Effect of vacuum vibroforming on porosity development during anode baking

The anode porosity and pore development depend on the raw materials and on the production process. The porosity of the baked anode consists of the coke pores and process pores that are created during the anode production steps mixing, forming and baking. Pilot-scale work was carried out in order to determine the effects of five parameters on the resulting porosity in the baked state. Anode samples were produced from a single source petrol coke in a two level, five-factorial experimental design with variable factors pitch content, aggregate size distribution, mixing time, atmospheric pressure vibroforming, and heating rate. Vacuum vibroforming was found to be an effective method for porosity reduction. A fully automatic image analysis method (optical microscopy) was utilized in order to determine the porosity in the baked samples. Reactivity (CO2 and air) and physical anode properties were also investigated.