Study On The Thermal Decomposition Kinetics And Explosion Temperature Calculated Of Dust Of Sulfide Ores

The dust of ores that produced during mining operation will be lead to explosion accident which satisfies some conditions in the underground high sulfur metal mines.It had brought a huge risk of the security of personnel and equipment to mine safety.In this paper,the thermal stability of dust of sulfide ores which is based on gas phase explosion mechanism was discussed to described the explosion possibility of class B(the sulfur content between 20% and 30%),class C(the sulfur content between 10% and 20%),class D(the sulfur content less than 10%)dust of sulfide ores by the thermal analysis technique.The explosion temperature of dust of sulfide ores was calculated according to the theory and method of thermodynamic calculation of dust explosion.All the work provide a theoretical basis for prevention and treatment and evaluation the explosion of dust of sulfide ores.Specific contents are as follows:(1)The thermal decomposition curves characteristics of dust of sulfide ores and the heating rate influence were clarified.The thermal decomposition reaction process of dust of sulfide ores can be divided into three stages:evaporation,mineral decomposition,product decomposition.With increment of temperature rising rate,all the thermal decomposition curves of various dust of sulfide ores have drift trend to high temperature region under the effect of heating hysteresis.(2)The kinetic triplet of thermal decomposition reaction of various dust of sulfide ores were obtained.The values of apparent activation energy of class B,class C,class D dust of sulfide ores were calculated that their were 160.57kJ/mol,183.44kJ/mol,142.58kJ/mol respectively by Popescu and Coats-Redfern method,meanwhile,the values of preexponential factor were 2.92×1010s-1,6.01×1011s-1,1.62×108s-1 respectively.(3)The thermal stability of various dust of sulfide ores were evaluated.The values of apparent activation energy can be used as the index to judge thermal stability and explosion possibility of various dust of sulfide ores.The results showed that thermal stability of various dust of sulfide ores sequence is class D<class B<class C.The explosion possibility sequence is class C<class B<class D.(4)The activation thermodynamic functions values of dust of sulfide ores were obtained.The results showed that transition state has a compact structure compare with structure of dust of sulfide ores in the thermal decomposition reaction of dust of sulfide ores.The reaction rate and thermal resistance ability were consistent with class B and class C dust of sulfide ores.The class D dust of sulfide ores has more quickly reaction rate and worse thermal resistance ability.(5)The influence of concentration on the explosive strength of various dust of sulfide ores were analysed.The explosion experimental of dust of sulfide ores were tested by using the 20 L explosion test chamber.The results showed that the bigger the sulfur content,the larger the maximum explosion pressure under the same particle size.All the explosion index of various dust of sulfide ores less than 8Mpa·m/s.The dust of sulfide ores is weak explosible dust that belongs to St1 degree of explosion severity classification.(6)The explosion temperature of class A dust of sulfide ores was calculated.The explosion products of 30 g weight class A dust of sulfide ores containing 0.048mol2 3Fe O,0.01mol2 3 2Al O ?2SiO,0.132mol2 SO,0.03mol2 CO,0.015mol2 H O and 0.114mol2 FeS unreacted by using the theory and method of thermodynamic calculation of dust explosion.Finally,the theory explosion temperature is 1282 K by using linear interpolation method.