Mathematical Simulation of the Process of Nickel Oxide Recovery in a Tube-Type Rotary Kiln

Abstract

Solid-phase reduction of nickel oxide is an important process stage in nickel production. The mathematical model of the steady-state operation of the apparatus is an important component, which allows determining the optimal operating mode of the rotary tube furnace (TRK). The automated software application ReactOp is capable of generating a mathematical model of the reactor on the basis of hydrodynamic and thermal models supplemented by the mechanism of chemical transformations, kinetic parameters, thermal and physical properties, and heat transfer parameters. The software complex is equipped with a user-friendly interface, which allows to interactively generate a runtime program based on the mathematical model. The software application ReactOp has built-in programs enabling numerical solution of differential equations and solution of inverse chemical kinetics problems, and is capable of providing statistical performance analysis and finding the optimal control solutions based on the methods of non-linear programming. The paper is dedicated to the development of a mathematical model of the steady-state TRK operation. Production of nickel from ores involves several stages of processing raw materials, wherein a corresponding intermediate product is obtained at each stage. As a result of the oxidizing roasting of the nickel flotation concentrate, a roasted product is obtained mainly comprising nickel oxide and other impurities, such as compounds of copper, cobalt, iron, sulfur, as well as rare and precious metals. This stage is followed by the process of solid-phase reduction of nickel oxide in the rotary tube furnaces aimed at obtaining a coarsened, mostly reduced product, which can be further subject to anode electric melting. The latter process allows reducing the consumption of electricity and a reducing agent. The paper further provides the results of mathematical modeling of the reduction process of oxidized copper-nickel ore concentrate in the rotary tube furnace.