Analytical study and cost modeling of secondary aluminum consumption for alloy producers under uncertain demands

Abstract

A series of case studies on raw materials inventory strategy for both wrought and cast aluminum alloy productions were conducted under recourse-based modeling framework with the explicit considerations of the demand uncertainty compared to the traditional strategy based on point forecast of future demand. The result shows significant economic and environmental benefits by pre-purchasing excess amount of cheaper but dirtier secondary raw materials to hedge the riskier higher-than-expected demand scenario. Further observations demonstrate that factors such as salvage value of residual scraps, cost advantage of secondary materials over primary materials, the degree of the demand uncertainty, etc. all have direct impacts on the hedging behavior. An analytical study on a simplified case scenario suggested a close form expression to well explain the hedging behavior and the impacts of various factors observed in case studies. The thesis then explored the effects of commonality shared by secondary materials in their application in multiple final products. Four propositions were reached.