Direct Leaching Process And Kinetics Research Of The Semi-Oxidized Manganese Ore

Manganese is a kind of important strategic resources, it occupies an important position in the national economy. In the case of lacking high-quality manganese ore resources, the low-grade manganese ore leaching technology has already become an increasingly important research content. In this paper, using sucrose as a reducing agent to study semi-oxidized manganese ore’s leaching process and reaction kinetics through direct reduction leaching method.In the semi-oxidized manganese ore leaching process experiment, we use the single factor experiment and the Box-Behnken response surface experiment to study respectively. Single factor experiment is designed to investigate the influences of factors such as liquid-solid ratio, sucrose concentration, sulfuric acid concentration, reaction time and reaction temperature on manganese leaching rate respectively. The experiment result indicates:temperature has a great influence on the leaching rate of manganese, it increases with the rising of temperature of manganese leaching rate. The leaching rate of manganese increases with the increasing of leaching time, sulfuric acid and sucrose concentration. However, the liquid-solid ratio is less affected on the leaching rate of manganese. On the basis of single factor experiments’ relevant experimental data. Experimental design uses Box-Behnken response surface method with H2SO4concentration, sucrose concentration, leaching time and leaching temperature as variables, Mn leaching rate as response values. On the condition of four factors and three levels, the semi-oxidized manganese ore leaching process is optimized. The results show that: the effects of the factors on leaching rate of manganese as follows:sulfuric acid concentration>sucrose concentration>leaching time>leaching temperature.The interactions between sulfuric acid concentration and sucrose concentration, leaching time, leaching temperature are small. What’s more, there is a certain degree of interactions between sucrose concentration and the leaching time, interaction between sucrose concentration and leaching temperature is small, the one between leaching time and leaching temperature is also small. Through the response surface optimization we obtain the optimal process condition:H2SO4concentration is5.52mol/L, sucrose concentration is13.33g/L, leaching time is160min, leaching temperature is90℃. The manganese leaching rate is92.48%under the above condition. In the semi-oxidized manganese ore leaching kinetics study, we study the total manganese leaching kinetics, leaching kinetics of quadrivalence Mn compounds, the leaching kinetics of bivalent manganese compound respectively. The results indicate that: the leaching process can be described by shrinking core model, reaction control process is a diffusion-chemical hybrid control. The apparent activation energy of total manganese leaching kinetics model is27.75KJ/mol, sulfuric acid and sucrose reactions series respectively are1.33,0.94. The macroscopic reaction kinetics equation is:The apparent activation energy of the quadrivalence Mn compound in semi-oxidized manganese ore leaching kinetics model is39.99KJ/mol, Sulfuric acid and sucrose reaction series respectively are1.49and1.49. The macroscopic reaction kinetics equation is:The apparent activation energy of bivalent manganese compound in semi-oxidized manganese ore leaching kinetics model is41.58KJ/mol, sulfuric acid and sucrose reaction series are1.26and0.73. The macroscopic reaction kinetics equation is:...