Research On Hemihydrate Phosphogypsum Based Mineral Filling Composites And Its Pipe Flow Performance

In view of the environmental pollution problems caused by phosphogypsum storage,as well as the traditional filling materials and the phosphorous gypsum filling technology,ha,ve the problems of high filling cost,large cement consumption,low solid body strength,etc.,relying on the National Natural Science Foundation project "Deep Well"."Hybrid strength evolution and regulation mechanism of filling body under multi-field coupling"(51674012)and horizontal subject "CH hemihydrate phosphogypsum filling cementing material and application",through hemihydrate phosphogypsum research through field investigation,laboratory test,mechanism analysis and industrial application Phosphogypsum gelation activity excitation and mine filling material ratio optimization and application technology research,aiming at exploring new ways for comprehensive utilization of phosphate gypsum and mine safety.The main work done in this paper is as follows:(1)Starting from the preparation of mineral filling composites with hemihydrate phosphogypsum,the physicochemical properties of hemihydrate phosphogypsum were systematically analyzed,and the gelling properties and key influencing factors of hemihydrate phosphogypsum were determined,and the gelation was proposed.The method of control of activity.(2)The single factor test and orthogonal test method data visualization method were used to optimize the ratio.For the first time,a series of mine-filled composite materials with fast-setting,early-strength and adjustable performance were successfully developed with hemihydrate phosphogypsum.The 3MPa strength target reduces the cost of filling materials by more than 90%.(3)Based on the hydration reaction theory of hemihydrate gypsum,the hydration reaction process of hemihydrate phosphogypsum was analyzed under the guidance of dissolving crystallization theory.The hemihydrate phosphogypsum-based mineral filling composite was analyzed from the microscopic point of view.The interaction between hydration products and raw materials and inert materials;from the chemical reaction kinetics,mechanical analysis,etc.,studied the influence mechanism of different raw materials on the filling materials;provided the application and promotion of the hemihydrate phosphogypsum-based mineral filling composite materials The necessary theoretical basis.(4)Determine the laminar flow critical conditions for the transportation of semi-aqueous phosphogypsum-based mine filled composite pipes.The analytical solution of the pipeline transportation of the filled slurry under laminar flow conditions was obtained,and the functional relationship between the self-flow flow rate and the rheological parameters such as the pipe diameter,filling doubled line and apparent viscosity was determined.The rheological test and pipeline test of hemihydrate phosphogypsum-based filling slurry were carried out.Based on the equation 3D visualization and parallel coordinate method,the transportability of the filled slurry was systematically analyzed.(5)According to the characteristics of hemihydrate phosphogypsum and the filling requirements of mine goaf,a special filling technology system of hemihydrate phosphogypsum based mineral filling composite was developed.The strength and transport properties of the hemihydrate phosphogypsum based mineral filling composites have been verified by the semi-industrial filling test,and it has been proved that the hemihydrate phosphogypsum based mineral filling composites have preliminary industrial application conditions.