Research And Application Of Grouting Materials Based On Electrolytic Manganese Sla

The electrolytic manganese slag in Tongren,Guizhou is growing at about 3 million tons per year,mainly in stockpiles.The harmful substances in manganese slag(sulfate,ammonia nitrogen and heavy metals such as manganese,arsenic,nickel and lead)are easily dissolved into water bodies,soil and air,polluting the environment.To address this problem,this paper takes the high water content electrolytic manganese slag from Songtao County,Tongren City as the research object.The scientific and technological research of desulfurization and gelling activity excitation of electrolytic manganese slag is established.Focus on 2 key scientific issues of mechanical characteristics of grouting gelling material,alkaline component of grouting material and effective curing of heavy metals.Focus on the mechanism of the role of manganese slag doping in the cementing system.The analysis of the cementing material’s compatibility,cementing time,compressive strength,microstructure evolution law,ion erosion and hydration process under different manganese slag doping and different water-cement ratio.The main conclusions are as follows:(1)It is clarified that the desulfurization rate of electrolytic manganese slag is about 89.6% and the highest activity index is 0.8 after high temperature thermal activation treatment at 900°C.When the NaOH doping is 15%,the potential active SiO2 and Al2O3 substances are excited to the maximum extent.(2)The optimum amount of manganese slag is 20%,and the threshold value of water-cement ratio is 0.45.The compressive strength of manganese slag-based cementitious material increases with the amount of manganese slag,and then decreases with the increase of water-cement ratio;the larger the water-cement ratio is,the smaller the compressive strength is in the early stage,but the most significant growth of compressive strength is in the middle and late stage,and the highest strength is 34 MPa at 28d;(3)superplasticizer and water retention agent on the slurry liquidity and compressive strength and other effects are significant.Superplasticizer has an enhancing effect on the fluidity.Water retention agent on the slurry water retention and stability has a role in enhancing.But when the amount exceeds 1.5%,there is a certain inhibitory effect on the compressive strength of the stone body.(4)Ionic erosion has a significant effect on the mechanical properties of manganese slag-based cementitious materials.The compressive strength of the specimens showed an overall trend of increasing first and then decreasing,and the compressive strength of the specimens was maximum at 6% Cl-ion concentration and maximum at 4% SO42-ion concentration.(5)The valence and coordination changes of Siand O elements were analyzed by X-ray photoelectron spectroscopy(XPS)to reflect the significant curing effect of gelling hydration process and Si、O coordination isomerization on metal elements.At the same time,the reaction hydration process through the Siand O elements of the binding energy change law,and through the electron microscope scanning of the hydration products of all ages of the consistency analysis.(6)The mineral phase composition of the hydration products was analyzed by X diffraction analysis(XRD).The hydration products are mainly plagioclase zeolite,CS-H gelling,N-C-S-A-H gelling,and N-S-A-H gelling material.Scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)is used to analyze the microstructure of nodules and the composition of hydrated materials.It is verified that the main elements of hydration products are Si,Ca,O,Al,Na,etc.(7)The main hydration products of the manganese slag-based cementitious materials were analyzed by SEM tests as needle-like or rod-like AFt,short rod-like plagioclase zeolite,and fibrous C-S-H cementitious material.The main reactions in the later stages of hydration are ground polymerization reactions,forming N-C-S-A-H gelling,N-S-A-H gelling material.The pores of the crystalline body are filled and covered with the surface of the early hydration products,and will be covered with the needle-like and fibrous surface,connecting all the hydrated materials into one whole.