Scheduling copper refining and casting operations by means of heuristics for the flexible flow shop problem

Abstract

ABSTRACT. Management of the operations in a copper smelter is fundamental for optimizing the use of the plant's installed capacity. In the refining and casting stage, the operations are particularly complex due to the metallurgical characteristics of the process. This paper tackles the problem of automatic scheduling of operations in the refining and casting stage of a copper concentrate smelter. The problem is transformed into a flexible flow shop problem and to solve it, an iterative method is proposed that operates in two stages: in the first stage, a sequence of jobs is constructed that configures the lots, and in the second, the constructed solution is improved by means of simulated annealing. Fifteen test problems are used to show that the proposed algorithm improves the makespan by an average of 9.42% and the mean flow time by 12.19% with respect to an existing constructive heuristic.

Automated scheduling and scientific management of copper smelters

“…Table 3 summarises the results of 300 simulated days, using randomly generated initial conditions (Navarra and Mendoza, 2013); 20 replicas were performed on each of the two modes, showing that mode B produces *15% more copper anodes than mode A. In both cases, the utilisation of the refining furnaces is remarkably low; scheduling algorithms may be designed to anticipate low usage of refining furnaces (Navarra and Mendoza, 2013;Pradenas et al, 2011), to decide when to deactivate a furnace, hence to control operating costs. Mode B is far more productive than mode A, even though it does not fully utilise the offgas capacity.…”

“…There are relatively few publications that describe the scientific management of copper smelters (Guo, 2003;Harjunkoski et al, 2008;Navarra and Acun ˜a, 2013;Navarra and Mendoza, 2013;Pradenas et al, 2006;Pradenas et al, 2011). This may be surprising, considering that the viability of a smelter is directly affected by its operational practices.…”