Cold Modeling On Flow Characteristics In Shaking Ladle And Its Mixing And Separation Behaviors Of Two Liquid Phases

The shaking ladle is one of the main equipment for producing low&medium carbon ferromanganses with electric furnace-shaking ladle process, and is widely used in the ferroalloy plants. Due to the lack of theoretical foundations, the operations of the shaking ladle is rely to a great extent on experience. The flow characteristics in shaking ladle and its mixing and separation behaviors of two fluids were studied in this thesis, and aimed to supply some useful direction for the plants. On the other hand, some science problem about the two liquids flow in shaking ladle was researched.The transient pressure at the bottom of shaking ladle was determined using the HFDPT (high frequency dynamic pressure transducer), and the pressure distribution under different conditions was studied. The results showed that the liquid was rotating periodically around the center axis of the shaking ladle. It was observed that the motion of water could be classified into two types:one is named wave rotation type while the other is named flow rotation type, and the transform of the two types could be judged by the slope of the relation curve between center pressure-shaking speed.The mixing time of single-phase liquid in shaking ladle was measured by the electrical conductivity probe method. A new criterion of mixing time named mixing intensity criterion was proposed to judge the mixing endpoint, which overcomed the shortage of the95%mixing criterion. A new concept of critical shaking speed based on mixing time was defined, and the effects of different condition on critical shaking speed was studied. It was found that the critical shaking speed was increased with the increasing of bath depth, and decreasd with the increasing of eccentricity. The Ishii’s formula were revised based on the present work.The flow patterns of two liquid phases in shaking ladle could be classified into three types:oscillatory flow pattern, lotus-leaf-like pattern and entrainment pattern. The cause of the lotus-leaf-like pattern was explained by the Kelvin-Helmholtz instability theory. The existence of a velocity shear of the upper and lower phases, increased with the shaking speed, was verified by flow field visualization with spherical floats. The period of the free surface wave was as the same as the period of the shaking of the ladle, however, the period of the interface wave was twice of it. The lotus-leaf-like pattern in shaking ladles with different diameters had the same form.The critical shaking speeds of lotus-leaf-like pattern and entrainment pattern have been studied experimentally using bean oil-water system and engine oil water system. It was found that both of the two critical shaking speeds were increased with the decreasing of ladle diameter, eccentricity and the density of the lower phase, and were increased with the increasing of lower phase height, the height difference and the density difference of the two phases, the viscosity of the two phases. The separation time of the emulsion in shaking ladle was studied by measuring the electrical conductivity of the mixture, and it was found that the separation time was shorter when shaking with a slow speed than keeping the ladle motionless. An empirical equation for the critical entrainment shaking speed was proposed as a function of ladle diameter, eccentric distance, the height and physical properties of the liquids, which could direct the operating parameter scalingupof the shaking ladle.P204+sulfonated kerosene/CoSO4solution system was used to verify the effect of mass transfer occurs between phases boundary to the mxing of the two phases. It was found that the Manrangoni effect caused bymass transfer could speed up the mixing to a certain extent. But the Manrangoni effectmay also affect the separation of the emulsion, and therefore, the reason of the bad separation was the nonequilibrium of the reaction of the slag and metal.