| Aiming at the shortcomings of low effic iency and large pollution of glauberite under traditional mining methods,the research team proposed an in-situ modified solid mineral fluidized mining method.It is planned to dissolve the calcium thenardite under the pressure leaching environment and weaken it to achieve the purpose of modification to improve the leaching efficiency.It is necessary to understand its dissolution and weakening characteristics under pressure leaching conditions.Therefore,the dissolution characteristics of glauberite under pressure water environment,the internal microscopic change characteristics after leaching and the changes of mechanical characteristics after leaching were studied.In this paper,the laboratory simulation test method is used to carry out the basic research of pressure leaching of glauberite through the self-developed pressure leaching device.The micro-CT scanning system and MATLAB analysis software were used to analyze the salt rock damage and internal fine The analys is of the law of evolution has revealed the relationship between the weakening of the salt rock strength after dissolution and the dissolution pressure and dissolution time.Finally,the numerical s imulation is used to simulate the dissolution of the salt rock under pressure dissolution.It can provide a strong basis for the design and control of the fluidized mining process of solid minerals later.The main conclusions obtained through research are as follows:(1)Pressure leaching mainly improves the dissolution rate of salt rock in the early stage of leaching.The initial dissolution rate under 0.2 MPa pressure water environment is 1.55 times that of natural water environment.With the increase of the leaching time,the difference between the dissolution rate gradually decreased,and the difference between the dissolution rate decreased from 35.83%to 33.04%after 6 days of leaching.Moreover,it is found that the dissolution of mudstone cementation is particularly active under pressure leaching.(2)The damage degree of salt rock after pressure leaching under the same leaching time is greater than that after natural leaching.After 48 hours of immersion in natural water,0.2 MPa,and 0.4 MPa pressure water,the mean value of the erosion density damage increment was-7.35×10-7,-16.4×10-7,-34.3×10-7.The porosity increased from the initial 0.75%to 1.78%,4.75%,and6.92%.The increase of the leaching pressure increases the internal dama ge of the salt rock and promotes the development of the internal pore structure of the salt rock.(3)Pressure leaching accelerates the decrease of salt rock strength,And found that the i MPact on strength is mainly concentrated in the early stage of leaching.The weakening coefficient in natural water environment is 0.91,the strength weakening coefficient after immersion for 24 h in 0.5 MPa,1.0 MPa,1.5 MPa pressure water environment is 0.77,0.67,0.55.It shows that the strength weakening coefficient decreases with increas ing pressure in a certain pressure range.(4)The results of numerical simulation analys is by COMSOL Multiphysics software show that the dissolution domain increases with the increase of the leaching pressure.After 1.0 MPa,1.5 MPa,and 2.0 MPa pressure dissolution for the same time,the dissolution area is 8.68 m2,11.02 m2,and 13.58 m2,respectively..But it does not increase linearly with the increase of the leaching pressure,and the rate of increase decreases with the increase of the leaching pressure. |
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