Preparation And Performance Of Electrolytic Manganese Residue-based Mine Filling Materials

While mining of mineral resources provides various industrial raw materials for human society,it also inevitably produces a large number of goafs.The existence of these goafs poses a serious threat to the safe mining of underground mines and the safety of people's lives and property.it will cause the danger of rock falling or ground collapse in the mining area if improperly handled.However,the cost of filling materials used in goaf management remains high,and how to effectively reduce the filling cost of mines has attracted widespread attention.Electrolytic manganese residue is an acidic solid waste produced during hydrometallurgical smelting of metal manganese.It contains a certain amount of silicon and aluminum sources and gypsum components,and is a potential resource that can be reused.The electrolytic manganese residue not only has a large amount of existing accumulation,but also continues to increase in the amount of one million tons per year.The huge accumulation amount of electrolytic manganese residue and its own properties make it have great application potential in field of mine filling.Based on the analysis of the characteristics of electrolytic manganese residue,The thesis uses electrolytic manganese residue,fly ash,Ordinary Portland cement,phosphogypsum,calcium hydroxide,and naphthalene-based water reducers as raw materials to prepare mine filling materials.This not only realizes the harmless treatment of electrolytic manganese residue,but also provides a cheap and easily available mine filling material for mines.In this thesis,the conveying performance,mechanical properties and long-term stability of cement-based cementitious filling materials prepared with different amounts of electrolytic manganese residue are studied.At the same time,the effect of mechanical ball milling of the raw materials on the properties of the above materials is comparatively studied.The research results show that when the electrolytic manganese residue content is 50-75%,the cementbased mine cementing filling material prepared with Portland cement as the main cementing material has the maximum compressive strength of 28 d and 56 d,respectively.0.18 MPa and0.21 MPa.When the raw material is mechanically ball milled,the compressive strength of the material increases significantly,and the maximum compressive strength of 28 d and 56 d can reach 0.23 MPa and 1.09 MPa,respectively.This is because the mechanical ball milling treatment makes the particle size of all raw materials in the mixed system smaller,the specific surface area increases,the activity is effectively improved,the activation energy between the reactants is reduced,the hydration reaction is easier to proceed,and the fine particles are effective Filling in the pores of the hydration product improves the density of the filling material.The fluidity,slump and expansion of cement-based cementitious filling materials decrease with the increase of the electrolytic manganese residue content.When the particle size of the raw material becomes smaller,the conveying performance will be more significantly reduced.Setting time decreases with the increase of electrolytic manganese slag content.Cement-based cemented filling materials will show certain bleeding and linear shrinkage during the curing process,but the bleeding rate of the material does not exceed 12%,and the linear shrinkage rate does not exceed 3%.XRD and SEM analysis showed that the C-S-H gel,calcium hydroxide,ettringite,glass beads and dihydrate gypsum in the cement-based cemented filling system were intertwined to form a dense,uniform and stable structure.In order to further reduce the filling cost,the thesis used fly ash,phosphogypsum and calcium hydroxide as cementitious materials to prepare multiple solid waste-based mine filling materials,and conducts research on their transportation performance,mechanical properties and long-term stability.Studies have shown that with the increase in the amount of electrolytic manganese residue in the system,the fluidity,slump and expansion of the multiple solid wastebased mine filling materials gradually decrease.After the raw material is mechanically milled,when the electrolytic manganese residue content in the system exceeds 50%,the filling material is no longer transportable.At present,the maximum compressive strength of multielement solid waste-based mine filling materials at 28 d and 56 d can reach 0.32 MPa and 1.33 MPa,respectively.After the raw materials were mechanically milled,its 28 d and 56 d maximum compressive strengths can reach 0.99 MPa and 1.79 MPa,respectively.The increase in the amount of electrolytic manganese residue makes the filling material condense faster.However,after the mechanical ball milling of the raw material,the setting time of the mine filling material shows a trend of first decreasing and then increasing.This is because after mechanical ball milling,there are more activated active silicon-alumina components in the fly ash that can participate in the hydration reaction.More multiphase coagulation nodules can be generated,and the coagulation speed of the cementitious material is significantly accelerated.However,when the content of electrolytic manganese residue in the filling system continues to increase,the content of gypsum in the system increases.The hydration reaction of gypsum,calcium hydroxide and active silicon-alumina in fly ash will produce ettringite.Ettringite,a hardly soluble mineral,will adhere to the surface of the cementitious material,thereby hindering the contact between the cementitious material and water molecules,delaying the progress of the hydration reaction in the system,and prolonging the setting time of the filling material again.The bleeding rate of multiple solid waste-based mine filling materials decreases with the increase of electrolytic manganese residue,but the bleeding rate is still less than 10%,and the linear shrinkage rate is less than 3%.XRD and SEM analysis showed that the fly ash reacted with calcium hydroxide and gypsum in the system,and the formed gel material could effectively bond the inert components in the system,thus forming a staggered and staggered structure.In summary,the application of electrolytic manganese residue in the field of mine filling has certain advantages and potential.The electrolytic manganese residue-based mine filling material not only provides an effective way for the harmless treatment of electrolytic manganese residue,but also provides a cheap and easy-to-obtain new mine filling material for mines.