The Adsorption Behavior of Moisture on Smelter Grade Alumina during Transportation and Storage—for Primary Aluminum Production

Abstract

Smelter grade alumina (SGA) plays multiple roles in the Hall–Héroult process for primary aluminum production. Given its very porous nature, one major role of SGA is to adsorb toxic hydrogen fluoride (HF) in the dry scrubber. However, also because of its porous nature, SGA inevitably adsorbs ambient moisture. This paper discusses the influence of alumina properties, including pore size distribution and specific surface area, on the physical adsorption of water vapor on SGA, as well as the adsorption kinetics. The result shows that the adsorption enthalpy of moisture on SGA is in the range of 4–13 kJ/mol. The adsorption capacity increases significantly with the particle specific surface area and total pore volume. A higher adsorption temperature indicates a much faster adsorption rate but corresponds to a lower equilibrium adsorption capacity.

Developing a Comprehensive Mathematical Model for Aluminium Production in a Soderberg Electrolyser

“…The thermal state of the electrolyser depends on the heat loss from the electrolyser surfaces to the environment, the total heat accumulated by the anode and the bottom separately, and the heat input from fuel combustion [26]. This condition is described by means of an energy balance.…”

“…The mathematical model is a system of equations that allows us to estimate and determine the parameters of the technological process that influence the main performance indicators of the electrolyser, as well as to establish internal and external relations for the object. The title of the formulae included in the mathematical model (26) are given in Table 9. The results obtained in the chapter can be used as a basis for the development of algorithms for optimal electrolyser control.…”