Experimental Study On Rheological Properties Of Red Mud

The red mud yard is a major hazard source as well as the tailings pond.Once the dam break occurs,it will cause serious disasters.It is of great significance to study the rheological characteristics of the red mud yard to predict the submerged depth and submerged range after the dam break of the red mud yard.At the same time,the rheological properties of red mud are also the basis for the development of mud mathematical model.The shear stress and apparent viscosity of red mud are important indexes of rheological parameters,which have an important influence on the debris flow movement formed by red mud.Based on the physical parameters of Bayer red mud measured by geotechnical test procedures,the rheological test of red mud body was carried out by RST-SST touch screen rheometer,and the physical and rheological properties of red mud body were studied.The main results are as follows:（1）According to the geotechnical test procedures,the red mud was tested in the geotechnical laboratory,and the basic physical parameters such as specific gravity,density,liquid limit,plastic limit and void ratio of red mud were obtained.（2）Through the analysis of the red mud shear stress,the results showed that the red mud shear stress at a lower shear rate(<2.17 s^-1),the red mud shear stress increased sharply,the shear stress curve convex to the shear stress axis,in the subsequent shear process,the red mud shear stress with the shear rate increased slowly,basically tended to linear growth.the shear stress of the first cycle was greater than that of the second cycle.When the water content was less than 91%,the shear stress of the two stages of the two cycles was quite different.when the water content was greater than 91%,there was no difference between the two stages of the two cycles.At the same shear rate,the shear stress of red mud with different water content decreased with the increase of water content in both growth stage and deceleration stage.Considering the shear rate and water content,the empirical formula of shear stress in the initial shear and reshear growth stages of red mud were obtained by fitting the shear stress data of red mud.The calculated values were in good agreement with the experimental values,which provided a reference for predicting the mechanical properties of red mud and the development of mathematical models.（3）Through the study of apparent viscosity of red mud,the results showed that at the same shear rate,the apparent viscosity of red mud with different water content decreased with the increase of water content.The apparent viscosity of red mud with different water content decreased rapidly with the increase of shear rate,and the red mud appeared shear thinning phenomenon.The apparent viscosity curve of red mud samples with 60%-80%water content could be divided into two stages.The first stage showed pseudo-yield plastic properties,and the second stage showed Bingham fluid properties.The apparent viscosity curve of red mud samples with 91%-104%water content could be divided into three stages.The first stage showed pseudo-yield plastic body characteristics,the second stage showed Bingham fluid characteristics,and the third stage showed Newtonian fluid characteristics.（4）Through the study of the applicability of red mud rheological model,the results showed that the three rheological models（Ostwald-de Waele Medole,Herschel-Bulkley Model and Bingham Model）fitted the red mud rheological test data,and the Herschel-Bulkley Model had the best fitting effect.