Grinding is one of the most costly operations in the mechanical breaking and mining.Determination of the breakage characteristics and preconditioning is important to increase the grinding efficiency.Investigations of ...Grinding is one of the most costly operations in the mechanical breaking and mining.Determination of the breakage characteristics and preconditioning is important to increase the grinding efficiency.Investigations of the seismic,mechanical and breakage properties of iron oxides are very important parameters for investigating the rock fragmentation by blasting and comminution processes in iron ore mines.In this paper,at first,geomechanical and seismic properties of the oxide ores(magnetite and hematite)in the Chadormalu iron ore mine were studied.The results showed that the percentage of magnetite has a direct relationship with uniaxial compressive strength,tensile strength and P and S wave’s velocities and has an inverse relationship with Poisson ratio and porosity.Moreover,to study breakage and preconditioning characteristics in the iron ores,two samples with different magnetite percents were blasted by detonation cord.The results showed that with higher percentage of magnetite,the number of fractures induced by blasting increased.Bond work index and magnetite percent were investigated in the 430 blasts in the mine.This investigation not only confirmed the small scale blasting results,but also showed that increasing the magnetite percent up to 50%noticeably reduces Bond work index and energy consumption in the grinding process.Also,the relationship between muck pile fragmentation and magnetite percentage were studied for several blasts that had the same blast pattern parameters and similar geology conditions.These results also confirmed precedents conclusions regarding magnetite percent and preconditioning relationship.展开更多
Based on the former performance capacity experiments of the magnet-friction energy dissipation devices, including the permanent magnet-friction energy dissipation device (PMF) and electromagnet-friction energy dissipa...Based on the former performance capacity experiments of the magnet-friction energy dissipation devices, including the permanent magnet-friction energy dissipation device (PMF) and electromagnet-friction energy dissipation devices (EMF), a 5-story steel frame model with spacious first story is designed and made according to a scale of 1/4. The magnet-friction energy dissipation devices can realize continuously varied controlling force, with rapid response and reverse recognition. Therefore, they overcome shortcomings usually found in energy dissipation devices whose force models are invariable. The two kinds of devices were fixed on the flexible first story of the structure model, and the shaking table tests have been carried out, respectively. In these tests, the performance of the devices and their effectiveness in structural control were confirmed. In this paper, the test results and analysis are discussed.展开更多
The iron and steel industry generally features the characteristics of large volume of energy consumption, multiple sorts of energy medium, complex secondary conversion, more recyclable extra energy, and the energy man...The iron and steel industry generally features the characteristics of large volume of energy consumption, multiple sorts of energy medium, complex secondary conversion, more recyclable extra energy, and the energy management of the field may involve the entire personnel, process and system, covering all links from designing, purchasing, energy storage, processing and conversion, distribution, energy use and extra energy recycling. The implementation guidelines summarizes the energy management experience and results and provide a systematic approach for the implementation of GB/T 23331-2012 and GB/T 29456-2012, sharing svstematic instructions and suggestions for the implementing paths and methods of creating, implementing, maintaining and improving the energy management system （EnMS） at the enterprise level.展开更多
文摘Grinding is one of the most costly operations in the mechanical breaking and mining.Determination of the breakage characteristics and preconditioning is important to increase the grinding efficiency.Investigations of the seismic,mechanical and breakage properties of iron oxides are very important parameters for investigating the rock fragmentation by blasting and comminution processes in iron ore mines.In this paper,at first,geomechanical and seismic properties of the oxide ores(magnetite and hematite)in the Chadormalu iron ore mine were studied.The results showed that the percentage of magnetite has a direct relationship with uniaxial compressive strength,tensile strength and P and S wave’s velocities and has an inverse relationship with Poisson ratio and porosity.Moreover,to study breakage and preconditioning characteristics in the iron ores,two samples with different magnetite percents were blasted by detonation cord.The results showed that with higher percentage of magnetite,the number of fractures induced by blasting increased.Bond work index and magnetite percent were investigated in the 430 blasts in the mine.This investigation not only confirmed the small scale blasting results,but also showed that increasing the magnetite percent up to 50%noticeably reduces Bond work index and energy consumption in the grinding process.Also,the relationship between muck pile fragmentation and magnetite percentage were studied for several blasts that had the same blast pattern parameters and similar geology conditions.These results also confirmed precedents conclusions regarding magnetite percent and preconditioning relationship.
文摘Based on the former performance capacity experiments of the magnet-friction energy dissipation devices, including the permanent magnet-friction energy dissipation device (PMF) and electromagnet-friction energy dissipation devices (EMF), a 5-story steel frame model with spacious first story is designed and made according to a scale of 1/4. The magnet-friction energy dissipation devices can realize continuously varied controlling force, with rapid response and reverse recognition. Therefore, they overcome shortcomings usually found in energy dissipation devices whose force models are invariable. The two kinds of devices were fixed on the flexible first story of the structure model, and the shaking table tests have been carried out, respectively. In these tests, the performance of the devices and their effectiveness in structural control were confirmed. In this paper, the test results and analysis are discussed.
文摘The iron and steel industry generally features the characteristics of large volume of energy consumption, multiple sorts of energy medium, complex secondary conversion, more recyclable extra energy, and the energy management of the field may involve the entire personnel, process and system, covering all links from designing, purchasing, energy storage, processing and conversion, distribution, energy use and extra energy recycling. The implementation guidelines summarizes the energy management experience and results and provide a systematic approach for the implementation of GB/T 23331-2012 and GB/T 29456-2012, sharing svstematic instructions and suggestions for the implementing paths and methods of creating, implementing, maintaining and improving the energy management system （EnMS） at the enterprise level.
