The Optimal Design On The Agitator Of Hydraulic Separating Equipment

According to the features of bauxite resources in China, a new type of hydraulic separating equipment was made for the removal of silicates from bauxite by selective flocculation. In order to improve the separation efficiency of hydraulic separating equipment, the key component of the hydraulic separating equipment, agitator, was designed optimally.The flow field inside the equipment was simulated by FLUENT, a CFD (computational fluid dynamics) numerical simulation software. The effects of structural and process parameters on the separating efficiency of equipment were systematic studied. The results show that the best process parameters are obtained as follows:the angular velocity of 50rpm, feeding velocity of 225ml/min and the agitator location of Z=-2cm. The separation efficiency of five type agitators under the best structure parameters were determined as follows:rake type>plate-frame typeⅡ> sweep type>palte-frame typeⅠ>propeller type. Rake type agitator is accorded with the stirred tank well, and the best separating efficiency was obtained when the arm length is 3.6cm, blade number is 4 and tooth depth is 10cm.The influences of process parameters (angular velocity of agitator) and structural parameters of rake type agitator (arm length, arm incline angle and tooth depth)on the separation efficiency were also studied by using the self-made agitators. The Al2O3/SiO2 of concentrate increases by 1.43 and the Al2O3 recovery is 67.61% while the angular velocity of agitator is 50rpm under the same process parameters. Based on the optimal process parameters, the increase of arm length and tooth depth are good for bauxite separation, but the increase of arm incline angle has reverse effect on the separation of bauxite. The results of ore separation experiments accorded with the results of numerical simulation well and these confirm the possibility by using FLUENT numerical simulation for the design of agitators.According to the analyzing of the forces acting on particle inside the hydraulic separator, the fluid properties and particle motions were also revealed. It is helpful to understand the separation principle of hydraulic separating equipment. Based on the relationship between power number and equilibrium time, the expression for the relation among agitator diameter, blade width and stirred tank diameter is determined. The expression presents good basis for the optimal design of agitator.