Nonlinear characteristics of induced spontaneous combustion process of sulfide ores
Autor: | Wei Pan, Ying Shi, Yue-ping Yang, Zi-jun Li, Chao Wu |
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Rok vydání: | 2016 |
Předmět: |
chemistry.chemical_classification
Correlation dimension Sulfide Metallurgy Metals and Alloys General Engineering Thermodynamics 02 engineering and technology Lyapunov exponent engineering.material 020501 mining & metallurgy law.invention Ignition system Nonlinear system symbols.namesake 0205 materials engineering chemistry law engineering symbols Pyrite Stage (hydrology) Spontaneous combustion |
Zdroj: | Journal of Central South University. 23:3284-3292 |
ISSN: | 2227-5223 2095-2899 |
DOI: | 10.1007/s11771-016-3394-4 |
Popis: | To investigate the relationship between nonlinear parameters and spontaneous combustion tendency of sulfide ores, nine different sulfide ore samples were taken from a pyrite mine in China, and induced spontaneous combustion experiment was carried out in the laboratory. Different stages of the induced spontaneous combustion process were studied by integrating wavelet technology and nonlinear dynamics theory. The results show that ignition points of all the ore samples are above 330 °C, indicating that sulfide ores of the pyrite mine are difficult to combust spontaneously under normal mining conditions. Spontaneous combustion process includes three stages: incubation stage, development stage and approaching stage. The average temperature rising rate of the three stages are 1.0 °C/min, 2.0 °C/min and 4.2 °C/min, respectively. During the spontaneous combustion process, mean values of approximate entropy and correlation dimension increase at first, and then decrease in the following stage. The mean value of the maximum Lyapunov exponent increases with the passage of reaction time. In a whole, correlation among the three nonlinear parameters firstly weakens, then enhances, and the best correlation period is at approaching stage. As ignition point increases, the maximum Lyapunov exponent of approaching stage decreases. Therefore, combustible tendency of sulfide ores could be qualitatively evaluated based on the maximum Lyapunov exponent of this stage. |
Databáze: | OpenAIRE |
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