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- Title
Kinetic and thermodynamic analysis on preparation of belite-calcium sulphoaluminate cement using electrolytic manganese residue and barium slag by TGA.
- Authors
He, Weilong; Li, Rui; Yang, Yanping; Zhang, Yu; Nie, Dengpan
- Abstract
Electrolytic manganese residue (EMR) is a solid filter residue obtained from manganese carbonate ore during the production of metal manganese. A potential avenue towards large-scale utilisation of EMR is its use in cement preparation. However, the preparation of cement materials using EMR requires high-temperature calcination. In this study, the thermal properties and pyrolysis kinetics of belite–calcium sulfoaluminate cement raw meal were systematically studied using a multiple-heating-rate method based on thermogravimetric analysis and a kinetic model. The kinetic and thermodynamic parameters was studied using non-isothermal Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), Friedman and Kissinger methods. The results showed that from 30 to 1300°C, the pyrolysis reaction of cement raw meal was mainly divided into four steps: the crystalline water removal from calcium sulphate dihydrate and bauxite, the ammonia nitrogen removal from ammonium salts and the calcium sulphate crystal transformation; the decomposition of calcium carbonate and carbon-containing organic matter; the sulphate and carbonate substance decomposition and the clinker mineral phase formation. The average activation energies calculated when using the non-isothermal FWO, KAS, Friedman and Kissinger methods were 244.49, 240.7, 239.24 and 380.60 kJ/mol and the average pre-exponential factors were 1.75 × 1020, 3.65 × 1020, 7.11 × 1021 and 1.55 × 1013 s−1, respectively. Herein, the pyrolysis kinetics of the cement raw meal was divided into two main stages: In stage 1 (α: 0.15–0.8, 524°C–754°C), the mechanism of P2/3 accelerated nucleation in the Mampel Power rule, and the reaction mechanism function was G(α)=α3/2. In stage 2 (α: 0.80–0.95, 754°C–1165°C), during the local conversion of α = 0.2–0.8, when α was <0.5, the chemical reaction mechanism of the R3 phase boundary was noted and the mechanism function was G(α) = 1 − (1−α)1/3; however, when α was >0.5, a random nucleation and subsequent growth mechanism of A6 was noted and the mechanism function was G(α) = [−ln(1 − α)]2/3.
- Subjects
ELECTROLYTIC manganese; SULFOALUMINATE cement; CALCIUM sulfate; PYROLYSIS kinetics; BARIUM; SLAG; THERMAL properties
- Publication
Environmental Science & Pollution Research, 2023, Vol 30, Issue 42, p95901
- ISSN
0944-1344
- Publication type
Article
- DOI
10.1007/s11356-023-29104-5