With the acceleration of world economic recovery and structural adjustment, especially in China's rapid economic development, boosting our steel industry continued high growth, China's steel output has ranked first in the world, more and more for iron ore import dependency High has become a major hidden danger in the economic security of China's steel industry. Therefore, it is urgent to rely on technological progress to maximize the use of existing iron ore resources in China, increase the self-sufficiency rate of iron ore, ease the pressure on imported ore, and maintain a stable, sufficient, high-quality supply of iron ore raw materials to safeguard the steel industry. Continued and stable development.
I. Polyiron ore beneficiation technology
Because the theoretical iron grade of siderite is low, and it is often symbiotic with calcium, magnesium and manganese , the iron ore grade is difficult to reach more than 45 percent by physical beneficiation method, but it is burnt after roasting. Larger and greatly improved iron concentrate grade. The more economical beneficiation method is re-election and strong magnetic separation, but it is difficult to effectively reduce the impurity content in iron concentrate. The strong magnetic separation-flotation combined process can effectively reduce the content of impurities in the iron concentrate, and the iron concentrate is still a high-quality ironmaking raw material after roasting.
Second, limonite ore dressing technology
Since limonite is rich in crystal water, it is difficult to achieve 60% grade of iron concentrate by physical beneficiation method, but the iron concentrate grade is greatly improved after calcination due to large burning loss. In addition, as limonite crushing grinding process can easily mudding, difficult to obtain high metal recovery. The limonite beneficiation process includes reduction magnetization roasting-weak magnetic separation, strong magnetic separation, re-election, flotation and a combined process. We conducted a selective flocculation-strong magnetic separation technology industrial test on Jiangxi Tiekeng limonite ore. The results show that the recovery rate of iron metal can be increased by more than 10 percentage points, but the control of flocculation equipment and selective flocculation process conditions has not yet passed. Failed to industrialize. In the past two years, with the successful development of new high-gradient magnetic separators and new high-efficiency reverse flotation reagents, the strong magnetic separation-reverse flotation-baking combined process has made significant progress in sorting limonite ore, that is, through strong magnetic - Reverse flotation to obtain iron concentrate with low impurity content, and then to produce pellets by ordinary roasting or mixing with magnet concentrate can greatly improve the iron grade of the product, and still be a high-quality ironmaking raw material.
Third, composite iron ore dressing technology
Most iron ores in China contain more than two kinds of iron minerals, and the more varieties, the worse their selectivity. Among these iron ore, symbiotic iron ore, such as hematite, mirror iron ore, goethite, siderite, limonite, etc., are more difficult to select. To this end, a large number of related research work has been carried out in recent years, and the more prominent research results are combined processes such as weak magnetic-strong magnetic-flotation and magnetization roasting-reverse flotation.
4. Multi-metal symbiotic iron ore beneficiation technology
China's difficult to choose polymetallic symbiotic iron ore mainly includes Baotou Bayan Obo rare earth iron ore and Panzhihua vanadium- titanium magnetite. This type of iron ore is characterized by complex mineral composition and symbiotic relationship, resulting in iron concentrate sorting index. The recovery rate of low and co-contributing valuable elements is low. Among them, Baotou Bayan Obo rare earth iron oxide ore is particularly difficult to choose. At present, the iron oxide ore mine of Baotou Steel Concentrator uses the weak magnetic-strong magnetic-reverse flotation process for iron selection. The strong magnetic concentrate mainly contains minerals such as easy-floating fluorite , carbonate and the like. Iron silicate minerals. For the mineral-coated blast furnaces such as fluorite and carbonate, it has formed a mature method through decades of research and production practice, namely, water-glass as an inhibitor and GE-28 as a collector. The anti-flotation production process, and the difficult-to-float iron-containing silicate minerals have not been effectively separated, resulting in a lower iron concentrate grade (below 55 percent) and a high potassium content in the concentrate. For the strong magnetic concentrate sample with the fineness of -0.076mm accounting for about 88% and iron grade of 43.5%, the optimized combination of reverse flotation-positive flotation process is used. Flotation operation adopts new high-efficiency collector. The whole process flotation closed-circuit test index is about 53% of concentrate production rate, 62% of concentrate iron grade, and about 75 percent recovery rate. At the same time, harmful elements such as P The reduction of K 2 O, Na 2 O, and F is very large, opening up an effective new way to improve the selection of iron ore of this type. In addition, for the Panzhihua vanadium-titanium magnetite ore, the fine screening-re-grinding process and the high-gradient magnetic-flotation process were used to select titanium, and the various indexes of the ore were significantly improved.
V. Ore-like hematite ore dressing technology
Oolitic disseminated fine particle size and often with siderite, chamosite and phosphorus-containing mineral association or another package, so Oolitic hematite is widely recognized as the most difficult type of iron selected . In the past, a large number of ore dressing experiments have been carried out on this type of iron ore. The selection index of the reduction roasting-weak magnetic separation process is relatively good, but because of its technical difficulty, it requires ultrafine grinding, and the current conventional beneficiation equipment It is difficult to efficiently recover -10 μm of fine-grained iron minerals, and thus this type of iron ore resource is basically not utilized. With the gradual reduction of available iron ore resources in China, the high-efficiency beneficiation technology for the study of braided hematite ore has highlighted its importance and urgency. Relevant preliminary research results prove that ultrafine grinding-selective flocculation (agglomeration)-strong magnetic separation or flotation, reduction roasting-ultrafine grinding-selective flocculation (agglomeration)-weak magnetic separation or flotation Or the combination of smelting and smelting has shown its superiority.
6. High-sulfur and phosphorus iron ore beneficiation technology
Most of China's iron ore contains harmful impurities such as sulfur and phosphorus. Especially for iron ore rich in pyrrhotite, fine-grained apatite or collophanite, the iron concentrate is extremely difficult to remove. The common processes for desulfurization of iron concentrates are flotation and roasting, while the latter is costly and environmentally polluted. Therefore, the main direction of research is to strengthen flotation. Our company has developed a high-efficiency separation process of magnetite and pyrrhotite with high-efficiency activator as the key technology. Through the research and application of sulfur reduction in a variety of pyrrhotite-type high-sulfur magnetites at home and abroad, it is proved that compared with conventional flotation, the iron content of iron concentrate can be reduced by 0.5%, and the important one is iron concentrate. The sulfur content can meet the requirements of subsequent users. A large number of research results prove that the phosphorus removal of iron concentrate can be magnetic separation, reverse flotation, selective flocculation (agglomeration), acid leaching, chlorination roasting - acid leaching, bioleaching and its combined processes, among which magnetic separation - Reverse flotation, selective flocculation (agglomeration)-reverse flotation combined process is more economical, chlorination roasting-acid leaching process has better phosphorus removal effect, but the cost is higher, and bioleaching is the future development direction.
Seven, conclusion
Through a large number of mineral processing technology research and research, in recent years, China's complex refractory iron ore beneficiation technology has made gratifying progress, but due to the complex nature of China's iron ore and the low level of comprehensive mineral processing technology, China's complex and difficult to choose The utilization rate of iron ore resources is extremely low, and even some minerals are basically not utilized. Therefore, technical research in the following aspects should be strengthened in the future:
1. Research and application of efficient multi-grinding and grinding technology and equipment.
2. Strengthen the research on high-efficiency roasting technology and equipment, focusing on fine-grained (powdered) material roasting technology and equipment.
3. Strengthen the research on high-efficiency fine-grain grinding grading process and equipment.
4. Strengthen the research on high-efficiency fine-grain iron ore beneficiation process and equipment, focusing on deep research on selective flocculation (agglomeration)-reverse flotation combined process, equipment and automatic control, research on combined metallurgy process and bioleaching process, and study efficiency A strong magnetic separator and flotation equipment for recovering fine-grained iron minerals.
5. Develop flotation reagents suitable for the efficient separation of iron minerals and iron-containing silicate minerals, sulfur, phosphorus and other harmful impurities, as well as high-efficiency dispersing agents, flocculation (agglomerating) agents and flotation of fine-grained iron ore. Pharmacy, etc.
Superaudio induction heating equipment is mostly used for surface quenching of industrial metal parts. It is a kind of metal heat treatment method that makes the workpiece surface generate a certain induced current, quickly heat the surface of parts, and then quickly quench. Super audio induction heating equipment, that is, induction heating of the workpiece, in order to quench the surface of the equipment.
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