Computational Approaches for Studying Slag–Matte Interactions in the Flash Smelting Furnace (FSF) Settler

Abstract

Computational methods have become reliable tools in many disciplines for research and industrial design. There are, however, an ever-increasing number of details waiting to be included in the models and software, including, e.g., chemical reactions and many physical phenomena, such as particle and droplet behavior and their interactions. The dominant method for copper production, flash smelting, has been extensively investigated, but the settler part of the furnace containing molten high temperature melts termed slag and matte, still lacks a computational modeling tool. In this paper, two commercial modeling software programs have been used for simulating slag-matte interactions in the settler, the target being first to develop a robust computational fluid dynamics (CFD) model and, second, to apply a new approach for molten droplet behavior in a continuum. The latter is based on CFD coupled with the discrete element method (DEM), which was originally developed for modeling solid particle-particle interactions and movement, and is applied here for individual droplets for the first time. The results suggest distinct settling flow phenomena and the significance of droplet coalescence for settling velocity and efficiency. The computing capacity requirement for both approaches is the main limiting factor preventing full-scale geometry modeling with detailed droplet interactions.

Modelling copper smelting – the flash smelting plant, process and equipment

“…It has been developed for simulating discrete (solid) particles’ interactions and behaviour in a fluid. It has now been tested and found suitable for modelling liquid matte droplet settling through a liquid slag layer (Jylhä and Jokilaakso 2019a). The ultimate objective of these efforts was to digitalise fundamental observations from the experimental research and the industrial experience into an intelligent process model and optimisation system [e.g.…”

“…Coupling CFD and DEM methods attains growing interest in processing areas involving particulate solid materials in different applications, such as cyclones and blast furnaces (Natsui et al 2011; Wei et al 2017). A novel alternative approach for including chemical kinetics into fluid flow by a coupled CFD-DEM software has been made for testing feasibility of the CFD-DEM technique for describing droplets’ settling though a slag layer (EDEM 2017; Jylhä and Jokilaakso 2019a, 2019b). A physical modelling study for water droplet settling through an oil was used for validating the CFD–DEM model (Jylhä and Jokilaakso 2019a, 2019b).…”

“…A novel alternative approach for including chemical kinetics into fluid flow by a coupled CFD-DEM software has been made for testing feasibility of the CFD-DEM technique for describing droplets’ settling though a slag layer (EDEM 2017; Jylhä and Jokilaakso 2019a, 2019b). A physical modelling study for water droplet settling through an oil was used for validating the CFD–DEM model (Jylhä and Jokilaakso 2019a, 2019b). In the simulation, fluid and particle flows were computed separately in CFD and DEM, respectively.…”

Matte-slag separation behavior as a function of iron phase reduction in copper slag

“…Oxygen-enriched smelting technology, which increases the driving force of sulfuroxygen transfer, allows solid materials to react strongly with both gas/liquid phases and achieves the efficient production of copper matte [9,10]. The high oxygen potential of the smelting process removes iron from the material to improve the grade of matte, but part of the iron phase over-oxidation would precipitate a high melting point Fe3O4 phase, leading to the increased viscosity of the copper slag and deteriorating the slag-matte separation conditions [11][12][13][14]. The Isa furnace is a typical representative of oxygenenriched bath smelting, where the smelting process is a cyclical release of a mixture of copper matte and slag [15,16].…”

Flash Smelting Settler Design Modifications to Reduce Copper Losses Using Numerical Methods

“…Numerical studies have been conducted regarding copper matte settling and losses in slag and how to minimize these losses [1][2][3][5][6][7][8][9][10][11][12]. The transient behavior of copper droplets' settling and losses in slag were numerically studied with the presence of the gas phase using coalescence and varying slag viscosity by Schmidt, Montenegro, and Wehinger [9].…”