Fluid Characterization Of Copper Converters

Abstract

Peirce-Smith converters (PSC) are used to obtain almost 90% of the blister copper. PSC are
long cylindrical chemical reactors where copper matte reacts with air. Traditionally, air is injected
laterally through submerged tuyeres at different subsonic velocities. There are several works on which
the fluid flow patterns inside the PSC are analyzed by means computational fluid dynamics (CFD)
tools. Also, several papers have studied the converter using physical water based models. Numerous
authors agree that the most important factors are bath depth and tuyere submergence. Nevertheless, air
injection at the converter bottom has not been fully characterized. The aim of bottom injection is to
maximize the copper kinetic energy meanwhile avoiding excessive reactor splashing. In this work, a
PSC with bottom air injection is studied by means of multiphase 3D CFD numerical simulations
considering multiple air velocities. A bubbling regime is displayed at low inlet velocity simulations. As
inlet velocity is increased, a transition to a jetting regime is obtained. However, a new transition to the
bubbling regime is observed when air is increased again. The unexpected transition is explained in
terms of bubble geometry close to the tuyere exit and metalostatic pressure, which directly depends on
the copper matte height. An almost linear relationship between copper matte kinetic energy and inlet
air velocity is observed. However, the lowest mixing efficiency is obtained at a medium inlet air
velocity.