber,basalt fiber and ligncellulose were mixed and mixed.The results show that,when the mixing ratio is 1:1:1,the flexural strength and compressive strength of PVA fiber and basalt fiber under dry condition are increased by 4.76%and 0.43%,respectively.Under saturated water absorption,the flexural strength and compressive strength are increased by 6.86%and 5.83%,respectively.In the test to explore the effect of admixtures on the properties of EPS grain/desulfurization gypsum,0.02%citric acid retarder was added to the composite material to meet the complex technological process.When the thickening admixture of HEC is 0.4%,the flexure strength of EPS grain/desulfurization gypsum is increased,the water resistance is also improved,and the grain distribution is more uniform.On the basis of adding thickening agent,adding 10%inorganic admixture composed of ordinary Portland cement:aluminate cement=68:32 realized the improvement of strength and water resistance;On the basis of adding inorganic admixtures,silicone water-repellent agent with solid content of 15%was sprayed externally,and the bending softening coefficient reached 0.613.The ultimate flexural strength of EPS grain/desulfurization gypsum was 4.74MPa and 2.91MPa in dry and saturated state.The compressive strength of dry state and saturated state are 7.61MPa and 2.76MPa.Water absorption rate was 5.25%;The bending and compression softening coefficients were 0.613 and 0.362;The apparent density was 0.827g/cm~3.