Research On Spontaneous Combustion Mechanism And Tendency Appraisal Of Sulfide Ores

Spontaneous combustion of sulfide ores is one of the most serious disasters in the mining of metal mines. Once a fire is initiated in stored sulfide ores or concentrates, the disaster will lead to a series of environment and safety problems, and causes economic losses. For a long time, many researchers have made a lot of investigation in the theory and technology of preventing the spontaneous combustion of sulfide ores. The spontaneous combustion of sulfide ores is a complex process, and considering the economic constraints, there are still many problems which has not been fundamentally resolved.By analyzing many former research results about spontaneous combustion hazard in mines, a lot of study work has been made by combining theoretical analysis, experimental determination and practical application, aiming at the mechanism of spontaneous combustion, the influence factors and the test method and standard for evaluating spontaneous combustion tendency of sulfide minerals. The main research contents and the achievements are as follows:(1) By analyzing the whole process of spontaneous combustion of sulfide ores, the spontaneous combustion of sulfide ores is complemented. The sulfide ores spontaneous combustion is divided into five stages, Crushing, physical adsorption, low-temperature oxidation, high-temperature oxidation and combustion. The definition of each stage as well as physical and chemical effects were introduced in detail, and the theory of physical absorbed oxygen and the theory of combustion are complemented. The mechanism of sulfide ore spontaneous combustion and the theory of appraisal technique of sulfide ores spontaneous combustion tendency was improved.(2) The influencing factors of the identification for spontaneous combustion tendency of sulfide ores, such as moisture content, temperature, particle size and the characteristic of the dust production, were analyzed complementally. Redefining the water content of the sulfide ores, it was divided into the initial water content and moisture content, and the effect on the oxidation rate of sulfide ores were studied. The combination of experimental test and data analysis was used to prove that the initial water content has an influence on all the process of oxygenation of sulfide ores, and that the temperature and oxidation rate are proportional on sulfide ores piles. The impacting dust characteristics experiment proved that the sulfide ores have different impacting dust characteristics. By oxidation weight increase method, it can prove that the differences between reaction passivation phenomenons of the sulfide ores with different particle size are not obvious.(3) The oxidation weight increase method, velocity constant of oxygen absorption, chemical composition analysis, self-heating and spontaneous combustion test were used to assess the spontaneous combustion tendency of7sulfide ore samples in a Mine. The early fire point was particular studied, and the spontaneous ignition temperature test was improved by the result.