硫酸铵与钛酸钙焙烧动力学

近年来，以硫酸铵为助剂，采用含钛高炉渣矿化CO₂同时提取其中的有价钛铝组分的研究日益受到关注。钛酸钙是含钛高炉渣的主要物相之一，其与硫酸铵焙烧过程的机理及动力学研究有助于深刻理解含钛高炉渣分解过程。本文分别采用等温法和非等温法研究了硫酸铵与钛酸钙的焙烧动力学，考察了焙烧反应的动力学参数和控制步骤。等温动力学结果表明，硫酸铵与钛酸钙的焙烧过程分为两步，即硫酸铵分解和硫酸氢铵与钛酸钙反应，其中硫酸铵分解为限制环节，受化学反应控制。单一硫酸铵分解反应活化能为65.56kJ/mol，加入钛酸钙后促进硫酸铵的分解，活化能降低至50.15kJ/mol。采用基辛格法、FWO法、KAS法三种非等温动力法测得整个焙烧过程的表观活化能分别为53.96kJ/mol、76.67kJ/mol和71.05kJ/mol，其中基辛格法的表观活化能结果与等温动力学相一致，而FWO法和KAS法所得表观活化能变化趋势验证了等温动力学结果对焙烧过程中控制步骤的选择。

Roasting kinetics of ammonium sulfate and calcium titanate

Recently, more and more attention has been paid to simultaneously mineralize CO₂ and extraction of valuable components from titanium-bearing blast furnace slag by ammonium sulfate roasting. Calcium titanate is one of the main phases of titanium-bearing blast furnace slag. The study on the mechanism and kinetics of the reaction between titanium-bearing blast furnace slag and ammonium sulfate is helpful to understand the decomposition process of the slag. In this study, isothermal and non-isothermal kinetics research methods were adopted to study the roasting reaction of (NH₄)₂SO₄ and CaTiO₃. The kinetic parameter and control step of the roasting reaction were investigated. Isothermal kinetics research results showed that the roasting reaction was divided into two steps, i.e. the decomposition of (NH₄)₂SO₄ and reaction between NH₄HSO₄ and CaTiO₃. The former was the limited step controlled by chemical reaction. The decomposition activation energies of single (NH₄)₂SO₄ was calculated as 65.56kJ/mol, while it decreased to 50.15kJ/mol after adding CaTiO₃. The apparent activation energies of the roasting reaction were measured as 53.96kJ/mol, 76.67kJ/mol and 71.05kJ/mol by three non-isothermal kinetics research methods including Kissinger, FWO and KAS, respectively. The apparent activation energy gained by Kissinger method was consistent with that in isothermal kinetics research method, and the trend of the apparent activation energy gained by FWO and KAS verified the rate control steps measured by isothermal kinetics research method.