Study On The Deep Reduction-separation And Classification Of Low-grade Iron Ore

Recently, with our country's rapid development of economy and steel production capacity, the contradiction between iron ore supply and demand becomes prominent, which bring tremendous hidden trouble to iron and steel industry and even domestic economy. The issue of how to effectively utilize low-grade iron ore and relieve the resource shortage has become an important project. The common characteristics of this ore are that the embedded relationship is complex and the gangue is wrapped up with iron minerals. Therefore, it is difficult to process the low-grade iron ore. Even some indicators in beneficiation are satisfactory, but when energy consumption and costs are taken into accounts, especially the resource utilization efficiency, traditional beneficiation method cannot meet the needs.Deep reduction-separation is a new technique to handle with low-grade iron ore. This paper was based on this technology and aimed at one kind of complex iron ores. The effects of reduction temperature, additives, reduction time, coal-contained index and coal particle sizes, were discussed, respectively. Then, the effects of different particle sizes on the magnetic separation were discussed and finally, high-quality product was obtained using classification. Main conclusions were proposed as follows.1. The main useful iron minerals of this iron ore is hematite, the gangue is wrapped up with iron minerals and the embedded relationship is complex, so it is hard to process this iron ore using traditional ore dressing method.2. Deep reduction-separation is a proper method the process the target ore. On the basis of this study, the most appropriate reduction condition is:reduction temperature of 1275?, 5% lime as additive, reduction time of 60min, coal-contained index of 1.5(the mass percent is 22.56%), coal particle size of less than 2.0mm.3. On the condition of this reduction procedure, the proper grinding condition of A ore is: grinding the ore till<0.074mm 90%, deep reduction, grinding the reduction production till <0.074mm 60%, magnetic separation, then the average grade of 92.14% was obtained; the proper grinding condition of B ore is:grinding the ore till<0.074mm 50%, deep reduction, grinding the reduction production till<0.074mm 30%, magnetic separation, then the average grade of 94.72% was obtained.4. Different level products were obtained using classification method after reduction and separation.The grade of Class 1 and Class 2 was about 92%-95% and the average grade of Class 3 and Class 4 was about 80-90%, which could be used as different iron-contained materials.