铜渣直接还原动力学

我国铜渣资源储量丰富，渣中含有多种有价金属，具有很高的二次利用价值.为了揭示铜渣提铁的碳热还原机理，以无烟煤为还原剂，进行铜渣含碳球团等温还原实验，并对其进行动力学分析.实验设定的还原温度为1 000 ℃、1 050 ℃、1 100 ℃、1 150 ℃和1 200 ℃，碳氧比即n_c/n_o=1.0.结果表明，对于铜渣含碳球团等温还原实验，温度对反应速率有重要影响；该反应主要限速环节为气相扩散，活化能数值为118.059 kJ/mol；对其进行阶段性动力学分析，其活化能在61.54~146.98 kJ/mol范围内，且活化能的数值随着还原度的变化而变化，具体表现为:第1阶段反应活化能数值较小，原因可能是该阶段反应刚开始，原铜渣中含有一些铁氧化物（Fe₃O₄）先参与了反应；第2阶段反应活化能较高，此时原铜渣中的铁氧化物已基本反应，铁以橄榄石的状态存在，且橄榄石呈液态，致使球团孔隙度降低，气体在球团内的扩散受阻. 

Direct reduction kinetics of copper slag

China has large reserves of copper slag that contains a variety of valuable metals and has a high secondary utilization value. In order to reveal the carbothermal reduction mechanism of iron extraction from copper slag, isothermal reduction experiments of carbon-bearing pellet in copper slag were carried out with anthracite as reducing agent, and the kinetic analysis was conducted to provide reference for the utilization of copper slag. The reduction temperatures set in this experiment were 1 000 ℃, 1 050 ℃, 1 100 ℃, 1 150 ℃ and 1 200 ℃, and the C/O molar ratio was 1.0. The results show that the temperature has an important effect on the reaction rate in the isothermal reduction experiment of carbon-bearing pellets in copper slag. The main rate limiting step of this reaction is gas phase diffusion, and the activation energy value is 118.059 kJ/mol. The phased kinetic analysis shows that the activation energy is in the range of 61.54~146.98 kJ/mol, and the value of the activation energy changes with the degree of reduction. The specific performances are as follows: the reaction activation energy value in the first stage is low, and the reason may be that in the initial stage of the reaction, the iron oxide (Fe₃O₄) contained in the original copper slag participates in the reaction first; the reaction activation energy in the second stage is higher, because the iron oxides in the original copper slag has all basically got reacted. The iron exists in the state of liquid olivine which lowers the porosity of the pellet, hindering the diffusion of gas within the pellet.