China Geological Survey Bureau of Geological Survey Projects - iron ore tailings resource utilization has made a breakthrough by the number of research institutes jointly developed "pre-oxidation - regenerative reduction - reoxidation" multi-stage suspension calcination new technology allows troubled mining enterprises for many years The tailings have returned to life and realized resource utilization.
Tailings have always been a major problem for iron ore enterprises. The problem of exposure is not only a safety issue, but also a contradiction between the traditional extensive economic growth mode and the new industrialization road, and the contradiction between resource shortage and sustainable development. At present, the comprehensive utilization of tailings has become a long-term national policy in China. In recent years, with the rapid development of the steel industry, the number of industrial waste gas, waste water and waste residue has increased year by year, and the amount of tailings and waste rock discharged every year in the world is as high as 10 billion tons or more. China's iron ore resources have low grades and high beneficiation ratios. The annual output of iron ore is about 1.5 billion tons, and the tailings amount is more than 1 billion tons. According to statistics, the existing stockpiles of tailings of Angang Group have reached more than 600 million tons, and more than 40 million tons of tailings are added each year. The eastern tailings of Anshan Iron and Steel Co., Ltd. are sourced from Qidashan Concentrator, Qidashan Iron Ore Dressing Plant and Anquan Mining Company's concentrating plant, with an annual discharge of 28.5 million tons. This type of iron ore tailings belongs to high silicon (SiO2>65%) high iron (TFe>10%) type, and the average tailings iron grade is more than 10%. The industrially available iron minerals are mainly red and limonite, which is harmful. The content of impurities S and P is extremely low.
Prof. Han Yuexin from Northeastern University, supported by the China Geological Survey's local project and the Ministry of Education's major innovation project, combined with Shenyang Xinbo Industrial Technology Co., Ltd. and the Institute of Minerals Comprehensive Utilization of the Chinese Academy of Geological Sciences for complex refractory iron ore minerals. complex composition, close symbiosis, the characteristics of many kinds of iron minerals, mineral processing, metallurgical and fluid multidisciplinary combine creatively proposed a "pre-oxidation - reduction regenerator - reoxidation" multi-firing suspension new technology.
It is understood that Suspension Roasting is a fluidized roasting, which is a method of heating the powder material in a suspended state to a certain temperature and then introducing a reducing gas to make hematite, siderite and brown in the material. The process of reducing iron ore into magnetite, and the calcined material is magnetically selected to obtain high quality iron concentrate. Combined with the mineral characteristics of the eastern tailings of Anshan Iron and Steel Co., Ltd., they successfully developed a new process of “pre-enrichment-suspension roasting-magnetic separation†in the eastern tailings of Anshan Iron and Steel Co., Ltd., forming a precise regulation of heterogeneous transformation of iron minerals and heterogeneous iron ore particles. A series of new technologies, such as suspension state maintenance, regenerative high-efficiency low-temperature reduction, and iron mineral phase control synchronous recovery of latent heat, solve the technical problem of efficiently recovering weak magnetic iron minerals from Anshan Iron and Steel Mine. In this process, "iron mineral suspension roasting system and roasting process", "suspended magnetization roaster", "a method of selecting iron concentrate from alkaline red mud and making tailings neutral" The national invention patents were authorized, and a complex and difficult-to-select iron ore suspension roasting pilot test and pilot test system were completed, and the design of a new set of suspension roasting industrial equipment was completed.
After the "pre-enrichment-suspension roasting-magnetic separation" pilot test, the TFE grade 11.48% of the eastern tailings of Anshan Iron and Steel Co., Ltd. obtained the "TFEE grade of iron ore concentrate 65.69%, the recovery rate of magnetic separation operation of roasting materials was 89.85%, the total recovery rate was 55.33. The good technical indicators of “%†lay a good foundation for the development of “pre-enrichment-suspension roasting-magnetic separation†(PSRM) industrialization technology for complex and difficult iron ore. Angang Mining Group adopts “pre-enrichment-suspension roasting-magnetic separation†technology to treat eastern tailings, and can recover 2.6 million to 3 million tons of qualified iron concentrates per year without increasing the amount of ore.
On the one hand, this technology realizes the effective sorting of a large number of siderites, limonite ore, lava rock and tailings that have not been utilized so far, and revitalizes a large amount of iron ore resources; on the other hand, it can greatly improve the recovery rate of the optional ore. To achieve the purpose of energy saving, consumption reduction and efficiency improvement. The implementation of this project will play an active role in improving the resource utilization rate of Angang Group, reducing the production cost of enterprises, revitalizing a large amount of iron ore resources, and realizing the goal of resource development and conservation, and the resource utilization of iron ore tailings in China. Utilization has opened up new avenues.
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