Depleted Copper Slag And Iron Resources To Restore The Recycling Experiments

The steel's production in China is the largest of the world, it attained to 50116 millions ton in 2008, occupying 36.39% of the total production of the world. The rapid development of Steel Industry asks for more iron ores supplyment, and most of the iron ores used in China mainly relies on the importments, beyond 60% of iron ores used imported from foreign countries, and the quantity of iron ores imported ranks first in the world. The dependence on importing is becoming more and more serious, it constrained the development of Steel Industry in China seriously. The price of iron ore has been rising quickly in recent years, it also did harm to the development of China's Steel Industry. So it is necessary to find other resources to instead iron ores as Iron-making materials. The copper production in China ranks second in the world, it attained to 3.71million tons in 2008, corresponding 8.16 million tons of copper slag were produced. These large quantities of copper slag,3.26 million tons of iron contained in. According to the situation of the development of Steel Industry in China, the copper slag can be used as Iron-making resources instead of iron ores, then it can ease the pressure of the development of China's Steel Industry.From the physical and chemical properties of the copper slag, this paper researched how relevant factors affected on the experiment of coal used to reduce iron from copper slag. It could be found that when CaO was not added to the copper slag, meaning the alkalinity was equal to 0.187,the activity of (FeO) in the reaction was lower, equal to 0.3405 based on Molecular theory of hypothesis, and the temperature of the reaction initial temperature was higher, equal to 1273K. With more and more CaO added to the copper slag, the activity of (FeO) of copper slag in the reaction was becoming higher and higher. When the proper quantity of CaO added to the copper slag to make the basicity of copper slag equals to 1.2, the activity of (FeO) increased to 0.5712, and the temperature of the reaction initial temperature could be lowered to 653K.During the reaction of coal used to reduce iron from copper slag, the basicity(1.2) and holding time kept constant(120min at 1500℃), When C/Fe was equal to 1.33, the iron reduction rate in the copper slag reached the maximum equal to 93.82%.The quality of the coal used increased, the iron reduction rate kept stability, and the C content in the iron layer increased; the C/Fe(1.33) and holding time (120min at 1500℃)kept constant, the basicity of copper slag increased, the iron reduction rate in the copper slag rised firstly and then reduced. When the basicity of copper slag was equal to 1.2, the reduction rate reached the maximum. As the quality of the CaO added increased, the S content in the iron layer reduced; When CaO was not added to copper slag, the basicity of copper slag was equal to 0.187,the holding time at 1500℃was beyond 40min, the reduction of iron finished basicly. When the proper quality of the CaO added to the copper slag to make the basicity of copper slag was equal to 1.2, the reduction time of iron could be shortened to less than lOmin holded at 1500℃, and the time of iron separated from slag was equal to less than 20min; when the basicity of the copper slag was equal to 1.55, the viscosity of the copper slag increased fast, the time of iron separated from slag increased to more than 40min.Above all, the best combination of parameters in this experiment to reduce iron from copper slag was as below:the grain size of solid reductant and copper slag was below to 40 mesh, the basicity of the copper slag was equal to 1.2, C/Fe was equal to 1.33.N2 was used to keep the reaction was un-oxidized, the holding time at 1500℃was 20min.