Wangxing Li

Simulation of Anode Bubble: Volume of Fluid Method

In an aluminum reduction cell, bubbles are generated on the anode surfaces. Before they get out of the bath, they linger over between gap of the anode and the cathode, which leads to additional voltage drop. The alumina concentration adjacent to the anode is also affected. How are the bubbles formed and what kinds of shape they have are the important issues. Numerical simulation can provide detailed information about bubbles. The volume of fluid model (VOF) was applied in the bubble simulation. The flow difference between different locations was presented.

Current Efficiency Predictive Model and Its Calibration and Validation

Current efficiency is one of the most important technical and economic parameters. Current efficiency loss is due to dissolved aluminum reacting with the anode bubbles by the back reaction, which is assumed to be responsible for the largest part of current efficiency loss in Hall-Heroult aluminum reduction cells. The magnetichydrodynamics flow in cells can be seen as a gas-liquid-liquid flow by neglecting the mina effect of alumina particles. An current efficiency predictive model (CEPM) was developed based on multiphase multicomponent flow. The model takes the flow in cells as a three-phase(the bath, the metal, and the anode bubbles) and multicomponent problem(the bath phase: bath species and dissolved Al species; the anode-bubble phase:CO2 and CO), which is able to incorporate the mechanism of current efficiency loss in cells. The model was calibrated by a 160kA cell and validated by a 300kA cell. This study provides a new approach for predicting current efficiency of aluminum reduction cells.

Theory and Experiment on Cooling Strategy during Seeded Precipitation

The η-t curve is derived from the dynamic equation of seeded precipitation. The curve has the characteristic of a hyperbolic function and the experimental results conform to the characteristics of the curve. The η-t curve indicates that the precipitation ratio rises rapidly at the preliminary stage of precipitation, the precipitation ratio ascends slowly at middle stage of precipitation and the precipitation ratio increases more slowly at the final stage of precipitation. On the basis of this character of the η-t curve and the technology features of seeded precipitation in producing sandy alumina in Chinese alumina plants, various parameters are determined in the precipitation process as a result of intermediate lowering of temperature.

Simulation and Optimization of Cathode Current Distribution to Reduce the Horizontal Current in the Aluminum Liquid

In an aluminum electrolysis cell, the movement of molten aluminum is driven by electromagnetic forces resulting from the current fields in the cell. A rapid movement of the aluminum liquid results in a noisy operation of the cell with an increase in both the voltage and the energy consumption. For a long time designers have endeavored to reduce the magnetic field intensity and decrease the Lorenz force to lower the flow speed of the aluminum liquid by optimizing the layout of the bus bars. In the present work, the effect of the design and the material of the cathode on the horizontal current in aluminum liquid were studied by .

Thermal and Electrical Analysis of the Anode

Thermal and electrical shocks are the main causes for the anode cracking, which results in severe cell disturbance and higher net carbon consumption. A parametrical finite element analysis (FEA) model is developed to simulate the thermal distribution of an anode after setting. The actual temperature and voltage drop of the anode was measured in industrial cell. The temperature and voltage drop of the anode were analyzed.

A Techno-Economic Optimization Model for Aluminium Electrolysis Production

The major factors affecting the profit of an enterprise are the price of the product, the price of raw materials and energy consumed, depreciation of fixed assets, labor cost, output and process consumptions, etc. In this paper, based on a cost-volume-profit (CVP) analysis method and the process techniques of aluminium production, a series of techno-economic analysis and optimization models for the production of the aluminium smelter enterprises are built. The models can be used for the aluminium smelters in various market situations to get the optimum technical parameters of production, which are necessary for obtaining the greatest economic benefit. Thus, it will guide the aluminium smelters in different market environment, according to their own conditions, to adopt different technical parameters of production to maximize the gains and to minimize the losses. We also have studied the optimization of potline current of a 300 kA aluminium smelter by the models as an example.