Process For Coal-based Direct Reduction And Magnetic Separation Of High-iron Manganese Ore

The distribution of manganese ore resources in China is very imbalance, in which the impurity content is very high, most of the manganese depesits are multi-metal associated, and70%of the iron content in manganese ore is slightly higher. All of these lead to a result that the traditional separation methods such as mechanical beneficiation, chemical mineral processing, etc produced poor effect. Based on the research on the properties of a certain high-iron manganese ore, a process in which the coal was the reducing agent for coal-based direct reduction and magnetic separation of the ore was studied, which can provide theoretical basis for the comprehensive utilization of high-iron manganese ore. Here are the main creative poits and conclusions:(1) Based on the mineralogy characteristic of the high-iron manganese ore, the explanations to the poor separateing effect for traditional separation methods were gave. The main mineral in the high-iron manganese ore were hematite-limonite and (Mn,Fe)2O3, and some of the iron minerals and manganese minerals were intergrown and asslciated.(2) The analysis of thermodynamics and kinetics of the process for coal-based direct reduction and magnetic separation of the high-iron manganese ore were reviewed, and the results showed that the unreacted core model was basically corresponded. In the process, the decomposition and transformation function of hematite-limonite and MnO2appeared at the first, which were step-by-step reduced subsequently into metallic iron and MnO. But board iron and manganese oxides (Mn,Fe)2O3was decomposed to iron oxide and manganese oxide firstly, and then the gradual deoxidizing process of the oxides appeared. The metallic iron nucleus was formed from the grated style in board (Mn,Fe)2O3. When the condition was reduction temperatures(1100℃), duration(100min), the particle size of the iron was5μm at least, in which the ratio of the manganese was9%-17%.(3) In the studies on the process for coal-based direct reduction and magnetic separation of the high-iron manganese ore, the experimental results demonstrated that the effect of reduction and separation was better and better with the increasing the reduction temperatures and the time and the optimize conditions was reduction temperatures(1100℃), duration(100min), the grinding fineness of reduction-roasting products(about90%-0.074mm), and the magnetic field intensity in the low intensity magnetic separation (150kA/m), under which the iron grade was56.13%and the content of the manganese was24.71%in the magnetic products in which the recovery of iron was92.60%while the iron grade was only3.95%and the content of the manganese was61.43%in the non-magnetic products. Therefore, the separating effect of coal-based direct reduction and magnetic separation of the high-iron manganese ore was remarkable.