Thermodynamics and Kinetics Research of the Fluorination Process of the Concentrate Rutile

Vladimir A Karelin,Alexander V Sazonov,Alexander N Strashko,Nadezhda V Karelina,Son Hai Le,Huong M T Le

doi:10.3390/met12010034

Abstract

The growth in the production of titanium metal and its compounds leads to an increase in the amount of toxic waste. As a result, at the legislative level, emissions of such wastes are limited, which leads to a drop in the production of titanium-containing products and a shortage of titanium in the international market. This paper presents the results of the process of fluorination of rutile concentrate from the Tarsky deposit (Russia, Omsk region) with elemental fluorine using a laboratory setup of a special design. For fluorination, samples of rutile concentrate weighing 0.1–1.0 g were used. The particle size distribution of particles varied from 2 × 10−6 to 2 × 10−5 m. To determine the possibility of carrying out the process, the calculation of the change in the logarithm of the equilibrium constant versus temperature was performed. The influence of the following operating parameters on the fluorination process has been studied: various concentrations of F2 in a fluorinating mixture of fluorine with nitrogen; process time from 0 to 9 min; different ratios of the initial solid phase to fluorine (10 and 50% excess of fluorine and 10 and 50% of its deficiency); fluorination temperature in the range of 300–1800 K. A kinetic equation is selected that most accurately describes the fluorination process. The values of the activation energy and the preexponential factor in the kinetic equation are determined. The obtained results show that with an increase in the fluorine content in the fluorinating gas mixture and the temperature of the process, the fluorination rate increases. Optimal conditions for fluorination: temperature—680 K; time—5 min excess fluorine in the fluorinating mixture—20–25%. The obtained results allow to propose and consider the conditions of process execution on industrial equipment.

Highlights

With the development of science-intensive technologies, the need for the creation of structural materials that work in critical conditions is sharply increasing
The creation of technological processes allowing to ensure high quality of titanium alloys and their minimum cost is the key task of technologies for obtaining high-tech structural materials
The development of modern technologies for the chemical processing of titanium concentrates and the synthesis of high-purity metallic titanium is one of the main processes preceding the creation of titanium alloys, since the physicochemical properties and cost of products made of titanium and its alloys depend on the content of impurities in a titanium product

Summary

Introduction

With the development of science-intensive technologies, the need for the creation of structural materials that work in critical conditions is sharply increasing. As a result of the interaction of titanium and iron oxides with aqueous solutions of ammonium fluoride, aqueous solutions of HF (hydrofluoric acid) are formed, which, under the conditions of the process, have a strong corrosive effect on the material of the apparatus This does not allow the use of this method in an industrial environment. The process of synthesis of rutile from titanium slags from the Panzhihua deposit (China) by oxidative roasting of these slags at 1100 ◦C for 2 h is presented [12] This method is not new since it is described in the preparation of various titanium ores for the Kroll process—the reduction in TiO2 with magnesium. A method of processing titanium-containing minerals is introduced by fluorine technology with rutile as the raw material, and some thermodynamic and kinetic parameters are calculated to evaluate and propose a schematic diagram of a facility for fluorination of rutile concentrate in industrial conditions

Materials

Experiment

Results

Discussion

In atmosphere